751 results on '"AMINE"'
Search Results
2. Optimization of amine-based carbon capture: Simulation and energy efficiency analysis of absorption section
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Moghaddam, Amin Hedayati, Esfandyari, Morteza, and Sakhaeinia, Hossein
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- 2024
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Catalog
3. Magnetic particles (Fe3O4) magnify ion transfer processes at the electrified liquid-liquid interface. Case study: Levamisole detection
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Laroui, Abdelatif, Kwaczyński, Karolina, Dąbrzalska, Monika, Glazer, Piotr, and Poltorak, Lukasz
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- 2025
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4. Structural investigation and application of ruthenium(II)-benzimidazole complexes for N-alkylation
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Karabekmez, Funda Doğan, Karaca, Emine Özge, Gürbüz, Nevin, Özdemir, Namık, and Özdemir, İsmail
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- 2025
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5. CO2 photoreduction integrated with oxidative coupling of amines over WO3/Cu(BTC) nanocomposite
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Malik, Anil, Saini, Nitish, Kumar, Amod, Prajapati, Pankaj, Tripathi, Deependra, and Jain, Suman L.
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- 2024
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6. Palladium-catalyzed oxidative three-component tandem annulation reaction: Access to polysubstituted pyrroles
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Bashkar, Mohammad and Nowrouzi, Najmeh
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- 2024
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7. Reaction kinetic modeling of carbon dioxide desorption in aqueous amine solutions
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Jia, Rui-Qi, Liang, Shuang, Xue, Zhi-Yuan, Chu, Guang-Wen, Zhang, Liang-Liang, and Chen, Jian-Feng
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- 2025
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8. Simple synthesis of copper sulfide film using self-reducible copper formate-amine-sulfur complex paste at less than 200 °C
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Yabuki, Akihiro, Tachibana, Tomoyuki, Wadamori, Hijiri, and Lee, Ji Ha
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- 2022
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9. Connecting precursors to a protic ionic liquid: Effects of hydrogen bond synergy in acid-base binary mixtures on the solvent-solute interactions
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Reid, Joshua E.S.J., Shimizu, Seishi, and Walker, Adam J.
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- 2020
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10. High-throughput screening of a transition metal single-atom electrocatalyst for the CH3NO2 reduction reaction.
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Xie, Kefeng, Xu, Shengyuan, Song, Xiaohong, Liu, Mingqiang, and Xu, Kai
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CATALYTIC activity , *HYDROGEN evolution reactions , *NITRO compounds , *CHEMICAL industry , *GIBBS' free energy , *TRANSITION metal catalysts - Abstract
The hydrogenation reduction of nitro compounds involves the wide application of functional amines as important chemical intermediates in the fine chemical industry. However, the development of low-cost, mild reaction conditions and high-performance catalysts for the reduction of nitro compounds is challenging. In this study, the potential of electrocatalysts in which 26 transition metal atoms are anchored to the surface of N-doped graphene (TMN 4 @G) was explored to determine the mechanism of the electrocatalytic CH 3 NO 2 reduction reaction (CNORR) via density functional theory. First, the stability of TMN 4 @G was evaluated to screen out the catalyst which is stable at 300 K via ab initio molecular dynamics. Second, the Gibbs free energy with all possible reaction pathways of the CNORR was calculated to search for high-performance catalysts. These results demonstrate that monodentate adsorbed CdN 4 @G, FeN 4 @G, CoN 4 @G and bidentate adsorbed MoN 4 @G exhibit excellent catalytic activity. The overpotential of MoN 4 @G is only 0.357 V. Finally, Finally, the role of central metal atom on the catalytic activity of single-atom catalysts in CNORR and the impact of hydrogen evolution reaction on the adsorption of CH 3 NO 2 were further discussed. We hope that this theoretical simulation provides an effective scheme for the reduction of nitro compounds under mild conditions. [Display omitted] • 26 transition metal atoms are anchored to the surface of N-doped graphene was explored to determine the mechanism of the electrocatalytic CH 3 NO 2 reduction reaction via DFT. • CoN 4 @G and MoN 4 @G exhibit excellent catalytic activity considering HER competitive reaction. [ABSTRACT FROM AUTHOR] more...
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- 2024
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11. Comparative assessment of Pb (II) adsorption in different generations of magnetic-cored dendrimers: The significance of amine end group activity.
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Kim, Hyun-Kyung, Anwer, Hassan, and Park, Jae-Woo
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OUTER space ,THERMOGRAVIMETRY ,VOLUMETRIC analysis ,AMINES ,DENDRIMERS - Abstract
[Display omitted] • Amine groups in generation 1 to 4 of magnetic-cored dendrimers were quantified. • Reduced number of end groups in generation 3 was due to blocking and narrowed space. • Active amines in generation 4 were increased due to enlarged internal cavities. • Active amine end groups are key to determine the adsorption potential. The number of amine end groups in the first (G1), second (G2), third (G3), and fourth (G4) generations of magnetic-cored dendrimers (MCD) was determined experimentally and effect on Pb (II) adsorption was investigated. Calculated end groups in different generation MCDs obtained by thermogravimetric analysis appeared an increase with successive generations, but not doubled. Decrease in end groups was due to the blocking of branches during synthesis and narrow space between end groups. Active amine end groups were also quantified via acid-base titration experiment. The active amines were increased with the generations, except for G3-MCD because of the reduced distance between end groups. However, the active amines were drastically increased in the G4-MCD because the hydrophilic amine groups were stretched in the outer space by the repulsive hydrophobic inner structure of MCD chains. Maximum Pb (II) adsorption was 44.49 mg/g (G1-MCD), 79.57 mg/g (G2-MCD), 44.35 mg/g (G3-MCD), and 116.19 mg/g (G4-MCD), respectively. They are very well correlated with the titration results, confirming the adsorption was directly affected by active amines in MCDs. [ABSTRACT FROM AUTHOR] more...
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- 2024
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12. Extraterrestrial amino acids and amines identified in asteroid Ryugu samples returned by the Hayabusa2 mission.
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Parker, Eric T., McLain, Hannah L., Glavin, Daniel P., Dworkin, Jason P., Elsila, Jamie E., Aponte, José C., Naraoka, Hiroshi, Takano, Yoshinori, Tachibana, Shogo, Yabuta, Hikaru, Yurimoto, Hisayoshi, Sakamoto, Kanako, Yada, Toru, Nishimura, Masahiro, Nakato, Aiko, Miyazaki, Akiko, Yogata, Kasumi, Abe, Masanao, Okada, Tatsuaki, and Usui, Tomohiro more...
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ASTEROIDS , *AMINO acids , *AMINO acid analysis , *ALIPHATIC amines , *EXTRATERRESTRIAL beings , *SPACE environment , *AMINES , *LIQUID chromatography-mass spectrometry - Abstract
The hot water and acid extracts of two different Ryugu samples collected by the Hayabusa2 mission were analyzed for the presence of aliphatic amines and amino acids. The abundances and relative distributions of both classes of molecules were determined, as well as the enantiomeric compositions of the chiral amino acids. The Ryugu samples studied here were recovered from sample chambers A and C, which were composed of surface material, and a combination of surface and possible subsurface material, respectively. A total of thirteen amino acids were detected and quantitated in these samples, with an additional five amino acids that were tentatively identified but not quantitated. The abundances of four aliphatic amines identified in the Ryugu samples were also determined in the current work. Amino acids were observed in the acid hydrolyzed and unhydrolyzed hot water extracts of asteroid Ryugu regolith using liquid chromatography with UV fluorescence detection and high-resolution mass spectrometry. Conversely, aliphatic amines were only analyzed in the unhydrolyzed hot water Ryugu extracts. Two- to six-carbon (C 2 -C 6) amino acids with individual abundances ranging from 0.02 to 15.8 nmol g−1, and one- to three-carbon (C 1 -C 3) aliphatic amines with individual abundances from 0.05 to 34.14 nmol g−1, were found in the hot water extracts. Several non-protein amino acids that are rare in biology, including β-amino- n -butyric acid (β-ABA) and β-aminoisobuytric acid (β-AIB), were racemic or very nearly racemic, thus indicating their likely abiotic origins. Trace amounts of select protein amino acids that were enriched in the l- enantiomer may indicate low levels of terrestrial amino acid contamination in the samples. However, the presence of elevated abundances of free and racemic alanine, a common protein amino acid in terrestrial biology, and elevated abundances of the predominately free and racemic non-protein amino acids, β-ABA and β-AIB, indicate that many of the amino acids detected in the Ryugu water extracts were indigenous to the samples. Although the Ryugu samples have been found to be chemically similar to CI type carbonaceous chondrites, the measured concentrations and relative distributions of amino acids and aliphatic amines in Ryugu samples were notably different from those previously observed for the CI1.1 carbonaceous chondrite, Orgueil. This discrepancy could be the result of differences in the original chemical compositions of the parent bodies and/or alteration conditions, such as space weathering. In addition to α-amino acids that could have been formed by Strecker cyanohydrin synthesis during a low temperature aqueous alteration phase, β-, γ-, and δ-amino acids, including C 3 – C 5 straight-chain n -ω-amino acids that are not formed by Strecker synthesis, were also observed in the Ryugu extracts. The suite of amino acids measured in the Ryugu samples indicates that multiple amino acid formation mechanisms were active on the Ryugu parent body. The analytical techniques used here are well-suited to search for similar analytes in asteroid Bennu material collected by the NASA OSIRIS-REx mission scheduled for Earth return in September 2023. [ABSTRACT FROM AUTHOR] more...
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- 2023
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13. Design of amine-functionalized resin via a facial method with efficient CO2 capture from air.
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Samaddoost, Leila, Soltani, Mahsa, Fatehifar, Esmaeil, and Abbasi Asl, Ebrahim
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CARBON sequestration , *ADSORPTION capacity , *CARBON dioxide adsorption , *GAS flow , *CARBON dioxide , *SORBENTS , *DESORPTION - Abstract
In this study, using A400 Purolite as a solid resin base, solid adsorbents were prepared for the direct adsorption of carbon dioxide gas from the ambient air. The resin was functionalized with different percentages of amine (TEPA). Then, the adsorption capacity was modified for better performance in the presence of STAB as a surfactant. Prepared samples were evaluated by CO 2 adsorption and the experiments were done at identical conditions (22 °C, CO 2 concentration 400 mg/L, and airflow of 2 L/min). The highest CO 2 capture was related to sample with 40 % amines, whose adsorption capacity was 58 mg/g after 24 h. Then different amounts of the surfactants were added to these samples. Modified adsorbents in 10 % surfactants and 40 % amines (T40/S10 sample) showed the best performance by 84 mg/g CO 2 adsorption in 24 h. The adsorption capacity of adsorbents increased after being functionalized with TEPA and the addition of STAB to the adsorbent surface, and led to increasing the adsorption capacity by 44 % (84 mg/g in 24 h). Also, the experimental results showed that the best performance of the adsorbent occurs at a loading of 0.5 gr and a gas flow of 0.3 L/min. Eventually, the influence of different operation parameters like adsorbent loading, airflow, and desorption temperature on the adsorbent performance in three cycles was investigated. Also, the reusability and stability of T40/S10 as the optimum sample was examined. [Display omitted] [ABSTRACT FROM AUTHOR] more...
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- 2023
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14. Prediction of CO2 solubility in aqueous amine solutions using machine learning method.
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Liu, Bin, Yu, Yanan, Liu, Zijian, Cui, Zhe, and Tian, Wende
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CARBON sequestration , *MACHINE learning , *MOLECULAR structure , *CARBON dioxide , *PARTIAL pressure - Abstract
• Molecular descriptors were used to represent the structure information of amine mocelus in QSPR modeling. • XGBoost and Random Forest models were developed to predict CO 2 solubility in amine solutions using QSPR methods. • The predicted CO 2 solubility closely matched experimental results, showing high accuracy and strong extrapolation potential. • The SHAP method provided interpretive analysis, enhancing the transparency and understanding of model predictions. In this study, a quantitative structure–property relationship (QSPR) model has been designed based on machine learning (ML) to offer a new method to accurately predict carbon dioxide (CO 2) solubility in aqueous amine solutions. Molecular descriptors are used to denote representative features of the amine molecular structure supplemented with amine solution concentration, CO 2 partial pressure, and temperature as inputs to the model. The coefficient of determination (R 2) of the well-trained ML model reaches 0.971, and the average absolute deviation (AAD) of independent experimental validation is 4.785 %, effectively demonstrating the model's reliability and generalization performance. Finally, SHapley Additive exPlanations (SHAP) is adopted to reveal the contribution of different features to the model predictions, making the model more transparent and interpretable. Overall work provides a novel, low-cost, efficient method to predict equilibrium CO 2 solubility in aqueous amine solution and offers a new perspective in developing advanced amine for CO 2 capture. [ABSTRACT FROM AUTHOR] more...
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- 2025
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15. Energy efficient ternary 2-amino-2-methyl-1-propanol, piperazine, and triethanolamine blend for post-combustion carbon capture.
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Apaiyakul, Rattanaporn, Theparayangkul, Watsawan, Haghani, Hossein, Imran-Shaukat, Muhammad, Chalermsinsuwan, Benjapon, Ngamprasertsith, Somkiat, Gao, Hongxia, Liang, Zhiwu, Tontiwachwuthikul, Paitoon, and Sema, Teerawat more...
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CARBON sequestration , *MASS transfer coefficients , *MASS transfer , *CARBON dioxide , *PIPERAZINE - Abstract
• Since AMP and PZ precipitated, TEA was used to elevate total amine concentration and enhance solvent regeneration. • Studied blends mostly precipitated, but 5 M blends (containing 1.5–2 M TEA) had potential. • Decreasing PZ/AMP and increasing TEA concentration favored CO 2 desorption but restrained CO 2 absorption. • 0.7/2.8/1.5 had 9 % capacity, 73 % cyclic capacity, 45 % mass transfer, and 26 % regeneration energy better than 5 M MEA. • Respecting AMP-PZ-MEA, AMP-PZ-TEA was easier to precipitate and poorer in CO 2 absorption but greater in CO 2 desorption. Energy efficient solvent was formulated from 2-amino-2-methyl-1-propanol (AMP), piperazine (PZ), and triethanolamine (TEA). Since AMP and PZ can precipitate, ternary blend was explored at unloaded and rich CO 2 loading (0.6 mol CO 2 /mol amine). Either too low TEA concentration, too low PZ/AMP molar ratio, or an increase total amine concentration from 5.0 to 5.5 or 6.0 M induced the precipitation at rich CO 2 loading. Even though equilibrium CO 2 loaded density and viscosity of the blends were higher than that of 5.0 M MEA (especially, viscosity), they are in operational ranges. A proper solvent formulation strategy was to trade-off between an increment of PZ/AMP molar ratio (favors the absorption) and an elevation of TEA concentration (positively affects the regeneration). Respecting 5.0 M MEA, 0.7/2.8/1.5 has 9 % higher capacity, 73 % greater cyclic capacity, 45 % larger mass transfer coefficient, 5 % higher CO 2 removal percentage, and 26 % lower regeneration energy. [ABSTRACT FROM AUTHOR] more...
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- 2025
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16. CO2-responsive switchable hydrophilic solvent as a novel extractant for selective extraction and separation of natural bioactive ingredients: A comprehensive review.
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Wei, Shuang, Wu, Yuntao, and Xi, Jun
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POLAR solvents , *ORGANIC solvents , *NATURAL resources , *HUMAN ecology , *CARBON dioxide - Abstract
When conventional solvents such as water, methanol, ethanol, hexane, petroleum ether, etc., are used to extract active ingredients from natural resources, an evaporation process is required to remove solvent from active ingredients, which not only consumes huge amounts of energy, but also causes harm to human health and the environment. The CO 2 -responsive switchable hydrophilic solvent (SHS) based on amines and water is an emerging, green and recyclable solvent, which not only has high extraction efficiency of active ingredients, but also can remove solvent from active ingredients without evaporation process. This paper reviews the research progress of amine-based SHS in the extraction of bioactive ingredients from natural resources. The process flow, extraction mechanism, critical influencing factors, recovery of amines and latest applications have been summarized. On this basis, some shortcomings of amine-based SHS are also pointed out. Finally, the improvement directions of amine-based SHS extraction in the future is prospected. • Amine-based SHS is a feasible alternative to traditional organic solvents. • The amine-based SHS extraction of active ingredients was comprehensively reviewed. • The mechanism, key factors, solvent recovery and latest applications were summarized. • The advantages, limitations, and future development directions were also discussed. • The amine-based SHS extraction has great potential in recovering bioactive ingredients. [ABSTRACT FROM AUTHOR] more...
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- 2025
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17. N-alkylation of amines with alcohols over hydrothermally prepared Nb-W mixed oxides.
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Abdullahi, Anas and Okumura, Kazu
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ALKYLATION , *AMINES , *ALCOHOLS (Chemical class) , *METALLIC oxides , *PRECIOUS metals , *HOMOGENEOUS catalysis - Abstract
• Nb-W-O has a pseudo-crystalline structure with long-range order in the c-direction. • Nb stabilizes the pseudo-crystalline phase and W5+ when Nb-W-O is calcined in N 2. • The optimal Nb concentration is 67 mol% (Nb/(Nb+ W) x 100). • Pseudo-crystalline phase and W5+ are indispensable in the N-alkylation reaction. • Nb-W-O activity correlates with acid amounts. Hydrothermally synthesized Nb-W mixed oxides (Nb-W-O) have been employed as a cost-effective and recyclable alternative to noble metals and homogeneous catalysts for the N-alkylation of amines with alcohols, with the model reaction of aniline and benzyl alcohol. The synergistic roles of Nb and W and the influence of calcination conditions were explored. Nb-W-O exhibited a linear packing of corner-sharing octahedra, analogous to the hexagonal tungsten bronze (HTB) structure, but without the long-range order of the HTB in the ab plane, characteristic of pseudo-crystalline materials. Calcination at 773 K in an N 2 flow preserved the pseudo-crystalline phase and generated additional Brønsted acid sites, associated with reduced tungsten oxide species stabilized by Nb. The primary reaction pathway involved the activation of the benzyl alcohol by Brønsted acid sites, followed by a nucleophilic attack of the formed carbocation by the aniline. Nb-W-O demonstrated superior activity to other solid acids including metal oxides, silica-alumina, and zeolites in the N-alkylation reaction. [Display omitted] [ABSTRACT FROM AUTHOR] more...
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- 2025
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18. Experimental and theoretical investigation of CO2 solubility in amine-based deep eutectic solvents.
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He, Nan, Zhang, Yukun, Song, Fenhong, Fan, Jing, and Zhang, Xiwu
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CARBON sequestration , *NUCLEAR magnetic resonance spectroscopy , *CARBON dioxide , *FOURIER transform infrared spectroscopy , *PRESSURE drop (Fluid dynamics) , *SOLUBILITY - Abstract
• Synthesized innovative and efficient deep eutectic solvents to capture CO 2. • Investigated effect of temperature, pressure and concentration on adsorption capacity of DESs for CO 2. • Revealed the mechanism of CO 2 adsorption by DESs. • Established experimental correlation and predicted accurately adsorption capacity of DESs for CO 2. Deep eutectic solvents (DESs) have appealed increasing research interest across various scientific and industrial applications, notably in relation to efforts in CO 2 capture. This study presents a novel series of DESs were synthesized on the basis of monoethanolamine (MEA) and N-methyldiethanolamine (MDEA) as hydrogen bond donors with tetrabutylammonium bromide (TBAB) and tetrabutylphosphine bromide (TBPB) salt as hydrogen bond acceptors. A gas solubility measurement experimental system based on pressure drop method has been established to evaluate the solubility of CO 2 in amine-based deep eutectic solvents. The evaluation was performed over a temperature range of 303.15 to 323.15 K and a pressure range of 100 to 1000 kPa. The results indicated that as the molar ratio of hydrogen bond donors increases, the solubility of CO 2 in DESs increases, while it was found to be less affected by the hydrogen bond acceptor. Of these, the solubility of CO 2 is strongest at a 1:10 molar ratio of TBAB and MEA. The nuclear magnetic resonance spectroscopy spectra (NMR) and FTIR spectroscopy revealed that the MEA-based DES mixture primarily exhibited chemical absorption of CO 2 , while the MDEA-based DES predominantly showed physical dissolution of CO 2. In addition, it was observed that both temperature and pressure significantly influenced the CO 2 solubility, and a successful correlation was developed using different semi-empirical models. [ABSTRACT FROM AUTHOR] more...
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- 2025
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19. Molecular simulation and experimental understanding of piperazine-promoted 2-cyclopentylaminoethanol for energy-efficient carbon capture.
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Gao, Jubao, Yuan, Junjie, Yu, Xiangzhou, Wang, Zhichao, Deng, Gaofeng, and Zhao, Xinglei
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CARBON sequestration , *MASS transfer , *CARBON dioxide , *ACTIVATION energy , *ENERGY consumption - Abstract
• PZ-activated CPAE is developed for CO 2 capture. • CPAE/PZ exhibits high CO 2 cycling capacity and a rapid reaction rate. • CPAE/PZ has lower energy consumption and is more stable than MEA. • Molecular simulations indicate the lowest energy barrier for carbon capture by CPAE. With the serious climate change and carbon emissions issues facing the world, it is becoming increasingly important to find effective methods to reduce the post-combustion CO 2 concentrations. Piperazine −enhanced aqueous amine solvents are still being developed due to the technology is more applicable to large −scale industry. However, the sustainability of the CO 2 capture process is still hindered by high energy consumption and amine losses. To tackle this issue, a novel secondary amine, 2-cyclopentylaminoethanol, was synthesized from a primary amine, monoethanolamine. It has a more stable structure than monoethanolamine and was further activated by piperazine. Its effectiveness was compared with piperazine-enhanced N-methyldiethanolamine, N-methyldiethanolamine/triethylenediamine, and 2-amino-2-methyl-1-propanol. The experimental results showed that 2-cyclopentylaminoethanol/piperazine presents the fastest CO 2 mass transfer rate, the largest CO 2 cyclic capacity and a lower latent heat. The regeneration energy consumption of the absorbent is approximately 2.44 GJ/ton CO 2 , which is approximately 37.45% lower than that of 30 wt% monoethanolamine solvent. The results are in accordance with the findings of a laboratory-scale pilot plant study, which demonstrated an average reduction of 35.3% in energy consumption. Molecular simulations have revealed that 2-cyclopentylaminoethanol exhibits the lowest energy barrier for reacting with CO 2 , rendering it more conducive to CO 2 reaction. The intermolecular interactions indicate that the hydrogen bonding in the solution after monoethanolamine reacts with CO₂ becomes more pronounced, coupled with a higher energy barrier. Consequently, a greater amount of energy is required during desorption. It can be inferred that 2-cyclopentylaminoethanol/piperazine is a promising energy-efficient and stable absorbent for post-combustion CO 2 capture. [ABSTRACT FROM AUTHOR] more...
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- 2025
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20. Amine-functionalized macroporous resin for direct air capture with high CO2 capacity in real atmospheric conditions: Effects of moisture and oxygen.
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Zhao, Shu, Zhang, Yiran, Li, Linjia, Feng, Jiaqi, Qiu, Wei, Wang, Yijun, Huang, Zhen, and Lin, He
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DESORPTION kinetics , *ADSORPTION kinetics , *ADSORPTION capacity , *CARBON dioxide , *CARBON sequestration - Abstract
• Optimizing the amine content in the DAC adsorbents for good CO 2 capacity and high adsorption and desorption kinetics. • Revealing the relation between the pore nature of resins and the performance of DAC adsorbents. • Revealing the effect of humidity and oxygen on the stability of amine-functionalized DAC adsorbents. Direct air capture (DAC) is an important negative carbon emission technology that has attracted increasing attention. Amine-functionalized porous CO 2 adsorbents are promising materials for DAC because of their high CO 2 capacities, fast adsorption and desorption kinetics, and low energy costs during regeneration. In this study, inexpensive macroporous resins with high specific surface areas and pore volumes were selected as carriers of tetraethylenepentamine (TEPA) or polyethyleneimine (PEI). Their DAC performances in relation to their microstructures were explored under different humidity and oxygen conditions. Moisture simultaneously enhanced the CO 2 capacity and slowed the adsorption/desorption process. Oxygen did not react with the resin and amine under ambient conditions, but physically adhered to the active sites of the adsorbents and caused a slight decrease in the CO 2 uptake capacity. The optimized material reached adsorption equilibrium in 7269 s with CO 2 uptake capacity of 5.4 mmol g−1 and desorbed CO 2 in 1611 s with CO 2 desorption capacity of 5.0 mmol g−1. After five cycles, the materials retained 82.2 % of the adsorption capacity. The findings indicate that amine-functionalized macroporous resins are promising DAC adsorbents under atmospheric conditions. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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21. A novel reaction between ammonia and Criegee intermediates can form amines and suppress oligomers from isoprene.
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Li, Xiaoying, Jia, Long, Xu, Yongfu, and Pan, Yuepeng
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- 2024
- Full Text
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22. Smartphone-based detection and discrimination of amine vapors by a single dye-adsorbed material.
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Teknikel, Efdal
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MOBILE apps , *SMARTPHONES , *TEST interpretation , *STAINS & staining (Microscopy) , *VAPORS - Abstract
[Display omitted] • An amine-selective sensor material has been developed by adsorbing a single BODIPY compound into a TLC plate. • The sensor exhibits structure-specific color changes in response to different amine vapors under both ambient and UV light. • Amine analysis can be conducted using hue data collected with a smartphone, eliminating the need for any additional analysis device. • A mobile application has been developed to analyze the collected data and provide analysis results. Smartphone-assisted analysis has become widely utilized for detecting various species in recent years. In such studies, multiple dyes should be employed to ensure selectivity and analyte discrimination. In our research, we have demonstrated the capability of a specially synthesized dye to selectively detect and discriminate liquid amine vapors. The developed material employs meso -toluene-α,β,α',β'-tetrabromoBODIPY immobilized on a thin-layer chromatography plate, exhibiting structure-specific color changes in response to amine vapors. The hue values of these colors, observed under both ambient and UV light, enable discrimination even among closely related amine structures. A mobile application has also been developed for the rapid interpretation of test results. [ABSTRACT FROM AUTHOR] more...
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- 2024
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23. Elevating biotransamiantion of pineapple peel-derived furfural into furfurylamine by recombinant Escherichia coli carrying pyruvate decarboxylase and mutant ω-transaminase with low loading of amine donor.
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Liu, Yuting, He, Yu-Cai, and Ma, Cuiluan
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MULTIENZYME complexes ,ESCHERICHIA coli ,PINEAPPLE ,ACETALDEHYDE ,VANILLIN ,FURFURAL - Abstract
Furfurylamine is a versatile compound used in perfumes, polymers, pharmaceuticals, and agrochemicals. To address the costly and inefficient furfural bioamination process, a strategy combining ω-transaminase with other enzymes was applied to construct a multi-enzyme system. Pyruvate decarboxylase (PDC) might transform amination byproducts into acetaldehyde, promoting the forward bioreaction. E. coli 20PDC was created by co-expressing PDC and mutated ω-transaminase (HN), which could be applied to efficiently aminate furfural, vanillin and 5-hydroxymethylfurfural into furfuryalmine, vanillylamine, and 5-hydroxymethyl-2-furfurylamine, respectively. Pineapple peel can be used as a suitable feedstock for production of furfural and furfurylamine. A chemobiological cascade reaction was built to transform pineapple peel into furan-based amines in deep eutectic solvent ChCl: p A-H 2 O. In ChCl: p A (10 wt%) at 170 °C, pineapple peel was converted to furfural within 10 min (65.2% yield, based on xylan), and the pineapple peel-derived furfural was resoundingly converted to furfurylamine at 35 °C with D -alanine (D -alanine:substrate = 2:1) in ChCl: p A (20 wt%, pH 7.5). This dual-enzyme co-expression strategy reduced the amine donor loading and realized the effectual bioamination from biomass-derived aldehydes. To sum up, the strategy for synthesis of FAM from pineapple peel by tandem chemocatalysis and biocatalysis in ChCl: p A-H 2 O holds significant promising in the valorization of biomass into valuable furans. [Display omitted] • Furfurylamine (FAM) was prepared from pineapple peel via chemobiocatalytic approach. • ChCl: p A–H 2 O catalyzed pineapple peel to FUR (65.2% yield) at 170 °C for 10 min. • E. coli 20PDC was created by co-expressing PDC and mutated ω-transaminase (HN). • A small amount of D -alanine was required for the bioamination of FUR into FAM. • The FAM yield was 0.47 g FAM/(g xylan in pineapple peel). [ABSTRACT FROM AUTHOR] more...
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- 2024
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24. Solar triggered CO2 regeneration and conversion using amine-based materials.
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Yuan, Junjie, Wang, Yinxi, Long, Qiujing, Cao, Qi, Deng, Gaofeng, Wang, Zhichao, and Gao, Jubao
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CARBON sequestration ,CARBON dioxide ,SOLAR energy ,INDUSTRIAL applications - Abstract
Leveraging solar irradiation for regenerating amine materials presents a promising alternative to conventional steam-based CO 2 regeneration, potentially mitigating environmental concerns associated with rising CO 2 levels. However, this method has limitations and needs substantial improvements in both regeneration efficiency and photo-thermal conversion efficiency, which are closely tied to the performance of the photo-thermal materials. The development of highly efficient photo-thermal conversion materials is crucial for the successful implementation of this technology. In this review, we focus on the utilization of light-irradiated amine materials for CO 2 regeneration and conversion. We compare and analyze their performance in terms of regeneration efficiency, temperature achieved, properties of the photo-thermal conversion materials and advantages and disadvantages of various photo-thermal materials. Additionally, we provide suggestions for enhancing these materials based on the research findings and discuss the potential future directions. Moreover, we address the challenges and feasibility of replacing traditional steam-based methods with light-activated CO 2 regeneration in industrial applications, aiming to foster more efforts towards the industrial-scale utilization of solar-irradiated CO 2 regeneration and conversion. [Display omitted] • Solar energy for CO 2 regeneration and conversion. • Materials for solar-induced CO 2 release. • CO 2 conversion using amine-based solutions. • Challenges and future developments in light-driven amine-based CO 2 capture. [ABSTRACT FROM AUTHOR] more...
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- 2024
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25. Hydrothermal liquefaction of green macroalgae Cladophora glomerata: Effect of functional groups on the catalytic performance of graphene oxide/polyurethane composite.
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Norouzi, Omid, Mazhkoo, Shahin, Haddadi, Seyyed Arash, Arjmand, Mohammad, and Dutta, Animesh
- Subjects
- *
BIOMASS liquefaction , *FUNCTIONAL groups , *CLADOPHORA , *POLYURETHANES , *MARINE algae , *GRAPHENE oxide , *METALLIC oxides - Abstract
This study highlights the challenges and opportunities of Hydrothermal Liquefaction (HTL) of Cladophora glomerata. It suggests functionalized graphene oxide/polyurethane (F-GO-PU) composite as the promising metal-free catalysts for sustainable algae upgrading. The catalysts contained three types of functional groups, including methyl (-CH 3), vinyl (-CH=CH 2), and amine (-NH 2), and were completely analyzed by FTIR, XRD, and SEM-EDS in terms of functional groups, crystalline structure, morphology, and surface elemental distribution, respectively. The results showed that F-GO-PU catalysts efficiently suppressed side reactions that would generate non-desired chemicals. Functionalization with vinyl increased the yield of bio-crude oil by about 54% and showed high selectivity for hydrocarbons with a yield of 15.66 wt%. This catalytic activity was due to the existence of stable and accessible Brønsted acid sites plus the hybrid structure of the composite, which enhanced the accommodation of reaction intermediates on the surface of the catalyst. Thus, as-prepared F-GO-PU composites may hold great promise as metal-free active phase catalysts to develop algae transformation reactions. [Display omitted] • Multi-functional catalytic system based on graphene and polyurethane. • Effect of functional groups on the green algae bio-products. • Challenges and opportunities of Hydrothermal Liquefaction (HTL) of Cladophora glomerata. • Functionalization with vinyl increased the yield of bio-crude oil by about 54%. [ABSTRACT FROM AUTHOR] more...
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- 2022
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26. Amine-modified magnetic particles: An efficient tool for enhanced RNA extraction.
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Vopařilová, Petra, Šplíchal, Zbyněk, Švec, Pavel, Kulich, Pavel, Malina, Ondřej, Otyepka, Michal, Zítka, Ondřej, and Kudr, Jiří
- Subjects
- *
MAGNETIC particles , *NUCLEIC acids , *TRANSMISSION electron microscopy , *RIBOSOMAL RNA , *GENE expression - Abstract
[Display omitted] • MPs with different amounts of amine groups and SiO 2 MPs were prepared. • The NA extraction properties using the mentioned MPs were tested. • Amine-modified MPs compared to SiO 2 MPs showed higher selectivity to RNA than gDNA. • RT-qPCR results were less biased by NAs isolated by aminated MPs than SiO 2 MPs. • Aminated MPs isolate NAs more effectively than SiO 2 MPs, even in low MPs amounts. Magnetic particles are an effective tool for simple, time-saving, and labour-saving nucleic acid extraction. In this study, we investigated the isolation of nucleic acids (NA) using 11 variants of magnetic nanoparticles (MPs, 52 ± 6.8 nm) with a surface concentration of amine groups up to 20.8 nmol · mg−1. All results were compared with morphologically identical magnetic material modified with SiO 2 grafted with (3-aminopropyl)triethoxysilane (APTES). The properties of these materials were characterized by transmission electron microscopy, scanning electron microscopy, dynamic and electrophoretic light scattering, and magnetometry. Concentrations of amine groups on MPs-APTES were determined by the chemical bind and release method with photometric quantification. The isolation potential of the proposed materials toward NAs was evaluated using gel electrophoresis with photometric determination of NAs concentrations and RT-qPCR. Our results show that the NAs yields of MPs-APTES are higher than the reference MPs-SiO 2 , regardless of the amine group concentrations. Although the total yield decreased with the concentration of amine groups, a different affinity towards genomic DNA (gDNA) was observed. A high concentration of grafted amine groups induced a preference for ribosomal RNA (rRNA) over gDNA and mediated effective NA elution. Densitometric image analysis of gDNA bands showed that NAs isolated by MPs-SiO 2 contained significantly higher DNA levels than MPs with 1/32 %, 1/2 %, and 16 % APTES modification, which was subsequently confirmed by qPCR. Gene expression analysis performed by RT-qPCR revealed that unwanted gDNA contamination did not significantly affect the threshold cycles (Ct) of target genes when cDNA-specific primers were used, but may lead to overestimation when targeting genes with low expression and no possibility to design cDNA-unique primers. From a practical point of view, MPs-APTES provided better dose-dependent NA isolation performance with stable NA quality. [ABSTRACT FROM AUTHOR] more...
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- 2025
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27. Solar induced low-temperature phase separation in thermomorphic solvents for CO2 capture.
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Gao, Jubao, Yuan, Junjie, Chen, Chengyi, Wu, Songyue, Long, Qiujing, Deng, Gaofeng, and Wang, Zhichao
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- *
CARBON sequestration , *PHOTOTHERMAL conversion , *CARBON nanotubes , *CARBON dioxide , *CARBOXYL group - Abstract
• Incorporation of MWCNT-COOH can enhance the thermomorphic solvent CO 2 capacity by 20.8%. • Thermomorphic solvents can be efficiently regenerated at approximately 325 K under solar irradiation. • Thermomorphic solvents can achieve a regeneration efficiency of 78.6%. • Thermomorphic absorbent exhibits a regeneration heat of 2.35 GJ/t CO 2. Replacing steam with solar for CO 2 regeneration is an incredibly promising approach. However, the high temperature required for solvent regeneration and the less-than-optimal photothermal conversion efficiency that prevents reaching the necessary regeneration temperature are significant limitations to this approach. In this work, thermomorphic solvents containing dimethylcyclohexylamine, N-methylcyclohexylamine and photothermal nanoparticles were prepared for CO 2 capture. Nano carbon black, multi-walled carbon nanotube and carboxyl group functionalized multi-walled carbon nanotube were used as promoter for photothermal conversion. The experimental results exhibit the high CO 2 absorption capacity of 0.1081 g/g solvent for the carboxyl group functionalized multi-walled carbon nanotube based solvent, and it can be efficiently regenerated under solar irradiation at a low temperature of ∼ 323 K. It is noteworthy that the photothermal material not only raise the solution temperature(∼325 K) during solar irradiation but also boosts the CO 2 absorption rate, and leads to a ∼ 20.8 % increase in CO 2 absorption capacity during the absorption process. Furthermore, the utilisation of photothermal regeneration for thermomorphic solvents can achieve an efficiency of 78.6 %, with a regeneration heat of 2.35 GJ/t CO 2 , resulting in an energy consumption reduction of approximately 41.1 % in comparison to 30 wt% monoethanolamine. The photo triggered regeneration of the thermomorphic solvent investigated in this study shows promising potential as an energy-efficient carbon capture technology. [ABSTRACT FROM AUTHOR] more...
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- 2024
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28. Structure–activity relationship of a dual-function amine-based electrolyte for integrated CO2 capture and electrochemical conversion.
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Li, Qiang, Qu, Tongxin, Tan, Shuting, Wang, Teng, Ding, Yuhang, Wang, Chang, Zhang, Junying, Xiong, Zhuo, and Zhao, Yongchun
- Subjects
- *
CARBON sequestration , *DENSITY functional theory , *INTERSTITIAL hydrogen generation , *PATH analysis (Statistics) , *CARBON dioxide , *ELECTROLYTIC reduction , *ZWITTERIONS - Abstract
[Display omitted] • The structure–activity relationship of ten dual-function amine-based electrolytes were investigated. • The 1,3-propanediamine (13DAP) system demonstrated improved CO 2 solubility uptake (58.1%), Faraday efficiency (10.6%), and current density (52.1%) compared to the ethanolamine (MEA) system. • Density functional theory shows carbamate charge distribution and N-C bond strength impact adsorption and Faraday efficiency. • The integrated reaction pathway based on the zwitterion mechanism is proposed. • The selection or design of dual-function electrolytes should with structural primary amines with a straight alkanol chain instead of branched. Integrated carbon dioxide (CO 2) capture and electrocatalytic reduction processes through dual-function amine-based electrolytes and their integration into a single reactor can lead to significant energy savings, simplified process flow, and reduced transportation risks. This work investigates the structure–activity relationship of dual-functional amine-based electrolytes for CO 2 capture and electrocatalytic reduction and develops an efficient dual-functional amine-based electrolyte system. We investigated 10 different amine-based solutions for their CO 2 capture and reduction performances. The substituents on the nitrogen atom of the intermediate carbamate and the positions of the hydroxyl and branched groups affect the capture and electrochemical reduction. The 1,3-propanediamine system demonstrated enhanced CO 2 solubility uptake (58.1 %), Faradaic efficiency (10.6 %), and current density (52.1 %) compared with the monoethanolamine system, indicating its potential as a dual-function amine-based electrolyte. Furthermore, density functional theory calculations indicated that the charge distribution of carbamate and the dissociation of C–N bonds directly influence the adsorption of carbamates on the electrode surface and the Faradaic efficiency of the reduced products. In addition, reaction path analysis based on the zwitterionic mechanism indicated that intermediates (carbamate R 1 R 2 NCOO-) with higher electronegativity are more conducive to adsorb onto the electrode surface and inhibit hydrogen generation from protonated amines (R 1 R 2 NHH+). The results suggest that the selection or design of dual-functional amine-based electrolytes should prioritize amines with straight alkanol chains rather than branched ones, which do not form intramolecular hydrogen bonds or heterocyclic structures. This work provides directions and guidance for designing and developing dual-functional electrolytes for integrated carbon capture and electrocatalytic conversion technologies. [ABSTRACT FROM AUTHOR] more...
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- 2024
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29. Platinum(II) complexes bearing the simplest olefin ligand: A new class potential for the development of anticancer drugs.
- Author
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Linh, Nguyen Thi Bang, Ninh, Nguyen Hoang, Thong, Pham Van, Dung, Tran Ngoc, Duong, Nguyen Manh, Duyen, Le Thi, Trang, Nguyen Thi Quynh, Hai, Le Thi Hong, and Chi, Nguyen Thi Thanh
- Subjects
- *
CYTOTOXINS , *MOLECULAR docking , *BLOOD proteins , *SERUM albumin , *CELL lines , *ATOMS - Abstract
Complexes (1 – 7) were generated by interaction of Zeise's salt with either monodentate amines (N) or derivatives of 8-hydroxyquinoline (N , O H). 1 exhibited high activity against Hep-G2 and no toxicity on HEK-239. The significant cytotoxicity of 5 and 6 against all tested cell lines (approximately 40–60 times higher than cisplatin) was consistent with the findings of molecular docking investigations aimed at the BSA. [Display omitted] Six new Pt(II) complexes containing ethylene and amine including trans -[PtCl 2 (C 2 H 4)(N)] (N: caffeine/ 1 ; PyCOOH/ 2 , PyCONH 2 / 3 ; i PrOQ/ 4) and [PtCl(C 2 H 4)](N^O)] (N^O: ClQO/ 5 ; BrQO/ 6) were synthesized and structurally characterized by ESI mass spectrometry, EDX, IR, 1H NMR spectroscopies and DFT calculation. The results showed that caffeine, PyCOOH, i PrOQ coordinated with Pt(II) via the N heterocyclic atom while PyCONH 2 coordinated with Pt(II) via the N atom of the NH 2 group. The deprotonated 8-hydroxyquinoline derivatives coordinated with Pt(II) via the N and O atoms in complexes 5 and 6. The ethylene coordinated with Pt(II) in the η 2 manner and at trans position compared to the coordinating N atom in all complexes 1 – 6. Among four tested cell lines complexes 1 and 4 exhibited high selective activities against Hep-G2 cell line with IC 50 values of about 5.5 µM, 2.5-fold more active than cisplatin. Complexes 5 and 6 showed significant activities on all tested cell lines with IC 50 values ranging from 0.66 to 2.95 µM and 40–60 times lower in comparison with cisplatin. Especially, complex 5 with the best activity among the tested complexes showed 4.5 times lower toxic on normal cell (HEK-239) than the cancer cells, complex 1 displayed no toxicity on the normal cell with the IC 50 > 262.3 µM. The significant cytotoxicity of complexes 5 and 6 observed was consistent with the findings of molecular docking investigations aimed at the Bovine Serum Albumin protein. [ABSTRACT FROM AUTHOR] more...
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- 2024
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30. Enhancing carbon mineralization of slag leachate using amine-functionalized magnetic nanoparticle clusters.
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Han, Hyunsoo and Jeon, Sangmin
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IRON oxide nanoparticles ,MASS transfer ,CARBONATE minerals ,CARBON dioxide ,NANOPARTICLES - Abstract
Carbon mineralization—converting carbon dioxide (CO 2) into stable carbonate minerals, such as calcium carbonate (CaCO 3)—has attracted much attention as a permanent way to sequester CO 2. In this study, we developed a novel method for improving the efficiency of carbon mineralization using amine-functionalized magnetic nanoparticle clusters (A-MNCs). To prepare them, magnetic nanoparticle clusters composed of tens of small Fe 3 O 4 nanoparticles were treated with 3-aminopropyltriethoxysilane to functionalize amine groups on their surfaces. When CO 2 was bubbled into a NaOH solution, the rate of CO 2 dissolution was enhanced in the presence of A-MNCs, mostly due to physical effects such as grazing and hydrodynamic effects that improved mass transfer between the solution and CO 2 bubbles. In addition, A-MNCs promoted carbon mineralization in a NaOH solution containing Ca
2+ by providing an additional mineralization route via carbamate formation, resulting in a threefold increase in efficiency to 81 %. We demonstrated that A-MNCs could be applied to leachate from slag, a byproduct of commercial steelmaking, increasing the efficiency by 2.6 times compared to the absence of A-MNCs. The resulting CaCO 3 precipitate was confirmed to be calcite using X-ray diffraction and scanning electron microscopy. Furthermore, after the mineralization, A-MNCs were easily separated from the solution using a permanent magnet, while retaining their performance. • A-MNCs improved CO 2 dissolution rate by increasing mass transfer between the solution and CO 2. • A-MNCs enhanced the carbon mineralization efficiency from 28 % to 81 %. • When A-MNCs were used in slag leachate, the mineralization efficiency reached 85 %. • The magnetically separated A-MNCs retained nearly consistent performance. [ABSTRACT FROM AUTHOR] more...- Published
- 2024
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31. Impact of coated and non-coated magnetic nanoparticles on oil-water separation in green surfactant-based emulsions.
- Author
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Viveros, Linda Tatiana Lezama, Rafati, Roozbeh, and Sharifi Haddad, Amin
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- *
MAGNETIC nanoparticles , *SURFACE charges , *EMULSIONS , *DEMULSIFICATION , *PETROLEUM , *NANOPARTICLES - Abstract
This study investigates the efficacy of magnetite nanoparticles as a means of demulsifying surfactant-based emulsions, focusing on light and medium crude oil emulsions. The demulsification capabilities of bare, amine-coated, and oleic acid-coated magnetite nanoparticles were tested. Nanoparticle concentrations ranged from 0.25 % to 8 %. The emulsions used Alpha Olefin Sulfonate and two environmentally friendly surfactants, Coco Glucoside and Greenzyme with sodium and potassium formate as eco-friendly alternatives and sodium chloride as the standard brine. Magnetic demulsification efficacy is highly dependent on the interplay between the nanoparticle surface charge and surfactant, thereby affecting surfactant adsorption onto the particle surface. While gravimetric separation alone has partial effectiveness, the magnetic field enhances particle movement, promoting greater instability. The nanoparticles play a key role in adsorbing surfactant species from the interfacial region, thus facilitating demulsification. Notably, magnetic demulsification is more effective with environmentally friendly surfactants, achieving 100 % separation in most cases. Demulsification of emulsions containing synthetic surfactants is most successful with light crude oil emulsions, and in select cases, achieves 100 % separation with medium crude oil emulsions. [Display omitted] [ABSTRACT FROM AUTHOR] more...
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- 2024
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32. Low vaporization enthalpy of modified chitosan hydrogel for high performance solar evaporator.
- Author
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Anukunwithaya, Patsaya, Liu, Nanxue, Liu, Siqi, Thanayupong, Eknarin, Zhou, Lili, Pimpha, Nuttaporn, Min, Jiakang, Chinsirikul, Wannee, Thitsartarn, Warintorn, Koh, J. Justin, and He, Chaobin
- Subjects
- *
HEATS of vaporization , *EVAPORATORS , *HYDROGELS , *WATER purification , *HYDROGEN bonding interactions , *CHITOSAN , *CARBON nanotubes - Abstract
The high vaporization enthalpy of water attributed to the strong hydrogen bonds between water molecules is limiting the performance of solar evaporators. This work demonstrates a deliberate attempt to significantly reduce the vaporization enthalpy of water through the introduction of weak water-amine hydrogen bond interactions in hydrogel evaporators. In this article, bio-based chitosan-agarose/multiwalled carbon nanotube hydrogel film evaporators (CAMFEs) exhibit larger vaporization enthalpy reduction with the presence of primary amine groups in chitosan. An interplay between vaporization enthalpy reduction and water diffusivity leads to an optimal ratio of chitosan to agarose = 7:1 (CAMFE7) showing an impressive evaporation rate of 4.13 kg m−2 h−1 under 1 sun irradiation. CAMFE7 also exhibits excellent salt resistance, with a stable water evaporation rate, using brine water of up to 10 % salinity under continuous 1 sun irradiation. The high mechanical robustness together with its scalability makes CAMFE7 a highly promising material for practical drinking water production. [Display omitted] [ABSTRACT FROM AUTHOR] more...
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- 2024
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33. Measurement of total amine site concentrations on bacterial cell surfaces using selective site-blocking and potentiometric titrations.
- Author
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Yu, Qiang and Fein, Jeremy B.
- Subjects
- *
BACTERIAL cell surfaces , *POTENTIOMETRY , *FORMYLATION , *SECONDARY amines , *PSEUDOMONAS putida , *AMINES - Abstract
Bacterial cell surface amine binding sites can form strong complexes with both toxic metal cations and anionic contaminants, thereby affecting the behavior of these contaminants in both natural and engineered systems. In this study, a novel approach was developed to measure the concentration of total amine sites on bacterial cell surfaces by combining selective site-blocking, potentiometric titrations and surface complexation modeling. Our controls show that the amine blocker sulfo-N-hydroxysulfosuccinimide acetate (SNHS) selectively reacts with primary and secondary amine sites but does not react with other binding sites on the bacterial cell surface. Amine site concentrations on bacterial cell surfaces, therefore, can be measured as the difference between the total site concentrations of un-blocked and SNHS-blocked bacterial samples. We measured amine site concentrations on Bacillus subtilis and Pseudomonas putida of 52 ± 5 and 78 ± 6 μmol/g, respectively, which account for 24% and 32% of the total binding sites on each bacterial surface. Our results suggest that amine sites can be present in relatively high concentrations on bacterial surfaces, and further studies that are focused on the role of cell surface amine sites on the transport and bioavailability of toxic metal cations and anionic contaminants are crucial. [ABSTRACT FROM AUTHOR] more...
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- 2024
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34. Silica supported Schiff-based palladium nanocatalyst for n-alkylation at room temperature.
- Author
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Sarkar, Shaheen M., Lutfor Rahman, Md., Hasan, Kamrul, Maksudur Rahman Khan, Md., Salim Akhter, Mohammed, and O'Reilly, Emmet J.
- Abstract
This works documents a new silica gel-supported nanocatalyst (Si@NSBPdNPs 3) with low Pd loadings for n -alkylation reactions at room temperature. Post synthesis characterisation using SEM-EDX and ICP techniques provided a quantitative assessment of palladium species. Additionally, TEM analysis unveiled an average palladium nanoparticle size of 5.87 ± 0.2 nm. In-depth X-ray Photoelectron Spectroscopy (XPS) analysis revealed its predominant composition as Pd(0) complexed to a Schiff base ligand on low cost silica matrix. The nanocatalyst exhibited high efficacy in the catalysis of n -alkylation (Michael addition) reactions with various α,β -unsaturated Michael acceptors, yielding the corresponding n -alkyl products at room temperature with exceptional yields. Notably, the catalyst exhibited good stability and could be easily separated from the reaction mixture. Moreover, the catalyst displayed recyclability potential, maintaining its original catalytic efficacy for up to seven cycles without any discernible loss. [ABSTRACT FROM AUTHOR] more...
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- 2024
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35. Prediction of CO2 absorbing performance of amine aqueous solution using random forest models.
- Author
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Fujii, Tatsuya, Sako, Masami, Ishihama, Keisuke, Kohno, Yuki, Makino, Takashi, Yasuo, Nobuaki, and Kawauchi, Susumu
- Subjects
CARBON dioxide ,AQUEOUS solutions ,RANDOM forest algorithms - Abstract
Designing an amine(s) solution for the chemical absorption of CO 2 for carbon capture, utilization and storage is a significant challenge. To accelerate the development of high-performance amine solutions, a method for predicting the CO 2 loading of amine(s) solution is studied. Available literature data are curated (45 amines, 3151 data points), and random forest regression is conducted using the data with descriptors calculated using HSPiP or RDkit software. The CO 2 loadings of single amine aqueous solutions are regressed with high accuracy (R
2 = 0.943, RMSE = 0.072–0.073 for the validation data). Feature importance analysis suggests that the partial charge of atoms in the amine is an important descriptor, as well as process parameters such as CO 2 partial pressure and temperature. Based on the analysis, a simpler descriptor list is developed with temperature, CO 2 partial pressure, and partial charges of N atoms calculated by density functional theory. CO 2 loading of a single amine solution is regressed with an accuracy comparable to that of the above models (R2 = 0.931, RMSE = 0.079) with only 5 descriptors. Moreover, data including both single and blended amine solutions are regressed with high accuracy (R2 = 0.944, RMSE = 0.073) with only 8 descriptors. The generalization performances of the models are evaluated using the leave-one-group-out procedure. Although some outliers exist, the overall trend of almost all amines can be predicted using the procedure in this study. [Display omitted] • CO2 absorbing performance of random forest regression model is evaluated. • The dataset is prepared from 45 amines and 3151 data points for single and blended amine solutions. • Good regression is obtained by the combination of process and molecular descriptors (R2 = 0.943). • A simpler but comparable model is developed by using partial charges of N-atom of amines. • Leave-one-group-out analysis clarifies the model predictivity and the existence of outliers. [ABSTRACT FROM AUTHOR] more...- Published
- 2024
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36. Mercury(II)-complex with 5-methyl-1,3,4-thiadiazole-2-thiol: kinetic studies of hydrogen storage.
- Author
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Al-Mouqdady, Omar D.H., Hatshan, Mohammad R., Fiahan, Ahmed S., Alheety, Mustafa A., and Al-Janabi, Ahmed S.
- Subjects
- *
HYDROGEN storage , *MOLAR conductivity , *MERCURY , *PHOSPHINES , *SULFHYDRYL group , *THIADIAZOLES , *ELEMENTAL analysis , *BIPYRIDINE - Abstract
Mixed ligand mercury(II) complexes of 2-meracpto-5-methyl-1,3,4-thiazdiazole (HmtzS) and phosphines or diamines having the general formulae [Hg(mtsZ) 2 (diphos)] {diphos = 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), 1,4-bis(diphenylphosphino)butane (dppe), 1,1′-bis(diphenylphosphino)ferrocene (dppf)}, [Hg(mtsZ) 2 (PPh 3) 2 ] and [Hg(mtsZ) 2 (diamine)] {diamine = bipyridyl (Bipy) or 1,10-phenthroline (Phen), were successfully synthesized by simple mixing method. The complexes were characterized by elemental analysis, molar conductivity, IR and NMR (1H, 13C and 31P) spectroscopic methods. The mtzS− ligand was coordinated through the sulfur atom of thiol group, whereas the diphosphine or diamine ligands bonded as bidentate chelating ligand to afford tetrahedral environment around the Hg(II) ions. Moreover, the complex [Hg(mtsZ) 2 ] was used in order to study its ability to store hydrogen. The results of hydrogen isotherm at different temperatures prove that [Hg(mtsZ) 2 ] was able to store 0.8 wt% at a pressure of 80 bar 77 K. Furthermore, the kinetic study of hydrogen storage was studied and the kinetic study was carried out using the Langmuir. Moreover, the adsorption kinetic results revealed that hydrogen storage in [Hg(mtsZ) 2 ] follow the pseudo-second-order model with coefficient regression equal to 0.99. • [Hg(mtsZ) 2 ] and its phosphines and diamines were synthesized and characterized. • Hydrogen storage in [Hg(mtsZ) 2 ] was applied. • Hydrogen adsorption in [Hg(mtsZ) 2 ] followed pseudo-second-order model. [ABSTRACT FROM AUTHOR] more...
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- 2022
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37. Influence of different concentrations of an iodonium salt on properties of amine-free resins.
- Author
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Salvador, Marcos Vinícius de Oliveira, Fronza, Bruna M., Braga, Roberto Ruggiero, Gonçalves, Luciano Souza, Oxman, Joe D., and Lima, Adriano F.
- Subjects
- *
IODONIUM salts , *FOURIER transform spectroscopy , *TUKEY'S test , *FLEXURAL strength , *FLEXURAL modulus - Abstract
to evaluate the effect of different concentrations of an iodonium salt on the degree of conversion, polymerisation rate, flexural strength and modulus of an amine-free photopolymerizable resin system. Two series of UDMA/TEGDMA resin mixtures (1:1 mass ratio) containing 0, 0.5, 1.0 or 2.0 mol% of bis(4-methyl phenyl)iodonium hexafluorophosphate(BPI): and 1 mol% camphorquinone (CQ) were evaluated. One of the series contained 2 mol% of the amine (2-(dimethylamino)ethyl methacrylate-DMAEMA), while the other series had only CQ and BPI as photoinitiators. Polymerisation kinetics and degree of conversion (DC) were evaluated by Fourier transform near-infrared spectroscopy (n = 3). Flexural strength (FS) and modulus (E) were evaluated by a three-point bending method (n = 12). Data were analysed by two-way ANOVA and Tukey's test. The system containing CQ + DMAEMA + BPI provided the highest DC and FS. Amine-free resins had similar E regardless of the presence of BPI. The resins containing CQ+DMAEMA with 1 and 2 mol% of BPI presented higher E compared with others. Amine-containing resins reached statistically higher DC, rate of polymerisation and FS than amine-free systems. The use of higher BPI concentrations did not improve the properties of amine-free resins. • Amine-free UDMA based resins can reach suitable properties for dental applications. • There are no need high concentrations of iodonium salt to improve the polymerisation. • UDMA resins with a ternary initiator system present high rate of polymerization. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
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38. A structure-property model for the prediction of pKa values of different amines in the CO2 capture process of concern to the prediction of thermodynamic properties.
- Author
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Eshaghi Gorji, Zahra, Ebrahimpoor Gorji, Ali, and Riahi, Siavash
- Subjects
- *
CARBON sequestration , *PREDICTION models , *GIBBS' free energy , *MOLECULAR structure , *AMINES - Abstract
[Display omitted] • Very simple and descriptive QSPR models were proposed to predict pKa of amines. • The effect of temperature on the pKa values was studied. • The validity of models was analyzed by internal and external validation methods. • Mor15p was the only molecular descriptor appeared in the models. In this study, Quantitative Structure-Property Relationship (QSPR) method has been applied on a dataset including the pKa values of 21 different structures (20 amines and ammonia) at four temperatures in the post-combustion-capture process using QSARINS. QSPR models have been accomplished in two situations, called fixed and unfixed temperatures. In the fixed temperatures, four predictive models with one descriptor have been separately developed at each temperature. Besides, thermodynamic properties have been calculated by the van't Hoff equation using predicted pKa values. In the unfixed temperatures, two general models were developed which take into account the effects of molecular structure and temperature, simultaneously. The predicted pKa values and calculated Gibbs free energy have a good consistency with related values in the literature. The reliability of each developed model has been examined using external assessments. The values of some statistical parameters such as R2 = 0.89 and AARD% = 2.68 verify the prediction capability of models. [ABSTRACT FROM AUTHOR] more...
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- 2022
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39. Acid–base bifunctional catalysis by a heteropolyacid and amines on the polyetheretherketone fiber for cleaner acceleration of the one-pot tandem reactions.
- Author
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Jiang, Lijuan, Shi, Xian-Lei, Lv, Yue, Gong, Honghui, Liu, Shuangshuang, Du, Mengmeng, Hu, Qianqian, and Shi, Keren
- Subjects
ULTRAVIOLET spectrometry ,BIFUNCTIONAL catalysis ,INDUCTIVELY coupled plasma atomic emission spectrometry ,ACID-base catalysis ,NUCLEAR magnetic resonance spectroscopy ,FOURIER transform infrared spectroscopy ,POLYETHER ether ketone - Abstract
[Display omitted] • Commercially available PEEK fiber firstly for the heterogeneous acid–base bifunctional catalyst. • Combining two antagonistic active functions for synergistic acceleration of the one-pot tandem reaction. • Higher catalytic efficiency with lower catalyst dosage of 0.3 mol% and shorter reaction time. • Prominent recyclability over 10 runs and superior stability at least up to 4 months. • Extremely simple separation procedure and efficient lager-scale process. The development of highly efficient, economical and environmentally friendly catalytic systems is of great significance from the green chemistry point of view. In this paper, we presented a succinct approach to create a heterogeneous acid–base bifunctional catalyst for one-pot tandem reaction from the commercially available textile fiber. The ultra-high strength textile fiber polyetheretherketone (PEEK) was functionalized by a post-grafting method to combine two antagonistic active functions in a synergistic catalyst, and the resulting fiber samples were characterized in detail by morphology, mechanical properties, elemental analysis, X-ray photoelectron spectroscopy, inductively coupled plasma-atomic emission spectrometry, X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet–visible spectrum, nuclear magnetic resonance spectroscopy and thermogravimetric analysis, and further revealed that the amines and the heteropolyacid were immobilized by acid–base interactions in the PEEK surface layer with sufficient stability. Moreover, the acid–base bifunctional catalyst can be successfully applied in the acceleration of the one-pot tandem deacetalization–Knoevenagel reactions with high-efficiency (lower catalyst dosage 0.3 mol%, higher product yields 81–92%), whereas the homogeneous catalysts were unable to initiate the reaction due to their mutual neutralization in solution, and the catalytic mechanism was elucidated by comparison. Furthermore, the fibrous catalyst could maintain its activities more than 10 cycles with a simple post-processing, and the mediated system was capable of enlarging to the gram-scale, which are envisaged for industrial operations and cleaner productions. [ABSTRACT FROM AUTHOR] more...
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- 2022
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40. Physicochemical properties of dental resins formulated with amine-free photoinitiation systems.
- Author
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Salvador, Marcos Vinícius, Fronza, Bruna M., Pecorari, Vanessa Galego Arias, Ogliari, Fabrício A., Braga, Roberto Ruggiero, Oxman, Joe D., and Lima, Adriano F.
- Subjects
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DENTAL resins , *FLEXURAL modulus , *ELECTRON donors , *IODONIUM salts , *FLEXURAL strength - Abstract
[Display omitted] • UDMA can work as an electron donor for free radical polymerisation systems. • BIsGMA is an inadequate electron donor in the presence of camphorquinone without amine. • Iodonium salts can improve the degree of conversion of amine-free systems. To assess the mechanical properties of two different dimethacrylate resin blends containing the photosensitizer camphorquinone (CQ) alone or in combination with one or more synergists including an amine and/or an iodonium. Two co-monomer resin blends were formulated using Bis-GMA/TEGDMA and UDMA/TEGDMA, both at 1:1 mass ratio. Each resin blend was divided into four groups, comprising the following four photoinitiation systems: (1) CQ + 2-(dimethylamino)ethyl methacrylate (DMAEMA); (2) CQ + DMAEMA + bis(4-methyl phenyl)iodonium hexafluorophosphate (BPI); (3) CQ; and (4) CQ + BPI. Materials were evaluated for polymerisation kinetics, water sorption, solubility, flexural strength and modulus. BisGMA/TEGDMA with CQ showed minimal and insignificant degree of conversion and was not tested for water sorption/solubility and mechanical properties. The ternary system (i.e., CQ + DMAEMA + BPI), promoted the highest degree of conversion for each monomer blend. The resins containing amine had higher mechanical properties than the amine free. However, the UDMA amine free resins exhibited greater flexural strength and modulus than the corresponding amine free BisGMA resins. BisGMA/TEGDMA containing CQ + DMAEMA or CQ + BPI had significantly higher water sorption and solubility than the other groups. Resins containing amine presented better properties than the amine-free systems. The addition of iodonium salt (BPI) improved the degree of conversion of the resins, even without an amine co-initiator. The amine-free initiator system (CQ + BPI) was more effective when used with UDMA versus BisGMA based-resins respectively. [ABSTRACT FROM AUTHOR] more...
- Published
- 2021
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41. Atomic surface of silicon wafers induced by grafted silica nanoparticles and sodium carbonate.
- Author
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Wang, Dong, Xie, Wenxiang, Zhang, Zhenyu, Wang, Jianmei, Shi, Chunjing, Meng, Fanning, Zhuang, Xuye, Tong, Dingyi, and Cao, Chun
- Subjects
- *
SILICON wafers , *SILICON surfaces , *X-ray photoelectron spectroscopy , *ELECTRIC potential , *DENSITY functional theory , *SILICA nanoparticles - Abstract
[Display omitted] • Novel grafted silica nanoparticles were prepared. • Novel green chemical mechanical polishing was developed. • A simple slurry was proposed, including only grafted silica and sodium carbonate. • Atomic surface is achieved on silicon surface. Atomic surface of silicon (Si) wafers is highly desired for integrated circuit (IC) industry. To meet this demand, traditional chemical mechanical polishing usually employs noxious slurries with complex compositions, containing oxidant, dispersant, inhibitor, surfactant, etc., resulting in the pollution of the environment and high-cost post-treatments. To settle this challenge, a novel green chemical mechanical polishing was developed, only including grafted silica nanoparticles and sodium carbonate. After CMP, surface roughness Sa of 0.219 and 0.247 nm are achieved on Si wafers using amine and methyl modified nanoparticles, respectively, corresponding to material removal rate (MRR) of 132.53 and 84.82 nm/min. Amino-modified nanoparticles increase 18.2 % MRR, and methyl modified ones reduce 24.4 % MRR, compared with those of unmodified nanoparticles. X-ray photoelectron spectroscopy reveals that amino-grafted nanoparticles have strong improvement for chemical reactions during CMP. Density functional theory calculations garner the electrostatic potential energy of 4.884 and 6.753 eV for amine and methyl-modified nanoparticles, respectively, corresponding to high and low effects for MRR. This work provides a new avenue to develop novel green simple CMP for Si wafers, reducing the pollution and cost for post-treatments. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
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42. Directly accessing the alkyne-aldehyde-amine (A3) coupling catalytic cycle using molecular gold(I) acetylide complexes for synthesizing propargylamines and amino indolizines.
- Author
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Singh, Jyoti, Dua, Purva, Rajaraman, Gopalan, and Ghosh, Prasenjit
- Subjects
- *
PROPARGYLAMINES , *ELECTRONIC structure , *ACETYLIDES , *HYDROGEN transfer reactions , *CATALYTIC activity - Abstract
• Acyclic aminooxy carbene (AAOC) ligands stabilize gold(I) acetylide (AAOC)Au(C CC 6 H 4 R) type complexes. • The (AAOC)Au(C CC 6 H 4 R) type complexes catalyzed Alkyne-Aldehyde-Amine (A3) coupling yielding propargylamines and amino indolizines. • The (AAOC)Au(C CC 6 H 4 R) based catalysts represent the first direct access of a catalytic intermediate in the A3 coupling catalysis. • The electronic structure and bonding characteristics of the 1-6 complexes as investigated using steric map plot analysis, 13C NMR analysis, and other supporting computational analyses, showed a robust concordance with the experimental data. • The rate-determining 1,2-intramolecular hydrogen atom transfer step is crucial for the formation of amino indolizine products. • The non-covalent Au•••H–C(alkyl) and Au•••H–C(aryl) interactions play a prominent role in the A3 coupling reaction. The gold(I) acetylide complexes of Acyclic Aminooxy Carbene (AAOC) ligands, [{(4-R1-2,6- t -Bu 2 -C 6 H 2 O)(NCy 2)}methylidene]Au[C C(p -C 6 H 4 R2)] [where R1 = H; R2 = H (1), and R1 = t -Bu; R2 = H (4)] efficiently catalyzed the three-component Alkyne-Aldehyde-Amine (A3) coupling yielding propargylamine and amino indolizine compounds, thereby implicating its direct role in the catalytic cycle. The DFT studies performed on a simplified gold(I) precatalyst, [{(2,4,6-Me 3 -C 6 H 2 O)(NCy 2)}methylidene]Au[C CPh] (4'), at B3LYP-D3/def2-TZVP of theory implicated the role of non-covalent Au•••H–C interactions in the A3 coupling reactions producing propargylamine and subsequently amino indolizine via intramolecular cyclization of propargylamine followed by an intramolecular 1,2-hydrogen transfer-step for the 2-formylpyridine substrate. The non-covalent Au•••H–C(alkyl) and Au•••H–C(aryl) interactions participate in tandem to influence the overall reaction kinetic barrier, and thereby illustrating the importance of such interactions in gold catalysis. The gold(I) acetylide complexes, [{(4-R1-2,6- t -Bu 2 -C 6 H 2 O)(NCy 2)}methylidene]Au[C C(p -C 6 H 4 R2)] [where R1 = H; R2 = H (1), Me (2), OPh (3): R1 = t -Bu; R2 = H (4), Me (5), OPh (6)] were conveniently synthesized from the corresponding chloro analogues [{(4-R1-2,6- t -Bu 2 -C 6 H 2 O)(NCy 2)}methylidene]AuCl (where R1 = H, t -Bu) by the treatment with terminal alkyne HC C(p -C 6 H 4 R2) (where R2 = H, Me, OPh) in the presence of K 2 CO 3 as a base in ca. 88−95 % yield. [Display omitted] Gold(I) acetylide acyclic aminooxy carbene complexes successfully catalyzed A3-coupling yielding propargylamine and amino indolizine compounds, and thereby implicating its role in the catalytic cycle. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
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43. Non-enzymatic degradation of aliphatic Brassicaceae isothiocyanates during aqueous heat treatment.
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Andernach, Lars, Schury, Carolina, Nickel, Marie, Böttger, Jana, Kaufmann, Martin, Rohn, Sascha, Granvogl, Michael, and Hanschen, Franziska Sabine
- Subjects
- *
ISOTHIOCYANATES , *HEAT treatment , *BRASSICACEAE , *FLAVOR , *ODORS , *BASIC needs , *FOOD industry - Abstract
Glucosinolate-derived isothiocyanates are valuable for human health as they exert health promoting effects. As thermal food processing could affect their levels in a structure dependent way, the stability and reactivity of 12 Brassicaceae isothiocyanates during aqueous heating at 100 °C and pH 5–8 were investigated. The formation of their corresponding amines and N,N′ -dialk(en)yl thioureas was quantified. Further, the potential to form odor active compounds was investigated by HRGC–MS-olfactometry. A strong structure-reactivity relationship was found and shorter side chains and electron withdrawing groups increase the reactivity of isothiocyanates. 3-(Methylsulfonyl)-propyl isothiocyanate was least stable. The main products are the corresponding amines (up to 69% recovery) and formation of N,N′ -dialk(en)yl thioureas is only relevant at neutral to basic pH values. Apart from allyl isothiocyanate also 3-(methylthio)propyl isothiocyanate is precursor to many sulfur-containing odor active compounds. Thus, the isothiocyanate-structure affects their levels but also contributes to the flavor of boiled Brassicaceae vegetables. • 12 aliphatic Brassicaceae isothiocyanates differed strongly in their heat stability. • Electron withdrawing groups in the side chain increased reactivity. • Amines are the main products from isothiocyanate hydrolysis at pH 5–7. • N,N′ -dialk(en)yl thioureas need neutral to basic pH conditions for formation. • Isothiocyanates can yield odor active compounds as studied by HRGC-MS-olfactometry. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
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44. Synthesis, crystal structures, photochromism and selective luminescence sensing property of Zn/Cd-viologen coordination polymers.
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Gao, Ying, Ma, XinYue, Li, Yuanyuan, Chu, JingYing, Gao, Zeyuan, Zhao, Mengnan, Li, Miao, Zhu, Baili, Cui, Shuxin, and Zuo, Minghui
- Subjects
- *
CRYSTAL structure , *PHOTOCHROMISM , *FLUORESCENCE quenching , *LUMINESCENCE , *COORDINATION polymers , *CARBOXYLIC acids - Abstract
Three compounds were synthesized and characterized based on the same viologen ligand and different metal salts. Although their range of applications is basically similar, their different internal structures result in different light response rates. [Display omitted] • Three new multifunctional viologen coordination polymers have been synthesized. • Three compounds all exhibit high sensitivity to UV light. • In the process of detecting ammonia, the three compounds showed excellent stimulus response ability. • The ability of the three compounds to detect different concentrations of Cr 2 O 7 2-anions was further verified by fluorescence quenching effect. Three Zn/Cd-viologen coordination polymers (CPs), namely, {Zn[(bcbpy) 0.5 (ipa)(H 2 O)]·H 2 O} n (1), {Zn[(bcbpy) 0.5 (ipa)(H 2 O) 0.5 ]·H 2 O} n (2), and {Cd[(bcbpy)(SO 4)]·2H 2 O} n (3), have been constructed using aromatic carboxylic acid and viologen-derived ligands, where H 2 bcbpy·2Cl represents 1,1′-bis((4-carboxyphenyl)-4,4′-bipyridine) dichloride and H 2 ipa stands for isophthalic acid. All three CPs display photochromic properties, transforming from yellow to dark blue upon irradiation with a xenon lamp. Notably, the photoresponse rates vary among these CPs, with compound 1 showing the fastest photoresponse, followed closely by compounds 2 and 3. Furthermore, CPs 1 , 2 , and 3 display a unique sensitivity to different concentrations of Cr 2 O 7 2- anion solutions. When immersed in these solutions, the compounds exhibit varying degrees of fluorescence quenching effects, allowing for the monitoring of even the lowest ion concentrations. Additionally, upon exposure to ammonia vapor, the three compounds undergo a color change from yellow to dark brown, indicating their sensitivity to ammonia vapor. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
45. Theoretical investigations of Co-catalyzed allylic aminations.
- Author
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Meng, Qingxi and Wang, Fen
- Subjects
- *
CATALYSIS , *DENSITY functional theory , *AMINE analysis , *ISOMERIZATION , *ALLYL group - Abstract
• Catalytic mechanism was elucidated from DFT calculations. • Origin of enantioselectivity and branch-regioselectivity were discussed thoroughly. And the TS interaction energy decided the enantioselectivity, and both the distorted energy of the NHPh group and the TS interaction energy were the key factors determining the branched regioselectivity. • Structure and reactivity of σ,η[ 3 ]-allyl cobalt species were discussed in detail. • The reactivity of racemic n-propyl allylic carbonates was similar, and (S)- n-propyl allylic carbonate was a little more reactive relative to (R)- n-propyl allylic carbonate. Cobalt-bisoxazolinephosphine-catalyzed regio- and enantioselective allylic amination of racemic n-propyl allylic carbonate and aniline was investigated by DFT calculations at the ωB97XD/6–31G(d,p) level (SDD for Co). The computational results revealed that cobalt-catalyzed allylic amination underwent mainly through oxidative addition of n-propyl allylic carbonate, coordination of aniline to cobalt, hydrogen migration, isomerization of allyl group, and reductive elimination. The oxidative addition of n-propyl allylic carbonate was the rate-determining step, the reductive elimination was the regioselectivity-limited and enantioselectivity-controlling step, and the most favorable product was of (R)-chirality, which was compatible with the experimental results. The oxidative addition, hydrogen migration, reductive elimination, and the reactivity of racemic n-propyl allylic carbonates were discussed at full length in this text. [Display omitted] [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
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46. Machine learning and DFT coupling: A powerful approach to explore organic amine catalysts for ring-opening polymerization reaction.
- Author
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Zhong, Haoliang, Wu, Ying, Li, Xu, and Shi, Tongfei
- Subjects
- *
RING-opening polymerization , *RING-opening reactions , *MACHINE learning , *STANDARD deviations , *ELECTRON configuration , *QSAR models - Abstract
[Display omitted] • Combining ML with DFT is a novel approach to efficiently screen amines. • ML results identified heterocyclic amines as promising catalysts in ROP reaction. • Significant features originate from structural and electronic configurations. • SHAP plot elucidated the design principles for developing amines in ROP reaction. Recently, using well-known data to drive the chemical feature of catalysts for the specified reaction has emerged as a prevalent approach in catalysis science. Amines as essential compounds play crucial roles in living organisms, pharmaceutical, agricultural applications, and various chemical reactions. However, developing a systematic strategy for the screening of amine as an organic catalyst in ring-opening polymerization (ROP) remains a significant challenge. In predicting the catalytic performance of ROP reactions, the proton affinity (PA) of amines serves as a significant indicator, which reflects the basicity of the catalyst and the activity of the ROP reaction. Herein, we conducted a systematical analysis on a dataset of 259 unique amine compounds, involving the application of seven classical machine learning models and 23 molecular descriptors. The predictive model was constructed with molecular descriptors and DFT-calculated PA values. Among the regression results, the Support Vector Machine (SV) model exhibited the optimal performance, with R2, average mean absolute error (MAE) and root mean square error (RMSE) achieving 0.84, 8.38 kJ/mol and 13.77 kJ/mol, respectively. We further employed SHAP (SHapley Additive exPlanations) to evaluate feature significance and provide insights into screening amine catalysts for ROP reaction. The top 10 amines with high PA values are enumerated and discussed. This workflow of coupling machine learning and the DFT approach proves an effective way for screening amine catalysts in ROP reaction. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
- View/download PDF
47. Identification of metabolites produced by six gut commensal Bacteroidales strains using non-targeted LC-MS/MS metabolite profiling.
- Author
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Fernandez-Cantos, Maria Victoria, Babu, Ambrin Farizah, Hanhineva, Kati, and Kuipers, Oscar P.
- Subjects
- *
BIOGENIC amines , *AMINO acid derivatives , *LIQUID chromatography-mass spectrometry , *METABOLITES , *ORGANIC acids , *HUMAN microbiota - Abstract
As the most abundant gram-negative bacterial order in the gastrointestinal tract, Bacteroidales bacteria have been extensively studied for their contribution to various aspects of gut health. These bacteria are renowned for their involvement in immunomodulation and their remarkable capacity to break down complex carbohydrates and fibers. However, the human gut microbiota is known to produce many metabolites that ultimately mediate important microbe-host and microbe-microbe interactions. To gain further insights into the metabolites produced by the gut commensal strains of this order, we examined the metabolite composition of their bacterial cell cultures in the stationary phase. Based on their abundance in the gastrointestinal tract and their relevance in health and disease, we selected a total of six bacterial strains from the relevant genera Bacteroides, Phocaeicola, Parabacteroides, and Segatella. We grew these strains in modified Gifu anaerobic medium (mGAM) supplemented with mucin, which resembles the gut microbiota's natural environment. Liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based metabolite profiling revealed 179 annotated metabolites that had significantly differential abundances between the studied bacterial strains and the control growth medium. Most of them belonged to classes such as amino acids and derivatives, organic acids, and nucleot(s)ides. Of particular interest, Segatella copri DSM 18205 (previously referred to as Prevotella copri) produced substantial quantities of the bioactive metabolites phenylethylamine, tyramine, tryptamine, and ornithine. Parabacteroides merdae CL03T12C32 stood out due to its ability to produce cadaverine, histamine, acetylputrescine, and deoxycarnitine. In addition, we found that strains of the genera Bacteroides, Phocaeicola, and Parabacteroides accumulated considerable amounts of proline-hydroxyproline, a collagen-derived bioactive dipeptide. Collectively, these findings offer a more detailed comprehension of the metabolic potential of these Bacteroidales strains, contributing to a better understanding of their role within the human gut microbiome in health and disease. [ABSTRACT FROM AUTHOR] more...
- Published
- 2024
- Full Text
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48. Modification of polysulfide electrolyte by applying various amines, thiourea and urea as efficient additives to improve photovoltaic performance of quantum dot-sensitized solar cells.
- Author
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Beiraghdar, Negin, Dehghani, Hossein, and Afrooz, Malihe
- Subjects
- *
SOLAR cells , *ELECTROLYTE solutions , *ELECTROLYTES , *AROMATIC amines , *UREA , *THIOUREA , *POLYSULFIDES - Abstract
[Display omitted] • The PCE of QDSSCs was improved by modifying polysulfide electrolytes. • The modified electrolytes were fabricated based on various additives. • The best-measured PCE was due to the presence of thiourea in the electrolyte. In this study, for the first time we reported a low-cost and straightforward method to modify the polysulfide electrolyte using amine additives including aromatic amines (1,8-naphthalenediamine, 1,5-naphthalenediamine), linear amines (ethylenediamine, diethylamine, ethylamine, tert -butylamine, and butylamine), thiourea, and urea in the polysulfide electrolyte system to improve the CdS/CdSe QDSSCs performance. The photovoltaic data showed that the highest power conversion efficiencies (PCEs) were obtained for 1,5-naphthalenediamine amongst aromatic amine groups, diethylamine amidst linear amine groups and thiourea. The best-measured PCE was 3.42% (J SC = 18.98 mA·cm−2, V OC = 0.50 V, FF = 0.36) at AM1.5, which was due to presence of thiourea additive in the polysulfide electrolyte. The results of data revealed that the interaction between thiourea additive, TiO 2 , and redox couple in the electrolyte solution caused to a molecular complex formation, increase the electron lifetime (τ), J SC and, ultimately, improve the PCE value compared to other additives under investigation in this study. [ABSTRACT FROM AUTHOR] more...
- Published
- 2021
- Full Text
- View/download PDF
49. Hydrothermal synthesis of new CuVO2 delafossite hexagonal nanoplates.
- Author
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Jiang, Xue, Jia, Baorui, Zhang, Deyin, Wu, Haoyang, Chu, Aiming, Qu, Xuanhui, and Qin, Mingli
- Subjects
- *
HYDROTHERMAL synthesis , *MONODISPERSE colloids , *ENERGY dispersive X-ray spectroscopy , *VANADIUM oxide , *COPPER oxide , *CHEMICAL properties - Abstract
Copper vanadium oxides have a variety of compositions and crystal phases and are widely used as sintering aids in ceramics, sensor materials, photocatalysts, photoanodes, battery materials, and other fields. Herein, we present a new phase of copper-vanadium oxide, delafossite-type CuVO 2 , and its hydrothermal synthesis using tetradecylamine (TDA) as a modifier. This delafossite phase has not been reported previously and was identified by a combination of X-ray powder diffraction Rietveld refinement, transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The multiple effects of TDA in the reaction are discussed in detail. The results show that TDA plays critical roles as a complexing agent, reducing agent, and capping ligand in the formation of the new delafossite CuVO 2 nanoplates. The resulting monodisperse particles have a hexagonal nanoplate morphology with a size distribution ranging between 1 and 2 μm and a thickness of 40 nm. This study illustrates the usefulness of long-chain amines in the wet chemical synthesis of copper vanadate, especially for preparing new crystalline structures. Additional research on the physical and chemical properties and applications of delafossite CuVO 2 nanoplates is strongly encouraged. [ABSTRACT FROM AUTHOR] more...
- Published
- 2020
- Full Text
- View/download PDF
50. Enhanced cyclic CO2/N2 separation performance stability on chemically modified N-doped ordered mesoporous carbon.
- Author
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Chang, Ren Wei, Lin, Chin Jung, Liou, Sofia Ya Hsuan, Bañares, Miguel A., Guerrero-Pérez, M. Olga, and Martín Aranda, Rosa María
- Subjects
- *
SURFACE chemistry , *ADSORPTION capacity , *MESOPOROUS materials , *FOURIER transform infrared spectroscopy , *X-ray photoelectron spectroscopy , *FLUE gases , *AMINO group - Abstract
• The sorbent with improved amine molecules dispersion was fabricated. • The capture capacity loss was insignificant after 20 cycles capture-regeneration test. • The outstanding selectivity toward CO 2 under CO 2 /N 2 mixture was presented. The modification of ordered mesoporous carbon (OMC) via NH 3 heat treatment and subsequent amine refluxing at increased temperature was investigated to improve their performances for cyclic CO 2 /N 2 separation stability and kinetics. Characterizations conducted with nitrogen adsorption/desorption isotherm, Fourier transform infrared spectroscopy, elemental analysis, and X-ray photoelectron spectroscopy demonstrated that the porosity and surface chemistry of the OMCs were tuned by modification. Adsorption evaluation with volumetric and gravimetric methods under various conditions indicated that the resulting amine-introduced N-doped OMC presented a high CO 2 adsorption capacity with fast kinetics, outstanding selectivity at 50 °C and maintained superior separation performance after 20 cycles. The presence of accessible amino groups in considerable amounts renders the modified mesoporous carbon a promising candidate for CO 2 capture from flue gas by using the temperature swing adsorption. [ABSTRACT FROM AUTHOR] more...
- Published
- 2020
- Full Text
- View/download PDF
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