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To enhance the bio-based synthesis of acrolein from glycerol, a hybrid approach combining in situ nonthermal plasma (NTP) with thermo-catalytic dehydration was employed. This study investigated the impact of the reaction temperature and NTP discharge field strength on glycerol conversion, acrolein selectivity, byproduct formation, and coke deposition using two catalysts of silicotungstic acid supported on mesoporous alumina and silica. The results revealed that, while the reaction temperature and NTP field strength exhibited complex interactions, the in situ application of NTP markedly improved both glycerol conversion and acrolein selectivity when optimized for specific temperature–NTP field strength combinations. Additionally, the reaction mechanisms of glycerol dehydration with the two catalysts, in the presence and absence of NTP, were systematically analyzed and discussed based on the experimental data. [ABSTRACT FROM AUTHOR]

The utilization of fossil fuels has been the leading choice in the industrial revolution despite its negative environmental impact. Biodiesel is a well-known alternative to replace fossil fuels because it is a renewable and environmentally friendly fuel. The use of biodiesel increases every year, causing new problems. The transesterification reaction to produce biodiesel also produces a by-product of glycerol. Glycerol is among the world's 12 most essential chemical raw materials. The abundance of glycerol has not been followed by the level of consumption, so it is necessary to increase the value of the glycerol. The transformation of glycerol into high-value-added chemicals is a promising solution to utilizing abundant glycerol. Glycerol transformation can be done through several reaction pathways catalyzed by zeolite. Zeolite is a heterogeneous catalyst with acid-base sites and good framework selectivity, making it suitable for catalytic glycerol transformation. Zeolite can be used to catalyze glycerol through various reactions into high-value-added chemicals such as glycerol oxidation to produce dihydroxyacetone, glycerol hydrogenolysis to produce propylene glycol, glycerol dehydration to produce acrolein, glycerol transesterification with dialkyl carbonate to produce glycerol carbonate, glycerol pyrolysis to produce syngas, and glycerol etherification to produce glycerol ethers. Statement of Novelty: This review highlights the current approaches to upgrade the value of glycerol, a by-product of biodiesel production, through catalytic transformation using zeolite as a heterogeneous catalyst. The catalytic processes of glycerol over zeolite with unique nanopore architectures with abundant acid sites could address the surplus glycerol problem enabling the production of high-value-added chemicals. Moreover, based on the current development, this review also provides areas of future research. [ABSTRACT FROM AUTHOR]

Confronted with the significant challenges of global climate change and environmental deterioration, the pursuit of carbon emission peaks and the realization of carbon neutrality have become a collective goal for countries worldwide. As an exemplary combustion technology noted for its efficiency and environmental friendliness, the circulating fluidized bed (CFB) is instrumental in curbing the release of carbon dioxide alongside other deleterious gases. The technology is pivotal in promoting the clean and efficient use of coal, simultaneously expediting the global shift towards a sustainable, green, and low-carbon future. This study employs a bibliometric analysis, a social network analysis, and information visualization techniques to delve into the evolution of CFB technology, leveraging the Web of Science database (SCI-EXPANDED and CPCI-S) and the Derwent Innovations Index (DII). Through a meticulous examination of academic papers and patent literature related to CFB technology, this research unveils the developmental trajectory and trends of CFB technology, providing a scientific foundation and reference for strategic technology planning and focused research in key areas. The findings indicate that, while there is a downward trend in the global publication of academic papers on CFB technology, the number of patent applications continues to grow steadily. CFB technology has achieved significant advancements in enhancing combustion efficiency, environmental protection, energy utilization, and waste management, and is progressing towards a direction of diversification and greater efficiency. Moving forward, the development of CFB technology should concentrate on pivotal areas such as material science, fluid dynamics simulation, environmental impact assessment, system integration, and intelligentization, to foster ongoing innovation and a broad application of the technology. [ABSTRACT FROM AUTHOR]

This document is a special issue of the journal Catalysts, featuring contributions from scientists in various fields discussing the topic of catalysis on zeolites and zeolite-like materials. The articles cover a wide range of topics, including the preparation and modification of zeolite-containing catalysts for the petrochemical industry, the synthesis of micro-mesoporous materials for efficient catalysis, the development of new zeolite systems for environmental catalysis, and the synthesis and characterization of nanoscale zeolites with various applications. The contributions emphasize the potential of zeolites and zeolite-like materials as catalysts due to their unique pore structures and surface properties. [Extracted from the article]

The chemical structure of 4,4′-trimethylenedipiperidinium hydrogen sulfate hydrate was investigated by single-crystal XRD, thereby the existence of hydrogen sulfate anions and the crystallization waters was proved. This fact confirmed that the FTIR spectrum can be used to distinguish [HSO4]− and [SO4]2− anions in organic salts. The organic acid salt with both Brönsted acid and acceptor–donor hydrogen bond sites was employed in the laboratory scale of a fundamental industrial process. The catalytic efficiency of the organic acid salt was investigated for the selective transformation of glycerol into triacetin, a well-known fuel additive, under different conditions. The catalytic efficiency of the organic acid salt was investigated for the selective transformation of glycerol into triacetin, a well-known fuel additive, under different conditions. Furthermore, the selective separation of di- and tri-acetin from the reaction medium during the acylation was performed through a continuous liquid–liquid extraction in situ technique. The combinatory effect of Brönsted acid-hydrogen bond catalysis and separation process improves the preparation and separation of triacetin. The main merits of the current work are the easy preparation and selective separation of valuable products under solvent-free, metal-free, and halogen-free conditions with high recycling and reusing of the catalytic medium. [ABSTRACT FROM AUTHOR]

The main groups of catalytic materials used in the conversion of methanol to dimethyl ether (the MTD process) were presented with respect to their advantages, disadvantages, and the methods of their modifications, resulting in catalysts with improved activity, selectivity, and stability. In particular, the effects of strength, surface concentration, and the type of acid sites, the porous structure and morphology of the catalytic materials, the role of catalyst activators, and others, were considered. The prosed mechanisms of the MTD process over various types of catalysts are presented. Moreover, the advantages of membrane reactors for the MTD process are presented and analysed. The perspectives in the development of effective catalysts for the dehydration of methanol to dimethyl ether are presented and discussed. [ABSTRACT FROM AUTHOR]

In a previous study, electrospray ionization, collision-induced dissociation (CID), and gas-phase ion–molecule reactions were used to create and characterize ions derived from homogeneous precursors composed of a uranyl cation (UVIO22+) coordinated by either formate or acetate ligands [E. Perez, C. Hanley, S. Koehler, J. Pestok, N. Polonsky and M. Van Stipdonk, Gas phase reactions of ions derived from anionic uranyl formate and uranyl acetate complexes, J. Am. Soc. Mass Spectrom., 2016, 27, 1989–1998]. Here, we describe a follow-up study of anionic complexes that contain a mix of formate and acetate ligands, namely [UO2(O2C–CH3)2(O2C–H)]− and [UO2(O2C–CH3)(O2C–H)2]−. Initial CID of either anion causes decarboxylation of a formate ligand to create carboxylate-coordinated U-hydride product ions. Subsequent CID of the hydride species causes elimination of acetaldehyde or formaldehyde, consistent with reactions that include intra-complex hydride attack upon bound acetate or formate ligands, respectively. Density functional theory (DFT) calculations reproduce the experimental observations, including the favored elimination of formaldehyde over acetaldehyde by hydride attack during CID of [UO2(H)(O2C–CH3)(O2C–H)]−. We also discovered that MSn CID of the acetate–formate complexes leads to generation of the oxyl-methide species, [UO2(O)(CH3)]−, which reacts with H2O to generate [UO2(O)(OH)]−. DFT calculations support the observation that formation of [UO2(O)(OH)]− by elimination of CH4 is favored over H2O addition and rearrangement to create [UO2(OH)2(CH3)]−. [ABSTRACT FROM AUTHOR]

Methionine (Met) and its hydroxy analogue (MHA) are important components of a multimillion tonne scale commodity market of supplements used in human and livestock nutrition. Currently the industrial chemical synthesis of Met and MHA depends on petroleum-derived feedstock, such as propene. Additionally, the conventional synthetic methods involve dealing with highly toxic compounds, such as acrolein or cyanide. Substituting the conventional processes with new ones dependent on bio-based feedstocks, and involving safer chemistries, will be of great importance to reach a sustainable future. This review discusses the current chemical processes to synthesize Met and MHA and critically assesses different approaches aiming to improve the sustainability of its key feedstock, namely acrolein, or the overall synthesis. The strengths, weaknesses, future opportunities and threats for each synthetic approach are highlighted. [ABSTRACT FROM AUTHOR]

During steam reforming, the performance of a catalyst and amount/property of coke are closely related to reaction intermediates reaching surface of a catalyst. Herein, modification of reaction intermediates by placing Mg-Al-hydrotalcite above Ni/KIT-6 catalyst in steam reforming of glycerol was conducted at 300 to 600 °C. The results revealed that the catalytic activity of Ni/KIT-6 in the lower bed was enhanced with either Mg1-Al5-hydrotalcite (containing more acidic sites) or Mg5-Al1-hydrotalcite (containing more alkaline sites) as upper-layer catalyst. The in situ infrared characterization of steam reforming demonstrated that Mg-Al-hydrotalcite catalyzed the deoxygenation of glycerol, facilitating the reforming of the partially deoxygenated intermediates over Ni/KIT-6. Mg-Al-hydrotalcite as protective catalyst, however, did not protect the Ni/KIT-6 from formation of more coke. Nonetheless, this did not lead to further deactivation of Ni/KIT-6 while Mg5-Al1-hydrotalcite even substantially enhanced the catalytic stability, even though the coke was much more significant than that in the use of single Ni/KIT-6 (52.7% vs. 28.6%). The reason beneath this was change of the property of coke from more aliphatic to more aromatic. Mg5-Al1-hydrotalcite catalyzed dehydration of glycerol, producing dominantly reaction intermediates bearing C=C, which formed the catalytic coke of with carbon nanotube as the main form with smooth outer walls as well as higher aromaticity, C/H ratio, crystallinity, crystal carbon size, thermal stability, and resistivity toward oxidation on Ni/KIT-6 in the lower bed. In comparison, the abundance of acidic sites on Mg1-Al5-hydrotalcite catalyzed the formation of more oxygen-containing species, leading to the formation of carbon nanotubes of rough surface on Ni/KIT-6. [ABSTRACT FROM AUTHOR]

This document is a special issue of the journal Processes titled "Biochemical Processes for Sustainability." It emphasizes the need for sustainable solutions that consider both environmental and economic sustainability. The document highlights the importance of biochemical processes, which are optimized chemical reactions that have evolved over millions of years. The special issue includes 15 cutting-edge studies that cover various aspects of sustainability, such as biotreatment with enzymes and microorganisms, advanced materials, pollution treatments, and nature-based solutions. The authors emphasize the importance of using nature's resources with ingenuity and combining them with scientific advancements. [Extracted from the article]

Unraveling the effect of spatially separated bifunctional sites on catalytic reactions is significant yet challenging. In this report, we investigate the role of spatial separation on the oxidation of methane in a series of Cu-exchanged aluminosilicate zeolites. Regulation of the bifunctional sites is done either through studying a physical mixture of Cu-exchanged zeolites and acidic zeolites or by systematically varying the Cu and acid density within a family of zeolite materials. We show that separated Cu and acid sites are beneficial for the formation of hydrocarbons while high-density Cu sites, which are closer together, facilitate the production of CO2. By contrast, a balance of the spatial separation of Cu and acid sites shows more favorable formation of methanol. This work will further guide approaches to methane oxidation to methanol and open an avenue for promoting hydrocarbon synthesis using methanol as an intermediate. Methane is a potent greenhouse gas, and its removal is critical. Here, the authors demonstrate that spatially separated Cu and acid sites in Cu/zeolites influence product distribution and efficiency for methane oxidation. [ABSTRACT FROM AUTHOR]

Background: White standard Dendranthema grandiflorum (D. grandiflorum) is widely used for ornamental purposes. The volatile organic components (VOCs) of D. grandiflorum vary depending on the geographical origin and cultivar, which influence the market value. Here, we applied headspace extraction coupled with gas chromatography–mass spectrometry (HS–GC–MS) for the first time to determine the different origins (Korea, China, Vietnam) of D. grandiflorum in three genotypes (Baekgang, Jinba, Iwa-no-hakusen) based on volatile fingerprints and to assess the correlation among the metabolites identified in Korean and non-Korean D. grandiflorum. Results: A total of 41 VOCs, mainly monoterpenoids, sesquiterpenoids, alcohols, and fatty acids, were identified. Principal component analysis showed that instead of geographical origin, genotype influences D. grandiflorum fingerprints. Cultivar discrimination was mainly affected by the metabolites associated with the alpha-terpinyl cation pathway. The orthogonal partial least squares discriminant analysis model achieved 100% and 93.3% accuracies in the calibration and validation sets, respectively. The results of volcano plots and clustering analysis, sesquiterpenoids were significantly more abundant in non-Korean than in Korean, whereas monoterpenoids were abundant in Korean samples. Conclusions: 41 makers confirmed robustness maintenance over two years. These findings can be useful for reliably identifying the geographical origin of D. grandiflorum and providing a comprehensive understanding of VOCs in D. grandiflorum cultivars grown in different countries of origins. [ABSTRACT FROM AUTHOR]

Annually, a growing demand was noted for replacing petroleum fuels with second-generation eco-friendly fuels like dimethyl ether (DME). Methanol dehydration into DME process has been considered as one of the potential pathways for the manufacture of a clean fuel. However, stable, and active catalyst is exceedingly requisite for generation of DME particularly at reasonably low temperature. In the current study, zirconia incorporated AlPO4 tridymite microporous molecular sieve catalysts were fabricated by a hydrothermal method in the presence of triethylamine (TEA) as a structure directing agent. The catalysts were characterized by X-ray diffraction (XRD), energy dispersive X-ray (EDX), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and N2-sorption assessments. Catalysts' acidity was estimated by decomposition of isopropanol, pyridine and dimethyl pyridine chemisorption, and pyridine-TPD. Results revealed that catalysts surfaces composed acid sites of Brønsted nature and of weak and medium strengths. Activity results showed that 1 wt% H2SO4 modified zirconia incorporated AlPO4-TRI catalyst calcined at 400 °C presented the best activity with a conversion of 89% and a 100% selectivity into DME at 250 °C. The significant catalytic activity is well-connected to the variation in BET-surface area, acidity, and activation energy of methanol dehydration. The catalysts offered long-term stability for 120 h and could be regenerated with almost the same activity and selectivity. [ABSTRACT FROM AUTHOR]

Acrylates/acrylic acid are important for polymer industry due to its very high volume applications in different sectors. Activity of Ba/Mg modified hydroxyapatite for vapour-phase dehydration of ammonium lactate with 100% conversion and 60% acrylate selectivity was attributed to fine tuning of acid/base properties and formation of surface Ba/Ca lactate species. [ABSTRACT FROM AUTHOR]

Dehydration of i-PrOH is used in academic research as a test reaction to probe the acid properties of solid acid catalysts. Also, it has practical importance for the utilization of surplus acetone produced by the Hock process for the combined manufacturing of phenol and acetone as well as for the production of propene from renewable resources and waste. This study demonstrates the excellent performance of polyoxometalate acid catalysts comprising silica-supported Keggin-type heteropoly acids H3PW12O40 and H4SiW12O40 for gas-phase i-PrOH-to-propene dehydration at ambient pressure. These catalysts show similar efficacies, giving an i-PrOH conversion and propene selectivity of 96.8 and 99.7% for 25%HPW/SiO2 and 97.1 and 99.4% for 25%HSiW/SiO2 in a fixed-bed reactor at 120 °C, a relevant-to-practice i-PrOH partial pressure of 15 kPa and a contact time W/F = 27 g h mol−1 (GHSV = 900 mL g−1 h−1). The catalysts are stable, resisting deactivation for at least 24 h time on stream. The HPA/SiO2 catalysts are superior to aluminosilicate zeolites such as H-mordenite, HZSM-5 and HY for i-PrOH-to-propene dehydration in terms of i-PrOH conversion, propene selectivity and catalyst stability. [ABSTRACT FROM AUTHOR]

The present study examined the production of Solketal, a gasoline additive, using glycerol and acetone. For the ketalization experiments, a potential cation exchange resin Ceralite IR-120 was utilized. The effect of agitation speed, temperature, catalyst dosage, and feed composition on the rate of glycerol conversion was studied. For a molar ratio of 1:16 between glycerol and acetone, the experimental results indicated a conversion rate greater than 90%. The experimental studies indicate low mass transfer resistances. The activation energy for the chemical reaction was calculated to be 54.34 kJ/mol, indicating that kinetics rather than thermodynamics dominates this process. A pseudo-homogeneous reaction model that characterizes the acetalization process over the catalyst also concurred with the experimentally determined conversion rate. Catalyst reusability studies showed catalytic activity for up to six recycles. [ABSTRACT FROM AUTHOR]