Search

We introduce the concept of quantum integration for interval-valued functions and establish new q-Hermite–Hadamard and q-Hermite–Hadamard–Fejér inequalities for left and right log⁢-⁢h{\mathrm{log}\text{-}h}-convex interval-valued functions. Our results generalize the known ones in the literature and serve as a foundation for future studies in inequalities for interval-valued functions and interval differential equations. We illustrate our results with examples.

Resource utilization and sustainable treatment of wastewater, which can achieve efficient energy utilization and environmental protection, have received hot social attention. Tetrahydrofuran and methanol are the two most common substances in pharmaceutical wastewater. It is very necessary to explore the wastewater treatment process containing these two substances. In this study, extractive distillation and reactive distillation were proposed to effectively separate the tetrahydrofuran-methanol-water component of pharmaceutical wastewater. To further reduce energy consumption, two strengthening processes, double-column reactive-extractive distillation and reactive-extractive dividing wall column distillation were designed. Taking the minimum operating and equipment cost as the objective function, the processes were optimized by using the multi-objective genetic optimization algorithm to obtain the best process parameters. Four processes were evaluated in terms of total annual cost, energy consumption, gas emissions and thermodynamic efficiency. Compared to the traditional three-column extractive distillation process, the above-mentioned four aspects of the reactive-extractive dividing wall column process was reduced by 40.63%, 43.13%, 43.14% and 17.71%, respectively. The reactive-extractive dividing wall column distillation process is of great significance for the efficient purification of valuable organic matter in wastewater and environmental protection.

The reductive amination of furfural to furfurylamine is an important and still challenging topic in the field of biomass conversion. In this work, we prepared a series of Ni/Al2O3-LaOxcatalysts by co-precipitation method, the role of La played in promoting the catalytic performances of reductive amination furfural was discussed based on the changes in the electronic state of Ni species, acidity, and Ni particle size. The catalytic activity and the selectivity of furfurylamine are highly dependent on the surface properties and the structure of the catalyst. The addition of La promoted the amount of strong acidic sites and the H2dissociation and spillover on the surface, thus inducing the improvement of the catalytic activity and furfurylamine selectivity. The Ni/Al2O3-0.5LaOxcatalyst with suitable acid sites gave a high yield of furfurylamine (94.9%) under mild reaction conditions. Moreover, the catalyst could be recycled five times without significant loss in activity. The Ni/Al2O3-LaOxcatalyst is of great promise in the production of amines viareductive amination reaction.

[Display omitted]

To establish the hydro-pneumatic suspension model more accurately and better analyze the influence of heavy vehicle hydro-pneumatic suspension system on road friendliness, the fractional order theory is applied to modeling, and the mathematical model and dynamics model of dual-chamber hydro-pneumatic suspension with fractional order are established by using Matlab/Simulink, and the fractional order differential term of the suspension system is calculated according to the improved Oustaloup filter. The effect of fractional order on suspension stiffness, damping and output forces is also investigated. The optimal fractional order is determined to be 0.9 for the design of a combined suspension performance index function. The vibration law of increasing amplitude and error of fractional-order is obtained through simulation, and the model with fractional-order is described more accurately. A sliding film variable structure controller was established for control. The simulation results were analyzed by means of theoretical road damage factors and dynamic load factors. The results show that the suspension system model with fractional order terms can effectively reduce the dynamic tire load and improve the suspension smoothness and road friendliness.

The production of biofuels (hydrocarbons) from renewable biomass resources has attracted much attention in the fields of green energy and sustainable chemistry. Herein, catalytic hydrodeoxygenation of methyl laurate (n-C11H23COOCH3) to produce hydrocarbons n-C12H26and n-C11H24has been investigated over Ru dispersed on acidic supports H-ZSM-5, Al2O3and SiO2, and the reaction rate and the product distribution were discussed and correlated with surface Brønsted and Lewis acid sites and active Ru species in detail. The reaction rate at the initial stage increased with the amount of the total acid sites, and the ratio of n-C12H26/n-C11H24and the selectivity to n-C12H26were positively correlated with the amount of Brønsted acid sites. The Ru active species presented to be more electron-deficient on the catalysts with a larger amount of Brønsted acid sites on which an η1-(O) adsorption configuration of 1-C11H23CHO was confirmed, which favoured the formation of n-C12H26, thus varying the product distribution. Besides, Brønsted acid sites could provide protons to promote the hydrogenolysis of n-C11H23COOCH3and the following dehydration to produce n-C12H26.

A series of silver sulfide composites were prepared via the hydrothermal method with l-cysteine and AgNO3in water at a range of l-cysteine/AgNO3molar ratio of 0.5–8. The prepared Ag/AgxS materials were consisted of Ag, Ag2S, Ag2S2, and Ag2Snspecies as confirmed by XRD, TEM, and XPS. The Ag/AgxS composites are active for the photocatalytic reduction of aromatic nitro compounds under the visible light irradiation. The composition of the stoichiometric Ag2S, the nonstoichiometric Ag2S2and Ag2Sn, and metallic Ag species affected the photocatalytic performances largely. When more nonstoichiometric Ag2S2and Ag2Snpresented on the surface, the absorption in the visible (vis) light region was enhanced remarkably and presented a blue shift, leading to a bigger band gap energy value (Eg) and higher cathodic conduction band edge potential (ECB), which promoted the formation of photogenerated electrons and inhibited the combination of photoelectrons and holes. When the more Ag0presented on the surface, the more photogenerated electrons were transferred from the conduction band of AgxS to Ag0, preventing the combination of photoelectrons and holes. Thus, the photocatalytic performances of the Ag/AgxS composites could be controlled by varying the surface composition.

A mixed system for separation of green fuel additives containing diethyloxymethane and ethanol by extractive pressure swing distillation for ionic liquids mixed with organic solvents as an entrainer was proposed for the first time. The interaction mechanism between entrainers and the azeotrope was deeply explored via quantum chemistry and molecular dynamics methods. The optimal ionic liquid entrainer was determined as 1-buty-3-methylimidazolium acetate, and the most suitable organic solvent as the entrainer was p-diethylbenzene. The separation process of the ethanol, diethyloxymethane, and toluene system was developed. The process operation parameters were optimized through a multiobjective optimization method. In order to improve the energy utilization and separation efficiency of the process, a heat pump-assisted extractive pressure swing distillation process was proposed. Compared with the mixed entrainer extractive distillation process, the heat pump-assisted extractive pressure swing distillation process reduced TAC by 1.2% and gas emissions by 17.5%, demonstrating economic advantages and environmental protection effects. This work demonstrates the application of ionic liquid mixed solvents in systems containing green fuel additives, providing guidance for the screening and application of ionic liquid as an entrainer.

A versatile gold(I)-catalyzed cross-coupling reaction of 3-diazooxindoles with diazoesters has been presented, affording (E)-3-alkylideneoxindoles stereoselectively. Density functional theory calculations rationalized the chemo- and stereoselectivity of the reaction, which was in good agreement with experimental observations. In addition, (E)-3-alkylideneoxindoles were converted into their (Z)-isomers under UV-irradiation facilely, indicating the great advantage of this approach in stereoselective synthesis of both (E)- and (Z)-3-alkylideneoxindoles.

The hydrodeoxygenation of a model compound, ethyl stearate, of biomass-derived resources into long chain alkanes was investigated with Re-modified Ru/TiO2catalysts. A monometallic Ru(1)/TiO2catalyst, in which Ru was loaded in 1 wt%, gave a selectivity of >95% to the long chain alkanes of n-octadecane and n-heptadecane at almost 100% conversion at 220 °C, while another monometallic Re(10)/TiO2catalyst was less active in spite of its higher metal loading (10 wt%). It is interesting that the addition of less active Re species to Ru(1)/TiO2not only enhanced the rate of hydrodeoxygenation and increased the ratio of n-octadecane/n-heptadecane, while the high total selectivity towards alkanes remained unchanged. The alkane ratio depended on the content of Re added, increasing significantly from 0.5 for Ru(1)/TiO2to 3.2 for Ru(1)Re(10)/TiO2. The impacts of Re addition on the catalytic performance of Ru/TiO2were discussed on the basis of physicochemical properties characterized for Re-modified and unmodified Ru/TiO2catalysts. It is suggested that the improved hydrodeoxygenation activity of Re-modified catalysts depends on the presence of Lewis acid sites, and the weak acid sites are important for determining catalytic selectivity. In addition, reaction pathways in the hydrodeoxygenation of ethyl stearate to n-octadecane and n-heptadecane were examined by control reactions with possible intermediates such as 1-octadecanol and stearic acid. The Re-modified Ru/TiO2catalysts were shown to be recyclable during repeated runs when the same mole ratio of catalyst to substrate was used.

The transformation of γ-valerolactone (GVL) into 1,4-pentanediol (1,4-PDO) and 2-methyltetra-hydrofuran (2-MTHF) in the presence of H2, one of the useful biomass conversion and utilization processes, was investigated with monometallic Cu/Al2O3and bimetallic ZnCu/Al2O3catalysts. A 10 wt% Cu-loaded monometallic catalyst produced 1,4-PDO and 2-MTHF in comparable quantities at a medium conversion (∼50%). When Zn was added in a range of Zn/Cu molar ratios of up to 2, in contrast, the catalysts yielded 1,4-PDO in a high selectivity of about 97% at low and high conversion levels. In addition, the 1,4-PDO selectivity over the ZnCu/Al2O3catalysts remained almost unchanged during recycled runs. That is, the addition of Zn to Cu/Al2O3switched the product selectivity and improved the catalyst stability and reusability. Furthermore, the physicochemical properties of the catalysts were characterized by several methods including XRD, TEM, TPR, XPS, FTIR of adsorbed pyridine, and so on. On the basis of those results, the relationships between the catalytic performance (activity, selectivity, and reusability) and the catalyst structural features were discussed.

Supported Ir catalysts were prepared using layered double hydrotalcite-like materials, such as Mg3Al1−xFex, containing Fe and Al species in varying amounts as supports. These Ir catalysts were applied for the selective hydrogenation of cinnamaldehyde (CAL). When xwas changed from 0 (Ir/Mg3Al) to 1 (Ir/Mg3Fe), the rate of CAL hydrogenation reached a maximum at approximately x= 0.25, while the selectivity to unsaturated alcohol, i.e., cinnamyl alcohol, monotonously increased from 44.9% to 80.3%. Meanwhile, the size of the supported Ir particles did not change significantly with x, remaining at 1.7 ± 0.2 nm, as determined by transmission electron microscopy. The chemical state of Ir and Fe species in the Ir/Mg3Al1−xFexcatalysts was examined by temperature programmed reduction by H2and X-ray photoelectron spectroscopy. The surface of the supported Ir particles was also examined through the in-situdiffuse reflectance infrared Fourier-transform of a probe molecule of CO. On the basis of these characterization results, the effects of Fe doping to Mg3Al on the structural and catalytic properties of Ir particles in selective CAL hydrogenation were discussed. The significant factors are the electron transfer from Fe2+in the Mg3Al1–xFexsupport to the dispersed Ir particles and the surface geometry.

The combination of CO2and H2O as green solvents has been used extensively in chemical reaction and attracted much attention. The conversion and/or selectivity could be improved in the presence of both CO2and H2O. In this paper, the promotion effects of CO2and H2O on the selective hydrogenation reactions are shortly reviewed.

Solvent effects in the selective hydrogenation of an α,β-unsaturated aldehyde of cinnamaldehyde (CAL) were investigated under gas–liquid–solid reaction conditions. A conventional 5 wt% Pd/C catalyst and twelve organic solvents were used, including apolar solvents (three) and protic (two) and aprotic (seven) polar ones. The total rate of CAL hydrogenation strongly depended on the solvents used. The relationship between the rate of CAL hydrogenation observed and a few different solvent parameters was examined. The main product was hydrocinnamaldehyde (HCAL) with a selectivity of 80% or higher in most of the solvents examined except for pyridine and 4-methylpyridine. In these two solvents, the CAL hydrogenation was slow and the main product was changed to cinnamyl alcohol (COL) with a selectivity of about 60%. The addition of a small volume of pyridine to other solvents such as 2-propanol and tetrahydrofuran could change the rate of hydrogenation and switch the main product from HCAL to COL. Possible interactions among the solvents, CAL substrate, and Pd/C catalyst were examined by FTIR (attenuated total reflection (ATR-) and diffuse reflectance modes (DR-)) and TPD to discuss the solvent effects observed in the Pd-catalyzed heterogeneous CAL hydrogenation.

Activation and transformation of CO2is one of the important issues in the field of green and sustainable chemistry. Herein, CO2as a carbon-oxygen resource was converted to CO2-polyurea with 1,6-hexanediamine through a two-step polymerization. The reaction parameters such as temperature, pressure and reaction time were examined; and several kinds of catalysts were screened in the absence and presence of NMP solvent. The formed oligomer and the final polyurea were characterized by FT-IR, VT-DRIFTS, NMR, XRD, AFM and their thermal properties were examined by TGA and DSC. It was confirmed that the final polyurea has a high thermal stability; the melting temperature is 269 °C and the decomposition temperature is above 300 °C. It is a brittle polymer with a tensile strength of 18.35 MPa at break length of 1.64%. The polyurea has a stronger solvent resistance due to the ordered hydrogen bond in structure. The average molecular weight should be enhanced in the post-polymerization as the appearance, hydrogen bond intensity, crystallinity, melting point and the thermal stability changed largely compared to the oligomer. The present work provides a new kind of polyurea, it is expected to have a wide application in the field of polymer materials.

Hexamethylenediamine (HMDA) is an important reagent for the synthesis of Nylon-6,6, and it is usually produced by the hydrogenation of adiponitrile using a toxic reagent of hydrocyanic acid. Herein, we developed an environmental friendly route to produce HMDA via catalytic reductive amination of 1,6-hexanediol (HDO) in the presence of hydrogen. The activities of several heterogeneous metal catalysts such as supported Ni, Co, Ru, Pt, Pd catalysts were screened for the present reaction in supercritical ammonia without any additives. Among the catalysts examined, Ru/Al2O3presented a high catalytic activity and highest selectivity for the desired product of HMDA. The high performance of Ru/Al2O3was discussed based on the Ru dispersion and the surface properties like the acid-basicity. In addition, the reaction parameters such as reaction temperature, time, H2and NH3pressure were examined, and the reaction processes were discussed in detail.

ScCO2-H2O was an effective and green medium for production of PAP from the hydrogenation of NB (Conv. 98.5%, Sel. 68.9%) over Pt/Al2O3catalyst, the acidity and CO formed in situwere demonostrated to promote the formation of PAP.

A kind of hydrophobic polyurea gel was synthesized by an isocyanate-free route via carbon dioxide and amino modified polysiloxane. The polyureas was hydrophobic and could absorb some organic solvents, and it is expected to have a promising application in the commercial removal of organic pollutants in water.

The utilization of CO2as a renewable and cheap carbon resource to produce fuels, chemicals and polymers has attracted more attention. This review will summarize the developments in the production of polymers like polyureas and polyurea hybrids with CO2as a monomer directly or indirectly. The influences of catalyst and the structure of diamine monomer on the molecular weight, thermal stability and mechanical properties of polyureas are discussed. In addition, the general properties and applications of functional CO2‐based polyureas are also described. A few examples of CO2‐based polyurea hybrids are also introduced. Finally, the future research priorities as well as the development trend of polyurea materials are depicted. The progresses achievedin the synthesis of polyureas and polyurea hybrids directly or indirectly from CO2have been reviewed, including the method, monomer structure, catalyst and properties.

AgxS crystals were synthesized via hydrothermal (AgxS-H) and in situion-exchange (AgxS-IE) methods. The samples were characterized by scanning electron microscopy, X-ray diffraction, ultraviolet-visible-near infrared absorption spectroscopy, N2adsorption-desorption, X-ray photoelectron spectroscopy and surface photovoltage measurements. The photocatalytic performance was investigated for the decomposition of methyl blue (MB) under visible light irradiation (λ≥ 420 nm). The AgxS-Hhad smaller particles, wider band gap and weaker recombination of photoinduced charges than AgxS-IE, resulting in a higher photocatalytic activity. Moreover, AgxS-Hwas stable, and could be reused five times without loss of photocatalytic activity. Additionally, a possible pathway for the photocatalytic degradation of MB over AgxS has been proposed, that MB was oxidized mainly by hydroxyl radicals and partly via electron holes generated in the AgxS. AgxS-His an efficient photocatalyst and has great potential for the degradation of harmful organic dyes in wastewater.

Carbon dioxide (CO2) as a sustainable resource instead of toxic reagents has attracted considerable attention in synthesis of chemicals and polymeric materials. Herein, a kind of cyclic oligourea was synthesized viapolycondensation of CO2with 4,7,10-trioxa-1,13-tridecanediamine (TTD) followed by effective separation and purification processes. We developed an efficient separation strategy in which the linear oligourea molecules were selectively transformed to macromolecular polyurea molecules by a reaction of the –NH2end group with 4,4′-diphenylmethane diisocyanate (MDI), followed by separation from cyclic oligourea using selected solvents. The structure and physicochemical properties were confirmed by MALDI-TOF mass spectra, NMR, Cryo-EM, thermal analysis and solubility measurement. The well-defined cyclic oligourea was produced with a high purity (99.4%) and the average-number molecular weight (Mn) of 1040 Da. It is semi-crystalline in structure with a melting point of 106 °C and glass transition point of −10 °C. The cyclic oligourea presented characteristically difference to its linear analogue. This work provides a new member to cyclic polymer family.

The chemoselective, Ni‐catalyzed hydrogenation of water‐insoluble aromatic nitro compounds in a water‐compressed CO2system is reported.

This green process utilizes the captured carbon dioxide to prepare urea derivatives, avoiding the use of toxic or expensive substrates.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.