Molecular Catalysis
·
2023
·
IF 4.6
Bowen Wu,Yixi Chen,Mingtai Liu,Yi Tang,Gengfeng Zheng,Linping Qian
The surface properties of CoMg/Al 2 O 3 were evaluated in the aerobic oxidation of p -cresol. The surface interaction is enhanced greatly after Co and Mg impregnation with the mole ratio of Co/Mg from 2 : 1 and 2 : 3. The strongest interaction for the nonpolarity and benzene ring was found on CoMg/Al 2 O 3 with Co/Mg of 2 : 3. But for the interaction with p -π group bonding with negative anion, the highest value appears on the catalyst with the Co/Mg of 2 : 2. In aerobic oxidation of p -cresol, the conversion is significantly increased with Co addition and reaches around 60 % after 24 h' reaction at 338 K. The highest selectivity of p -hydroxybenzaldehyde of 99 % is achieved on Al 2 O 3 with the co-impregnation mole ratio of Co/Mg of 2 : 2. It is suggested that medium adsorption of the reactants and strong stabilization of the intermediates facilitate the aerobic oxidation of p -cresol to p -hydroxybenzaldehyde.
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Catalysis Science & Technology
·
2023
·Vol. 14
·期 2
·334-342
·
IF 5
Zhou Yang,Ru Wang,Hongji Liu,Zhou Chen,Xiaoli Hu,Limin Sun,Weikun Lai,Yunyun Dong,Weiping Fang,Xiaodong Yi
Selective hydrogenation is a significantly important catalytic process in many industrial processes, where Pd-based catalysts are the most commonly used. Herein, the surface properties of γ-Al2O3 were modified by the layered flower-like architectures of alkaline MgO using a simple hydrothermal method. Then, a series of Pd/Al2O3–MgO catalysts were prepared by an incipient wetness impregnation method for the selective hydrogenation of isoprene. The results showed that the Pd/Al2O3–0.12MgO catalyst exhibited superior catalytic performance with a high activity (93%) and high selectivity (99%) for the semi-hydrogenation products. Systematic studies have demonstrated that the support effect plays an important role in dispersing and stabilizing palladium particles. The reasons for the improved catalytic performance were attributed to the high dispersion of Pd nanoparticles, the changed electronic structure of Pd, and the strong interaction between Pd nanoparticles and supports. This work opens a simple route to regulate the electronic properties of active metal sites via support modification for selective hydrogenation reactions.
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Petroleum Science
·
2023
·
IF 5.6
Shui-Sen He,Ting-Ting Huang,Chao Chen,Yu Fan
A H 2 O 2 etching strategy was adopted to introduce coordinatively unsaturated sites (CUS) on MoS 2 -based catalysts for dibenzothiophene (DBT) hydrodesulfurization (HDS). The CUS concentrations on MoS 2 slabs were finely regulated by changing the concentrations of H 2 O 2 solution. With the increasing H 2 O 2 concentrations (0.1–0.3 mol/L), The CUS concentrations on MoS 2 slabs increased gradually. However, the high-concentration H 2 O 2 etching (0.5 mol/L) increased the MoO x S y and MoO 3 contents on MoS 2 slabs compared to etching with the H 2 O 2 concentration of 0.3 mol/L, which led to the less CUS concentration in the sulfided Mo–H-0.5 catalyst than in the sulfided Mo–H-0.3 catalyst. A microstructure-activity correlation indicated that the CUS introduced by H 2 O 2 etching on MoS 2 slabs significantly enhanced DBT HDS. Different Co loadings were further introduced into Mo–H-0.3, which had the most CUS concentration, and the corresponding 0.2-CoMo catalyst with the highest CoMoS content (3.853 wt%) exhibited the highest reaction rate constant of 6.95 × 10 −6 mol g −1 s −1 among these CoMo catalysts.
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Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Xiujun Wang,Jian Zhang,Qian Xu,Ming Duan,Shenwen Fang,Chunsheng Zhang,Jiaqing Chen
Nonionic polyether water clarifier is commonly used in the treatment of produced water from offshore oilfield. At the meantime, hydrophobically modified polyacrylamide (HMPAM) is one of the commonly used polymer oil displacement agents. Predicting the influence of HMPAM on the performance of nonionic polyether water clarifier is of great significance for the treatment of produced water. This work explored the influence of different HMPAMs on the hydrophilic-lipophilic deviation (HLD) equation of a typical nonionic polyether water clarifier AE411 based on the HLD theory, and predicted their influences on the performance of AE411. The results showed that HMPAM had no effect on the parameter K (reflecting the interaction between AE411 hydrophilic groups and oil phase) and c t (reflecting the temperature sensitivity of AE411) in HLD equation of AE411, but reduced the parameter C cn (reflecting the micelle structure of AE411 in water) and led to an increase in temperature corresponding to AE411′s HLD = 0. It was predicted that higher temperature was needed to ensure the performance of AE411. The experimental results of produced water treatment confirmed this prediction. The results of the paper validated the reliability of HLD application in the field of produced water treatment and provided some guidance for the development of nonionic polyether water clarifier.
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Journal of Physical Chemistry C
·
2023
·
IF 3.7
Shifeng Ke,Boyu Peng,Ruihan Wu,Jie Ren,Yujie Zhao,Qiuyue Sheng,Hanying Li
Surface tension is a crucial factor in the crystallization of organic semiconductors from solutions. However, the current conclusions based on experimental results have been primarily empirical and qualitative, making it hard to distinguish the role of surface tension from other solvent properties. In this study, we employed both molecular dynamics simulations and experiments to investigate crystal nuclei behavior at the liquid-air interface. Through equilibrium simulations and free energy calculations, we quantitatively described the moving behavior of nuclei in various solvents, relating it to an interfacial transition, in terms of interfacial tension. Nuclei tend to remain at the liquid-air interface if the surface tension of solvents is higher than the surface free energy of nuclei but sink into the bulk liquid otherwise. Furthermore, aside from governing the nuclei behavior, surface tension also determines the crystallization location, as confirmed through growing crystals on substrates with Ag nanowires as impediments. By clarifying the role of surface tension, our research contributes to the knowledge of solution crystallization of organic semiconductors and the establishment of a framework for tuning processing conditions and crystal morphology for future studies.
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FOOD AND CHEMICAL TOXICOLOGY
·
2023
·
IF 4.3
Zhengchao Shen,Kexin Tian,Muhammad Mujahid Ali,Sifan Mei,Xin Ma,Jiang Liang,Feng Pan,Jianwen Li,Haixia Sui,Zhenxia Du
3-monochloropropane-1,2-diol esters (3-MCPDEs) and glycidyl esters (GEs) are food contaminants and have arisen continuous attention due to their toxicity, especially towards infants. Current risk assessment of these contaminants was mostly employing deterministic approaches, lacking quantitative characterization of the likelihood, incidence, or severity of the risks involved. Herein, 3-MCPDE and GE levels in 46 representative infant formulas (IFs) from Chinese market were determined by GC-MS/MS. Then, combining the occurrence data and consumption data from China National Food Consumption Survey, the Monte Carlo simulation-based probabilistic model for risk assessment of 3-MCPDEs and GEs in IFs from Chinese market was established. The results showed that all P90 (90th percentiles) hazard quotient values were below 1, demonstrating 3-MCPDEs didn't pose health risks to most populations aged 0–36 months old. However, for 0–12 months old groups, P10 (10th percentiles) margin of exposure values were all below 25000, indicating GEs may pose potential risks to 10% of this group. Uncertainty analysis revealed that the probabilistic model had considered uncertainties of model input and distribution, and realized refined assessment. This study is the first report on probabilistic assessment of 3-MCPDEs and GEs in IFs, which also provided references for the formulation of related regulatory limits in China.
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RSC Advances
·
2023
·Vol. 13
·期 32
·22172-22184
·
IF 3.9
Chang Liu,Yue Xu,Haikuan Yuan,Guangxin Tian,Xiaolan Qin,Boxuan Lou,Xijian Liu,Lijuan Zhang,Jie Lu
In this work, the solubility of resmetirom (form A) was initially measured in heptane and seven alcohol solvents by gravimetric methods. Then, the transformation temperature between form A and ethanol solvate was determined at 333.76 K. Subsequently, some commonly used models were applied to fit the solubility data, and it was found that the modified Apelblat equation and the Jouyban–Acree–van't Hoff (J–A–V) model achieved the highest correlation accuracy for those in mono-solvents and heptane + propanol, respectively. And the average relative deviation (ARD) values of models were less than 0.5%, indicating a good agreement with the experimental results. Additionally, through density functional theory calculation and the analysis of solvent parameters, it was observed that hydrogen-bonding played primary roles in the dissolution process of resmetirom. The multiple factors such as the polarity of solvent, active site interaction, the molecular size and free volume all affect the solubility of resmetirom. Furthermore, by comparing the experimental and simulated infrared spectra of form A and two alcohol solvates, five characteristic bands were selected for quantification. Partial least squares regression (PLSR), a multivariate statistical analysis method, was used to extract quantitative information. The quantitative analysis model was established based on specific wavelength intervals, which were associated with inter-molecular interactions. Combined with PLSR, a new high-precision quantitative method was established to study the solid transformation process between form A and solvates. From 303.15 to 323.15 K, the rate of transformation from form A to methanol solvate or ethanol solvate was decreased with increasing temperature, revealing that the transformation process was driven by the solubility difference between form A and solvates under the studied conditions. This research will definitely afford necessary solubility data and solvent selection for the design of the crystallization process of resmetirom (form A) in industry, and provide basic data for the production of resmetirom (form A) in the pharmaceutical industry.
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ChemistrySelect
·
2023
·Vol. 8
·期 28
·e202301088
·
IF 2.1
Hui Zhou,Xiaoliang Sun,Wenming Guo,Tingting Bao,Yi Zhang,Chenxu Guo,Hanning Xiao,Hang Qin,Pengzhao Gao
Graphical [+] These authors contributed equally to this articleDurable CuO/ZnO/CeO 2 /ZrO 2 catalyst on SiC support for methanol steam reforming was prepared by the combination of inverse microemulsion method and precipitation method. The methanol conversion of the catalyst was still reached 98.8 % after 150 h, considerably higher than that of solution combustion method (70 %), without carbon deposition and pronounced sintering after the reaction. Durable CuO/ZnO/CeO 2 /ZrO 2 catalyst on SiC support for methanol steam reforming (MSR) was prepared by the combination of inverse microemulsion method and precipitation method which is termed as inverse microemulsion/precipitation method. The presence of Ce−O−Zr solid solution facilitated the production of oxygen vacancies and Ce 3+ species in the prepared CuO/ZnO/CeO 2 /ZrO 2 catalyst. Owing to the unique tiny reaction pool and the addition of precipitant for inverse microemulsion/precipitation method, the particle size of the prepared catalyst was principally between 2 and 6 nm, with an average size of 3.66 nm. Besides, the small particle size and the highly dispersed of Cu species boosted the reduction performance of the catalyst, enabling the reduction temperature to be only 201 °C. The methanol conversion of the reduced catalyst was still reached 98.8 % after 150 h, considerably higher than that of solution combustion method (70 %), without carbon deposition and pronounced sintering after MSR reaction.
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CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Chengming Wu,Quan Wang,Jifan Li,Chun-Ling Liu,Wen-Sheng Dong
Catalytic conversion of biomass-derived platform chemicals into bulk chemicals p -xylene (PX) is appealing yet challenging due to low catalytic efficiency and severe reaction conditions. In this work, we fabricated a series of phosphate-modified ZrO 2 /SBA-15 ( x P-Zr/SBA-15) via adjusting the addition of phosphoric acid, and used them for the catalytic conversion biomass-derived 2,5-dimethylfuran (DMF) and ethylene to PX. Because of the enhanced adsorption capability for the reactant molecules (DMF and ethylene) and the good synergistic effect between Brønsted acid sites (P-OH) and Lewis acid sites (Zr 4+ ), 30P-Zr/SBA-15 revealed an excellent catalytic performance in the selective conversion of DMF into PX. The DMF conversion was 98.5%, PX yield was 92.0% at 250 °C for 12 h, and the corresponding PX productivity was upto 50.5 mmol PX ·g cat −1 ·h −1 . The results are far superior to those obtained on most previously reported catalysts in the literature under similar reaction conditions. The kinetic study revealed that 30P-Zr/SBA-15 has a lower apparent activation energy for the tandem reaction including the Diels-Alder reaction (57.0 kJ·mo −1 ) and dehydration reaction (37.7 kJ·mo −1 ). Moreover, the 30P-Zr/SBA-15 catalyst exhibited the excellent recyclability and could be recycled at least six times without a significant loss of activity. On the basis of the temperature-programmed surface reaction of DMF and ethylene, a reasonable reaction mechanism was proposed.
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RSC Advances
·
2023
·Vol. 13
·期 50
·35689-35694
·
IF 3.9
Huandi Hou,Ting Wang,Baohuan Wang,Wenting Guo,Xiang Miao,Xin Liang
Co–Mo–S based catalysts have promising applications in both the hydrogen evolution reaction (HER) and hydrodesulfurization (HDS). Herein, Co–Mo–S catalyst and Co–Mo–S catalyst with and without NaBH4 modification have been successfully synthesized by a simple hydrothermal synthesis method. Co–Mo–S catalysts with NaBH4 modification show better catalytic activity towards both HDS and the HER. The phase purity, morphology, crystal structures and electron valence distribution of the catalysts with and without NaBH4 modification were studied by experimental characterizations and theoretical calculations. The catalysts without NaBH4 modification are mostly 2H-MoS2, while the catalysts without NaBH4 modification have 1T-MoS2, and 1T-MoS2 is exposed to more active sites, which will be conducive to the results of HDS performance of the catalyst. DFT calculations investigated the required activation energies of 1T-MoS2 and 2H-MoS2 for HDS and HER, respectively. The activation energy required for both HDS and H2 generation of 1T-MoS2 is significantly lower than that for the 2H-MoS2 structure.
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JOURNAL OF SUPERCRITICAL FLUIDS
·
2023
·
IF 3.9
Yu Dong,Qiuyang Zhao,Hui Jin,Yan Miao,Yanlong Zhang,Xuetao Wang,Liejin Guo
Hydrogen donation is the key to supercritical water upgrading of heavy oil, because it benefits light distillate production and inhibits condensation , but the mechanism is still unclear. In this work, an isotope tracing method, combined with Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy analyses, was used to elucidate the hydrogen donation mechanism in supercritical water upgrading of asphaltenes . In asphaltenes upgrading, it was found that the aliphatic carbon at the end of the side chain of asphaltene macromolecules could capture deuterium from supercritical heavy water via free radical reactions , and the deuteration ratio at this position was 11 %. For supercritical water upgrading of vacuum residue which is generally considered as a system of asphaltenes dissolved in maltenes, the existing maltenes enhanced hydrogen donation to asphaltenes. Further, a possible hydrogen donation pathway was proposed. This work provides an in-depth understanding of the hydrogen donation mechanism for supercritical water upgrading.
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Materials Today Communications
·
2023
·
IF 3.8
Mingchao Wang,Zhiji Zhou,Zilong Liang,Shaowen Du,Guoshuai Cai,Xiangjian Wang,Yunlei Zhou,Haijun Zhang
Hydromagnesite (HM) is a widely distributed primary natural carbonate mineral . To expand the application range of hydromagnesite and tap its fire-extinguishing potential, a new type of high-efficiency KHCO 3 @HM dry powder was prepared by coating potassium bicarbonate on the surface of hydromagnesite with a dip coating method. KHCO 3 @HM dry powder obtained a chemical inhibition effect through this method, and the fire extinguishing efficiency has been further improved. A series of tests were carried out to confirm the excellent physical and chemical inhibition effect of KHCO 3 @HM dry powder. Specific surface area tests showed that the specific surface area of KHCO 3 @HM dry powder (31.405 m 2 /g) was higher than NH 4 H 2 PO 4 dry powder (12.766 m 2 /g). Flowability tests showed that KHCO 3 @HM dry powder (0.04 g/s) achieved the same flowability as NH 4 H 2 PO 4 dry powder (0.04 g/s). Local oil basin fire experiments showed that the average fire extinguishing time of KHCO 3 @HM dry powder was shorter with less powder consumption. Under 0.2 MPa driving pressure, the fire extinguishing time of KHCO 3 @HM dry powder was 2.2 s faster than NH 4 H 2 PO 4 dry powder, and the dry powder consumption was 3.71 g less than NH 4 H 2 PO 4 dry powder. The cooling effect of KHCO 3 @HM dry powder (208 ℃) in 10 s was better than NH 4 H 2 PO 4 dry powder (157 ℃), and KHCO 3 @HM dry powder (399 ppm) showed a better smoke suppression effect than NH 4 H 2 PO 4 dry powder (545 ppm). The pyrolysis of KHCO 3 @HM dry powder reduced the fire temperature, diluted the oxygen concentration, and captured free radicals. The final pyrolysis products formed a thick oxide film to provide good heat insulation and asphyxiation effects. The excellent cooling, dilution, asphyxiation, and chemical inhibition mechanisms of KHCO 3 @HM dry powder were demonstrated, and finally achieved a comprehensive performance comparable to NH 4 H 2 PO 4 dry powder.
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