INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2016
·
IF 2.567
Xuan Zhang,Rui Zhang,Haiyan Liu,Xianghai Meng,Chunming Xu,Zhichang Liu,Peter A. A. Klusener
Pyridine can act as a basic indicator for both Brønsted and Lewis acids forming different types of bonds. Infrared spectroscopy, in combination with 27Al NMR spectroscopy, was employed to study the interaction mechanism of pyridine and chloroaluminate ionic liquids (ILs). The acid type, acid amount, acidity, and even activity of chloroaluminate ILs could be determined. An in situ infrared complexometric titration was developed as a quantitative characterization method for determining the different acidities and catalyst activity. The method is based on the principle that Lewis acidic chloroaluminate [Al2Cl7]− anion reacts with pyridine to form the [AlCl4]− anion and pyridine–AlCl3 ([PyAlCl3]) complexes, while the Brønsted acid forms a pyridinium salt. Both product types showed characteristic shifts of the pyridine peaks in the infrared spectrum.
研究领域:
化学
·
催化科学
✓ 已验证
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2024
·
IF 3.9
Limin Ren,Yuxuan Xiao,Rameswar Bhattacharjee,Jingjing Wu,Pengyi Tang,Stavros Caratzoulas,Changgong Meng,Qiang Guo,Michael Tsapatsis
Graphical Bifunctional Ti-B-Beta zeolite is demonstrated to be an efficient catalyst for sorbose production via glucose isomerization. Ethanol directs the conformation of glucose, facilitating its selective isomerization to sorbose and enables this isomerization to surpass the thermodynamic equilibrium limit by engaging in reactions with the resultant sorbose. D-Glucose-to-L-sorbose isomerization on Lewis acidic zeolite is a highly attractive avenue for sorbose production. But the L-sorbose yield is limited by the competing D-glucose-to-D-fructose isomerization and reaction equilibrium. In this work, it is suggested that ethanol directs the glucose conformation for selective D-glucose-to-L-sorbose isomerization. It also reacts with the produced L-sorbose to form ethyl-sorboside, which allows the D-glucose-to-L-sorbose isomerization to proceed beyond the thermodynamic equilibrium limit. It is shown that a bifunctional zeolite Beta containing framework titanium (Ti) and boron (B) is a selective catalyst for this tandem reaction: Lewis acidic framework Ti catalyzes the D-glucose-to-L-sorbose isomerization via an intramolecular 5,1-hydride shift process as confirmed by isotopic tracing experiments followed by 13 C-NMR, while weak Brønsted acid framework B selectively promotes the sorbose ketalization with ethanol. A remarkably high yield of L-sorbose with a high fraction of sugar (>95 %: 27 % unreacted glucose, 11.4 % fructose, 57 % sorbose) was obtained after the mixture produced in ethanol was hydrolyzed.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
·
IF 3.375
Xue Wang,Jing Zeng,Xingmei Lu,Jiayu Xin,Suojiang Zhang
Butene plays an essential role in the area of petrochemical industry. The production of butene from the biomass-derived platform molecule γ-valerolactone (GVL) is of great interest. GVL decarboxylation reaction occurred under high temperature because the catalytic activity of the catalysts used before was not efficient for this reaction. In this work, beta zeolite with Si:Al = 5 was synthesized and used for GVL decarboxylation. It exhibited a higher catalytic performance than other commercial zeolites due to a large number of Lewis acid sites and relatively large micropore size. At 300 °C, 99.5% GVL conversion and 98% butene yield were obtained after condition optimizing. For further research, the influence of the Brønsted/Lewis acid ratio was investigated, and it turned out that Lewis acid was more active than Brønsted acid in crystalline material on GVL decarboxylation for the first time.
研究领域:
石油化工
·
催化
·
绿色化学
·
可再生能源
✓ 已验证
DOI
高影响因子
JOURNAL OF POLYMER SCIENCE
·
2020
·Vol. 58
·期 6
·803-810
·
IF 0
Jinbo Zhang,Lebin Wang,Shaofeng Liu,Zhibo Li
The synthesis of high-molecular-weight polyesters via the ring-opening alternating copolymerization (ROAC) of cyclic anhydrides and epoxides using organocatalysts remains a major challenge. In this context, the organic cyclic trimeric phosphazene base ( CTPB ) was used as an efficient catalyst for the ROAC of phthalic anhydride (PA) with epoxides. It was found that the activity and PA conversion dramatically increased with the addition of triethyl borane (TEB) as a cocatalyst, even a small amount of TEB, for example, 5 mol % relative to CTPB . The molecular structures of obtained polyesters were characterized by nuclear magnetic resonance ( 1 H NMR, 13 C NMR) and matrix-assisted laser desorption/ionization time-of-flight (MALDI TOF), which demonstrated the formation of perfectly alternating polyesters with unimodal and narrow molecular weight distributions. Different molecular weight polyesters (up to 118.5 kg mol −1 ) were facilely prepared by reducing the loading of CTPB and TEB, while the polymerizations were fast (turnover frequency, TOF up to 500 h −1 ). Thermal analysis of the resulting polymers indicated that the alternating polyesters were amorphous, and their T g s increased with the increment of molecular weights. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58 , 803–810 Graphical Organic cyclic trimeric phosphazene base ( CTPB ) with triethyl borane (TEB) as a co-catalyst (even 5 mol% relative to CTPB ) is highly active toward ring-opening alternating copolymerization (ROAC) of phthalic anhydride (PA) with various epoxides. The polymerizations are fast (TOF up to 500 h −1 ), and the resulting polymers have high molecular weights (up to 118.5 kg mol -1 ) and perfect alternating sequences (ester > 99%).
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
RSC Advances
·
2019
·Vol. 9
·期 27
·15229-15237
·
IF 3.049
Xiaoning Ren,Zhixin Zhang,Yehong Wang,Jianmin Lu,Jinghua An,Jian Zhang,Min Wang,Xinkui Wang,Yi Luo
Understanding of surface active sites (SAS) of CeO2 is crucial to its catalytic applications. In the present study, we have employed capping experiments, DFT calculations, and spectroscopic characterization to study pristine CeO2 catalyst. We find that multiple SAS coexist on the CeO2 surface: oxygen vacancies as redox sites and the coordinately unsaturated Ce cations near the oxygen vacancies and the neighboring oxygen ions as Lewis acid–base sites. Dimethylsulfoxide (DMSO), pyridine, and benzoic acid are utilized to cap the redox sites, Lewis acid sites, and base sites, respectively. Selective capping on the redox site does not have much effect on the acid–base catalysis, and vice versa, indicating the distinct surface proximity and independent catalysis of these SAS. We draw attention to a relationship between the well-known redox sites and the surface Lewis acid and Lewis base pairs on CeO2 surface, which are responsible for driving various heterogeneous catalytic reactions.
研究领域:
材料科学
·
催化化学
✓ 已验证
DOI
PubMed
高影响因子
ChemistrySelect
·
2024
·Vol. 9
·期 31
·e202400459
·
IF 1.9
Yongyu Huang,Xinxin Xia,Pei Li,Yaqian Gu,Hua Song,Cuiqin Li,Feng Li
Graphical Hydrogenation of furfural to furfuryl alcohol under H 2 and N 2 atmosphere are studied over PdCu/ZrPO with metal and Lewis acid sites. The PdCu metal active sites of PdCu/ZrPO involve both direct hydrogenation and transfer hydrogenation activities, and the Zr 4+ −O 2− Lewis acid-basic pairs of ZrPO have transfer hydrogenation activity. Hydrogenation of furfural to furfuryl alcohol under H 2 and N 2 atmosphere was studied over zirconium phosphonate (ZrPO)-supported PdCu (PdCu/ZrPO) catalysts. The direct hydrogenation and transfer hydrogenation activities of PdCu metal active sites and the transfer hydrogenation activity of Zr 4+ −O 2− Lewis acid-basic sites were investigated, respectively. The size and the distribution of Cu particles could be adjusted by altering the P/Zr molar ratio. Bimetallic PdCu could enhance the acidity of the PdCu/ZrPO catalysts, and improve the ratio of Lewis/Brønsted acid, which led to an increase in the transfer hydrogenation activity of Lewis acid-basic pairs. The electronic effect between Pd and Cu promoted furfural to absorb onto electron-deficient Cu through η1(O)-aldehyde configuration, which contributed to the direct hydrogenation and the transfer hydrogenation at metal active sites. Especially, the adsorption and dissociation of H 2 in electron-rich Pd were promoted, which significantly improved the direct hydrogenation activity.
研究领域:
催化化学
·
能源化学
✓ 已验证
DOI
高影响因子
GREEN CHEMISTRY
·
2017
·Vol. 19
·期 16
·3869-3879
·
IF 9.125
Shurong Wang,Yuan Zhao,Haizhou Lin,Jingping Chen,Lingjun Zhu,Zhongyang Luo
For the purpose of building a green reaction system to produce furfural (FF), the conversion of two important pentoses from hemicellulose, namely xylose and arabinose, was investigated in an aqueous reaction system including a Lewis acidic ionic liquid as a catalyst and renewable γ-valerolactone (GVL) as a co-solvent. The results showed that the introduction of GVL greatly improved the reactivity of pentose and inhibited the secondary decomposition reaction of FF compared to a pure-water reaction system. NMR analysis suggested that the composition of pentose conformers was greatly altered towards a reactive distribution. The highest FF yields were 79.76% (from xylose) and 58.70% (from arabinose), which were obtained at 140 °C. The influence of reaction parameters on pentose conversion was also studied. A comparison between different reaction conditions suggested that arabinose had less reactivity than xylose, leading to its lower conversion rate and FF yield. Furthermore, xylan and real biomass materials were tested in the proposed reaction system, and decent FF yields of up to 69.66% (from xylan) and 47.96% (from corn stalk) were obtained.
研究领域:
生物化学
·
绿色化学
✓ 已验证
DOI
高影响因子
Sustainable Energy & Fuels
·
2020
·Vol. 4
·期 10
·5327-5338
·
IF 5.503
Meng Xia,Wenjie Dong,Zheng Shen,Shaoze Xiao,Wenbo Chen,Minyan Gu,Yalei Zhang
In the catalytic transformation of biomass into valuable chemicals, it is extremely important to inhibit undesirable reactions to increase the yield of target products. In this study, the introduction of indium and tin into Beta zeolites promoted the transformation of glucose into lactic acid with a high yield of 53%. Selective experiments and a developed kinetic model confirmed the sensitivity of the main reaction rate to the action of tin, including those of the isomerization and retro-aldol condensation reactions, and shielding of the side reactions by indium. An in-depth analysis of the catalyst acidity showed that weak Lewis acidity in the indium and tin species promoted the main reaction steps, whereas the decreased amount of strong Lewis acidity by introduction of indium into the Sn-Beta catalyst suppressed the side reactions. The coupling of multifunctional active sites provides a new strategy for addressing challenges in commercial lactic acid production.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 12
·6877-6882
·
IF 10.733
Yuanyuan Zhao,Yudi Wang,Jialong Duan,Xiya Yang,Qunwei Tang
Substitution of Pb2+ sites with smaller isovalent ions has been regarded as an effective strategy to optimize the crystal lattice of organic–inorganic hybrid perovskites such as releasing lattice strain, increasing the formation energy of vacancies and tuning the bandgap energy distribution. We report here the compositional engineering of the inorganic CsPbBr3 perovskite by doping divalent hard Lewis acids (Mg2+, Ca2+, Sr2+ and Ba2+) and their application in all-inorganic perovskite solar cells free of hole transporting layers and precious metal electrodes. By optimizing the doping dosage, a maximal power conversion efficiency as high as 9.63% is achieved for a CsPb0.97Sr0.03Br3 based photovoltaic device, mainly attributed to the enlarged grain sizes and suppressed formation of point defect (vacancies) within perovskite films, therefore reducing the photocurrent loss within modules. Furthermore, the unencapsulated Sr-containing solar cell shows ultrastability comparable to that of state-of-the-art CsPbBr3 perovskite solar cells under persistent attack in 80% relative humidity over 800 h. The increased efficiency and improved stability demonstrate all-inorganic perovskite solar cells with divalent hard Lewis acid doped CsPbBr3 perovskites to be a new frontier for thin-film photovoltaics.
研究领域:
材料科学
·
能源技术
·
光伏器件
✓ 已验证
DOI
高影响因子
AICHE JOURNAL
·
2013
·Vol. 59
·期 8
·2966-2976
·
IF 2.493
Jiajun Gao,Xingyu Chen,Nannan Ren,Wenjiao Wu,Chunxi Li,Hong Meng,Yingzhou Lu
Excellent desulfurization is achieved via reactive adsorption using Friedel-Crafts acylation materials, that is, acylating reagents and Lewis acids, such as acetyl chloride (AC) and AlCl 3 , being named as acylation desulfurization (ACDS). For model oil, thiophenic compounds, namely, dibenzothiophene, benzothiophene, and thiophene, are removed completely by AC–AlCl 3 within 30 min at room temperature. In this process, thiophenic compounds are acylated by AC under the catalysis of AlCl 3 , and the acylated derivatives are stronger base than original ones due to incorporation of O-containing carbonyl group (CO) and, thus, adsorbed more easily by AlCl 3 via Lewis acid–base complexation. Further, ACDS mechanism is identified by acylated product characterization and quantum chemistry calculation. Satisfactorily, ACDS is still effective for toluene-rich and real oils, and real oil quality is improved with desulfurization proceeding. © 2013 American Institute of Chemical Engineers AIChE J , 59: 2966–2976, 2013
研究领域:
化学工程
·
石油加工
·
催化化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Lin Sun,Yu Liu,Ming Yan,Qingjun Yang,Xiaoying Liu,Weidong Shi
The ideas of high effective specific surface area, multi-component and multi-phase synergistic are introduced to construct high-performance and high-stability electrodes. After etching and exchanging with Lewis acid (nickel ion) and annealing selenization, the hierarchical multi-phase Ni x Co 1-x Se 2 /carbon–nitrogen frameworks (CNFs, Zeolitic-Imidazolate-Framework-L derivatives) on CoO is synthesized. After systematic research, it is found that the concentration and reaction time of the Lewis acid and selenization conditions can directly affect the structure and composition (bimetal) of the electrode. In the optimal electrode, CNFs with the larger effective specific surface area can fully expose the active material to the electrolyte, the bimetal synergy (Ni-Co), and the multiphase synergy ((Ni, Co)Se 2 and CoSe 2 ) can effectively enhance the performance. The anode demonstrates a high mass-specific capacity of 207.8 mAh g −1 . A hybrid supercapacitor (Ni x Co 1-x Se 2 /CNFs/CoO@CC//activated carbon) is fabricated and displayed superior performance and stability: high energy density (45.0 Wh kg −1 , 800.0 W kg −1 ), and a cycle retention rate of 98.0% (12,000 cycles). LEDs in parallel were lit up by the devices, showing their practical value and potential.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
LANGMUIR
·
2022
·
IF 4.331
Yuqing Ye,Yuan Li,Jie Wang,Shuai Yuan,Xiaojun Xu,Xinning Zhang,Junwen Zhou,Bo Wang,Xiaojie Ma
Environmentally persistent free radicals (EPFRs) have been recognized as one of the important emerging contaminants with biological toxicity, environmental persistence, and global mobility. Previous studies have identified the catalytic role of surface metal oxides in EPFRs formation and illustrated the metal-dependence of EPFRs by studying on various metal oxide nanoparticles and single crystals. However, there is still lack of an understanding on the formation of EPFRs from the point of view of metal sites. Various factors (e.g., crystalline phases and surface species) of metal oxides are regarded to contribute to the generation of EPFRs, which present profound difficulties for scientists to tease apart the impact of metal type. Herein, a laboratory investigation, in terms of the acidity and oxidation strength of metal cations, was conducted by selecting metal-variable isostructural metal–organic frameworks as material platforms. Specifically, we evaluated EPFRs generation on MIL-100(M) (M = Al, Cr, Fe) from chlorine-substituted phenol vapor and catechol under thermal conditions. It is found that high Lewis acidity of metal sites is crucial for capturing the above two phenolic precursors, activating the O–H bond and promoting EPFRs formation. Radical species with half-life as long as 70 days were generated on MIL-100 rich in 5-fold coordinated Al3+ sites. The unpaired electron spin density donation was further confirmed by using 27Al solid-state nuclear magnetic resonance spectroscopy. Despite their higher oxidation power than Al3+, the exposed Cr3+ and Fe3+ sites show undetectable catalytic activity for the formation of EPFRs, because of their insufficient Lewis acidity. Our results suggest that the surface species rather than Lewis acid sites may be a major contributor to the formation of EPFRs on metal oxides like Fe2O3.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）