CHEMICAL PAPERS
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2022
·Vol. 76
·期 4
·2145-2152
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IF 2.146
Zhu Xingji,Kou Xinhui
We disclose a metal-free catalyst system of organic bases/protic acids for effective fully alternating copolymerization of cyclohexene oxide and phthalic anhydride. A series of commercial organic bases and protic acids were employed as binary catalysts, and the effects of different kinds and ratios of organic bases and protic acids were performed to find optimal conditions for achieving the highest catalytic performance. And our results indicated that DMAP/DPP showed higher activity (TOF = 574 h −1 at 140 °C) and perfectly alternating selectivity (ester > 99%), producing polymers with narrow polydispersity (Ð = 1.08 ~ 1.22). Moreover, analysis of the resultant polymers was confirmed by GPC, NMR spectra and MALDI-TOF MS techniques which revealed that P(PA- alt -CHO) polyester with well-defined alternating structure without formation of polyether and DMAP can act as an initiator in DMAP/DPP catalyst system, resulting more effective ring-opening alternating copolymerization. However, trace amount of phthalic acid as an impurity in the system also acted as a bifunctional initiator influencing the molecular weight of the polymer. In addition, the DMAP/DPP catalytic system remained stable at high temperature and the development of this simple catalytic process provided a new chance to exploit in organocatalyzed polymerization.
研究领域:
高分子化学
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有机催化
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DOI
高影响因子
Journal of the American Chemical Society
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2019
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IF 14.695
Cheng-Jian Zhang,Tian-Cheng Zhu,Xiao-Han Cao,Xin Hong,Xing-Hong Zhang
The synthesis of poly(thioether), a highly desired sulfur-containing polymer, is still a key challenge. Herein, we report a simple and facile approach to poly(thioether)s by closed-system one-pot reaction of carbonyl sulfide (COS) and epoxides. This route underwent the coupling reaction of COS with epoxides, followed by decarboxylative ring-opening polymerization (ROP) of the generated mixed cyclic thiocarbonates with releasing of CO2 and a little bit of COS. Organic base was used as catalyst and initiator in the two steps, respectively. The oxygen/sulfur exchange reaction was driven by successive regioselective elementary reactions and spontaneous releasing of CO2 (COS), leading to the sulfur atom of COS transferring to poly(thioether)s, which was well demonstrated by DFT studies. This work provides an easy-to-handle, metal-free route to poly(thioether)s bearing diverse structures by using readily available chemicals.
研究领域:
高分子化学
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材料科学
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DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2023
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IF 5.2
Hao Deng,Ziqi Chen,Yuanzhi Chen,Jie Mei,Wanjie Xu,Laisen Wang,Dong-Liang Peng
Solvothermal synthesis offers an important approach to prepare nickel particles with high crystallinity and low agglomeration. In this study, submicron nickel particles are prepared by a solvothermal approach involving alcohol reduction with the assistance of different types of organic bases. The influences of the types of organic bases and solvents, and the amount of organic bases on the particle size and morphology of nickel are studied. It is found that an organic base with a stronger alkalinity is able to generate nickel particles with smaller size. Smaller nickel particles are also prone to be obtained from solvents with a stronger reducing ability. Moreover, the formation mechanism of nickel particles is investigated. It is found that the nickel precursor and OH − form nickel layered hydroxide salts at the initial stage, and then the nickel layered hydroxide salts gradually dissolve to form nickel particles. Magnetic measurement reveals the morphology-dependent magnetic properties . Although the sample which has the smallest size exhibits a relatively high coercivity , samples which have a rather large particle size but consist of smaller primary nanoparticles also show relatively high coercivity values.
研究领域:
材料科学
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化学
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产品关联
DOI
高影响因子
DESALINATION
·
2023
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IF 9.9
Huiying Ding,Yuting Liu,Zhong Zhang,Yanjun Cheng,Jiahao Mo,Lu Elfa Peng,Cheng Xiang,Hongchang Pei,Xianhui Li
In the synthesis of the polyamide nanofiltration (NF) membrane, the hydrogen chloride is a by-product generated at the organic interface from interfacial polymerization , which reduces the reactivity of amine monomers due to protonation . Herein, a strategy of addition of an organic base in the organic phase to neutralize the H + was reported. The performances of the membranes produced using three organic bases with different chain lengths were explored. The results showed that the organic base neutralized the H + and promoted the rate of interfacial condensation reaction , which facilitated the formation of a dense and thin polyamide layer. Moreover, compared to control membrane, the membrane modified by organic base exhibited higher water permeance without sacrificing salt rejection. Higher diffusion rate of HCl through PES substrate compared to NF membrane indicated that HCl diffusion was mainly affected by the resistance of polyamide layer. Molecular simulations demonstrated that triethylamine (TEA) has lower energy barrier of neutralization and higher reaction heat in comparison with tripropylamine and N, N-diisopropylethylamine. The TEA modified membrane thereby displayed a permeance up to 24.3 L h −1 m −2 bar −1 and Na 2 SO 4 rejection of 98.8 %. This work provided a promising strategy for the regulation of interfacial polymerization in achieving high-permselective nanofiltration.
研究领域:
材料科学
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环境工程
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产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
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2017
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IF 4.857
Lei Mei,Cong-zhi Wang,Liu-zheng Zhu,Zeng-qiang Gao,Zhi-fang Chai,John K. Gibson,Wei-qun Shi
The reaction of uranyl nitrate with terephthalic acid (H2TP) under hydrothermal conditions in the presence of an organic base, 1,3-(4,4′-bispyridyl)propane (BPP) or 4,4′-bipyridine (BPY), provided four uranyl terephthalate compounds with different entangled structures by a pH-tuning method. [UO2(TP)1.5](H2BPP)0.5·2H2O (1) obtained in a relatively acidic solution (final aqueous pH, 4.28) crystallizes in the form of a noninterpenetrated honeycomb-like two-dimensional network structure. An elevation of the solution pH (final pH, 5.21) promotes the formation of a dimeric uranyl-mediated polycatenated framework, [(UO2)2(μ-OH)2(TP)2]2(H2BPP)2·4.5H2O (2). Another new polycatenated framework with a monomeric uranyl unit, [(UO2)2(TP)3](H2BPP) (3), begins to emerge as a minor accompanying product of 2 when the pH is increased up to 6.61, and turns out to be a significant product at pH 7.00. When more rigid but small-size BPY molecules replace BPP molecules, [UO2(TP)1.5](H2BPP)0.5 (4) with a polycatenated framework similar to 3 was obtained in a relatively acidic solution (final pH, 4.81). The successful preparation of 2–4 represents the first report of uranyl–organic polycatenated frameworks derived from a simple H2TP linker. A direct comparison between these polycatenated frameworks and previously reported uranyl terephthalate compounds suggests that the template and cavity-filling effects of organic bases (such as BPP or BPY), in combination with specific hydrothermal conditions, promote the formation of uranyl terephthalate polycatenated frameworks.
研究领域:
化学
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材料科学
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DOI
高影响因子
ACS Applied Polymer Materials
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2025
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IF 4.7
Wenjun Lu,Baiwang Sun
Trifluoroacetic acid (TFA) is a ubiquitous and persistent environmental pollutant with significant environmental and human health impacts. To the best of our knowledge, no study has reported the use of porous organic polymers to adsorb TFA vapor. In this study, we successfully synthesized a polymer (POPSP-4) that exhibits both physical and chemical adsorption for efficient TFA capture, and physical adsorption can occur at the sulfur sites. With the assistance of organic bases, the adsorption capacity of the polymer increases from 2.3 g·g–1 to over 4 g·g–1 in 1 h and effectively prevents the escape of TFA from the polymer. This study presents a promising methodology for the design and synthesis of porous organic materials, specifically for the efficient capture of TFA vapor.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
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2018
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IF 6.759
Jun Tang,Qi Zhang,Kecheng Hu,Shixiong Cao,Shouhao Zhang,Jianli Wang
A novel magnetic Pickering interfacial catalyst (MPIC) was developed and used for highly effective and clean production of biodiesel. The catalyst was synthesized by immobilization of 1,1,3,3-tetramethylguanidine (TMG) onto the shell of Fe 3 O 4 @Chloromethyl PS nanohybrids. The resultant Fe 3 O 4 @PS-TMG was measured by transmission electron microscope (TEM), dynamic lighting scattering (DLS), Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA), thermogravimetric analysis (TG), contact angles (CA). The results showed that surface property and TMG loading of catalyst can be finely regulated via adjusting the feeding of TMG. Fe 3 O 4 @PS-TMG with amphiphilic surface can stabilize soybean oil-in-methanol Pickering emulsion, which would offer large interfacial area and surface enrichment of reactants, leading to a significant enhancement of such liquid-liquid (L-L) biphasic reaction with high mass transfer resistance. Furthermore, the MPIC can be facile separated from the mixture of reaction by magnet, and showed excellent stability over 5 recycles.
研究领域:
化学工程
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材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2025
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IF 9
Zhe Liu,Shiyu Zhang,Tao Wu,Baoyu Wang,Wangluo Liu,Hao Deng,Yifan Li,Jingtao Wang,Runnan Zhang,Zhongyi Jiang
Developing advanced nanofiltration membranes for molecular separation in organic solvents is imperative. Microporous polyamide membranes have attracted much attention due to high porosity which can facilitate solvent permeation. However, manipulating the interfacial polymerization of twisted monomers to simultaneously achieve high permeance and precise molecular sieving capacity remains challenging. Herein, we propose using organic base to regulate the interfacial polymerization of tetra-(4-aminophenyl) methane (TAM) and trimesoyl chloride at the alkane/ionic liquid interface. Triethylamine (TEA) is incorporated with TAM and can effectively suppress the protonation of TAM amino groups. Accordingly, the reactivity of TAM monomer is enhanced, leading to higher crosslinking degree of the resultant membrane with the harmonic amide bond density increased from 3.78 mmol g −1 to 4.31 mmol g −1 . The resultant ultrathin microporous polyamide membrane exhibits remarkable solvent permeance of 135.81 L m −2 h −1 bar −1 for ethanol and 311.89 L m −2 h −1 bar −1 for methanol, as well as sharp molecular sieving property with the difference between MWCO (603 Da) and MWRO (518 Da) of only 85 Da, outperforming the state-of-the-art membranes. This research opens a novel pathway to fabricating high-performance microporous polyamide membranes for organic solvent nanofiltration.
研究领域:
材料科学
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分离技术
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纳米科技
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2017
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IF 6.216
Guoqiang Wu,Zhengguo Lin,Liang Li,Lei Zhang,Yanping Hong,Wenjun Wang,Chao Chen,Yan Jiang,Xianzai Yan
An efficacious approach to improve the catalytic performance of titanium silicalite-1 (TS-1) catalysts in epoxidation of allyl chloride with hydrogen peroxide has been developed. A series of modified TS-1 catalysts were prepared by corroding the classic TS-1 catalyst with different concentrations of tetrapropyl ammonium hydroxide (TPAOH) under controlled conditions. The resultant catalyst samples were characterized by XRD, ICP, N 2 -adsorption, FT-IR, UV–vis, SEM and TEM. The catalytic activity of the modified TS-1 catalysts is significantly improved, which could be attributed to the increase of the mesopore volume and pore diameter and decrease of the diffusion limitation but without obvious changes of the framework structure, framework Ti content, the outer surface shape and crystal size of the modified TS-1. Furthermore, the kinetics of the epoxidation of allyl chloride over TS-1-0.05 catalyst was also systematically studied, the apparent orders of reaction with respect to H 2 O 2 and allyl chloride are 0.68 and 0.62, respectively, and the activation energy of the epoxidation reaction on the TS-1-0.05 catalyst is 57.4 kJ mol −1 .
研究领域:
化学工程
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催化科学
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产品关联
DOI
高影响因子
DESALINATION
·
2024
·
IF 8.3
Lin Yu,Jia-Yue Dai,Zhen-Liang Xu,Yin-Xin Fang,Rui Jia,Yong-Jian Tang
Covalent Organic Frameworks (COFs) composite nanofiltration (NF) membrane has high permeation flux and rejection. However, the reaction rate of COFs is relatively slow. Adding acid catalyst is a common method to shorten reaction time. However, the dissatisfactory synthesis rate will lead to irregular structure of COFs materials. In this work, it is the first time to use organobase as a catalyst to prepare COFs composite membrane. The COFs structure will be optimized and the membrane performance can be enhanced. The prepared TpPa-PIP membrane compared with acid catalyzed TpPa-HAc membrane has better permeability, permeance of 89 L m −2 ·h −1 ·bar −1 and CR rejection of 99.54 %. This improvement is because of the TpPa-PIP intermediate made slower reaction speed that improves the overall regularity and crystallinity of COFs. Therefore, it is better method for broadening the application of organobase-catalyzed in preparing membranes.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
ChemistrySelect
·
2022
·Vol. 7
·期 35
·e202202475
·
IF 2.307
Zhiqiang Zhang,Qingyan Chu,Yuan Sun,Hao Wang,Deming Lu,Yuying Liu,Haibin Xiao,Ping Wang,Hongyou Cui,Ming Wang
Graphical The hierarchical TS-1 with abundant mesopores was prepared by TPAOH/TIPA treatment, which was applied to the reaction of the ammoximation-oxidation of acetone to 2-nitropropane. Hierarchical TS-1 catalyst performed excellent reusability and catalytic activity with 97.5 % conversion and 96.8 % selectivity. The novel technology for clean and mild synthesis of nitroalkanes has been developed. Modified TS-1 catalysts for the acetone ammoximation-oxidation reaction were prepared by post-treating TS-1 with different concentrations of TPAOH/TIPA, and the effects of alkali treatment on the catalytic performance were systematically investigated. The techniques such as XRD, SEM, TEM and N 2 sorption were used to characterize the catalyst samples, which exhibited that the introduction of alkali increased the volume and quantity of mesopores, while there was no obvious influence on the framework structure and titanium content in the framework. And the improvement in catalyst performance after alkali treatment was attributed to the increase of mesopores and the decrease in diffusion limitation. In addition, three common ammoximation catalysts (Ti-MOR, Ti- MWW and TS-1) were systematically investigated in this reaction. Ti-MOR showed superiority in the ammoximation to oxime, while TS-1 displayed the best catalytic performance in the ammoximation oxidation of ketones to nitroalkanes. It was indicated that modified TS-1 could be a promising catalyst for the ammoximation-oxidation reaction of acetone.
研究领域:
催化化学
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绿色合成
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ChemCatChem
·
2022
·Vol. 14
·期 18
·e202200704
·
IF 5.497
Fan Song,Shuangshuang Cen,Cong Wan,Lijun Wang
Graphical This work presented a stable and high-efficient synergistic catalytic system based on Au nanoparticle anchored in organic base group-grafted silica aerogel for oxidative esterification of furfural with H 2 O as a by-product, which has excellent resistance to deactivation induced by product adsorption and leaching of the components, and can almost completely convert furfural to alkyl furoate in 7 cycles. Inorganic metal (hydro)oxide supports with appropriate basicity or acid-base properties can promote oxidative esterification of furfural over Au-based catalysts, however, they suffer the problems of easy inactivation induced by the leaching of the components in this water-producing reaction and the shield of catalytic sites by product adsorption. In this work, we report efficient and stable oxidative esterification of furfural over Au nanoparticles anchored in aminopropyl-grafted silica aerogel. The support is insoluble and possesses no strong Lewis acid sites to adsorb oxygen-containing products or intermediates, reducing the probability of catalyst deactivation induced by adsorption. In 7 cycles of reactions, the catalyst maintained the initial activity without any treatments, the yields of alkyl furoate kept above 98 %, and no agglomeration and leaching of Au occurred. Moreover, the roles of Au, alkyl chain, −NH 2 group and Au-activated O species in reactions were clarified, and accordingly, a possible catalytic mechanism involving oxidative dehydrogenation was given.
研究领域:
化学工程
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催化材料
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）