MATERIALS CHEMISTRY AND PHYSICS
·
2021
·
IF 4.094
Jinkai Lu,Shaoqing Liu,Aihao Xu,Lijian Jin,Hanwen Chi,Ying Li,Bin Li,Lihui Dong,Minguang Fan
3–5 μm ionic liquid polymer microspheres (TBB-Bpy) were synthesized with bipyridine and tetrabromotoluene through alkylation reaction and simple solvothermal method, and then a variety of alcohol amine, imidazole or pyridine was grafted onto the TBB-Bpy. And the catalytic activity of different supported ionic liquids was explored. After comparative experiments, ionic liquid polymer microspheres grafted with pyridine (TB-Py) were the most active catalysts for the synthesis of cyclic carbonates from epoxides and CO 2 . Morphology, structure, and stability of catalysts was explored by a variety of characterization methods (FT-IR, SEM, XPS, EA , and TGA). And various factors that affect the catalytic efficiency of TB-Py be researched, such as reaction temperature, pressure, catalyst dosage and reaction time. The selectivity and yield be analysis and detection by gas chromatography (GC-2010 Plus), under the reaction condition of 0.15 g catalyst, 80 °C, CO 2 pressure of 1 Mpa, and 24 h, the yield of propylene carbonate can reach 96.52%. After 5 times of repeated use, the yield still has more than 90%, and the selectivity was always above 99%. It was easy to separate and reused after the reaction, and a reasonable reaction mechanism was proposed.
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高影响因子
Foods
·
2021
·Vol. 10
·期 8
·1755
·
IF 4.35
Zhili Sheng,Junmei Liu,Bao Yang
Astragalus membranaceusis a functional food with multiple bioactivities. It presents differentiated health benefits due to origins. Polysaccharides (APS) are the leading bioactive macromolecules ofA. membranaceus, which are highly related to its health benefits. However, the effect of origin on the structural characteristics of APSs remains unclear. In this work, polysaccharides from four origins were isolated and identified by NMR. The results showed APSs of four origins had identical monosaccharide composition and glycosidic linkage. Rhamnogalacturonan II pectins and α-(1→4)-glucan were the dominant polysaccharides. However, the level of methyl ester in pectins varied to a large extent. The molecular weight profiles of APSs were also different. Inner Mongolia APS had the largest percentage of 20–40 kDa polysaccharides. Molecular weight and methyl ester level were two important parameters determining the difference of APSs from four origins. These results were helpful to recognize the origin-related quality ofA. membranaceus.Keywords:glycosidic linkage;monosaccharide composition;NMR;pectin
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PubMed
高影响因子
MICROCHEMICAL JOURNAL
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2021
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IF 4.821
Liyuan Zhang,Runzhong Yu,Yingbo Yu
The gas chromatography-mass spectrometry was used to isolate and identify metabolites of non-transgenic and Bacillus thuringiensis transgenic maize. The non-targeted metabolomics technique was used to analysis the metabolic pathway and mechanism of two kinds of maize. The methanol was used as extractant and the N,O-bis(trimethylsilyl) trifluoroacetamide was used as derivatization reagent. 38 kinds of metabolites were isolated and identified from non-transgenic maize, and 61 kinds of metabolites were isolated and identified in Bacillus thuringiensis transgenic maize. The specific metabolites between non-transgenic and Bacillus thuringiensis transgenic maize were analyzed. The metabolic pathway of specific metabolites was analyzed by KEGG annotation. The metabolic mechanism of non-transgenic maize and Bacillus thuringiensis transgenic maize was explored. The result indicated there were more metabolites involved in metabolic pathways in Bacillus thuringiensis transgenic maize than in non-transgenic maize, and tricarboxylic acid cycle and energy metabolism pathways of Bacillus thuringiensis transgenic maize are found to be higher than that of non-transgenic maize. The metabolic pathway of Bacillus thuringiensis transgenic maize conforms to the biological activity law.
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ACS Sustainable Chemistry & Engineering
·
2021
·
IF 8.198
Wen Li,Kuncan Wang,Guowu Zhan,Jiale Huang,Qingbiao Li
Transformation of CO2 with the help of green hydrogen (prepared from renewable energy) into valuable light olefins (C2=–C4=) is a promising route for utilizing the carbon resource in CO2. Currently, most of the reported bifunctional catalysts for CO2 hydrogenation to light olefins follow a methanol-mediated route that adopts SAPO-34 as the zeolite component. Although ZSM-5 has been widely used in the methanol to propylene process using fixed bed reactors due to high shape-selective property and long lifetime, ZSM-5-based bifunctional catalysts have seldomly been used for CO2 hydrogenation to light olefins. Herein, we proposed a novel synthetic strategy for bio-ZSM-5 with mild acid strength and relatively low acid density using the natural rice husk as a template. The bio-ZSM-5 was integrated with ZnZrOx solid solution nanoparticles, and the derived ZnZrOx&bio-ZSM-5 catalysts exhibited a high C2=–C4= selectivity of 64.4% and total C2–C4 selectivity of 94.5%, but relatively low CH4 selectivity (5.5%) and aromatic selectivity (<1%). The post-modified ZnZrOx&bio-ZSM-5 catalysts further enhanced the catalytic stability with less coke deposition and regulated the ethylene to propylene ratio in light olefin distribution. Furthermore, *CHxO was found to be the key intermediate formed on the ZnZrOx surface and was transferred to the Brønsted acid sites in the bio-ZSM-5 for the subsequent conversion to light olefins, as confirmed by in situ DRIFTS and chemical trapping mass spectrometry.
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POLYMERS FOR ADVANCED TECHNOLOGIES
·
2021
·Vol. 32
·期 9
·3740-3749
·
IF 3.665
Tianwen Dai,Shuaiwei Yuan,Huawei Zou,Pengbo Liu
A kind of four-functional epoxy resin containing tertiary ester groups (FETE) was designed and synthesized by two-step reaction: first, the nucleophilic substitution reaction between linalool and isophthaloyl chloride, and then epoxidation. The chemical structure of obtained product was determined by infrared (IR) spectroscopy and nuclear magnetic resonance spectroscopy. Unlike traditional thermosetting epoxy resins, the cured FETE could degrade rapidly at low temperature (200–300°C). Dynamic mechanical analysis analysis showed that through copolymerization of FETE with (4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester) epoxy resin (TDE-85), the glass transition temperature (Tg) of copolymer system could be adjusted in the range of 136–179°C; FETE had good miscibility with TDE-85. The thermal degradation behavior of the copolymer system was studied by theoretical calculation, thermogravimetric (TG), and TG coupled with FTIR analysis, the results showed the thermal decomposition performance of the copolymer system could be adjusted in the range of 200–400°C. The tertiary ester groups in FETE were easy to thermally degrade and caused the network skeleton of the copolymer system to collapse. The FETE would have good prospects in reworkable electronic packaging, recycling or degradable epoxy resin area.
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高影响因子
ChemSusChem
·
2021
·Vol. 14
·期 11
·2341-2351
·
IF 8.928
Bo Zhou,Fan Song,Xinyue Ma,Lijun Wang
Graphical The batch is back : A scalable green catalyst system based on a TiO 2 nanoparticle–exfoliated montmorillonite composite catalyst with hard Lewis acid sites and abundant accessible Brønsted acid sites is developed for the rapid preparation of furfural acetals, which are a promising biofuel with high octane value, high calorific value, and high oxidation resistance. Furfural acetals with high octane value, high calorific value and high oxidation resistance are considered promising biofuels or fuel precursors with huge potential demand. However, there are few studies on efficient scalable catalyst systems, including continuous-flow catalyst systems, for their preparation. In this work, TiO 2 nanoparticles supported on exfoliated montmorillonite, with strong Lewis acid sites and abundant accessible Brønsted acid sites, is used to catalyze the acetalization reactions of biomass-derived furfural and alcohols. Low dosage of the catalyst made the reaction reach equilibrium in a very short time (TOF=690–1305 min −1 ) at room temperature with the acetal as the only product. In continuous-flow reactions, the catalyst showed a stable product output with conversion close to that for the batch reaction with a short catalyst-reactant contact time of 150 s. Contrast experiments revealed that both Lewis and Brønsted acid sites on the catalyst were indispensable for maximizing the catalytic performance, and simultaneously activating both furfural and alcohol on the adjacent Lewis and Brønsted acid sites was proposed to be responsible for the high catalytic performance.
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JOURNAL OF MOLECULAR LIQUIDS
·
2021
·
IF 6.165
Shahid Hussain,Haifeng Dong,Shaojuan Zeng,Muhammad Umair Ahmad,Farooq Khurum Shehzad,Hui Wu,Yanqiang Zhang
Ionic liquids, which are designable and nonvolatile, have become a hot topic in the field of CO 2 separation from industrial gases. In order to utilize the nonvolatile and low heat capacity of ionic liquids, it is necessary to solve the problem of high viscosity of pure ionic liquids. In the present study, ether functionalized pyridinium ion [E 1 Py] + with good biodegradability and low viscosity was selected as cation. Ions containing cyano groups were used as anions, such as thiocyanate ion [SCN] - , dicyanamide ion [N(CN) 2 ] - , tricyanomethanide ion [C(CN) 3 ] - . Three ionic liquids with low viscosity were synthesized and characterized by 1 HNMR, 13 CNMR and FTIR. The physiochemical properties of ionic liquids such thermal decomposition temperature, density and viscosity were tested. The CO 2 absorption capacity was systematically studied by using intelligent gravimetric analyzer at the pressure range between 0 and 15 bars and the temperature range from 303.15 to 333.15 K. The results showed that the order of CO 2 absorption capacity of these three ionic liquids is [E 1 Py][C(CN) 3 ] > [E 1 Py] [N(CN) 2 ] > [E 1 Py][SCN], which showed that the solubility increased by increasing more cyano groups in ionic liquids. Thermodynamic properties such as enthalpy, entropy, and Gibbs free energy were also calculated for CO 2 absorption.
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高影响因子
JOURNAL OF ELECTRONIC MATERIALS
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2021
·Vol. 50
·期 6
·3078-3083
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IF 1.938
Wu Wanyi,Wang Mengkun,Huang Huihui,Gu Wenxian,Yan Chengzhan,Chen Guang,Yin Dewu,Jin Huile,Wang Jichang,Wang Shun
In this work, hierarchically porous carbon spheres co-doped by iron and nitrogen were synthesized via in situ dehalogenation. The rich porous structure and relatively high specific surface area (210 m 2 /g) facilitate the formation of an ultra-fine Fe 2 N active phase and FeN 4 active centers within the carbon matrix. Transmission electron microscopy and X-ray photoelectron spectroscopy analysis further reveal the presence of a dominant Fe 2 N phase and minor FeN 4 bonds in the as-prepared Fe-N-C-pd-800 samples. Because of this, the oxygen reduction reaction (ORR) process can more readily take place on Fe 2 N than on FeN 4 , and the Fe 2 N phase enriched Fe-N-C-pd-800 carbon spheres exhibit a promising onset potential ( E onset =1.02 V) and half-wave potential ( E 1/2 =0.86 V) in alkaline media. In addition, Fe-N-C-pd-800 also shows excellent methanol resistance and long-cycling stability.
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Catalysis Science & Technology
·
2021
·Vol. 11
·期 10
·3527-3538
·
IF 6.119
Kaixin Li,Limin Deng,Shun Yi,Yabo Wu,Guangjie Xia,Jun Zhao,Dong LU,Yonggang Min
Hydrogen-bonding (HB) induced by the water solvation shell is vital in chemical and biological systems. Herein, HBs related to the binding behavior of protonic ionic liquids (PILs) with water molecules were found to dominate in the acid catalysis of the glycosidic bond in hydrolysis. Spectroscopic techniques, including temperature-related NMR and solvatochromic UV/vis, were employed to investigate the distinct HB interactions of the PILs in the continuous solvent phase. The results revealed that both the sulfonic groups and the N-containing groups synergistically govern the deprotonation of the PILs and consequently the reaction efficiency of the PILs via HBs. Furthermore, the intermolecular HBs between the PIL and the solvent clusters were found to be responsible for the superior catalytic activity of the PILs over the conventional sulfuric acid. A linear correlation between the hydrolysis rate (k–k0) and catalyst concentration was established in the PILs and sulfuric acid. Their linearization indicates a secondary proton release from the anion of PILs, which was not observed in the case of sulfuric acid. Computational studies showed that the PIL-catalysed mechanism obeyed the dynamic “one-step” protonation of the glycosidic bond by the surrounding explicit solvent water molecules. A lower free energy barrier was obtained by the PILs in comparison with sulfuric acid. The reasons behind this were concluded to be the easy secondary proton release from the PILs by the consecutive nucleophilic activation of water molecules via HBs, offering a more acidic solution for reactant protonation, and the other was the background positive charge of solvent water molecules induced by HBs, stabilizing the transition state in the process.
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高影响因子
MOLECULAR PHARMACEUTICS
·
2021
·
IF 4.939
Chao Li,Yao Lu,Lili Cheng,Xiaoge Zhang,Jun Yue,Jie Liu
As a noninvasive therapy, high-intensity focused ultrasound (HIFU) shows great potential in inducing anticancer immune responses. However, the overall anticancer efficacy of HIFU is still limited due to the rapid attenuation of ultrasound waves and inadequacy of ultrasound waves to spread to the whole tumor. Here, we combined HIFU with the ultrasound contrast agent/chemotherapeutic drug co-delivery nanodroplets to achieve synergistic enhancement of anticancer efficacy. Different from the widely used thermal HIFU irradiation, by which excessive heating would result in inactivation of immune stimulatory molecules, we used short acoustic pulses to trigger HIFU (mechanical HIFU, mHIFU) to improve anticancer immune responses. The nanodroplets displayed a mHIFU/glutathione (GSH)-dual responsive drug release property, and their cellular uptake efficacy and toxicity against cancer cells increased upon mHIFU irradiation. The generated immunogenic debris successfully induced the exposure of damage-associated molecular patterns on the cell surface for dendritic cells (DCs) maturation. In vivo experiments with tumor-bearing mice showed that the co-delivery nanodroplets in combination with mHIFU could effectively inhibit tumor growth by inducing immunogenic cell death, activating DCs maturation, and enhancing the effector T-cell infiltration within tumors. This work reveals that combined treatment with nanodroplets and mHIFU is a promising approach to eradicate tumors.
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PubMed
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
·
2021
·Vol. 39
·期 9
·1161-1168
·
IF 3.603
Gao Dan-Ni,Zhao Yu-Lai,Cai Jing-Yu,Hou Lin-Xi,Xiao Long-Qiang
Reversible chain transfer catalyzed polymerization (RTCP) is a practical and efficient process for the precise synthesis of polymers with special architecture by using simple phenols (2,4,6-trimethylphenol, TMP) or hydrocarbons (xanthene, XT) as efficient organocatalysts. Herein, alkyl iodide (R-I), which was generated from in situ bromine-iodine transformation of alkyl bromide (R-Br) with sodium iodide (NaI), was served as initiator to mediate RTCP with TMP or XT. MMA and other functional methacrylates, including GMA, DEAM, DMAEMA and BzMA, were successfully initiated by combining organocatalysts and azo initiators to yield polymers with low-polydispersity ( M w / M n =1.1–1.5) and ideal monomer conversions (50%–90%) at moderate temperature. Moreover, 3-armstar polymers were also obtained by this method. The high chain-end fidelity of the obtained poly(methyl methacrylate) with iodine as chain-end group (PMMA-I) was confirmed by chain-extension reaction. The environmentally friendly initiators and organocatalysts exhibit powerful polymerization properties toward RTCP, providing a significant method to synthesize functional polymers.
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高影响因子
ACS Sustainable Chemistry & Engineering
·
2021
·
IF 8.198
Yi Zhang,Yu Deng,Weidong Guo,Donghao Liu,Yigang Ding
Developing the efficient ionic liquid (IL)-based extractants for the solvent extraction of the rare earth elements (REEs) is crucial but still facing challenges. In this study, two carboxylic acid-functionalized upper critical solution temperature (UCST)-type ILs, N-carboxymethylpyridinium bis(trifluoromethylsulfonyl)imide ([HbetPy][Tf2N]) and N-carboxymethyl-N-methylmorpholinium bis(trifluoromethylsulfonyl)imide ([HbetMor][Tf2N]), are successfully synthesized and characterized. The extraction and separation performance toward scandium [denoted as Sc(III)] in nitrate medium aqueous solution have been carefully investigated in the homogeneous liquid–liquid extraction system under different conditions (e.g., equilibrium time, initial acidity, salting-out agent concentration, and REE concentration). The results reveal that the enhanced extractabilities of Sc(III) can be observed in homogeneous extraction compared to the biphasic system owing to the improved metal ion transfer and accelerated extraction kinetics. Meanwhile, [HbetPy][Tf2N] and [HbetMor][Tf2N] both illustrate high selectivity for Sc(III) separated from another five REEs (including La, Nd, Eu, Ho, and Yb), with the separation factors of 749 and 499 for Sc(III)/Yb(III), respectively. Moreover, the mechanism investigation indicates the formation of the Sc(III) complex via a proton exchange, evolved from the slope analysis and Fourier-transform infrared results. This study provides a prototype for the construction of the homogeneous liquid–liquid extraction system via the novel UCST-type ILs for highly efficient REE extraction and supplies the future application for the recovery of REEs from wastes.
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危险品化学品经营许可证（带存储）