Chemical Engineering and Processing-Process Intensification
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2021
·
IF 4.237
Zhou Lan,Yangcheng Lu
In this work, a tubular reactor with a micromixer was introduced in attempt to enhance the amination reaction of 4-nitrochlorobenzene in terms of the process efficiency and safety. It was found that the reaction system containing a large excess of ammonia water can become homogeneous at high temperature. Thus, as both micromixing and the heat transfer performance were guaranteed, the set-up combining a micromixer and a microtube reactor enabled the reaction to exhibit homogeneous reaction characteristics, meeting the demands of efficiency and reliability. Furthermore, using a multi-channel sampling system connected behind the micromixer, the reaction kinetics were studied in a modified “stop flow” mode, which is adaptable for in-situ fast homogenization, high temperature, and high pressure. The reaction conditions were screened and a kinetic model was developed. Accordingly, we propose and verify a self-circulation strategy to reduce the burden of ammonia separation and recovery in a continuous tubular reactor system.
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SOLAR ENERGY
·
2019
·
IF 4.674
Wenhui Zhao,Xiaoyan Gan,Lili Ke,Liling Guo,Hanxing Liu
Two-dimensional layered organic-inorganic perovskite hybrids have attracted increasing attention due to their outstanding moisture resistance and promising optoelectronic properties. However, the photovoltaic performance in solar cells is still a huge challenge for two-dimensional perovskite films. With the aim to improve the efficiency of 2D perovskite solar cells, the new (ClC 6 H 4 C 2 H 4 NH 3 ) 2 MA n−1 Pb n I 3n+1 perovskite family (abbreviated as (CPEA) 2 MA n−1 Pb n I 3n+1 ) are synthesized by a simple one-step hot-casting method in this study. It is found that the variation of n value (n = 3–6) has great influence on the microstructure, grain size, charge mobility, trap density and photovoltaic performance of the 2D (CPEA) 2 (MA) n−1 Pb n I 3n+1 . Due to the best film quality and prolonged carrier lifetime, the (CPEA) 2 MA 4 Pb 5 I 16 (n = 5) perovskite solar cell exhibits a highest efficiency of 11.86%, with a V oc of 0.989 V, a J sc of 19.92 mA/cm 2 and FF of 60%, respectively. It is anticipated that our approach to explore new organic spacer cations in 2D perovskites may pave the way for their application with high performance.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 26
·期 9
·9161-9173
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IF 2.914
Zhang Tingting,Yang Yanling,Li Xing,Wang Nan,Zhou Zhiwei
Ultrasound-assisted regeneration of powdered activated carbon (PAC) saturated with 4-chlorophenol (4-CP) was investigated in this work. The variables, i.e., acoustic frequency, density levels, regenerating solution species, spent PAC mass, and the number of repeated cycle, were optimized. The UV–Vis spectra, thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), and pore structure analysis were used to characterize the regenerated PAC as compared to the virgin and spent PAC. The adsorption experiments indicated that the adsorption kinetics of 4-CP fitted well with the pseudo-second-order model, and the main chemisorption process was nonlinear and heterogeneous. The desorption results showed that the optimized regenerated conditions were identified as 40 kHz of frequency, 0.18 W/mL of sonication intensity, 0.1 M NaOH and 50% ( v / v ) ethyl alcohol mixture of regeneration solution, and 1 g/L of saturated PAC mass. Under this condition, the regeneration efficiency reached up to 86.81%. Hydroxylated oxidation products especially benzoquinone and hydroquinone were formed during ultrasound regeneration. Ultrasound mainly acted on surface functionalities, mesopores, and macropores of PAC through the hydroxyl radical oxidization resulted from the cavitation effect.
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RSC Advances
·
2019
·Vol. 9
·期 17
·9449-9456
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IF 3.049
Yuhua Zhang,Jiayi Jiang,Ningbo Qin,Qian Zhang,Chunyan Yan
Cambial meristematic cell (CMC) suspension cultures were investigated as a new biotransformation system for the first time. Four 4-methylcoumarins substrates were transformed by CMCs of Camptotheca acuminata into four corresponding products, including 4,8-dimethylcoumarin-7-O-β-D-glucopyranoside (I-1), 4,7-dimethylcoumarin-6-O-β-D-glucopyranoside (II-1), 6-hydroxy-7-methoxyl-4- methylcoumarin (III-1), and 4,7-dimethylcoumarin-5-O-β-D-glucopyranoside (IV-1), of which I-1, II-1, and IV-1 were new compounds. In addition, the biotransformation time and the amount of substrate were investigated to compare the biotransformation rate and optimize the biotransformation conditions of the four substrates in C. acuminata CMCs suspension cultures. The results suggested C. acuminata CMCs were able to select glycosylate phenolic hydroxyl groups of 4-methylcoumarins I, II, and IV, with high regio- and stereoselectivity, but no corresponding glycoside of any phenolic hydroxyl group of compound III was detected. Simultaneously, the result also showed that the C. acuminata CMCs were able to transform the 7-hydroxy groups of substrate III to its corresponding methylated products. Furthermore, the monoamine oxidase (MAO) inhibition activities of biotransformed products were evaluated, and the data showed that all the products possessed good MAO inhibition activities in vitro. In conclusion, C. acuminata CMCs could be applied to glycosylation biotransformation as a novel plant-based system due to the successful application of bioconversion of exogenous coumarins.
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Chinese Physics B
·
2018
·Vol. 27
·期 6
·066108
·
IF 1.321
Qing Yu,Jiangjian Shi,Pengpeng Zhang,Linbao Guo,Xue Min,Yanhong Luo,Huijue Wu,Dongmei Li,Qingbo Meng
A study of the self-healing phenomenon of Cu2ZnSn(S, Se)4 (CZTSSe) solar cells has shown more than 10% enhancement in cell performance after storage at room temperature for a week, with a significant improvement in the open-circuit photovoltage (Voc) and fill factor (FF). In addition, up to 10.45% power conversion efficiency (PCE) has been achieved. No obvious change in crystallinity, crystal phase, optical absorption or elemental distribution in the CZTSSe films was detected on examining the x-ray diffraction (XRD) pattern, Raman spectrum, ultraviolet-visible (UV-Vis), and TOF-SIMS. Further investigations on the charge carrier concentration, charge radiative recombination, and band structure suggest that the enhancement in PCE stems mainly from a reduction in deep defects of the CZTSSe semiconductor film.
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POLYMER
·
2018
·
IF 3.483
Yongjian Lou,Zhongxiang Zhao,Zhiwei Chen,Zenghui Dai,Feiya Fu,Yanyan Zhang,Lei Zhang,Xiangdong Liu
High melting temperature and viscosity of most benzoxazine monomers are challenging problems in processing, especially for preparation of composites. The present work introduces the “reactive diluent” concept to improve the processability of benzoxazines. A benzoxazine monomer having a vinyl group is first synthesized from 4-vinylguaiacol (4VG), and then dissolved in a reactive diluent, styrene or methyl methacrylate . The resulting solutions show low viscosity (less than 2 mPa s), and exhibit high reactivity during free radical and ring-opening polymerizations, successively. Furthermore, the solutions are applied to fabricate cotton fabrics reinforced composites. Both of them possess high glass transition temperature and excellent mechanical properties , which have potential applications as structural components.
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DALTON TRANSACTIONS
·
2014
·Vol. 43
·期 26
·10057-10063
·
IF 4.097
Xin Yang,Junhai Wang,Dongyue Su,Qingdong Xia,Fang Chai,Chungang Wang,Fengyu Qu
Rapid and sensitive detection of 2,4,6-trinitrotoluene (TNT) and 4-nitrophenol (4-NP) has attracted considerable attention due to their wide applications as nitroaromatic explosive materials. A novel fluorescence method for TNT and 4-NP based on bovine serum albumin functionalized fluorescent gold nanoclusters (BSA Au-NCs) has been developed. The detection probe BSA Au-NCs can be used as a fluorescent probe for the sensitive and selective detection of TNT and 4-NP simultaneously. A good linearity of fluorescence detection using BSA Au-NCs as a fluorescent probe was observed for TNT and 4-NP concentrations in the range of 10−8–5 × 10−5 M and 10−9–5 × 10−5 M, with a detection limit of 10 nM and 1 nM, respectively. The high specificity of TNT and 4-NP with BSA Au-NCs interactions provided excellent selectivity towards detecting TNT and 4-NP over other relevant nitroaromatic compounds. This system can be applied to test strips to detect TNT and 4-NP with high sensitivity and selectivity. The vapour of TNT and 4-NP can be detected using BSA Au-NCs test paper within 1 min with a detection limit of 10 pM and 1 pM.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2017
·
IF 3.671
Ke-Lin Chen,Ling Gan,Zhen-Hua Wu,Jin-Fang Qin,Wen-Xia Liao,Huang Tang
A series of 4- substituted sampangine derivatives (4-aminoalkylaminosampangine Ar–NH(CH 2 ) n NR 1 R 2 ) has been designed, synthesized, and tested for their ability to inhibit acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and β-myloid (Aβ) aggregation. The synthetic compounds exhibited high AChE inhibitory activity and a significant in vitro inhibitory potency toward the self-induced Aβ aggregation. While, treatment of SH-SY5Y cells overexpressing the Swedish mutant form of human β-amyloid precursor protein (APPsw) with derivatives was associated with significant reduction of Aβ42 secretion levels. Moreover, most of the synthetic compounds were predicted to be able to cross the blood-brain barrier (BBB) to reach their targets in the central nervous system (CNS) according to a parallel artificial membrane permeation assay for BBB. The result encourages us to study this class of compounds thoroughly and systematically.
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HIGH PERFORMANCE POLYMERS
·
2016
·
IF 1.045
Xiaodong Ji,Jingling Yan,Xiuju Liu,Zikun Wang,Zhen Wang
Several partially bio-based polyimides have been successfully synthesized by polycondensation between bis(4-aminophenyl)isohexides with various commercial dianhydrides. Flexible and free-standing films were readily obtained from their poly(amic acid) or polyimide solutions. A systematic investigation of the structure–property relationship of polyimides highlights the significant impact of the isohexides moieties on their physical and mechanical properties (glass transition temperature, inherent viscosity, thermal stability, solubility, and mechanical properties). The results revealed that these polyimides exhibited comparable thermal stability and mechanical properties to those of petrochemical-based ones.
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CHEMISTRY OF NATURAL COMPOUNDS
·
2017
·Vol. 53
·期 5
·860-865
·
IF 0.46
Li Na,Wang Bing,Sun Jing-yong,Wang Xiao-jing,Sun Jie
Twelve 4-aryl-3,4-dihydrocoumarins were synthesized by the condensation of phenols with the corresponding substituted cinnamic acids in the presence of nitrobenzene and sulfated montmorillonite K-10. This method displayed the property of green chemistry with respect of reuse of the catalyst. These compounds were evaluated for hydroxyl radical scavenging activity in vitro. Results showed that compounds with 7,8-dihydroxy groups had relatively strong hydroxyl radical scavenging activity.
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CHINESE CHEMICAL LETTERS
·
2016
·
IF 1.947
Shi-Guo Zhang,Zong-Bo Xie,Lian-Sheng Liu,Meng Liang,Zhang-Gao Le
We discovered that α -chymotrypsin has a promiscuous ability to catalyze the cyclocondensation of aromatic and aliphatic aldehydes with 2-aminobenzamides to afford the corresponding 2,3-dihydroquinazolin-4(1 H )-ones successfully in high yields (90%–98%) under alcohol solvent. The catalytic activity of α -chymotrypsin was evaluated through investigating the temperature, the enzyme loading and the ratio of substrates in the enzyme-catalyzed reactions. The present method proves to be efficient and environmentally friendly in terms of short reaction time, high yield, green catalyst and the clean products obtained without further purification processes.
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TALANTA
·
2024
·
IF 5.6
Qing Liu,Si Chen,Yiming Nie,Qian Li,Fang Chen
4- n -butylresorcinol (4nBR) is a frequently utilized as whitening ingredients in skincare cosmetics. Compared with other whitening ingredients, it can effectively inhibit tyrosinase with lower toxicity and superior inhibition efficacy. Under alkaline conditions, an induced oxidative coupling reaction can occur between 4nBR and dopamine (DA) to generate strong fluorescent substance azamonardine with an intense emission band centering at 476 nm when excited at 440 nm. This phenomenon can be used to establish a fluorescence analysis method for 4nBR. The results indicated that the linear range of the method was 1.0–24.0 nmol L −1 , and the detection limit was as low as 0.25 nmol L −1 . The method showed high sensitivity, good selectivity, mild experimental conditions and low cost. The proposed method was successfully used to detect 4nBR in cosmetics, and the results were consistent with those of HPLC. The spiking recoveries were between 98.2% and 108 %.
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