期刊：
JOURNAL OF ORGANIC CHEMISTRY,2021年86(21):15658-15664 ISSN：0022-3263
通讯作者：
Chen, Shanping;Deng, Guo-Jun
作者机构：
[Fang, Fang; Jiang, Shuxin; Chen, Shanping; Deng, Guo-Jun; Chen, SP; Deng, GJ; Lei, Hanwen] Xiangtan Univ, Coll Chem, Minist Educ,Key Lab Green Organ Synth & Applicat, Key Lab Environm Friendly Chem & Applicat, Xiangtan 411105, Peoples R China.;[Fang, Fang] Hunan City Univ, Coll Mat & Chem Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Chen, SP; Deng, GJ] X;Xiangtan Univ, Coll Chem, Minist Educ,Key Lab Green Organ Synth & Applicat, Key Lab Environm Friendly Chem & Applicat, Xiangtan 411105, Peoples R China.
摘要：
A convenient and efficient strategy for the synthesis of dibenzoxazepinamines and dibenzothiazepinamines has been developed. This three-component approach started from 2-nitrobenzaldehydes, 2-aminophenols, and methoxyammonium chlorides under metal-free conditions. The protocol has the advantages of readily available starting materials, simple and facile conditions, gram-scale synthesis, and broad substrate scope, providing an efficient and practical strategy for the preparation of potential drug-active dibenzoxazepinamines and dibenzothiazepinamines in one pot.
期刊：
Materials Research Express,2021年8(5):055303 ISSN：2053-1591
作者机构：
[Yang, Haiyang; Lang, Feng; Song, Ling; Li, Duxin; Shangguan, Jinfei] Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;[Yang, Haiyang; Song, Ling; Wang, Jin; Shangguan, Jinfei; Jiang, Qibin] Zhuzhou Times New Mat Technol Co Ltd, Zhuzhou 413000, Peoples R China.;[You, Yilan] Hunan City Univ, Coll Mat & Chem Engn, Yiyang 413000, Peoples R China.
关键词：
MC nylon;polydimethylsiloxane;MoS2;friction performance
摘要：
MoS2 reinforced PDMS/MC nylon composites had been fabricated by in situ polymerization to further enhance the comprehensive properties of nylon material. Polydimethylsiloxane was pre-sythesized as the activator of the system and MoS2 was compounded as the wear-resisting agent. The thermal stability, mechanical properties, friction and wear properties of composites with different MoS2 contents were tested. The results showed that the crystallization and thermal stability of nylon matrix were increased with the addition of MoS2, while the tensile strength and impact strength were slightly reduced. The composites finally presented excellent friction properties with 3 wt% MoS2, whose friction coefficient was reduced to 0.75 (18.48% decrease) corresponding to the wear rate of 0.4145 x 10(-8) g Nm(-1).
期刊：
Journal of Applied Polymer Science,2021年138(31):50750- ISSN：0021-8995
通讯作者：
Li, Duxin
作者机构：
[Lang, Feng; Song, Ling; Li, Duxin; Lin, Yi] Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.;[Song, Ling; Jiang, Qibin] Zhuzhou Times New Mat Technol Co Ltd, Zhuzhou, Peoples R China.;[You, Yilan] Hunan City Univ, Coll Mat & Chem Engn, Yiyang, Peoples R China.
通讯机构：
[Li, Duxin] C;Cent South Univ, State Key Lab Powder Met, Changsha 410083, Peoples R China.
关键词：
copolymers;friction;polyamides;wear and lubrication
摘要：
A poly(phenylsulfone)-urea (PPSUU) macro-activator is synthesized by in situ anionic polymerization of 4,4 '-diaminodiphenylsulfone and hexamethylene diisocyanate. The PPSUU segment is embedded into the nylon molecular chain through copolymerization to improve the wear resistance and flame retardancy of monomer cast nylon 6 (MC PA6) materials. The mechanical properties, thermal stability, friction and wear properties and combustion heat release rate of copolymers with different macro-activator contents are tested. Results indicate that a small amount of PPSUU can improve the wear resistance and impact properties of nylon materials. The wear loss of MC nylon is 54.8% less than pure MC nylon from 1.049 x 10(-8) to 0.474 x 10(-8) g/Nm with 6 wt% PPSUU. Moreover, better flame retardancy is verified. The peak of HRR reduced 36.8% from 654 to 413 kw/m(2) with 4 wt% PPSUU, accompanied by advanced ignition time and flame extinction time, thus reducing the risk of fire.
摘要：
In this study, reduced graphene oxide sheets (RGO) were previously modified by silane coupling when composited with Poly (phenylene sulfide) (PPS)/polyamide 6 (PA6) blends with a mass proportion of 4:6. Then the blends of RGO/PPS/PA6 were prepared under different mixing sequences, and it was found that the thermal conductivity of composite prepared by two-step blending showed enhanced values for immiscible blends compared with the one-step blending method at the same RGO loading. At the RGO loading of 4.06 wt%, the thermal conductivity of RGO/PPS/PA6 composite reached 0.74 W/(m center dot K) through the two-step blending method, which is 23.7% higher than that prepared by the one-step blending method. Moreover, great influences on the thermal conductivity and crystallization behavior of RGO were discussed. The thermal conductivity of RGO/PPS/PA6 composite with 36.36 wt% RGO reached 2.83 W/(m center dot K), which is 10.66 times higher than that of pure PPS/PA6 blend. Especially, based on DSC data, the introduction of PPS phase and RGO was proved to have little effect on the melting behavior of the composites, but a prominent heterogeneous nucleation effect and increased crystallization temperature were observed.
作者机构：
[Zhang, Xiao-Hua; Wang, Deguo; Mu, Shu-Ting; Zheng, Jing-Jing; Zhou, San-Jiu] Xuchang Univ, Food & Pharm Coll, Henan Key Lab Biomarker Based Rapid Detect Techno, Xuchang 461000, Peoples R China.;[Qing, Xiang-Dong] Hunan City Univ, Coll Mat & Chem Engn, Hunan Prov Key Lab Dark Tea & Jin Hua, Yiyang 413049, Peoples R China.;[Kang, Chao] Guizhou Univ, Sch Chem & Chem Engn, Guiyang 550025, Peoples R China.;[Liu, Zhi] Hunan Univ Humanities Sci & Technol, Coll Agr & Biotechnol, Loudi 417000, Peoples R China.
通讯机构：
[Xiao-Hua Zhang] H;[Zhi Liu] C;Henan Key Laboratory of Biomarker Based Rapid-detection Technology for Food Safety, Food and Pharmacy College, Xuchang University, Xuchang, 461000, PR China<&wdkj&>College of Agriculture and Biotechnology, Hunan University of Humanities, Science and Technology, Loudi, 417000, PR China
摘要：
The installation of a HCF2 group is a research area that has received increasing attention, and deoxydifluorination of aldehydes have served as an attractive protocol due to the wide availability of aldehydes. Herein we describe a Ph2S/Selectfluor-promoted deoxydifluorination of aldehydes under mild conditions. Compared with previous deoxydifluorination methods, which usually use hazardous reagents such as SF4, DAST and Deoxo-Fluor, this protocol is quite attractive because of the safe and convenient operations, and the use of easily available reagents. (C) 2021 Elsevier Ltd. All rights reserved.
摘要：
In this study, PM10 samples at four locations of Loudi, China were collected from January 2017 to March 2017 and December 2017 to February 2018 at first. Then, a new analytical strategy of second-order calibration based on the alternating trilinear decomposition (ATLD) coupled with gas chromatography-mass spectrometry (GC-MS) was firstly developed for quantitative analysis of seven polycyclic aromatic hydrocarbons (PAHs) in these samples. This strategy is more sensitive and efficient than traditional chromatography not only, but also it can resolve the problems of baseline drift and peaks overlapping in chromatographic analysis. Without the need for intricate pretreatment process and any derivation reactions, useful qualitative and quantitative information of seven PAHs was quickly extracted from the GC-MS-Sample data array by replacing chemical or physical separation with mathematical separation. In validation samples, the average recoveries of seven PAHs ranged from (96.7 +/- 4.8) % to (107.9 +/- 4.2) %, and the root-mean-square errors of prediction (RMSEPs) were within the range of 0.03-0.35 mu g mL(-1). The highest concentrations of individual PAHs in these samples were for phenanthrene (1.34 mu g mL(-1) in monitoring station), acenaphthylene (0.79 mu g mL(-1) in municipal government) and chrysene (0.53 mu g mL(-1) in monitoring station). Identified by component analysis, coal combustion and vehicle exhaust were the most possible sources of Loudi, China. These results demonstrated that the proposed method is characterised as a more precise, simple and promising analytical strategy to identify and quantify PAHs in actual aerosol.
摘要：
Hydrogen energy, characterizing by high-energy density, non-pollution and renewability, is regarded as an ideal clean green energy, and the chemical hydrogen storage is an optimal strategy to realize its large-scale utilization. In this study, to enhance the hydrogen evolution rate in the dehydrogenation of methylcyclohexane (MCH), Pt supported on Mg-Al oxide catalysts were prepared and the effects of the co-precipitation reaction time during the preparation of Mg-Al hydrotalcite on their structural properties were studied in detail. The results showed that both the pore diameter and Pt dispersion were increased after prolonging the precipitation reaction time. During the dehydrogenation of MCH, these resultant catalysts presented high activity and good stability: hydrogen evolution rate reached up to 1892 mmol.g(Pt)(-1) min(-1) at 623 K and the conversion was still held at 92% after 218 h. Of course, a slight decrease on the conversion during the dehydrogenation reaction was also observed, which was mainly attributed to the aggregation of Pt particles at high temperature. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
摘要：
Nickel-based compounds have been regarded as potential sulfur carriers in Li-sulfur (Li-S) battery. However, the relationship between the anions in those compounds, which are crucial to the intrinsic properties, and their electrochemical performances remains unclear. Herein, nickel compounds with the same morphologies, i.e., Ni5P4, NiO, and NiS, grown on carbon cloths (noted as Ni(x)A(y)@CC (A = O, S, P)) have been rationally designed to act as sulfur hosts in Li-S batteries to investigate the compositional effects on their catalytic activities and chemical absorption abilities. Density functional theory (DFT) results demonstrate that such variations in electrochemical performance are attributed to the interaction between polysulfides (PSs) and nickel compounds, leading to different adsorption energies and interfacial states. Among them, Ni5P4@CC exhibits the best electrochemical performance, delivering capacities of 1349.5, 1020.4, 803.7, 656.7 mAh g(-1) at rates of 0.1, 0.5, 2, and 3C, respectively. Moreover, super stable cycling performance has been achieved at 1C and 3C by Ni5P4@CC-based electrode, showing an ultralow decay ratio of 0.0357% and 0.0173% per cycle for over 1000 and 2000 cycles, respectively. In contrast, NiS@CC and NiO@CC show 0.0796% and 0.0787% per cycle at the cycling test. (C) 2020 Elsevier Ltd. All rights reserved.
摘要：
An esterification and amination of benzylic C-H bonds was developed by using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) under metal- and iodide-free conditions. Both carboxylic acids and amines could be used as ideal coupling partners for the oxidative coupling reactions with various diarylmethanes. A close to equal amount of coupling reagents was enough to afford the product in good to high yields.
期刊：
Journal of Chromatography A,2020年1618:460905 ISSN：0021-9673
通讯作者：
Zhang, Xiao-Hua;Liu, Zhi
作者机构：
[Zhang, Xiao-Hua; Mu, Shu-Ting; Zhou, Qian; Liu, Pan-Hua; Zheng, Jing-Jing] Xuchang Univ, Food & Bioengn Coll, Key Lab Biomarker Based Rapid Detect Technol Food, Xuchang 461000, Peoples R China.;[Liu, Zhi] Zhejiang Acad Agr Sci, State Key Lab Managing Biot & Chem Threats Qual &, Inst Qual & Stand Agr Prod, Hangzhou 310021, Peoples R China.;[Qing, Xiang-Dong] Hunan City Univ, Coll Mat & Chem Engn, Hunan Prov Key Lab Dark Tea & Jin Hua, Yiyang 413049, Peoples R China.
通讯机构：
[Zhang, Xiao-Hua] X;[Liu, Zhi] Z;Xuchang Univ, Food & Bioengn Coll, Key Lab Biomarker Based Rapid Detect Technol Food, Xuchang 461000, Peoples R China.;Zhejiang Acad Agr Sci, State Key Lab Managing Biot & Chem Threats Qual &, Inst Qual & Stand Agr Prod, Hangzhou 310021, Peoples R China.
关键词：
Analysis of tea polyphenols;HPLC-DAD;Second-order advantage;Second-order multivariate methods;Time drift calibration
摘要：
Retention time shifts in second-order calibration-assisted chromatographic analysis seriously impact the modeling and quantitative accuracies in complex systems. In this work, three second-order methods, i.e. alternating trilinear decomposition (ATLD) algorithm, multivariate curve resolution-alternating least squares (MCR-ALS), alternating trilinear decomposition-assisted multivariate curve resolution (ATLD-MCR), were compared their performance to process liquid chromatographic data in the presence of retention time shifts and overlapped peaks. Firstly, the validation samples contain five tea polyphenols at three concentrate levels within the calibration ranges, helped to understand, visualize and interpret these features of three second-order multivariate methods. Secondly, experimental data were studied concerning the determination of polyphenols in Chinese tea samples by HPLC-DAD. The results showed that all three second-order multivariate methods realized satisfactory quantification for five targeted analytes in Pu-Er ripe tea samples and Green tea samples even with the interference of slight retention time shifts, average recoveries were 91.23% -113.16% for ATLD, 89.96%-115.96% for ATLD-MCR, 90.64%-117.60% for MCR-ALS, respectively. However, ATLD was disappointing in the case of larger time shifts (approx. 4.00 s and 6.40 s) occurring for the quantitative analysis of Black tea and Clinacanthus nutans tea, the average recoveries were just 67.33-84.05%. Relatively, MCR-ALS and ATLD-MCR were more significantly excellent, satisfactory results still can be obtained, the average recoveries for MCR-ALS and ATLD-MCR were in the range of 86.04-117.60% and 89.96-115.96%, respectively. (C) 2020 Elsevier B.V. All rights reserved.
期刊：
Ecotoxicology and Environmental Safety,2020年190:110140 ISSN：0147-6513
通讯作者：
Xiao, Guqing
作者机构：
[Meng, Qiudong; Xiao, Guqing] Hunan City Univ, Coll Mat & Chem Engn, Yiyang 413000, Peoples R China.
通讯机构：
[Xiao, Guqing] H;Hunan City Univ, Coll Mat & Chem Engn, Yiyang 413000, Peoples R China.
关键词：
Adsorption;Coordination;D151 resin preloaded with Fe(3+);Glyphosate;Salt resistance
摘要：
D151 resin preloaded with Fe(3+) [denoted as R-Fe(3+)] was to investigate R-Fe(3+) as an adsorbent for glyphosate from water in the presence high concentration of salt. The adsorption mechanism revealed the coordination of Fe(3+) inside R-Fe(3+) with O atoms of P-O and N atoms in glyphosate molecule. The adsorption capacity of glyphosate by R-Fe(3+) was much larger than that of D151 resin preloaded with Ni(2+), Cu(2+), Na(+) and H(+). Even in glyphosate solutions containing 16% NaCl, R-Fe(3+) showed the constant adsorption capacity of glyphosate. The result provided the fi rst evidence of R-Fe(3+) as a salt resistant adsorbent for glyphosate. The adsorption capacity of glyphosate was the maximum at pH 3.35. The adsorption thermodynamics showed that the adsorption of glyphosate by R-Fe(3+) was the ligand exchange of glyphosate and water. The maximum coordination ratio of glyphosate to Fe(3+) inside R-Fe(3+) was 1:1. The maximum adsorption capacity of glyphosate by R-Fe(3+) was up to 481.85 mg/g, which is much higher than that of other reported adsorbents in the presence 16% NaCl. 2 mol/L NaOH, 2 mol/L H2SO4 and 2 mol/L Fe2(SO4)3 could all be used to achieve over 97% regeneration of R-Fe(3+).
作者机构：
[Liu, Jingxiao; Chen, Xiaohua; Tang, Qunli; Liu, Zheng; Chen, Xingzhu; Hao, Yisu; Hu, Aiping] Hunan Univ, Coll Mat Sci & Engn, Hunan Prov Key Lab Adv Carbon Mat & Appl Technol, Changsha 410082, Peoples R China.;[Liu, Zheng] Hunan City Univ, Coll Mat & Chem Engn, All Solid State Energy Storage Mat & Devices Key, Yiyang 413000, Peoples R China.
通讯机构：
[Liu, Z; Chen, XH; Liu, Zheng] H;Hunan Univ, Coll Mat Sci & Engn, Hunan Prov Key Lab Adv Carbon Mat & Appl Technol, Changsha 410082, Peoples R China.;Hunan City Univ, Coll Mat & Chem Engn, All Solid State Energy Storage Mat & Devices Key, Yiyang 413000, Peoples R China.
关键词：
Graphene-like porous carbon;Nitrogen-doped;Catalytic graphitized melamine-formaldehyde;Surface area specific capacitance
摘要：
The synthetic methodology for direct indole functionalizations is of great significance in indole chemistry and has been intensively investigated in the last few decades. From the perspective of green chemistry, oxygen is the best choice as the terminal oxidant in molecular synthesis. Hence, aerobic oxidative functionalization of indoles became a hot research topic in the last decade. Numerous efficient protocols in this field have been discovered that enable facile and efficient transformations of indoles to related valuable compounds, which are summarized and discussed in detail in this review.
