MAIN GROUP CHEMISTRY
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2020
·Vol. 19
·期 3
·227-235
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IF 0.845
Lu Yan-Qi
A new hybrid compound consisting of 1,4-bis(4-pyridylthio)butane ([Bpytb]) ligand, namely {[Bpytb]Ag2I3}n (1), has been prepared and characterized by IR spectroscopy, solid UV-visible diffuse reflectance spectrum, X-ray Powder Diffraction (PXRD) and TG. Compound 1 consists of 1D anion chain structure. Crystal system: Monoclinic, Space group: P2/c, a = 4.5092(3), b = 11.1895(9), c = 21.3893(14), α= 90°, β= 92.907(2)°, γ= 90°, V = 1077.82(13) Å3, Z = 2, Dcalc = 2.693 g cm–3. The photocatalytic property of compound 1 was also studied and it exhibits a better degradation effect on organic dye MB.
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2020
·
IF 2.627
Haiyan Zhou,Yizuo Li,Rui Jiang,Xianlin Wang,Yuanshan Wang,Yaping Xue,Yuguo Zheng
R -2-(4-hydroxyphenoxy)propionic acid ( R -HPPA) is a key intermediate for the synthesis of classic herbicides with high selectivity against grassy weed. The main route for R -HPPA biosynthesis is to hydroxylate the substrate R -2-phenoxypropionic acid ( R -PPA) at C-4 position with microbes. In order to provide sufficient R -PPA for the industrial production of R -HPPA, an effective R -PPA synthesis method was established and optimized in this work. The synthesis process mainly consisted of two steps: (1) synthesis of S -2-chloropropionic acid from L-alanine via diazotization and chlorination reactions; and (2) synthesis of R -PPA from S -2-chloropropionic acid and phenol via etherification reaction. The optimal reaction conditions were as follows: HCl: NaNO 2 : KI: L-Ala = 2.0: 1.2: 0.7: 1.0 (in molar), 125 °C reflux for 1.5 h, with KI as catalyst, and KI: S -2-chloropropionic acid: phenol = 0.075: 1.2: 1.0 (in molar). Under these conditions, an improved molar conversion rate (74.9%, calculated in phenol) was achieved. After extraction using anionic exchange resin Amberlite IRA-400 (CI), R -PPA product with a purity of 95.08% was obtained. The purified R -PPA was identified and evaluated in the application of the biotransformative production of R -HPPA. The results indicated that the synthesized R -PPA supported the R -HPPA biosynthesis with a comparable yield as that of the standard R -PPA. The R -PPA synthesis method provided herein exhibited the advantages of low price and easy availability of raw materials, less toxicity of reagents, simple manipulations, and low equipment/instrument requirements.
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TALANTA
·
2021
·
IF 6.057
Jinying Liu,Jiabao Zhang,Yue Zhang,Yan Wang,Mengke Wang,Ziwen Li,Guannan Wang,Xingguang Su
In this paper, we proposed a dual-signal fluorometric and colorimetric system based on silicon quantum dots (SiQDs) and 4-nitrophenol (4-NP) for pH and urease sensing. SiQDs with fluorescence emission of 460 nm were prepared via aqueous-phase synthesis. As the pH of the system gradually increased, the absorption band of 4-NP at 400 nm increased and a color reaction from colorless to yellow occurred. The absorption of 4-NP overlapped quiet well with the fluorescence excitation spectrum of SiQDs, which can effectively quench the fluorescence of SiQDs. Therefore, the change of fluorescence and absorption intensities could be used to quantify pH value. The fluorometric and colorimetric pH-sensing systems both exhibited a linear respond to pH ranging from 6.0 to 7.8 with an interval of 0.2 pH unit. Urease could specifically hydrolyze urea to generate carbon dioxide and ammonia, causing an obvious increase of the pH value. Thus, urease could also be detected quantitatively by the above dual-signal pH sensing system. The linear ranges of the fluorometric and colorimetric methods for urease detection were both 2–40 U L-1. The limits of detection were 1.67 and 1.07 U L-1, respectively. More importantly, this established dual-signal system has been successfully exploited in the detection of urease in real samples with satisfactory recoveries. Compared with other traditional single-signal assay strategies, the results obtained by dual-signal methods are more accurate and reliable.
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CHEMICAL PAPERS
·
2020
·Vol. 74
·期 7
·2049-2057
·
IF 1.68
Ren Peng,Li Yang,Wang Zhifen,Geng Yanxia,Yu Tao,Hua Rong
Thorium is much more abundant than uranium in nature and has become one of the important potential energy sources in the future. It is because that a thorium-232( 232 Th) nucleus has the ability to produce a uranium-233( 233 U) nucleus by absorbing a neutron. The aim of this paper is to investigate the extraction and separation of thorium ions and uranyl ions from aqueous solution with N,N’ -dimethyl- N,N’ -dioctyl-4-oxaheptanediamide (DMDOHA) into ionic liquids of 1-methyl-3-butylimid-azolium bis(trifluoromethanesulfonyl)imide ([C 4 mim][NTf 2 ]). The results show that the extractant DMDOHA has a good affinity toward thorium ions than uranyl ions in the present system, the maximum value of separation factor SF Th(IV)/U(VI) is 21.9 at pH 2.24. The extraction process of thorium ions and uranyl ions was confirmed to proceed by cation-exchange extraction mechanism. The DMDOHA extractant formed a major 3:1 complex with thorium ion and a major 2:1 complex with uranyl ion based on the relationship between log[DMDOHA] with logD.
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SOLAR ENERGY
·
2019
·
IF 4.674
Huiling Cai,Liquan Yao,Yingsen Xia,Chunyan Dao,Jianmin Li,Limei Lin,Zhiping Huang,Guilin Chen
In this work, a three-step (sulfurization-selenization-sulfurization) annealing process was designed to optimize the surface constitution of Cu 2 ZnSn(S, Se) 4 (CZTSSe) thin films, which was prepared by oxide nanoparticles-based approach. The devices with the Mo/CZTSSe/CdS/ZnMgO/ZnO:Al/Al structure were fabricated and their performances were studied. The additional post-sulfurization with low toxicity sulfur powder has negligible impact on the structure, morphology and composition of CZTSSe bulk, however, it improves open circuit voltage of device significantly. The open circuit voltage can be increased significantly from 408 mV (without surface sulfurization) to 497 mV (with surface sulfurization). This is benefited from the increase of surficial sulfur content and the broadening of the surface band-gap of the CZTSSe thin film. The result is confirmed by X-ray photoelectron spectroscopy analysis. Such a crucial three-step annealing process promotes the power conversion efficiency from 4.71% (2-step) to 6.37% (3-step), which is the champion efficiency of oxide precursor derived CZTSSe solar cell.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2019
·
IF 4.084
Chunmei Wang,Hai Qiang Li,Zhe Wang,Jingmei Xu,Chang Liu,Wenchang Liu,Zhaoyu Chen,Xinming Du
A series of sulfonated poly(arylene ether ketone sulfone)s polymer having a degree of sulfonation of 80% and a carboxyl group in the side chain (C-SPAEKS) were prepared by polycondensation . The 4-aminopyridine grafted sulfonated poly(arylene ether ketone sulfone)s polymer membranes (SPPs) were prepared by amidation reaction with the carboxyl group to immobilize 4-aminopyridine on the side chain. The 1 H NMR results and Fourier transform infrared of SPP membranes demonstrated the successful grafting of the 4-aminopyridine. Proton conductivity , water absorption, swelling ratio, and thermal stability of different proportions of SPP membranes were investigated under the different conditions. With the increase of pyridine grafting content, the methanol permeability coefficient of the membrane decreased significantly from 8.17 × 10 −7 cm 2 s −1 to 8.92 × 10 −8 cm 2 s −1 at 25 °C. And, the proton conductivity and relative selectivity of the membrane were positively correlated with the grafted pyridine content. Among them, the SPP-4 membrane exhibited the highest proton conductivity of 0.088 Scm −1 at 100 °C. The relative selectivity increased from 4.73 × 10 4 S scm −3 to 9.84 × 10 4 S scm −3 .
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2019
·
IF 2.298
Yuli Shi,Haojian Zhang,Xiaomin Hong,Xiaodong Wang
Four solvents (ethanol, isopropanol, ethylene glycol (EG), and N,N-dimethylformamide (DMF)) that can be mixed with water in any ratio were selected to determine the dissolution performance of 7-amino-4-methylcoumarin by the classical shake-flask method. The measured temperature range began at 278.15 K and ended at 303.15 K, and the pressure environment was controlled at standard atmospheric pressure (101.1 kPa). Results reveal that with the addition of organic solvents, the solubilization effect of 7-amino-4-methylcoumarin was very significant and the larger the amount of addition, the more obvious was the effect of solubilization. Not only that, the temperature change had a non-negligible effect on the dispersion of 7-amino-4-methylcoumarin; the temperature increased monotonically, and the better was the dissolution. When the external conditions were kept constant, the addition of DMF made the solubilization effect of 7-amino-4-methylcoumarin most obvious among all organic solvents used. This study involved three models, including the Jouyban–Acree model and its two variants (van’t Hoff–Jouyban–Acree model and Apelblat–Jouyban–Acree model), which were used to correlate the solubility data of 7-amino-4-methylcoumarin in aqueous cosolvent mixtures. The relative average deviation (RAD) and root-mean-square deviation (RMSD) reaches to 3.47 × 10–2 and 1.79 × 10–3 rooting in the van’t Hoff–Jouyban–Acree model. The relevant parameters obtained through model calculation and experimental means are essential for product synthesis, separation, and purification processes.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2019
·
IF 4.784
Yancun Yu,Yi Li,Changyu Han,Liguang Xiao
The aim of this study is to use natural orotic acid (OA) as a sustainable, environmentally friendly additive to improve the crystallization, rheological, thermal, mechanical, and biodegradation properties of bacterially synthesized poly(3-hydroxybutyrate- co -4-hydroxybutyrate) (P34HB). OA was found to be an efficient nucleating agent for P34HB, and dramatically enhanced both non-isothermal and isothermal crystallization rates. The incorporation of OA increased nucleation density and decreased spherulite size, but had little effect on the crystalline structure. The rheological properties of the P34HB were greatly improved by the solid filler OA, particularly when a percolation network structure was formed in the blends. The thermal stability of P34HB was strongly enhanced, as exemplified by the ~23 °C increase in the onset thermal decomposition temperature ( T o ) for the blend loaded with 5 wt% OA compared to that of pure P34HB. Moreover, the yield strength and elongation at break of P34HB containing 0.5 wt% OA increased by 25% and 119%, respectively. The most intriguing result was the clear enhancement in the enzymatic hydrolysis rates of the P34HB/OA blends compared to that of neat P34HB. The synergetic improvement in these properties may be of significant importance for the wider practical application of biosourced P34HB.
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EUROPEAN POLYMER JOURNAL
·
2019
·
IF 3.621
Muhammad Atif,Chaoshi Chen,Muhammad Irfan,Fatima Mumtaz,Kang He,Miao Zhang,Lijuan Chen,Yanmei Wang
In this work, poly[(2-methyl-2-oxazoline)-random-glycidyl methacrylate] (PMOXA-r-GMA) and poly(4-vinyl pyridine)-block-poly(glycidyl methacrylate) (P4VP-b-PGMA) were synthesized by cationic ring opening polymerization (CROP) of 2-methyl-2-oxazoline (MOXA) and reversible addition-fragmentation chain transfer (RAFT) polymerization of 4-vinyl pyridine (4VP) followed by their random and block copolymerization with glycidyl methacrylate (GMA), respectively. Then poly(2-methyl-2-oxazoline)/poly(4-vinyl pyridine) (PMOXA/P4VP) based binary polymer brushes on silicon/glass substrate were fabricated using spin coating of the mixture of PMOXA-r-GMA and P4VP-b-PGMA copolymer solution followed by annealing process at 110 °C. Afterwards, these polymer brushes were characterized via water contact angle (WCA), X-ray photoelectron spectroscopy (XPS), variable angle spectroscopic ellipsometry (VASE), and atomic force microscopy (AFM) techniques. The results showed that the surface composition on the substrate surface could be adjusted by tuning the composition of the mixture of polymer solution used for the preparation of mixed brushes. Moreover, it also showed the swelling and de-swelling of mixed polymer brushes in a systematic way between two specific points during varying the pH of the surrounding medium from 2 to 10. Finally, the tunable behavior of PMOXA/P4VP based mixed brushes against bovine serum albumin (BSA) adsorption/desorption was investigated by fluorescein isothiocyanate-labelled BSA (FITC-BSA) assay and ellipsometry measurements. The results indicated that by changing the pH value from 2 to 10, the PMOXA/P4VP based mixed brushes could adsorb and desorb protein from very low to high amount depending upon the composition of PMOXA-r-GMA and P4VP-b-PGMA in preparing solution used for the PMOXA/P4VP based coatings, and ~89% of the adsorbed protein could be desorbed under the selected conditions.
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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2019
·Vol. 138
·期 2
·1251-1257
·
IF 2.471
Wang Yanfei,Liu Xiaoyu,Zhao Xiaoyu,Chen Zhao,Yang Libin,Zhu Liang
Solid–liquid-phase equilibrium is an important part of chemical thermodynamics, and its basic theoretical research plays a vital role in the advancement of the chemical industry. Solid–liquid equilibria for binary mixtures of 3-nitrotoluene and 4-nitrotoluene were measured using differential scanning calorimetry under atmospheric pressure (101.3 kPa). The results showed that the phase diagram of the 3-nitrotoluene + 4-nitrotoluene binary system presented a eutectic behavior, and the eutectic point was x 1 = 0.6487, T E = 272.15 K. Furthermore, the experimental results were correlated with Wilson and nonrandom two-liquid (NRTL) activity coefficient models well. The relative standard deviations were 0.496 and 0.236, respectively, and the absolute mean deviations were 0.005 and 0.001, respectively.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2018
·
IF 3.909
Wei Li,Yun Yang,Chong Qiao,Guolin Zhang,Yinggang Luo
Galanthamine (GAL), the well-known Amaryllidaceae alkaloid, is a clinically used drug for the treatment of Alzheimer's disease. L-Phenylalanine (Phe) and trans -cinnamic acid (CA) were enzymatically transformed into the catechol portion of GAL. Herein, a Phe ammonia-lyase-encoding gene LrPAL3 and a cinnamate 4-hydroxylase-encoding gene LrC4H were cloned from Lycoris radiata , a GAL-producing plant. LrPAL3 was overexpressed in Escherichia coli and purified to homogeneity. LrPAL3 catalyzes the forward deamination conversion of L-Phe into trans -CA. The 3-chloro- and 4-fluoro-L-Phe were deaminated to generate the corresponding 3-chloro- and 4-fluoro- trans -CA by LrPAL3. LrPAL3-catalyzed reverse hydroamination was confirmed by the conversion of trans -CA into L-Phe with exceptional regio- and stereo-selectivity. LrC4H was overexpressed in E. coli with tCamCPR , a cytochrome P450 reductase-encoding gene. LrC4H catalyzes the regioselective para -hydroxylation on trans -CA to form p -coumaric acid. The transcriptional levels of both LrPAL3 and LrC4H were positively associated with the GAL contents within the leaves and flowers of L. radiata , which suggested that their expression and function are co-regulated and involved in the biosynthesis of GAL. The present investigations on the biosynthetic genes of GAL will promote the development of synthetic biology platforms for this kind of important drug via metabolic engineering.
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ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Bin Wen,Jinqiao Xue,Xianjing Zhou,Qingwen Wu,Jingjing Nie,Junting Xu,Binyang Du
Tetra(4-pyridyl)porphyrin (TPyP)-functionalized thermosensitive ionic microgels (TPyP5-MGs) were synthesized by a two-step quaternization method. The obtained TPyP5-MGs have a hydrodynamic radius of about 189 nm with uniform size distribution and exhibit thermosensitive character. The TPyP5-MG microgel suspensions can optically respond to trace Pb2+ ions in aqueous solution with high sensitivity and selectivity over the interference of other 19 species of metal ions (Yb3+, Gd3+, Ce3+, La3+, Bi3+, Ba2+, Zn2+, Ni2+, Co2+, Mn2+, Cr3+, K+, Na+, Li+, Al3+, Cu2+, Ag+, Cd2+, and Fe3+) by using UV–visible spectroscopy. The sensitivity of TPyP5-MGs toward Pb2+ can be further improved by increasing the solution temperature. The limit of detection for TPyP5-MG microgel suspensions in the detection of Pb2+ in aqueous solution at 50 °C is about 25.2 nM, which can be further improved to be 5.9 nM by using the method of higher order derivative spectrophotometry and is much lower than the U. S. EPA standard for the safety limit of Pb2+ ions in drinking water. It is further demonstrated that the TPyP5-MG microgel suspensions have a potential application in the detection of Pb2+ in real world samples, which give consistent results with those obtained by elemental analysis.
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