阴离子交换树脂交换容量测定

对强碱性阴离子交换树脂交换容量的测定方法进行了改进、简便易行。     

一种新的氨基硫脲类阴离子受体的合成及其性质研究

合成了一种新的阴离子受体化合物PySN,通过1H NMR对其进行了表征。受体分子结合不同阴离子的紫外-可见光谱和荧光发射光谱变化表明:在非质子性溶剂中,PySN可选择性识别和传感氟离子、醋酸根及磷酸二氢根离子。     

酯化反应合成甲氧基氰乙酸乙酯

用氰乙酸、乙二醇单甲醚为原料,阳离子交换树脂A-15作为催化剂,以甲苯为带水剂,进行酯化反应制备甲氧基氰乙酸乙酯。通过试验得到最佳的工艺条件为：乙二醇单甲醚与氰乙酸的物质的量比3,催化剂A-15用量4%（质量分数,以氰乙酸为基准,下同）,反应温度130℃,反应时间6h,制备甲氧基氰乙酸乙酯,收率达93%,纯度达95%。产物经IR、1HNMR和GC-MS进行了确定。     

Sorption of Cd(II), Co(II), and Zn(II) Complexes with MGDA on Anion Exchange Resins: A Study of the Influence of Various Parameters

The strongly basic polystyrene gel resins Amberjet 4200, Amberjet 4600, and the macroporous strongly basic polystyrene Purolite A 520E were investigated for their sorption properties towards Cd(II), Co(II), and Zn(II) complexes with MGDA. The object of the study was the sorption behavior of three metal ions on the above-mentioned anion exchangers, depending on the metal ions’ concentration, pH, contact time, and temperature. MGDA is an alternative, environmentally friendly complexing agent. The sorption data were fitted to the Langmuir and Freundlich models. Three different kinetic behaviors: pseudo first order, pseudo second order, and intraparticle diffusion were tested. The variations of thermodynamic functions were also calculated.     

Analysis of 235U Enrichment by Chemical Exchange in U(IV)‐U(VI) System on Anionite

Abstract

A theoretical study about ²³⁵U enrichment by the chemical exchange method in U(IV)‐U(VI) system on anion‐exchange resins is presented. The ²³⁵U isotope concentration profiles along the band were numerically calculated using an accurate mathematical model and simulations were carried out for the situation of product and waste withdrawal and feed supply. By means of numerical simulation, an estimation of the migration time, necessary for a desired enrichment degree, was obtained. The required migration distance, the production of uranium 3 at.% ²³⁵U per year and the plant configuration are calculated for different operating conditions. An analysis of the process scale for various experimental conditions is also presented.     

2,4-二羟基苯甲酸在3种树脂上的吸附特性

通过静态和动态吸附实验, 研究了717(凝胶型,强碱)、D201(大孔型,强碱)和D301R(大孔型,弱碱)3种阴离子交换树脂对水溶液中2,4-二羟基苯甲酸的吸附特性. 结果表明,717和D201在pH 4~11时、D301R在pH 3~9时吸附能力最好. 在pH=5及温度293~313 K、初始浓度0.6488~6.488 mmol/L条件下,D301R, 717和D201对2,4-二羟基苯甲酸的等温吸附规律均符合Freundlich模型,最大平衡吸附量分别为2.98, 2.66和2.54 mmol/g(吸附未达饱和),均为物理性自发吸附的放热过程. 动力学实验数据用准一级模型方程拟合比准二级更接近实验值. 5%(w) NaCl+2%(w) NaOH脱附液100 mL均可有效洗脱3种树脂上吸附的2,4-二羟基苯甲酸,脱附率达99%. 相同条件下,D301R树脂对2,4-二羟基苯甲酸的吸附性能优于D201和717树脂.     

Imidazolium functionalized poly(vinyl alcohol) membranes for direct methanol alkaline fuel cell applications

In this study, imidazolium functionalized poly(vinyl alcohol) (PVA) was synthesized by acetalization and direct quaternization reaction. Afterwards, composite anion exchange membranes based on imidazolium‐ and quaternary ammonium‐ functionalized PVA were used for direct methanol alkaline fuel cell applications. ¹H NMR and Fourier transform infrared spectroscopy data indicated that imidazole functionalized PVA was successfully synthesized. Inductively coupled plasma mass spectrometry data demonstrated that the imidazolium structure was efficiently obtained by direct quaternization of the imidazole group. Composite anion exchange membranes were fabricated by application of the functionalized PVA solution on the surface of porous polycarbonate (PC) membranes. Fuel cell related properties of all prepared membranes were investigated systematically. The imidazolium functionalized composite membrane (PVA‐Im/PC) exhibited higher ionic conductivity (7.8 mS cm^?1 at 30 °C) despite a lower water uptake and ion exchange capacity value compared to that of quaternary ammonium. In addition, PVA‐Im/PC showed the lowest methanol permeation rate and the highest membrane selectivity as well as high alkaline and oxidative stability. Dynamic mechanical analysis results reveal that both composite membranes were mechanically resistant up to 10⁷ Pa at 140 °C. The superior performance of imidazolium functionalized PVA composite membrane compared to quaternary ammonium functionalized membrane makes it a promising candidate for direct methanol alkaline fuel cell applications. © 2020 Society of Chemical Industry     

Synthesis and Characterization of 5-Coordinate Tungsten Hydride Anions: [(tBu3SiNH)(tBu3SiN=)2HWR]M

Treatment of (^tBu₃SiNH)(^tBu₃SiN=)₂WH ( 1 -H) with small alkyl anions (RM) afforded tungsten alkyl hydride anions [(^tBu₃SiNH)(^tBu₃SiN=)₂HWR)]M ( 3 -(R)M: R=CH₃, M=Li; R=ⁿBu, M=Li; R=^neoPe, M=Li; R=CH₂Ph (Bn), M=K (two isomers); R=CCH, M=Na; R=CH=CH₂ (Vy), M=Li). The saturated alkyl anions 3 -(R)M ( 3 -(R)M: R=CH₃, M=Li; R=ⁿBu, M=Li; R=^neoPe, M=Li; R=CH₂Ph (Bn), M=K) degraded via apparent 1,2-RH-elimination to produce the known [(^tBu₃SiN=)₃WH]M ( 2 -HM), but the acetylide ( 3 -(C₂H)Na) and vinyl ( 3 -(Vy)Li) anions converted to their hydrogenated isomers, [(^tBu₃SiN=)₃WVy]Na ( 2 -VyNa) and [(^tBu₃SiN=)₃WEt]Li ( 2 -EtLi), respectively. The structure of 3 -(ⁿBu)Li is reported, and a discussion of tungsten-hydride coupling constants in ^tBu₃SiX-ligated (X=O, NH, N) systems is given.     

聚4-乙烯吡啶基碱性膜的制备及性能分析

采用自由基聚合制备聚4-乙烯吡啶(P4VP)。引入溴乙醇(BE)对制备的P4VP进行季铵化处理,合成一系列不同季铵化取代度的季铵化聚4-乙烯吡啶(QPVPE),最后,引入戊二醛(GA)与QPVPE进行交联,制备得到适合燃料电池使用的交联型聚4-乙烯吡啶基碱性膜。实验过程中,借助傅里叶变换红外光谱(FTIR)、紫外光谱(UV)、扫描电子显微镜(SEM)、热重分析(TGA,DTG)及力学性能测试等分析手段,对得到的导电膜结构及其理化性能进行分析,并对其导电性能进行性能测试。结果表明,QPVPE77.6%-GA16.87%膜综合性能最佳,该膜的电导率为10.48 mS/cm、含水率(WU)86.4%、溶胀率(SR)66.8%、拉伸强度为23.97 MPa。在25℃条件下,于1 mol/L的KOH溶液中浸泡192 h后,电导率损失为19%。因此,该膜具有较好的耐碱性能。     

Pd-Decorated Tungsten as Pt-Free Bimetallic Catalysts for Hydrogen Oxidation Reaction in Alkaline Electrolyte

Developing Pt-free catalysts for hydrogen oxidation reaction (HOR) in alkaline solution is becoming a key challenge in the development of anion exchange membrane fuel cells and electrochemical reactors. Herein, we present the preparation, HOR activity, and stability of Pd-decorated tungsten (Pd-d-W) catalysts. The Pd-d-W catalysts were prepared by the chemically activated surface of tungsten nanoparticles by Pd ions. The resultant bimetallic catalysts consisted of crystalline phases of both Pd and W nanoparticles. The CO stripping voltammograms and H-desorption (H_des) peak potential of hydrogen desorption in Pd suggests that the enhancement of HOR catalytic activity observed in Pd-d-W catalyst can be ascribed to the modification of electronic property of Pd and availability of OH_ad near-surface Pd atoms.