Oxygen permeation and phase structure properties of partially A-site substituted BaCo_(0.7)Fe_(0.225)Ta_(0.075)O_(3-δ) perovskites

Ba0.9R0.1Co0.7Fe0.225Ta0.075O3-δ(BRCFT, R = Ca, La or Sr) membranes were synthesized by a solid-state reaction. Metal cation Ca2+,La3+or Sr2+doping on A-site partially substituted Ba2+in BaCo0.7Fe0.225Ta0.075O3-δoxides, and its subsequent effects on phase structure stability, oxygen permeability and oxygen desorption were systematically investigated by XRD, TG-DSC, H2-TPR, O2-TPD techniques and oxygen permeation experiments. The partial substitution with Ca2+, La3+or Sr2+, whose ionic radii are smaller than that of Ba2+, succeeded in stabilizing the cubic perovskite structure without formation of impurity phases, as revealed by XRD analysis. Oxygen-involving experiments showed that BRCFT with A-site fully occupied by Ba2+exhibited good oxygen permeation flux under He flow, reaching about 2.3mL min-1 cm-2at 900 ℃ with 1 mm thickness. Of all the membranes, BLCFT membrane showed better chemical stability in CO2, owing to the reduction in alkalinity of the mixed conductor oxide by La doping. In addition, we also found the stability of the perovskite structure under reducing atmospheres was strengthened by increasing the size of A-site cation(Ba2+La3+Sr2+Ca2+).     

Poly(amide-6-b-ethylene oxide)/SAPO-34 mixed ma-trix membrane for CO2separation

In this paper, poly（amide-6-b-ethylene oxide） （Pebax1657）/SAPO-34 mixed matrix membranes （MMMs） were prepared by solvent-evaporation method with acetic acid as a novel solvent. CO2, N2, CH4 and H2 permeation properties were investigated, and the physical properties of Pebax/SAPO-34 MMMs were characterized by XRD and SEM. At low SAPO-34 content, it was homogeneously distributed in the Pebax ma- trix, and then precipitated and agglomerated at high SAPO-34 content. The crystallinity of Pebax phase in Pebax/SAPO-34 MMMs decreased initially and then rebounded as a result of phase separation. With the increase of transmembrane pressure difference, CO2 permeability was en- hanced due to the effect of pressure-induced plasticization. Owing to the happening of stratification, the CO2 permeability of Pebax/SAPO-34 MMMs （50 wt% SAPO-34） increased to 338 Barrer from 111 Barrer of pristine Pebax, while the selectivities of CO2/CH4 and CO2/N2 were almost unchanged. Compared with the pristine Pebax, the gas separation performances of Pebax/SAPO-34 MMMs were remarkably enhanced.     

4-单取代-1,2,3-三氮唑的合成进展(Ⅱ)—通过去取代基反应

1,2,3-三氮唑衍生物是近些年研究热点化合物之一,随着4-单取代型衍生物在医药、农药、材料等领域的广泛应用,该类化合物的合成及应用近些年引起了广大研究者的关注并获得了可喜进展。本文阐述了4-单取代-1,2,3-三氮唑衍生物的合成发展历史,着重综述了近十年来该类唑衍生物的合成发展情况。内容主要涵盖二取代-1,2,3-三氮唑的去取代基反应,包括脱羧、脱苄基、脱羟(酰氧)基及脱取代乙基等反应。文章还包括一些合成方法及其产物的应用,并对一些重要的反应机理做了分析。文章最后对该类化合物的合成做了总结并展望了未来发展方向。     

凝胶色谱/超高效液相色谱-串联质谱法测定饲料中16种脂溶性染料的研究

应用凝胶色谱/超高效液相色谱-串联三重四极杆质谱建立了饲料中16种脂溶性染料测定的新方法。样品经20 m L乙酸乙酯-环己烷(1∶1)提取,凝胶色谱系统净化后,以0.1%甲酸溶液-甲醇为流动相进行梯度洗脱,各脂溶性染料经C18柱得到良好分离。16种染料在2~100μg/L范围内线性关系良好,相关系数(r2)不小于0.99。其检出限为25μg/kg,定量下限为50μg/kg。饲料样品在低、中、高3个加标浓度下,16种脂溶性染料的回收率为66.4%~108.5%,结果表明方法适用于饲料中16种脂溶性染料的检测。该方法操作简单、准确、杂质干扰少。     

新型联苯基三苯胺聚合物的合成与性能研究

以4,4'-二溴联苯和苯胺为原料,经钯催化氨基化反应制得N,N'-二苯基联苯胺(1);以1为单体,分别与对二溴苯(2a),4,4'-二溴二苯砜(2b)和4,4'-二溴二苯甲酮(2c)通过钯催化的C-N交叉偶联反应,合成了3个新型的联苯基三苯胺聚合物:联苯基三苯胺苯(3a,收率88%),联苯基三苯胺砜(3b,收率94%)和联苯基三苯胺酮(3c,收率91%),其结构经1H NMR,IR和XRD表征。采用UV-Vis,TG,DSC,荧光光谱和循环伏安法对3a~3c的性能进行了研究。结果表明:3a~3c失重5%的温度分别为479℃,482℃和355℃;玻璃化转变温度分别为199℃,248℃和215℃;λmax分别位于354 nm,359 nm和385 nm;λem分别为489 nm,472 nm和518 nm;EHOMO值分别为-3.96 eV,-3.89 eV,-3.94 eV;ELUMO值分别为-1.16 eV,-1.17 eV和-1.39 eV。     

C_(60)亚甲基衍生物的制备与表征

对富勒烯C60进行化学改性,合成的材料适用于聚合物太阳能电池的受体材料。以对甲氧基苯甲醇为起始原料,再经过几步酯化反应,生成不对称丙二酸双酯,最后利用Bingel反应制备出一种C60富勒烯衍生物,作为潜在的光电材料,其光电特性经CV和UV表征。通过经验公式计算其LUMO能级比PCBM高出0.13eV,是一种潜在的受体材料。     

混合基质水处理膜:材料、制备与性能

以反渗透、纳滤为代表的膜技术已广泛应用于海水和苦咸水脱盐等水处理过程。通过将纳米颗粒添加到传统复合膜基质中,可以制备具有高分离性能和耐污染性的新型膜材料。混合基质膜结合了无机材料及有机聚合物各自的优点,是新型水处理膜材料的发展方向。本文综述了添加无机纳米颗粒的混合基质反渗透、纳滤及正渗透膜的研究进展,详细讨论了不同类型纳米材料的性质和功能,分析了表面有机改性对改善纳米材料分散性以及与聚合物基质相容性的作用,探讨了纳米材料添加方式和膜制备方法对膜结构和性能的影响。在此基础上,进一步探究了混合基质膜的成膜及分离机理,归纳了目前研究中存在的主要问题,并对未来水处理膜材料的研发方向提出了建议。     

三-2-吡喃酮与二苯酮的固相[2+2]光环加成反应

4-羟基-6-甲基-2-吡喃酮分别与原甲酸三氯乙酯,三(溴甲基)氧磷和1,3,5-三(溴甲基)苯经取代反应制得三-2-吡喃酮(3a~3c);3a和3b分别与二苯酮(4)通过经历4的三线激发态,横穿3的C5-C6,C5'-C6'和C5″-C6″双键经固相[2+2]光环加成反应,高位置、高配向选择性地合成了4个新型的氧杂类化合物(5a,5a',5b和5b'),其结构经1H NMR,13C NMR,IR,LR-MS和HR-MS表征。     

新型含磷腈环氧树脂的合成及其阻燃性能

六氯环三磷腈与对羟基苯甲醛经亲核取代反应制得六对醛基苯氧基环三磷腈(HAPCP);HAPCP经高锰酸钾氧化得六对羧基苯氧基环三磷腈(HCPCP);以苄基三乙基氯化铵为催化剂,HCPCP与环氧氯丙烷经开环闭环反应合成了一种新型的含磷环氧树脂(PN-EP),其结构和热稳定性经1H NMR,IR和TGA表征。结果表明,PN-EP的初始分解温度为278℃,在700℃时残炭量为40.5 wt%,具有很好的热稳定性和成炭性能。采用二氨基二苯甲烷对PN-EP进行固化,并通过极限氧指数(LOI)和垂直燃烧(UL-94)对其阻燃性能进行测试。结果表明:PN-EP固化物通过UL-94 V-0级测试,氧指数33%。     

烯烃类衍生物的碘三氟甲基化反应

在ZnI2为催化剂,Togni试剂为三氟甲基化试剂,CHCl3为溶剂的条件下,以中等收率(30%~65%)实现烯烃的碘三氟甲基化反应,合成了一系列既含碘又含三氟甲基的酯类、酮类、酰胺类、腈类等化合物,其结构经1H NMR,13C NMR,19F NMR,IR,MS和HR-MS表征。其中4,4,4-三氟-2-碘丁酰胺,4,4,4-三氟-2-碘-N,N-二甲基丁酰胺和6,6,6-三氟-4-碘-3-己酮为新化合物。