以磷钨杂多酸银盐为催化剂合成丁酮乙二醇缩酮

以磷钨杂多酸银盐(AgxH3-xPW12O40,0相似文献   

反应控制相转移催化剂催化环己烯氧化制己二酸

The goal of modern organic synthesis is to develop efficient catalytic methods to produce desired compounds in a cost-effective and environmentally benign manner. Hydrogen peroxide is a highly attractive oxidant because it is a cheap, mild and environmentally friendly reagent with a high content of active oxygen, and water is the only by-product.     

磷钨杂多酸银盐催化合成缩酮(醛)

利用沉淀法制备了一系列磷钨杂多酸银盐(AgxH3-xPW12O40,0相似文献   

12-钨磷酸钙与丁二酰亚胺加合物的制备和性质研究

本文研究了12-钨磷酸钙与丁二酰亚胺和邻苯二甲酰亚胺的加合反应,制备了12-钨磷酸钙的丁二酰亚胺加合物Ca_(3/2)PW_(12)O_(40)·4(CH_2CO)_2NH·7H_2O,测定了加合物的红外光谱、拉曼光谱和热重差热分析曲线,用X射线粉末衍射方法研究了加合物的结晶学特征.结果表明.配体丁二酰亚胺以一个羰基氧与金属阳离子配位,加合物的形成对杂阴离子的Kcggin结构没有明显影响.但WO_6八面体发生一定的畸变.其中W-O_d键减弱,W-O_c键增强.加合物属单斜晶系,晶胞参数为:a=25.839(6).b=13.223(2),c=18.438(2)(?),β=97.06(2)°,V=6251.88(?)~3,可能的空间群为C_2h~5-P2_1/c或C_2h~2-P2_1/m或C_2~2-P2_1,品质因子F_(30)=54(0.012,45).     

1-丁基-3-甲基咪唑磷钨酸盐的制备及其对酯化反应的催化性能

以溴化1-丁基-3-甲基咪唑盐([bmim]Br)和磷钨酸(H3PW12O40)为原料制备了1-丁基-3-甲基咪唑磷钨酸盐([bmim]3PW12O40)催化剂,并用傅里叶变换红外光谱、热重分析-差示扫描量热法、正丁胺电位滴定及元素分析等技术对催化剂进行了表征,考察了催化剂对乙醇与乙酸酯化合成乙酸乙酯反应的催化活性.结果表明,[bmim]3PW12O40中有3个结晶水,并保持有H3PW12O40的Keggin结构和酸强度,[bmim]3PW12O40的酸量明显少于H3PW12O40的酸量.在乙醇与乙酸酯化合成乙酸乙酯反应中,[bmim]3PW12O40催化剂具有较高的催化活性和较好的重复使用性能.     

Preparation of 1-butyl-3-methylimidazolium dodecatungstophosphate and its catalytic performance for esterification of ethanol and acetic acid

1-Butyl-3-methylimidazolium dodecatungstophosphate catalyst ([bmim]₃PW₁₂O₄₀) with high water tolerance was prepared from 1-butyl-3-methylimidazolium bromide ([bmim]Br) and phosphotungstic acid (H₃PW₁₂O₄₀). The catalyst was characterized by means of Fourier transform infrared spectroscopy, thermogravimetry-differential scanning calorimetry, n-BuNH₂ potentiometric titration, elemental analysis and so on. Its catalytic activity for esterification of ethanol and acetic acid to ethyl acetate was measured. The results show that there were three crystal-water molecules in the [bmim]₃PW₁₂O₄₀ catalyst, and it preserved the primary Keggin structure and acid strength of H₃PW₁₂O₄₀. The acid amount of [bmim]₃PW₁₂O₄₀ catalyst was less than that of H₃PW₁₂O₄₀. The [bmim]₃PW₁₂O₄₀ catalyst exhibited higher catalytic activity and reusability in the esterification of ethanol and acetic acid to ethyl acetate. __________ Translated from Chinese Journal of Catalysis, 2008, 29(7) (in Chinese)     

12-钨磷酸二甲基胺盐的制备和结构研究

本文由12-钨磷酸与二甲基甲酰胺反应制备了12-钨磷酸二甲基胺盐[(CH)_3)_2NH_2]_3(PW_(12)O_(40))·nH_2O,用红外光谱和热重差热分析研究了化合物的性质,用X射线单晶结构分析测定了化合物的结构。晶体属单斜晶系,空间群为C_(2h)~3-C2/m,结晶学参数为:a=19.345(7),b=16.506(2),c=12.711(2)(?),β=101.83(2)°,V=3972.5(?)~3,Z=4,Dc=3.037g/cm~3。结构测定共收集了4414个独立衍射点,其中2917个I>3σ(I)独立可观察衍射点,结构用全矩阵最小二乘法修正后最后R=0.0856,R_w=0.1186。在分子结构中,杂阴离子为完整的α-Keggin型结构,三个二甲基胺阳离子位于一组W_3O_(13)三联体与其他三组W_3O_(13)三联体通过共顶点相连而形成的面上。由于阳离子与杂阴离子骨架氧之间的氢键作用。致使WO_6八面体发生较大的畸变,与阳离子发生氢键作用的WO_6八面体中的W-O键显著减弱,在红外光谱中表现为υ_(W-O)吸收峰的分裂。     

Aluminum dodecatungstophosphate (AlPW12O40) as a non-hygroscopic Lewis acid catalyst for the efficient Friedel-Crafts acylation of aromatic compounds under solvent-less conditions

Stable and non-hygroscopic aluminum dodecatungstophosphate (AlPW₁₂O₄₀), which is prepared easily from cheap and commercially available compounds was found to be an effective catalyst for Friedel-Crafts acylation reactions using carboxylic acids, acetic anhydride and benzoyl chloride in the absence of solvent under mild reaction conditions.