Critical assessment of the efficiency of chitosan biohydrogel beads as recyclable and heterogeneous organocatalyst for C–C bond formation
作者:Dennis Kühbeck、G. Saidulu、K. Rajender Reddy、David Díaz Díaz
DOI:10.1039/c1gc15925a
日期:——
The effectiveness of neutral pH chitosan hydrogel beads (CSHB) as a green organocatalyst for a variety of CâC bond forming reactions (i.e. aldol reaction, Knoevenagel condensation, nitroaldol (Henry) reaction, Michael addition) has been comprehensively evaluated. Reaction rates, conversions and selectivities were studied as a function of a series of input variables including size, pH and reactive surface area of the beads, catalyst loading, temperature, molecular weight of the biopolymer, concentration, solvent system and molar ratio of reactants. Moreover, the catalytic biohydrogel beads were characterized by a variety of techniques including, among others, SEM, FT-IR, TGA and DSC.
中性pH壳聚糖水凝胶珠(CSHB)作为一种绿色有机催化剂,在多种C-C键形成反应(例如醛醇反应、Knoevenagel缩合反应、硝基醛醇(Henry)反应、Michael加成反应)中的有效性已得到全面评估。研究了反应速率、转化率和选择性随一系列输入变量(包括珠子大小、pH值、反应表面面积、催化剂负载量、温度、生物聚合物分子量、浓度、溶剂体系和反应物摩尔比)的变化情况。此外,通过多种技术手段(包括扫描电镜(SEM)、傅里叶变换红外光谱(FT-IR)、热重分析(TGA)和差示扫描量热法(DSC))对催化性生物水凝胶珠进行了表征。