Development of heterogeneous catalysts with molecular recognition by a molecular imprinting technique

本研究的目的是利用分子印迹技术开发具有分子识别功能的多相催化剂，并尝试制备一种具有酸碱催化性能的分子印迹催化剂。假设以四面体配位构象作为酯水解的过渡态模型，我们以磷化合物为模板分子进行乙酸乙酯的水解反应。磷模板被吸附在氧化铝表面，随后在模板周围形成二氧化硅基质覆盖层。然后用乙醇提取模板。吸附在表面上的大约85%的模板被移除，以在模板后面留下一个空腔。制得的催化剂对乙酸乙酯的水解反应具有良好的催化性能。在模板腔的分子印迹催化剂上，抑制了大于模板尺寸的酯分子的水解，而促进了分子尺寸等于或小于模板尺寸的酯分子的水解。

The aim of this study is to development of heterogeneous catalysts with molecular recognition by a molecular imprinting technique.We attempted to prepare a molecular imprinting catalyst which exhibits acid-base catalysis for hydrolysis of esters. Assuming a tetrahedral coordination conformation as a transition state model for the ester hydrolysis, we used a phosphorous compound as a template molecule for hydrolysis of ethyl acetate. The phosphorous template was adsorbed on an alumina surface, followed by formation of silica matrix overlayers surrounding the template. Then the template was extracted with ethanol. About 85 % of the templated adsorbed on the surface was removed to leave a cavity behind the template. The obtained catalyst showed a good performance for the hydrolysis of ethyl acetate. Hydrolysis of the larger ester molecules than the template was inhibited, while hydrolysis of the esters with molecular sizes equivalent to and smaller than the template size was promoted on the molecular imprinting catalyst with the template cavity.