固载化亚胺乙酸-铜配合物催化剂在分子氧氧化有机物过程中的催化性能

摘要

Polyethyleneimine (PEI) grafted onto micron-sized silica gel particles was made to react with chloroactic acid to form the imido-acetic acid (IAA)-type composite chelating particles, IAA-PEI/SiO2. Subsequently, the coordinative chelation reaction between IAA-PEI/SiO2 and copper salt was performed, which obtains immobilized imido-acetic acid-Cu(II) complex, Cu(II)-IAA-PEI / SiO2. This immobilized complex was used as a heterogenous catalyst in the oxidation reaction of ethylbenzene and benzyl alcohol with molecular oxygen, and the catalytic activities and the mechanisms of the catalytic oxidations were investigated. The experimental results show that the immobilized imido-acetic acid-Cu(II) complex, Cu(II)-IAA-PEI/SiO2, can efficiently catalyze the oxidation process of ethylbenzene by molecular oxygen, and the main product is acetophenone. Under the suitable temperature (130℃) and used amount of the catalyst, acetophenone yield is 40%. The composite catalyst consisted of 2,2,6,6-tetramethyl-piperidinyloxyl (TEMPO) and Cu(II)-IAA-PEI/SiO2 can highly efficiently catalyze the oxidation reaction of benzyl alcohol to form benzaldehyde with molecular oxygen as oxidant. Under the mild conditions (with oxygen at atmospheric pressure and at the temperature of 80℃), the yield of benzaldehyde can be up to 75%.%　　利用接枝于微米级硅胶表面的聚乙烯亚胺(PEI)与氯乙酸反应，制备了亚胺乙酸(IAA)型复合螯合微粒IAA-PEI/SiO2,再使之与铜(Ⅱ)盐配位螯合，形成固载化亚胺乙酸-铜配合物 Cu(Ⅱ)-IAA-PEI/SiO2。将微粒Cu(Ⅱ)-IAA-PEI/SiO2用作非均相催化剂，用于分子氧氧化乙苯与苯甲醇的氧化反应，研究了催化活性与催化氧化机理。研究结果表明，固载化亚胺乙酸-铜配合物 Cu(Ⅱ)-IAA-PEI/SiO2可有效地催化分子氧氧化乙苯的过程，主产物为苯乙酮，在适宜的温度(130℃)与适宜的催化剂用量条件下，苯乙酮的得率为40%。Cu(Ⅱ)-IAA-PEI/SiO2与2,2,6,6-四甲基哌啶氧自由基(TEMPO)所构成的复合催化剂，可高效地催化分子氧氧化苯甲醇的氧化反应，产物为苯甲醛，在温和条件下(常压下的氧气、80℃)，苯甲醇的转化率可达75%。