含钴介孔分子筛Co-MCM-41耦合溴化四丁基铵协同催化苯乙烯直接氧化碳酰化制备苯乙烯环状碳酸酯

Direct Oxidative Carboxylation of Styrene to Styrene Carbonate over Cobalt-containing Mesoporous Molecular Sieves(Co-MCM-41) and Tetrabutylammonium Bromide Co-catalysts

以苯乙烯为起始物,经催化环氧化然后环氧化物与二氧化碳环加成反应"串联一锅"制备苯乙烯环状碳酸酯,反应工艺简单(避免了中间体环氧化物的事先合成与分离)且绿色经济(原料苯乙烯比苯乙烯环氧化物价格低廉且毒性小),工艺具有潜在的工业应用前景。探讨了掺杂不同金属(Co,Fe,Ni,Mn,Cu,Ti)的MCM-41介孔分子筛催化剂对苯乙烯环氧化的转化率和选择性,研究表明以含钴介孔分子筛Co-MCM-41为最佳,并以Co-MCM-41耦合溴化四丁基铵(TBAB)为催化剂,考察了苯乙烯直接氧化碳酰化制苯乙烯环状碳酸酯反应。从影响反应活性和产物选择性的因素来优化反应,在80℃、4 MPa、CO2压力下,反应7 h,碳酸酯的收率达到46.1%。Co-MCM-41催化第一步苯乙烯环氧化反应,溴化四丁基铵催化第二步环加成反应。

Synthesis of cyclic carbonate from styrene and CO2 gives a simple route that avoids the preliminary synthesis and isolation of epoxides. This direct synthesis route for cyclic carbonate from olefin is not only energy saving but also simple and economical. Herein, we synthesized various metal-dopped MCM-41 such as M-MCM-41 （M = Co, Fe, Ni, Cu, Ti）, and Co-MCM-41 catalyst showed the highest selectivity and yield to styrene epoxide among the various catalysts in the epoxidation of styrene. Then Co-MCM-41 was chosen to combine with tetrabutylammonium bromide （TBAB） to catalyze the direct oxidative carboxylation in one-pot. It was found that the Co-MCM-41/TBAB catalysts efficiently catalyzed the direct oxidative carboxylation of styrene to styrene carbonate. An improved styrene carbonate yield of 46. 1% was obtained under mild reaction conditions of 80 ℃, 7 h, and 4 MPa CO2 pressure. It was found that Co-MCM-41 catalyzed the first epoxidation reaction and TBAB catalyzed the second cycloaddition reaction of CO2.