双功能金属卟啉催化环氧化合物与CO_2偶联反应合成环碳酸酯

Bifunctional Metalloporphyrins-Catalyzed Coupling Reaction of Epoxides and CO_2 to Cyclic Carbonates

合成了新颖的双功能水溶性金属卟啉催化剂M(TTMAPP)I4(X)(M=Co,Fe,Mn和Cr;X=OAc,CF3COO,CCl3COO,OTs,Cl,Br和I),研究了它们催化CO2与末端环氧化合物合成环碳酸酯的偶联反应.分别考察了反应温度、不同金属的Lewis酸中心、抗衡离子和催化剂重复使用次数对反应性能的影响.当以Co(Ⅲ)(TTMAPP)I4(OAc)为催化剂,底物与催化剂摩尔比为1000,温度为353K,CO2压力为667kPa和无溶剂条件下,反应5h时丙烯环碳酸酯收率为95.4%.在298K,底物与催化剂之比为2000时,加入1ml甲醇,反应24h丙烯环碳酸酯收率为19.4%.催化剂可以用乙醚回收,循环使用5次后催化剂活性没有明显降低.

New catalysts of water soluble bifunctional metalloporphyrins M（TTMAPP）I4（X） （M = Co, Fe, Mn, and Cr; X = OAc, CF3COO, CCI3COO, OTs, C1, Br, and I） were synthesized and used to catalyze the synthesis of cyclic carbonate through the coupling reaction of terminal epoxides and CO2. The effects of reaction temperature, various metals as the Lewis acidic center, counterions, and recycling of the catalysts were studied. 5,10,15,20-Tetra-（p-N,N-trimethylphenyl ammonium iodide）porphyrinium cobalt（III） acetate [Co（III）- （TTMAPP）Ia（OAc）] was efficient in the coupling reaction of various terminal epoxides and CO2 at 353 K under 667 kPa of CO2 pressure without solvent and molar ratio of epoxide：catalyst = 1000. It gave a propylene carbonate yield of 95.4% within 5 h. At 298 K in the presence of 1 ml methanol with the molar ratio of epoxide：catalyst = 2000, it gave a propylene carbonate yield of 19.4% within 24 h. The catalyst could be recovered with diethyl ether and reused five times without significant loss of catalytic activity.