离子液体中催化香茅醛一锅合成薄荷醇

摘要

研究制备了Cu/ZrO2-SiO2双载体催化剂,并在离子液体介质中研究香茅醛催化加氢合成薄荷醇反应。结果表明：离子液体中的阳离子与香茅醛分子中的羰基形成氢键,使香茅醛更容易异构化为胡异薄荷醇,提高了催化剂选择性;特别是可调节酸度的[bmim][AlmCln]离子液体,有效提供香茅醛的异构化所需的路易斯酸条件,在竞争性加氢中促进了香茅醛向生成薄荷醇的方向转化。在0.8 MPa,90℃,2 h的反应条件下,香茅醛转化率为100%,对薄荷醇的选择性为91.3%。而且,催化剂和离子液体可回收和重复使用。%The simple and efficient catalyst of Cu/ZrO2-SiO2 was prepared and chemselective hydrogenation of citronellal over this catalyst at room temperature ionic liquids as clean solvent was performed.The isomerization of citronellal under very mild hydrogenation conditions can be favor toward isopulegols that was hydrogenated to further menthols in Lewis ionic liquids.Citronellal can be converted,100% of conversion and 91.3% of selectivity base on menthols,in onepot process into menthols by competitive hydrogenation.The products distribution was found to depend strongly hydrogen bond formed between carbonyl group of citronellal and cation of ionic liquids.This reaction process was discussed especially and its evolution was also suggested to use in the future.The catalysts and ionic liquids can readily be recovered and reused.