磷酸和离子液体协同催化杂环化合物与乙酸酐的乙酰化反应

Acylation of Hetercycle with Acetic Anhydride Synergistically Catalyzed by H_3PO_4 and Ionic Liquids

以磷酸为催化剂,研究不同离子液体对呋喃、噻吩与乙酸酐的乙酰化反应影响。还考察了原料比例、反应温度和时间对反应的影响。结果表明:[Bmim]PF6、[Bmim]BF4与磷酸存在协同催化作用。离子液体中的阳离子[Bmim]+可能对呋喃等杂环起稳定作用且减少缩合,阴离子可促进反应。50℃,反应8 h,n(呋喃):n(乙酸酐)=1:1.5,m(呋喃):m(磷酸):m([Bmim]PF6)=13.6:1:1,转化率94.8%,收率88.5%。噻吩乙酰化时,m(呋喃):m(磷酸):m([Bmim]PF6)=16.8:1:1,其他条件同呋喃一样,收率95.4%。

The influence of ionic liquids on Friedel-Crafts acylation of furan and thiophene with acetic anhydride catalyzed by H3PO4 was studied.The effects of material ratio,reaction temperature and reaction time were investigated.The results shown： PF6,BF4 and H3PO4 showed synergistic effect in the process.The cation ＋ may played a role in stabilizing condensation of heterocyclic compounds as furan,and the anion of ILs synergized with H3PO4 catalyzed the acylation of furan and thiophene.Under the optimum conditions of 50 ℃,and 8 h,n（furan）：n（acetic anhydride）=1：1.5,m（furan）：m（H3PO4）：m（PF6）=13.6：1：1,the conversion rate and yield are 94.8 % and 88.5 %.When using thiophene as raw material,the other reaction conditions the same as furan,m（thiophene）：m（H3PO4）：m（PF6）=16.8：1：1,the yield was 95.4 %.