Esterification of atopic acid and 1-butanol catalyzed by SO3H-functionalized ionic liquid

摘要

Several SO_3H-functionalized acidic ionic liquids (ILs) were synthesized by two-step method, using 1, 3-propane sulfone and 1, 4-Butanesultone as raw materials, respectively. It is noteworthy that the ionic liquid using 2-ethyl-4-methylimidazole as source has not been reported. Esterification of 1-butanol with atopic acid was carried out by using these different Bronzed acidic ionic liquids as catalysts. The relationship between the Bronzed acidity-catalytic activity and the relative acidity was studied. Their thermal stability, structure and acidity were characterized by TG-DTG, NMR, UV, respectively. Moreover, the reaction conditions of reaction temperature, molar ratio of reactants, reaction time and ionic liquid amount were optimized. The results indicated that, [2,4-EmiN(CH_2)_4SO_3H][HSO_4] acidic ionic liquid was the best catalyst, and under the optimized reaction conditions of 110°C, n(1-butanol): n(atopic acid)=6:1, m(cat): m(atopic acid)=1.5 %, 3 h, the conversion of atopic acid was 90 % without water-carrying agent.