摘要
醋酸正丙酯对多种合成树脂具有优良的溶解能力,常用于有机合成过程和用作涂料、印刷油墨等的溶剂,也是工业上常用的脱水剂。醋酸正丙酯酯化反应通常采用浓硫酸作为催化剂,但存在设备腐蚀严重、副反应多、后处理过程复杂和污染环境等缺点。利用离子液体具有的稳定性好、不挥发、与有机物相容性可调、酸性可调等特性,制备适用于醋酸正丙酯酯化反应的烷基咪唑磺酸盐酸性离子液体催化剂,并对其性能进行了实验考察。实验结果表明:合成的烷基咪唑磺酸盐离子液体pH值只有2左右,其酸性比浓硫酸低很多,但其酯化催化活性高,催化活性稳定,可重复使用,不具有氧化性,腐蚀性小,不水解,不挥发,属于环境友好的新型酯化催化剂,性能优于Lewis酸催化剂。采用烷基咪唑磺酸盐离子液体催化合成醋酸正丙酯,在乙酸与正丙醇摩尔比(物质的量比)为1∶1.05,催化剂加量与反应物料质量比为1∶9,反应时间为3h的反应条件下,其酯化转化率可达90.0%～97.7%。
n-propyl acetate has excellent solvability to a range of synthetic resins.It is widely used in organic synthesis process and as solvent in the production of paint and printing ink.It is also a commonly used industrial dehydrating agent.The use of concentrated sulfuric acid as a catalyst is very common in the esterification of n-propyl acetate although there are some downsides of the use of the acid such as serious equipment corrosion,excess side reaction,complicated post-treatment process and environmental pollution.To exploit the many good properties of ionic liquid such as good stability ,non-volatilization,adjustable compatibility with organic substance and adjustable acidity,researchers prepared an alkyl imidazole sulfonate acidic ionic liquid catalyst suitable for use in the esterification of n-propyl acetate and tested its performance through experiment.The experimental results show that the pH of the alkyl imidazole sulfonate acidic ionic liquid synthesized is only about 2.Its acidity is much lower than that of concentrated sulfuric acid but it has higher catalytic activity in esterification and stable catalytic activity.It is recyclable,nonoxidizable,less corrosive,unhydrolyzed and nonvolatile.It is a new type of environmentally friendly esterification catalyst with properties better than Lewis acid catalyst.In synthesizing n-propyl acetate in the presence of alkyl imidazole sulfonate acidic ionic liquid catalyst,when the molar ratio of acetic acid to n propanol is 1：1.05,the ratio of the amount of catalyst used to the weight of the reaction mass is 1：9 and the reaction time is three hours,the esterification conversion rate could reach 90.0%-97.7%.
出处
《中外能源》
CAS
2010年第5期84-87,共4页
Sino-Global Energy
关键词
离子液体
酯化
醋酸
正丙醇
ionic liquid
esterification
acetic acid
n-propanol
