对甲苯磺酸催化合成草酸二异戊酯的研究

以草酸和异戊醇为原料,对甲苯磺酸为催化剂,环己烷为带水剂,合成了新型柴油十六烷值改进剂草酸二异戊酯。考察了酸醇的物质的量比、反应时间、催化剂用量和带水剂用量等因素对酯收率的影响。结果表明:当反应温度为回流温度(85~100℃),n(草酸)∶n(异戊醇)=1∶3.5,催化剂用量为草酸质量的1.5%,带水剂用量为10mL/0.1 mol草酸,反应时间110~120 m in时,草酸二异戊酯的收率大于88%。与现有工艺相比,采用对甲苯磺酸为催化剂,环己烷为带水剂,具有反应温度低、反应时间短、带水剂的毒性较小、草酸二异戊酯的收率和纯度较高等优点。产物经红外光谱和气相色谱分析,证明确为草酸二异戊酯且纯度大于98%。

Research on the synthesis of diisopentyl oxalate catalyzed by p-toluene sulphonic acid

The new type of cetane improver diisopentyl oxalate is synthesized by esterification of oxalic acid and isopentyl alcohol with p-toluene sulphonic acid as catalyst and cyclohexane as water-carrying agent.Influences of the mole ratio of reactants,reaction time,dosage of catalyst and cyclohexane on yield are discussed.Under the optimum reaction conditions:reaction temperature is 85~100℃,n(oxalic acid)∶n(isopentyl alcohol)=1∶3.5,catalyst amount is 1.5% weight of oxalic acid,water-carrying agent amount is 10 mL cyclohexane per 0.1 mol oxalic acid,the reaction time is 110~120 min,the yield can be more than 88%.Compared with the reported technology,this method has many advantages such as lower reaction temperature,shorter reaction time,less toxic water-carrying agent,higher yield and purity.The product is analyzed by IR and GC.The purity of the product is over 98%.