Reactive Extraction Based Ionic Liquid For Caproic Acid Esterification

In chemical industry,preparation method of fatty esters with more than ten carbon is catalytic esterification reaction with sulfuric acid.The traditional method has high purification cost and makes huge pollusion.Ionic liquid is a new type of catalysts and green solvent which has attract popular attention in recent years.The work aims two reaction systems?hexanoic acid and n-butanol and hexanoic acid and isoamyl alcohol?to explore a general optimization method in which the ionic liquid[C₄mim][HSO₄]is both catalyst and extractant.Firstly,the solubility of between reactants and products with[C₄mim][HSO₄]was predicted by COSMO-RS.To verify the accuracy,liquid liquid equilibrium?LLE?of three systems?[C₄mim][HSO₄]-hexanoic acid-butyl caproate,[C₄mim][HSO₄]-n-butanol-butyl caproate and[C₄mim][HSO₄]-isoamyl alcohol-isopentyl hexanoate?were measured and the binary interaction coefficients of NRTL were fitted using LLE data.The results show that[C₄mim][HSO₄]is comfirmed to be a feasible extractant in the esterification process and the COSMO-RS molecular fingerprint information ?-profile and ?-potential could confinedly predict intersolubility between organic matters and ionic liquid.Secondly,the results of reactive extraction using ionic liquid were tested to determine the influence of reactants solubility.Analyzed the experimental results and LLE data,the conclusions are proved that the intersolubility between alcohol and ionic liquid can affect the reaction extraction for different reaction systems and high conversion of hexanoic acid and high selectivity of ester could be obtained.Compared with traditional preparation,the reactive extraction using[C₄mim][HSO₄]requires harmless catalyst,simple process and less energy consumption.