Esterification reaction using ionic liquids (ILS) as homogeneous catalyst

Abstract

Ionic Liquids (ILs) based on 1-n-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI.NTf2) and ILs based on choline chloride (ChCl) under acidic condition was used as catalysts for esterification reaction between alcohol with fatty acid. Combination various acid namely sulphuric acid, perchloric acid, p-toulene sulphonic and various chloride salts such as ZnCl2, SnCl2 and FeCl3 with ionic liquids BM.NTf2 and choline chloride gave acidic ILs. These acidic ILs were tested as catalysts for esterification reaction. Esterification of alcohol (methanol) with fatty acid (lauric acid) using BMI.NTf2 ILs combination with H2SO4 gave high activity (100 %) and selectivity (100 %) was observed over a period of 2 hours reaction with reaction temperature 70 °C. The ester was easily separated due to ILs form as biphasic with product after reaction where is ester accumulates as the upper phase and ILs with water that produce after reaction at below phase. These ILs were characterized using FTIR and NMR. From FTIR result no significant difference between ILs with combination ILs in acidic condition. The advantages of ILs as catalyst are “clean process” and “green chemistry” due to its behaviour such as non-volatile, no loss of solvent through evaporation and reduced environmentally impact. This ILs-catalyst system can be recycle for futher reaction.