Guanidine based task specific ionic liquids for the synthesis of biolubricant range esters under solvent-free condition

Abstract

Guanidine-based task specific ionic liquids (ILs) were synthesized from the reaction of 1,1,3,3-tetramethyl guanidine with protic acids and used for the synthesis of higher alcohol esters of fatty acids as biolubes under solvent free condition. The synthesized 1,1,3,3-tetramethylguanidinium hydrogen sulphate (TMG·HSO₄) was found to be most effective among the different ILs including 1,1,3,3-tetramethylguanidinium acetate (TMG·Ac), 1,1,3,3-tetramethylguanidinium hydrogen phosphate (TMG·H₂PO₄) and 1,1,3,3-tetramethylguanidinium trifluoro acetate (TMG·TFA). The effect of various reaction parameters such as reaction temperature, reaction time, catalyst amount etc. has been studied. After completion the reaction the esterification product was isolated and the recovered IL was reused for several runs without loss in catalytic activity.