Ionic liquids derived from esters of Glycine Betaine: Synthesis and characterization

A series of new “green” ionic liquids was prepared in two or three steps from natural and low expense Glycine Betaine (GB). Esterification of GB was carried out with methanesulfonic acid and primary alcohols with alkyl chains containing 6, 12, 14, 16 and 22 atoms of carbon. Anionic metathesis from these cationic esters with inorganic (ClO4−, BF4−) or biobased ((S)-CH3-CHOH-COO− (Lac−)) anions was then achieved to afford a range of fully characterized ionic liquids. The influence of the alkyl chain length and the chemical nature of the counter anion on physicochemical properties such as melting point, glass transition, decomposition temperatures and viscosity has been investigated.