NMR and HPLC characterisation of <i style="mso-bidi-font-style:normal">O</i>-alkanoyl lactates prepared by lipase catalysis

Abstract

Lactic acid esters of organic acids like lauroyl, palmitoyl and stearoyl lactic acids prepared by using lipases have been characterized by ¹H and ¹³C NMR spectra. The reaction mixture indicates the presence of several species due to complex esterification equilibria. Crystalline lactic acid employed for reactions shows more lactylate content than the commercially available lactic acid. The -CH-O- region between 4.03 and 5.13 ppm gives quite a lot of information on the ester formation as this region contains signals from free lactic acid, hydroxyl terminal group of lactylates, carboxyl terminal group of lactylates and lactic acid and lactylate esters of organic acids employed. The ester yields determined by HPLC and NMR are comparable and are less than those determined by titration method.