Sonochemical enzymatic esterification of oleic acid and tri-ethanolamine for a fabric softener in textile application

Abstract The present study deals with the ultrasound-assisted enzymatic synthesis of diester from oleic acid and triethanolamine (TEA) for the preparation of esterquat. The effect of reaction conditions such as sonication time, reaction temperature, sonication power, enzyme loading on the % of esterification has been investigated. Acid value analysis was used to check the progress of the reaction. The formed product was confirmed with Fourier-transform infrared spectroscopy (FTIR) analysis. The highest esterification (%) was found at sonication time of 2.5 h (150 min), a reaction temperature of 40 °C, sonication power of 80 W and catalyst concentration of 3 wt. % lipase. The enzymatic ultrasound method (EUS) compared with conventional heating method (NUS) and the conventional enzymatic method (NEUS). EUS method requires only 2.5 h while the NUS and NEUS method requires 8 h and 24 h of time for the esterification reaction respectively. Catalyst reusability has been investigated. The important surface-active properties of the prepared esterquat have been investigated and it shows the excellent application in the textile as a fabric softener. Ultrasound-assisted synthesized esterquat has a great potential in terms of economical product to serve desirable property to the fabric.