Sintesis Surfaktan Non-Ionik Berbasis Asam Palmitat Melalui Reaksi Esterifikasi dengan Gliserol
Emma Purbaningdyah, Prof. Ir. Hary Sulistyo, S.U., Ph.D., IPU. ; Prof. Ir. Wahyudi Budi Sediawan, S.U., Ph.D.2023 | Tesis | S2 Teknik Kimia
Monoacylglycerol (MAG) and diacylglycerol (DAG) are non-ionic surfactants that are most widely used in various industries such as the food, pharmacy and cosmetic. MAG and DAG are used for edible emulsifiers that aim to maintain the stability of an emulsion and can improve the texture of food products so as to increase the selling value of these food products. Esterification of glycerol using fatty acids is one of the methods used in the conversion of glycerol to synthesize MAG and DAG products. This study aims to determine the effect of operating temperature and the mole ratio of glycerol to palmitic acid on the esterification reaction rate of MAG and DAG product formation. Furthermore, modeling the kinetics of esterification reaction between glycerol and palmitic acid in the synthesis of MAG and DAG.
This research was conducted in a batch system with temperature variations of 90°C, 100°C, 110°C and 120°C; using HCl catalyst concentration of 1% of palmitic acid mass, and variations of reactant mole ratios (palmitic acid/glycerol) of 1:1, 1:2, 1:3, and 1:4. Samples were taken every 10 minutes with a reaction time of 120 minutes. MAG, DAG, TAG, and FFA (Free Fatty Acids) concentration fractions were analyzed by TLC (Thin Layer Chromatography) to determine palmitic acid conversion and product concentration fractions to obtain the best operating conditions. Furthermore, modeling the kinetics of the esterification reaction of glycerol and palmitic acid with HCl catalyst followed the Scatchard-Hildebrand model (Regular Solution Theory) with the help of MATLAB software.
The experimental results show that an increase in temperature increases the formation of products, thereby increasing the product concentration fraction. The increase in temperature will increase the reaction rate because the reaction gets additional energy to reach its activation energy. In addition, the experimental results show that increasing the mole ratio of glycerol to palmitic acid increases the concentration fraction of MAG while the conversion of palmitic acid and the concentration fraction of DAG and TAG decrease, this is because glycerol can react with HCl catalyst to produce by-products. The highest MAG concentration fraction of 8.26% was obtained at 120°C and palmitic acid/glycerol mole ratio (1:4). The best operating conditions were obtained at 120°C and palmitic acid/glycerol mole ratio (1:1) with MAG concentration fraction of 3.29% with the palmitic acid conversion of 80.45% and DAG and TAG concentration fractions of 42.43% and 34.73%. Furthermore, the kinetic mechanism of the esterification reaction of glycerol and palmitic acid with HCl catalyst following the reaction kinetics model with the Scatchard-Hildebrand (Regular Solution Theory) approach has results that are close to the ideal model and shows results that have high accuracy and can represent the reaction well with SSE (Sum of Squared Errors) of 0.0043.
Kata Kunci : glycerol, palmitic acid, HCl, esterification, edible emulsifier