Highly Selective Synthesis of Monolaurin via Enzymatic Transesterification under Batch and Continuous Flow Conditions

New Technology for the Synthesis of Glycerol Monooleate

Herein, a new approach for glycerol monooleate (GMO) was developed. GMO was synthesized via the esterification method using self-made sodium oleate and 3-chloro-1,2-propanediol as reactants, tetrabutylammonium bromide as the catalyst, and toluene as the solvent. The effects of the reaction molar ratio, type and amount of catalyst, and reaction temperature and time on the yield were investigated. Results showed that the optimal process conditions for synthesizing GMO were as follows. The molar ratio of sodium oleate to 3-chloro-1,2-propanediol was 1:2, the reaction temperature was 115°C, the reaction time was 6 h, weight of toluene was 25 g, and the catalyst dosage was 3.5%. Under these conditions, high-purity GMO was synthesized with a yield of 89.02%.

Improved Synthesis of α-Glycerol Monolaurate Using Lipozyme TL IM

This study aimed to synthesize α-Glycerol Monolaurate from protected glycerol (glycerol 1,2-acetonide) using Lipozym TL IM as a catalyst. In the first step, transesterification of methyl laurate and glycerol 1,2-acetonide with Lipozyme TL IM produced 1,2-acetonide-3-lauryl glycerol. In the second step, deprotection of 1,2-acetonide-3-lauryl glycerol with Amberlyst-15 produced α-Glycerol Monolaurate. Furthermore, the optimum yield (82.1%) of 1,2-acetonide-3-lauryl glycerol (light yellow liquid, purity of 92%) was achieved at a reactant mole ratio of 1, n-hexane (4 mL) with a reaction time of 12 hours, and total Lipozyme TL IM of 5% (w/w of the total weight of reactants) at a temperature of 35°C. Deprotection of 1,2-acetonide-3-lauryl glycerol with Amberlyst-15 was conducted at room temperature for 24 hours. At a melting point of 62.8°C, and purity of 100% α-Glycerol Monolaurate in the form of a white solid was obtained with a yield of 74.6% after the recrystallization of the crude product. This α-glycerol monolaurate synthesis reaction pathway can be referred to as a green α-monoacylglyceride synthesis method.