Two-Step Catalytic Synthesis of Lactose Monolaurate as a Bio-Based Surfactant

A two-step catalytic process for the gram-scale chemical synthesis of lactose monolaurate ester, a promising bio-based surfactant, was developed. A relatively low critical micelle concentration (CMC) of 0.04 w/v%, combined with a hydrophilic–lipophilic balance (HLB) of 14, makes lactose monolaurate an effective surfactant for stabilizing oil-in-water emulsions. ZnCl2 catalyzed the esterification of lactose to lactose octalaurate using lauric anhydride. In the second step, a catalytic amount of KOH was used to hydrolyze lactose octalaurate to produce lactose monolaurate ester. The major side product formed, ethyl laurate, can be used as a biodiesel precursor. This process is scalable and an innovative eco-friendly method for producing bio-based surfactants, contributing to advancements in sustainable chemistry and green technologies.