Intensified modified fruit blender reactor for emulsifier synthesis via glycerol esterification of free fatty acids at mild conditions

Abstract

A modified fruit blender reactor (M−FBR) was applied to synthesize monoacylglycerols (MAGs) and diacylglycerols (DAGs) through biphasic esterification of glycerol (Gly) with oleic acid (OA). The high stirring speed in the M−FBR provided a high mixing efficiency to generate significantly small droplets and cavitation compared to those in conventional processes. The increased interfacial surface area and distribution of dispersed phases into continuous phases promote momentum, heat, and mass transfer to improve mixing efficiency and high glycerol esterification rate. The reaction time and methanesulfonic acid (MSA) concentration were the most significant factors, affecting both OA conversion and MAG-DAG yields, while the Gly/OA molar ratio exhibited a less significant effect. The highest yields for MAG-DAG in 60 min using the M−FBR were 80.4 and 82.9% at 110 and 130 °C, respectively. The values of yield efficiency of M−FBR were 67.3 x 10⁻⁴ g/J at 110 °C and 69.8 x 10⁻⁴ g/J at 130 °C, which were up to 25–fold higher than that of the mechanical stirred reactor. The M−FBR generated small glycerol droplet (46–56 µm) to enhance the glycerol solubility in the OA phase, allowing the MAG and DAG synthesis to be conducted at a lower Gly/OA molar ratio. This offered higher selectivities of MAG and DAG and prevent undesirable TAG. Additionally, the simplified evolution of MAG-DAG formation during the glycerol esterification of OA was elucidated by ATR-FTIR spectroscopy.