Solvent-free lipase-catalyzed production of (meth)acrylate monomers: Experimental results and kinetic modeling

Abstract

This paper gives detailed insight in the solventless synthesis of (meth)acrylate esters catalysed by Novozym 435 with a focus on the quantitative understanding of the reaction kinetics. The (meth)acrylate esters were formed from various (heavy boiling) alcohols by applying methyl (meth)acrylate in excess. Attractive ester titers were obtained (up to 800 g.kg−1 for citronellyl acrylate) combined with a depletion of the (heavy boiling) alcohols, simplifying downstream processing. To study the kinetics, all experimentally obtained progress curves were simultaneously used from every conversion as input for nonlinear regression. The generic developed model based on second order reaction kinetics resulted in a good fit with the experimental data. Higher reaction rate constants were systematically obtained for methyl acrylates (from 0.69 kg/mol/h for 2-hexyl-1-decyl acrylate to 1.69 kg/mol/h for citronellyl acrylate) compared to methyl methacrylate (from 0.35 kg/mol/h for tetrahydrofurfuryl methacrylate to 0.44 kg/mol/h for 4-methoxybenzyl methacrylate). This proves the former to be a better accepted substrate for Novozym 435 compared to the latter.