Reactive extraction for intensifying 2-ethylhexyl acrylate synthesis using deep eutectic solvent [Im:2PTSA]

Abstract

2-Ethylhexyl acrylate (2-EHA) is one of the most widely used acrylates in the polymer industry, which is synthesized via Fisher esterification that is limited by chemical equilibrium. To intensify the esterification process, in this work, reactive extraction concept is proposed, with halogen-free deep eutectic solvent (DES [Im:2PTSA]) as dual solvent-catalyst that consists of imidazole (Im) and p-toluenesulfonamide (PTSA). The bifunctional effects of the DES [Im:2PTSA] are evaluated by thermodynamic analysis and experimental study. Favorable phase splitting is verified by σ-potential analysis predicted by COSMO-RS theory, combined with experiments, and the optimal acid-to-alcohol molar ratio is set to 1.2. The esterification kinetics is then experimentally determined and fitted using the molar-based and activity-based pseudo-homogeneous (PH) models, respectively. The activity-based PH model, that considers the bifunctional roles of the DES, proves to be more accurate with small RMSD of 0.0344. The stability of DES after recycling is validated to further confirm the industrial prospects of DES [Im:2PTSA] in 2-EHA production.

Keywords

• 2-Ethylhexyl acrylate
• Deep eutectic solvent
• Reactive extraction
• Esterification kinetics
• COSMO-RS