Catalysts, kinetics and process optimization for the synthesis of methyl acrylate over Cs–P/γ-Al2O3

Abstract

Bifunctional catalysts Cs–P/γ-Al₂O₃ were developed and firstly applied in a one-step synthesis of methyl acrylate using methyl acetate (Ma) and formaldehyde (FA). The catalysts were prepared using impregnation and characterized with X-ray diffraction, transmission electron microscopy, thermogravimetry and differential thermal analysis, nitrogen adsorption–desorption, ammonia- and carbon dioxide-temperature programmed desorption methods. The catalytic performance was evaluated using a fixed-bed microreactor. Experimental results indicated that the P loading had significant influence on the catalytic activity by modifying the acid–base surface properties of the catalyst. The process optimization using response surface methodology was performed and the interactions of operational variables including the Ma/FA molar ratio, reaction time and temperature were elucidated. Then the kinetics of the aldol condensation reaction was studied using a pseudo-homogeneous kinetic model. In addition, the lifetime of optimum Cs10%–P5%/γ-Al₂O₃ catalyst was evaluated over a continuous period of 400 h, and did not exhibit an obvious decrease in efficiency.