Acrylic acid synthesis by aldol condensation of acetic acid and formaldehyde on V-Ti-PO4 catalysts

Abstract

The purpose of this work is to research process of aldol condensation of acetic acid with formaldehyde to acrylic acid in the gas phase, namely: to develop effective catalysts for the process of aldol condensation with acetic acid to acrylic acid; to determine optimum conditions for the process; to investigation of the influence of titanium content in a V-Ti-PO4 catalyst and the effect of catalyst calcination on its efficiency in the process of aldol condensation of acetic acid with formaldehyde to form acrylic acid. In order to solve this problem, we designed catalysts based V-Ti-PO4 catalysts. The effect of temperature was examined on the conversion of reagents, the selectivity of formation and the yield of acrylic acid on the created catalysts. With increasing temperature, the conversion increases, the selectivity of formation of acrylates decreases and the total yield of acrylic acid has the maximum. It was shown that the effect of calcination of the catalysts doesn’t significantly affect their efficiency in investigated process. It was determined that after calcining the activity of the catalyst K1 has decreased. The yield of acrylic acid on the non-roasted catalyst is 40%, and on the roasted catalyst - 19%. At the catalyst K2, the acrylic acid slightly increased - 18.2%, but the selectivity acrylic acid of decreased. Application of the developed catalyst, synthesized by co-precipitation of TiOSO4 and VSO4 from aqueous solution, allows to achieve 29 % yield of acrylic acid, 30 % acrylic acid selectivity at 97 % acetic acid conversion. The optimum conditions for acrylic acid obtaining are 648 K and 8 s residence time