Reaction between methanol and acetic acid catalyzed by SiO₂‐supported V‐P‐O catalyst in oxygen atmosphere

Abstract

SiO 2 -supported V-P-O catalysts prepared by the incipient-wetness impregnation method beginning with ammonium metavanadate and phosphoric acid were used in the catalytic reaction between methanol and acetic acid in an oxygen atmosphere. The SiO 2 -supported V-P-O catalysts were composed of VOPO 4 and (VO) 2 P 2 O 7 phases. Both the acidic and alkaline sites were co-present in the catalysts. The vanadium species catalyzed the oxidation of methanol to formaldehyde. The V-P-O(20-30 wt%)/SiO 2 catalysts with a P/V mole ratio of 2:1 exhibited higher catalytic activity for the formation of acrylic acid and methyl acrylate with a total selectivity of ∼28 % at 380°C. The acid sites of the catalysts also catalyzed the formation of methyl acetate with a selectivity of ∼65 %. Methanol can be an alternative to formaldehyde for the synthesis of both acrylic acid and methyl acrylate through the aldol condensation reaction.

Acrylic acid synthesis via condensation of acetic acid and formaldehyde catalyzed by silica aerogel‐supported SiW/PW/PMo oxides

“…For all samples, the total amounts of surface acid and alkali of desorption are calculated according to the area of the desorption peak. According to the temperature of the desorption peak, the strength of acidic sites is classified into three types: desorption peaks below 300 °C, at 300–500 °C and above 500 °C correspond to weak, medium strong and strong acid sites, respectively …”

“…Various catalysts have been employed in the aldol condensation reaction of acetic acid and formaldehyde, such as acids, bases and base–acid bifunctional catalysts, among which acid–base bifunctional catalysts attract most attention owing to the cooperation between acid and base active sites. The acidic sites, especially the weak ones, are essential to trigger the aldol condensation reaction, and the high acid amount is favorable for formaldehyde conversion.…”