The Production of Methacrylic Acid by the Vapor-Phase Aldol Condensation over V–Si–P Ternary Oxide Catalyst

Abstract

Abstract The vapor-phase aldol condensation of propionic acid with formaldehyde was performed over a V–Si–P ternary oxide catalyst of atomic ratio of 1:2:2.2. The one-pass yield of methacrylic acid was 55 mol% on the charged formaldehyde basis at the propionic acid/formaldehyde molar ratio of 2. The maximum yield of methacrylic acid remained unchanged with the variation in temperature and the dilution of reactants, but it increased with the propionic acid/formaldehyde ratio; the yield reached 82 mol% at the propionic acid/formaldehyde ratio of 6. The effects of reaction variables such as temperature, concentrations of propionic acid, formaldehyde, water vapor, methacrylic acid, and oxygen, and propionic acid/formaldehyde ratio were examined.