BACKGROUND The demand for acrylic acid continues to increase rapidly due to its widespread application. The traditional production of acrylic acid originates from non-sustainable propylene oxidation. Considering the environmental requirements and economic sustainable development, it is of great significance to exploit new routes to replace the petrochemical route. RESULTS Comparison of silica aerogel-supported SiW/PW/PMo catalysts shows that PW/SiO2 catalyst with 30 wt% loading and calcined at 450 degrees C provides the best performance for the condensation of acetic acid and formaldehyde. Increasing the reaction temperature from 340 to 400 degrees C leads to the best acrylic acid selectivities of 87.1-84.2% at formaldehyde conversions of 35.7-45.2%. CONCLUSIONS The catalytic performance of PW/SiO2 catalyst increases with increasing PW loading. The acidic and basic sites of the catalyst, especially the weak ones, are of vital importance to the synthesis of acrylic acid via the aldol condensation of acetic acid and formaldehyde. (c) 2020 Society of Chemical Industry