BACKGROUND Catalytic formation of lactic acid from biomass glycerol is a sustainable alternative to the conventional fermentation process starting from carbohydrate and the chemical route using HCN and acetaldehyde. Highly concentrated glycerol can be effectively converted to lactic acid using hydroxyapatite‐supported palladium particles in the presence of NaOH. RESULTS The 3% hydroxyapatite‐supported palladium catalyst (Pd3/HAP) demonstrates excellent activity (TOF = 1274 h−1 for a batch time of 90 min) with a high selectivity (95%) towards lactic acid at 99% glycerol conversion (230 °C, NaOH:glycerol molar ratio = 1.1, and glycerol/total Pd intake = 1926). Under the same reaction conditions, the selectivities of lactic acid were 82% and 90% on Pd0.75/HAP and Pd1.5/HAP catalysts, respectively. The Pd3/HAP catalyst was recycled five times in a batch set‐up without a significant drop in activity and lactic acid selectivity, which is indicative of good catalyst stability. CONCLUSIONS Pd‐based catalysts on available hydroxyapatite supports are efficient catalysts for glycerol selective oxidation. The catalysts possess active PdO and Pd0 species well dispersed on the functionalized hydroxyapatite support. Pd0 nanoparticles and NaOH synergistically catalyze the reaction process. © 2018 Society of Chemical Industry

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.

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/SiO 2 catalyst with 30 wt% loading and calcined at 450°C provides the best performance for the condensation of acetic acid and formaldehyde. Increasing the reaction temperature from 340 to 400°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/SiO 2 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.