Selective catalytic decarboxylation of biomass-derived carboxylic acids to bio-based methacrylic acid over hexaaluminate catalysts

Abstract

Methacrylic acid (MAA) is a polymer molecular constituent in related plastics industry, presently produced from supplied fossil-based resources. This scientific paper reports an environmentally-benign catalytic process for the production of MAA via the decarboxylation of carboxylic groups. Various hexaaluminate catalysts were synthetized examined and tested to achieve the maximum amount yield of MAA from biomass derived carboxylic acids. Active phases on catalyst surfaces were characterized with numerous microscopic, spectroscopic and chemi-/physi-sorption techniques. Among hexaaluminate catalysts, the highest selectivity towards MAA (50%) was accomplished over barium hexa-aluminate at relatively mild reaction conditions (3 h, 250 °C and 20 bar). In addition, the catalyst could be reused four times without the loss of activity. A plausible pathway mechanism was also hypothesized. The high catalytic activity of BHA catalyst compared to the other tested catalysts believed to be associated with its peculiar layered structure, surface defect sites, moderate basicity and high surface area. The newly developed catalyst and corresponding process avoid the use of expensive noble or transition metals and corrosive alkalis. Overall, the development of catalysis presents a step forward in the synthesis of a sustainable structural constituent.