Catalysis performance comparison of a Bronsted acid H2SO4 and a Lewis acid Al2(SO4)3 in methyl levulinate production from biomass carbohydrates

An experimental investigation was conducted to understand the roles of the Bronsted acid H2SO4 and Lewis acid Al-2(SO4)(3) in methyl levulinate (ML) production from biomass carbohydrates, including glucose, fructose and cellulose. The product distributions with different catalysts revealed that the Lewis acid was responsible for the isomerization of methyl glucoside (MG), producing a significant amount of the subsequent product 5-methoxymethylfurfural (MMF), while the Bronsted acid facilitated the production of ML from MMF. Al-2(SO4)(3) was efficient for monosaccharide conversion but not for cellulose. Using ball-milled cellulose with Al-2(SO4)(3) resulted in a desired ML yield within a reasonable reaction time. The significant catalysis performances of two types of acids will guide the design of efficient catalytic processes for the selective conversion of biomass into levulinate esters. (C) 2017 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.