Production of levulinic acid from corn cob residue in a fed-batch acid hydrolysis process

[Display omitted] •A fed-batch process for producing high concentration of levulinic acid.•The hydrolysis process could effectively reduce the consumption of sulfuric acid.•The soluble humin analogues affect the yield of levulinic acid.•The yield of levulinic acid was not influenced by lignocellulose, salts and ash. Levulinic acid (LA) is an important platform chemical, the production of which by using biomass resources such as corncob is of great significance to the sustainable development. Traditional hydrolysis processes yield low concentrations of levulinic acid with large amounts of acid being consumed. In this paper, a new fed-batch process for hydrolyzing corncob residues with sulfuric acid being utilized as the catalysis to produce levulinic acid at high concentrations is proposed. The mass concentration of the levulinic acid increased with growing the times of feeding and a 107.93 g/L of the levulinic acid can be reached at the 7th hydrolysis. However, the yield of levulinic acid reduces gradually during the fed-batch process. To explore the phenomenon, the reaction mechanism of cellulose acid hydrolysis was experimentally studied. It can be deduced that the reduction of the levulinic acid yield was caused by the polymerization of the soluble humin analogues and the 5-hydroxymethyl furfural (5-HMF) as well as the glucose.