Transformation of Corn Lignin into Sun Cream Ingredients

Production of value-added chemicals from lignocellulose is one of the key strands of the emerging bio-economy. A synthetic approach has been developed to produce p-methoxy coumarate esters from waste corn stover and corn bran, and further transform these compounds into consumer products. In the first step, p-coumaric acid (pCA) and ferulic acid (FA) are released through mild alkaline hydrolysis of corn waste, in more than 20 mg g⁻¹ yield (10 wt % based on lignin content). Subsequently, heterogeneous solid acids catalyze the esterification of pCA with various alcohols. Amberlite IR-15 shows the best catalytic performance, owing to its optimal acid density, large surface area, and suitable pore diameter. The solid acid catalyst can be recycled with slight activity loss and regenerated by acid washing and vacuum drying. Finally, methylation of p-coumarate ester to give target product p-methoxy coumarate esters is carried out by using commercially available and low-cost inorganic bases (e. g., K₂CO₃). Base-catalyzed transesterification of methyl p-methoxy coumarate to p-methoxy coumarate esters is also investigated.