Direct catalytic production of sorbitol from waste cellulosic materials

Abstract

Cotton wool, cotton textile, tissue paper and printing paper, all potential waste cellulosic materials, were directly converted to sorbitol using a Ru/CNT catalyst in the presence of H-2 and using only water as solvent, without any acids. Conversions up to 38% were attained for the raw substrates, with sorbitol yields below 10%. Ball-milling of the materials disrupted their crystallinity, allowing reaching 100% conversion of cotton wool, cotton textile and tissue paper after 4 h, with sorbitol yields around 50%. Mix-milling these materials with the catalyst greatly enhanced their conversion rate, and the materials were efficiently converted to sorbitol with a yield around 50% in 2 h. However, ball-and mix-milled printing paper presented a conversion of only 50% after 5 h, with sorbitol yields of 7%. Amounts of sorbitol of 0.525, 0.511 and 0.559 g could be obtained from 1 g of cotton wool, cotton textile and tissue paper, respectively.