Transformation of cellulose into non-ionic surfactants in a one pot catalytic process

Abstract

Alkyl glucosides surfactants have been synthesized by a cascade process which involves the methanolysis of cellulose into methyl glucosides followed by the transacetalization with n-octanol. The first step was carried out using methanol as solvent and acid catalysts (such as inorganic acids, heteropolyacids, ion-exchange resins or modified carbon materials). Subsequently long chain alkyl glucosides can be obtained in a second step by transacetalization which involves the reaction of methyl glucosides with a fatty alcohol using the same acid catalyst. The overall process was performed under mild conditions. Amorphous sulfonated carbon catalyst achieved the best results for the complete conversion of cellulose in methanol at 200 οC with yields higher than 80 % of methyl α,β-glucopyranosides. Moreover, this material containing -SO3H groups is optimal to perform the second step obtaining octyl and decyl glucosides in yields higher than 73 % at 120 οC. In addition, catalyst reusability has been tested showing that sulfonated carbon catalyst (C-SO3H) can be reused with only a slightly decrease of its activity after four consecutive cycles.