Controlled desilylation of cellulose with stoichiometric amounts of water in the presence of ammonia

Abstract

Desilylation of trimethylsilyl cellulose with stoichiometric amounts of water has been achieved in THF/ammonia in the presence of saccharin as catalyst. Experimental degrees of silylation are in close agreement with calculated ones. Deviations occur if the desired DS is near 1. These are due to the insolubility of silyl cellulose with DS 1 in THF/ammonia and to the heterogeneous character of the reaction at this point. Hydrolysis of 1,2-bis(trimethylsiloxy)propane in THF/ammonia showed that the secondary siloxy group is more readily cleaved than the primary. It also proved that the slow conversion of trimethylsilanol to hexamethyldisiloxane is responsible for the rather long reaction times required.