BROMINATION OF CELLULOSE WITH TRIBROMOIMIDAZOLE, TRIPHENYLPHOSPHINE AND IMIDAZOLE UNDER HOMOGENEOUS CONDITIONS IN LIBR-DIMETHYLACETAMIDE

The bromination of microcrystalline cellulose with tribromoimidazole, triphenylphosphine and imidazole was studied under homogeneous conditi ons in LiBr-N,N-dimethylacetamide. Bromodeoxycellulose samples having ds values up to 1.6 were obtained at high molecular ratios of brominat ion reagents to the repeating unit of cellulose (5 or higher). Recover ies of high ds samples were below 50%. 3,6-Dibromo-3,6-dideoxyglucose units were present in the samples having high ds values together with 3,6-dibromo-3,6-dideoxyallose and 6-bromo-6-deoxyglucose units. The di bromoglucose units were formed from dibromoallose units by a nucleophi lic substitution of bromine atoms at C-3 with bromide ions present in the system.