Solvent-free fatty acylation of cellulose and lignocellulosic wastes. 2. Reactions with fatty acids

The mixed acylation of cellulose with fatty acids and acetic anhydride was accomplished in an excess of fatty acid, thus avoiding the addition of a toxic solvent. The experimental design enabled the parameters of a model reaction with octanoic acid to be optimized. The products contained both acetyl and octanoyl acyl groups in a 2.4/1 ratio and the maximum degree of substitution (DS) was 2.2. The use of fatty acids higher than C(8) resulted in a decrease of the DS. The model reaction was applied to the esterification of four lignocellulosic wastes (LW). Their reactivity was comparable to that of cellulose when no pretreatment was used. A solvent-exchange pretreatment improved the acylation of LW by about 60%, whereas that of cellulose was increased by more than 400%. The hydrophobic character of the esterified products was confirmed.