Efficient Acetylation of Xylans by Exploiting the Potassium Acetate Formed During the Alkaline Extraction

Isolation of hemicelluloses through alkaline extraction results in formation of salts, which usually necessitates additional salt removal steps. In this study, acetylation of xylans was studied without the removal of potassium acetate (KAc), a commonly produced salt during the alkaline extraction, to find a facile method to alter the hydrophilic characteristics of hemicelluloses. The acetylation reaction was carried out solely with acetic anhydride without any catalysts or solvents added. The weight gain and ATR-FTIR analyses verified the acetylation of xylans in the presence of KAc. A significant decrease in water solubility and moisture uptake was observed upon acetylation in the presence of KAc which is also accompanied by an increase in thermal stability, disclosing an easy, efficient and environmentally friendly method to obtain hydrophobically modified xylans without the use of toxic catalysts and costly salt purification steps.