Acetylation of wheat straw hemicellulose B in a new non-aqueous swelling system

• Published in: Carbohydrate polymers Vol. 41; no. 4; pp. 379 - 387
• Main Authors: Fang, J.M, Sun, R.C, Tomkinson, J, Fowler, P
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.04.2000; Elsevier Science
• Subjects: Acetylation; Applied sciences; Cellulose and derivatives; Exact sciences and technology; Hemicellulose B acetate; Homogeneous system; Natural polymers; Physicochemistry of polymers; Wheat straw; Acetylation; Hemicellulose B acetate; Homogeneous system; Wheat straw; Chemical solution; Hemicellulose; Catalytic reaction; Vegetal by product; Organic anhydride; Experimental study; Optimization; Thermal stability; Homogeneous reaction; Chemical modification; Reaction mechanism; Processing parameter
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/S0144-8617(99)00102-2

The acetylation of wheat straw hemicellulose B was carried out in a homogeneous N, N-dimethylformamide and lithium chloride system with acetic anhydride using 4-dimethylaminopyridine as a catalyst. The degree of substitution of hemicellulose B acetates ranged between 0.59 and 1.25 as a function of experimental conditions. Under an optimum condition (85°C, 60 h), approximately 75% of the free hydroxyl groups in native hemicellulose B were acetylated. The molecular weight measurements (31,890–34,090 g mol −1) showed a controllable degradation of hemicellulose B chains during the reactions at temperature 60–85°C and duration of 2–60 h. It was found that the thermal stability of the products was increased by chemical modification.