Ass Beatriz A P, Ciacco Gabriela T, Frollini Elisabete
Instituto de Química de São Carlos, Universidade de São Paulo, C.P. 780, CEP 13560-970, São Carlos, SP, Brazil.
Bioresour Technol. 2006 Sep;97(14):1696-702. doi: 10.1016/j.biortech.2005.10.009. Epub 2005 Nov 28.
We report the acetylation of celluloses from sisal (untreated and alkali treated) and cotton linters (alkali treated), under homogeneous solution conditions, using DMAc/LiCl as solvent system. Our target was to evaluate the effects of cellulose dissolution and reactions conditions on the product properties. The products were characterized in terms of degree of substitution (DS) by 1H NMR, and molar weight distribution (MWD) by size exclusion chromatography. Changes in the DS of the products were correlated with reaction conditions and solution properties. It was found that the dissolution of celluloses and degree of substitution of cellulose derivatives depends on a fine adjustment of the dissolution/derivatization conditions, as well as on the origin (sisal or linters) of celluloses.
我们报道了在均相溶液条件下,以N,N-二甲基乙酰胺/氯化锂(DMAc/LiCl)为溶剂体系,对剑麻纤维素(未处理和碱处理)以及棉短绒纤维素(碱处理)进行乙酰化反应。我们的目标是评估纤维素溶解和反应条件对产物性能的影响。通过1H NMR表征产物的取代度(DS),通过尺寸排阻色谱表征产物的分子量分布(MWD)。产物DS的变化与反应条件和溶液性质相关。结果发现,纤维素的溶解以及纤维素衍生物的取代度取决于溶解/衍生化条件的精细调节,以及纤维素的来源(剑麻或棉短绒)。