离子液体对锯末中纤维素的溶解及再生研究

The Dissolution and Regeneration of Cellulose in Sawdust from Ionic Liquids

探讨了离子液体1-(4-磺酸基丁基)-3-甲基咪唑的硫酸氢盐(IL-1)作为催化剂,金属氯化物作为助催化剂时纤维素的水解,利用离子液体IL-1对杨木锯末中纤维素的直接溶解并再生,考察了温度、碱性溶液的浓度以及溶解时间对溶解率的影响,通过傅里叶红外光谱FT-IR、X-射线衍射仪及热失重对处理前后锯末、再生纤维素的结构、结晶性及热性能进行了研究.结果表明,温度为90℃,NaOH质量分数为6%,溶解时间为2 h时,离子液体对杨木锯末具有最佳的溶解性,溶解率可达45%左右.离子液体主要溶解杨木锯末中的纤维素,且为非衍生化的直接溶解,再生后的纤维素结晶形态由纤维素I变为II,热稳定性能有所降低.

Ionic liquid 1-（4-sulfonic acid）-butyl-3-methylimidazolium hydrogen sulfate （IL-I） was used as a cata- lyst; metal chlorides were used as promoter to catalyze the hydrolysis of cellulose. Also, IL-1 was used to dissolve cellulose in sawdust and cellulose regeneration. Influence of temperature, alkali concentration and time on the dis- solution of cellulose in sawdust was investigated. The pretreated sawdust and regenerated cellulose from ionic liquid were characterized using FT-IR spectroscopy, X-ray diffraction and TGA. The results showed that ionic liquid is a good solvent for cellulose, the optimal conditions for cellulose activation were 90℃ for 120 rain with 6% NaOH, by which 45% of dissolution rate of cellulose was achieved. It was also observed that ionic liquid was a non-detribali- zing solvent for cellulose. The regenerated cellulose from ionic liquid showed a crystalline form of cellulose II and was less thermally stable than sawdust.