Carbon Dioxide Mediated Cellulose Dissolution and Derivatization to Cellulose Carbonates in a Low-pressure System

Carbohydrate Polymer Technologies and Applications

卷:3

Gang Wu¹  Dr. He-Kuan Luo²  Ting Ting Lin³  Zibiao Li³  Agnes Mei Xian Lee⁴  Chen-Gang Wang⁴  Ning Li⁴  Shuo-Wang Yang⁴ 

[1] Institute of Bioengineering and Bioimaging (IBB), A*STAR, 31 Biopolis Way, The Nanos, No. 07-01, Singapore 138669;

[2] Corresponding author.;

[3] Institute for High Performance Computing (IHPC), Agency for Science, Technology and Research (A*STAR), 16-16 Connexis (North), 1 Fusionopolis Way, Singapore 138632;

[4] Institute of Materials Research and Engineering (IMRE), Agency for Science, Technology and Research (A*STAR), 2 Fusionopolis Way, Innovis, No. 08-03, Singapore 138634;

关键词: Microcrystalline cellulose;    Carbon dioxide;    Cellulose carbonate;    Dissolution;    BTMG;   

DOI  :  

来源: DOAJ

【 摘 要 】

An effective switchable solvent system using carbon dioxide (CO2) and 2-tert-butyl-1,1,3,3-tetramethylguanidine (BTMG) for cellulose dissolution and derivatization was developed. High concentration cellulose solution (up to 10 wt%) could be achieved by dissolving microcrystalline cellulose rapidly, within 5 min, into DMSO in presence of BTMG and 1 atm CO2 at room temperature. The cellulose-carbonate anion intermediate was characterized by 1H and 13C NMR spectroscopies, emphasizing the generation of cellulose carbonate anions and protonated BTMG. Addition of organochlorides into the cellulose solution triggers a nucleophilic substitution with cellulose-carbonate anions, producing various cellulose benzyl carbonates and a cellulose-carbonate-ester with degree of substitution (DS) up to 1.83 at 1 atm CO2 pressure and room temperature. The activation energy (Ea) and Gibbs free energy change (ΔG) of CO2-mediated dissolution and nucleophilic substitution were calculated by density functional theory. The results showed that the nucleophilic substitution is the rate-limiting step.

【 授权许可】

Unknown