title: Isolation of cellulose from rice straw and its conversion into cellulose acetate catalyzed by phosphotungstic acid.
abstract: Cellulose was isolated from rice straw by pretreatment with dilute alkaline and acid solutions successively, and it was further transferred into cellulose acetate in the presence of acetic anhydride and phosphotungstic acid (H3PW12O40·6H2O). The removal of hemicellulose and lignin was affected by the concentration of KOH and the immersion time in acetic acid solution, and 83wt.% content of cellulose in the treated rice straw was obtained after pretreatment with 4% KOH and immersion in acetic acid for 5h. Phosphotungstic acid was found to be an effective catalyst for the acetylation of the cellulose derived from rice straw. The degree of substitution (DS) values revealed a significant effect for the solubility of cellulose acetate, and the acetone-soluble cellulose acetate with DS values around 2.2 can be obtained by changing the amount of phosphotungstic acid and the time of acetylation. Both the structure of cellulose separated from rice straw and cellulose acetate were confirmed by FTIR and XRD.
authors.affiliation: School of Chemical and Environmental Engineering, Wuhan Polytechnic University, Wuhan 430023, China. fgzcch@whpu.edu.cn
authors.forename: Guozhi
authors.initials: G
authors.lastname: Fan
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.forename: Chongjing
authors.initials: C
authors.lastname: Liao
authors.forename: Tao
authors.initials: T
authors.lastname: Fang
authors.forename: Jianfen
authors.initials: J
authors.lastname: Li
authors.forename: Ronghui
authors.initials: R
authors.lastname: Zhou
mesh_terms: D000089:Acetic Anhydrides / Q000737:chemistry; D000107:Acetylation; D002384:Catalysis; D002482:Cellulose / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000302:isolation & purification*; D006878:Hydroxides / Q000737:chemistry; D007700:Kinetics; D012275:Oryza / Q000737:chemistry*; D010316:Particle Size; D010772:Phosphotungstic Acid / Q000737:chemistry*; D035261:Plant Components, Aerial / Q000737:chemistry*; D017680:Potassium Compounds / Q000737:chemistry; D033362:Powder Diffraction; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
chemical_list: D000089:Acetic Anhydrides; D006878:Hydroxides; D017680:Potassium Compounds; D012997:Solvents; D010772:Phosphotungstic Acid; C031800:acetic anhydride; C005062:acetylcellulose; D002482:Cellulose; C029943:potassium hydroxide