At relatively high cellulose mass concentrations(8%,10%,and 12%),homogeneous acetylation of cellulose was carried out in an ionic liquid,1-allyl-3-methylimidazolium chloride(AmimCl).Without using any catalyst,cellulos...At relatively high cellulose mass concentrations(8%,10%,and 12%),homogeneous acetylation of cellulose was carried out in an ionic liquid,1-allyl-3-methylimidazolium chloride(AmimCl).Without using any catalyst,cellulose acetates(CAs)with the degree of substitution(DS)in a range from 0.4 to 3.0 were synthesized in one-step.The effects of reaction time,temperature and molar ratio of acetic anhydride/anhydroglucose unit(AGU) in cellulose on DS value of CAs were investigated.The synthesized CAs were characterized by means of FT-IR, NMR,and solubility,mechanical and thermal tests.After the acetylation,the used ionic liquid AmimCl was easily recycled and reused.This study shows the potential of the homogeneous acetylation of cellulose at relatively high concentrations in ionic liquids in future industrial applications.展开更多
Homogeneous acetylation of cellulose in 1-allyl-3-methyl-imidazolium chloride(AMIMCl) was carried out. Acetic anhydride and acetyl chloride were used as acetylating agents in the absence and presence of pyridine. The ...Homogeneous acetylation of cellulose in 1-allyl-3-methyl-imidazolium chloride(AMIMCl) was carried out. Acetic anhydride and acetyl chloride were used as acetylating agents in the absence and presence of pyridine. The degree of substitution(DS) of the products and the distribution of substituents were determined by titration and {} 13C NMR techniques respectively. It was observed that acetyl chloride reacted faster than {anhydride}. Further, pyridine accelerated the reactions when anhydride was used as the acetylating agent, while it slowed down the reactions when acetyl chloride was used. An interesting distribution of DS_ C-2 DS_ C-3 for substitutes was observed in the product with acetic anhydride/pyridine system.展开更多
基金Supported by the National Basic Research Program of China(2009CB219901)
文摘At relatively high cellulose mass concentrations(8%,10%,and 12%),homogeneous acetylation of cellulose was carried out in an ionic liquid,1-allyl-3-methylimidazolium chloride(AmimCl).Without using any catalyst,cellulose acetates(CAs)with the degree of substitution(DS)in a range from 0.4 to 3.0 were synthesized in one-step.The effects of reaction time,temperature and molar ratio of acetic anhydride/anhydroglucose unit(AGU) in cellulose on DS value of CAs were investigated.The synthesized CAs were characterized by means of FT-IR, NMR,and solubility,mechanical and thermal tests.After the acetylation,the used ionic liquid AmimCl was easily recycled and reused.This study shows the potential of the homogeneous acetylation of cellulose at relatively high concentrations in ionic liquids in future industrial applications.
文摘Homogeneous acetylation of cellulose in 1-allyl-3-methyl-imidazolium chloride(AMIMCl) was carried out. Acetic anhydride and acetyl chloride were used as acetylating agents in the absence and presence of pyridine. The degree of substitution(DS) of the products and the distribution of substituents were determined by titration and {} 13C NMR techniques respectively. It was observed that acetyl chloride reacted faster than {anhydride}. Further, pyridine accelerated the reactions when anhydride was used as the acetylating agent, while it slowed down the reactions when acetyl chloride was used. An interesting distribution of DS_ C-2 DS_ C-3 for substitutes was observed in the product with acetic anhydride/pyridine system.
