微晶纤维素氰乙基化及其反应动力学研究  

Study on Cyanoethylation of Microcrystalline Cellulose and Its Reaction Kinetics

作　　者：曲保雪[1,2,3] 秦特夫[1,2] 李燕[1,2,4] 储富祥[4] 

机构地区：[1]中国林业科学研究院木材工业研究所 [2]国家林业局木材科学与技术重点实验室,北京100091 [3]河北农业大学林学院,河北保定071000 [4]中国林业科学研究院林业新技术研究所,北京100091

出　　处：《林产化学与工业》2010年第5期5-11,共7页Chemistry and Industry of Forest Products

基　　金：国家林业局948创新重点项目(2006-4-C03);中国林科院林业新技术所中央级公益性科研院所基本科研业务费专项资金(CAFINT2008k01)

摘　　要：通过微晶纤维素的氰乙基化试验,研究了反应温度和反应时间对氰乙基化产物取代度(DS)的影响,表明在50℃以下,微晶纤维素的氰乙基化取代度随反应温度的升高和反应时间的延长而增加。傅里叶红外光谱分析显示微晶纤维素氰乙基化后羟基峰明显减弱,并形成了新的碳氮三键吸收峰,证明纤维素中的部分羟基氢被氰乙基所取代。X射线衍射分析显示微晶纤维素中原有的结晶结构被破坏。X4显微熔融温度测定仪、维卡软化点测定仪等的分析表明微晶纤维素氰乙基化产物的热塑性先随取代度的升高而提高,取代度超过1.43后,产物的热塑性又随取代度的升高而下降。确定了微晶纤维素氰乙基化在不同温度(30、35、40和45℃)下的反应速率常数(分别为1.30、1.61、1.94和2.26 s-1),计算出了微晶纤维素氰乙基化反应的表观活化能为29.8 kJ/mol。Microcrystalline cellulose was cyanoethylated by using acrylonitrile as etherifying agent.Effects of reaction time and reaction temperature on degree of substitution（DS） of the product were studied.It was indicated that DS of microcrystalline cellulose increases with prolonging of reaction time or increment of reaction temperature under 50 ℃.The peak of hydroxyl group of the cyanoethylated microcrystalline cellulose obviously became weaker and shaped cyano absorption peak was observed by FT-IR.It was concluded that part of hydrogens of hydroxyl group were substituted by cyanoethyls.X-Ray diffration pattern showed that the original crystal structure of microcrystalline cellulose was broken.With increase of DS of cyanoethylated microcrystalline cellulose,thermoplasticity increased before DS reach 1.43,then receded with increase of DS,as shown by X4 microscopic melting-point and Vicat softening-point measurements.It was concluded in this study that the rate constant of cyanoethylation of microcrystalline cellulose was ordered by 1.30,1.61,1.94 and 2.26 s-1 under reaction temperature of 30,35,40 and 45 ℃ respectively.Activation energy of cellulose cyanoethylation was 29.8 kJ/mol.

关 键 词：微晶纤维素 取代度 氰乙基化 动力学 热塑性 

分 类 号：TQ351[化学工程]