高取代度羧甲基淀粉的制备研究

Research on preparation of carboxymethyl starch with high degree of substitution

研究了在非均相体系中,以玉米淀粉为原料,采用分步加碱法制备高取代度羧甲基淀粉的方法。经单因素试验,选取反应温度、反应时间、碱用量、甲醇浓度、液固比、一氯乙酸(一氯乙酸钠)用量等进行响应面试验,并得出获得高取代度羧甲基淀粉(CMS)的最佳实验条件为:nNaOH/nAGU(碱化时)为0.73,nClCH2COOH/nAGU为1.16,nNaOH/nAGU(醚化时)为0.27,反应温度为61℃,反应时间为3.2h,vCH3OH/wAGU为2.63,甲醇浓度为76.3%。经反应,制得的羧甲基淀粉的取代度0.482,粘度(浓度为2%)为21760mp.s。产品经红外光谱分析验证为羧甲基淀粉。

the method to prepare carboxymethyl corn starch with high degree of substitution by twice steps in non - homogeneous medium is researched. After mono-factor experiment, reaction temperature, reaction time, the amount of sodium hydroxide, the concentration of methanol, ratio of liquid to solid, the amount of monochloroacetic acid etc. are taken to carry through response surface analyse. The optimal conditions to achieve the highest degree of substitution was found to be that at the time of basification the molar ratio of the sodium hydroxide to AGU of 0.73, the molar ratio of monochloroacetic acid to AGU of 1.16, at the time of aether the molar ratio of the sodium hydroxide to AGU of 0.27, the reaction temperature at 61 ℃, the etherifi- cation time of 3.2h, liquor/material ratio of 2.63, the concentration of methanol was 76.3 %. The carboxymethyl starch with a degree of substitution of 0.482 and a high viscosity（concentration 2%） of 21760mp.s was obtained. It＇s indicated that the product was carboxymethyl starch by FTIR.