制备羧甲基淀粉的研究

Studies on the preparation of Carboxymethyl starch

羧甲基淀粉是重要的变性淀粉之一，用途广泛。本研究用乙醇溶剂法制备羧甲基淀粉。结果表明，增加一氯醋酸用量，降低淀粉乳浓度，能提高醚化取代度；氢氧化钠用量和水份含量对反应影响显著，选用适当的量能有效地促进醚化反应；在一定范围内，随着反应温度升高，反应时间延长，取代度随之增高。乙醇溶剂法能有效地抑制淀粉在反应过程中糊化，反应进行均匀，并且具有反应时间短、操作简单，易于控制，能制得高取代度、高质量产品等优点。

Carboxymethl starch is an important kind of indeed starch with great prospects of application.In the present investigation, carboxymethyl starch has been prepared by the alcohol medium method,the effects of reaction temperature,reaction time,starch concentration,monochloroacetic acid concentration ,sodium hydroxide concentration water content on the etherification reaction have been studied.The results indicate that in a certain range the etherification degree increases with the increase of reaction temperature and the,the degree of substitution of carboxymethyl can be increased by increasing the menochloroacetic acid concentration and decreasing the starch concentration,the effects of sodium hydroxide concentration and water content in the system are important the both values should be properly selected.The results also indicate that alcohol medium method can effectively inhibit the gelatinization during the reaction and then the reaction proceed homogeneously,this method for preparing the carboxymethyl starch has many advantages,such as shorter reaction time:easier operation,higher degree of substitution,and higher quality of products.