カノレボキシメチルデンプンの製造法と生成物の性質
1976 年 23 巻 1 号 p. 49-58
詳細
1976 年 23 巻 1 号 p. 49-58
The relationship between the various conditions for carboxymethylation of starch and the properties of the products was investigated, and the following results were obtained. 1) When the reaction temperature in carboxymethylation reaction of starch is 20°C (room temperature), the reaction velocity is very slow regardless of the amount of monochloroacetic acid. But as the temperature rises above 35°C, the reaction velocity increases gradually. 2) The degree of substution (DS) of products was generally proportional to the amount of monochloroacetic acid used, but the amount of the acid reacted with starch decreased in accor dance with the increasing amount of the monochloroacetic acid used in the reaction medium. 3) The concentration of sodium hydroxide in the reaction medium influenced the physical properties of the products. 4) The aqueous solution of crude sodium carboxymethylstarch (CMSNa) of higher DS was stable on the viscosity than that of lower DS. 5) CMS acid was easily precipitated from the paste of crude CMSNa by treating it with dilute sulfuric acid, but the CMS acid produced could not be washed with water ;because it swelled in water. The CMS acid was easily washed with methanol, but the difficulty of neutralization of CMS acid with sodium carbonate was recognized. Therefor, the washing with methanol without the sulfuric acid treatment was a desirable method for the purification of crude CMS Na.
