PURPOSE: To easily obtain at low cost a low-molecular weight and orally administrable water-soluble kraft lignin having anti-AIDS virus activity and immunoactivating action by purifying kraft lignin obtained from the waste liquor resulted from kraft pulp production process followed by carboxymethylating the kraft lignin.
CONSTITUTION: This water-soluble kraft lignin 0.4 in carboxymethyl substitution degree is obtained by purifying kraft lignin obtained by spray drying of a black liquor discharged during kraft pulp production process followed by carboxymethylation of the purified kraft lignin. Specifically, for example, isolated kraft lignin on the market is dissolved in 10 times (vol/vol) of 90% dioxane and the resultant impurity precipitate is filtered off; the filtrate is then dripped into 10 times (vol/vol) of diethyl ether under vigorous agitation to precipitate purified kraft lignin which is then washed and dried, and one pt.wt. of the purified product is dissolved in 20 pts.wt. of 2mol sodium hydroxide, and one pt.wt. of solid monochloroacetlc acid is added to the resultant solution to conduct a reaction 55°C followed by neutralizing the reaction liquor with hydrochloric acid, thus obtaining the objective water-soluble kraft lignin.
CHI BATSUKU CHIYUETSUTO RAMU
ISHIDA TAKEHIKO
ISHIDA KAKU
ISHIDA KAKU
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