Premium
Chemical Factors Affecting Preparation of Carboxymethyl Starch
Author(s) -
Hebeish A.,
Khalil M. I.
Publication year - 1988
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.19880400406
Subject(s) - chloroacetic acid , sodium hydroxide , chemistry , starch , nuclear chemistry , sodium , organic chemistry
Preparation of carboxymethyl starch using chloroacetic acid and sodium hydroxide was investigated under different conditions. The carboxymethylation reaction was studied with respect to the degree of substitution (D. S.) of the carboxymethyl starch and the reaction efficiency (R. E.) of carboxymethylation variables studied included concentration of reactants and liquor ratio as well as reaction time and temperature. D. S. and R. E. were greatly enhanced by decreasing the liquor ratio. D. S. and R. E. increased also by increasing the reaction time. On the other hand, increasing the monochloroacetic acid concentration was accompanied by enhancement in the D. S. and decrement in the R. E., while both the D. S. and R. E. exhibited maximum values at 4N sodium hydroxide. The combined effect of increasing both monochloroacetic acid and sodium hydroxide concentrations was to bring about increased D. S. and decreased R. E. irrespective of the reaction temperature. Of particular interest were the results obtained at 100°C for 1 h; carboxymethyl starch of D. S. 0.436 with R. E. of ca. 79% could be achieved using solid reactants/liquor ratio of 1: 1.