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Synthesis of Carboxymethyl Starch
Author(s) -
Stojanović Željko,
Jeremić Katarina,
Jovanović Slobodan
Publication year - 2000
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 - 10.1002/1521-379x(200011)52:11<413::aid-star413>3.0.co;2-b
Subject(s) - starch , chemistry , sodium hydroxide , viscosity , ethanol , limiting , nuclear chemistry , chromatography , organic chemistry , materials science , mechanical engineering , engineering , composite material
Carboxymethyl starch (CMS) was obtained under heterogeneous conditions as a product of the reaction of starch and monochloroacetic acid (MCA) in the presence of sodium hydroxide. The influence of the composition of the reaction mixture, the reaction time and temperature and the type of starch being carboxymethylated on the degree of substitution, DS, and limiting viscosity number, [η], was studied. The reaction temperature influenced the DS values, the highest values of the DS being obtained when the carboxymethylation was performed at 58 °C. Increase of the molar ratio of NaOH to anhydroglycose units leads to an increase in DS, but only to certain extent. The values of the DS and [η] of CMS increased almost linearly with increasing MCA amount in the reaction mixture. The reaction mixture changes caused by adding water to ethanol influenced the DS values of the obtained CMS samples, the maximum DS value being obtained for CMS sample synthesized in ethanol with 25% (v/v) water.