The present invention relates to an
infrared synthetic method of a cross-linked
carboxymethyl starch, comprising (1) adding the
monochloroacetic acid into the container, neutralizing the
monochloroacetic acid by the
sodium hydroxide, cooling the solution, adding the
ethanol solution, dripping the chloroepoxy
propane, and then adding the primary
starch; (2) stirring and pre-reacting the materials in the container, then pouring the mixture out from the container, centrifuging the mixture to remove a little liquid, and then breaking the
filter cake; (3) putting the broken
filter cake into the
infrared reactor, auto reacting at a constant temperature to obtain the
modified starch, putting the
starch out to crush. The invention uses the technology of
infrared catalyzing and etherifying as well as heating and
drying at the same time to accelerate the reaction, improve the
product property, increase the
viscosity of the
aqueous solution of
carboxymethyl starch and broaden the range of use of the product. And at the same time, the invention reduces the consumption of the
organic solvent, has no need to recycle the
alcohol, reduces the
energy consumption, shortens the reaction time, raises efficiency, and reduces the production cost of the cross-linked
carboxymethyl starch.