The invention discloses a high esterification degree
isopropyl alginate preparation method, which comprises: adding
alginic acid to
anhydrous isopropanol, stirring, adding a dehydrating agent having the same
molar water content as the
alginic acid, adding a catalyst, carrying out stirring heating to achieve a
reflux state, adding the remaining dehydrating agent in a dropwise manner when the
reflux temperature is achieved, continuously carrying out a
reflux reaction for 4-15 h after the remaining dehydrating agent is uniformly added in the dropwise manner within 2-4 h, completing the reaction, cooling to a
room temperature, adjusting the pH to 6.5-7.0 with an alkali liquid, filtering, washing the
filter cake by using an isopropanol
aqueous solution with a
mass concentration of higher than 60%, and
drying at a temperature of 40 DEG C to obtain the
isopropyl alginate. According to the present invention, with the
isopropyl alginate preparation method, the esterification degree of the prepared isopropyl alginate is higher than 65% and is significantly higher than the esterification degree of the
straight chain alkanol ethyl alginate prepared by using the existing technology.