The invention relates to a synthesis method of
ethyl gallate. The method comprises the following steps: carrying out esterification on
gallic acid, absolute
alcohol and
sulfuric acid used as raw materials in a reaction kettle, sending water-
ethanol mixed steam into a rectification
tower directly connected with the reaction kettle to perform separation, controlling the
reflux ratio to control the
tower top temperature at 80-85 DEG C, returning the distilled
ethanol into the reaction kettle to continue reaction, sending the cooled substance (water-
ethanol mixture) on the rectification
tower bottom into the reaction kettle via a constant-pressure
dropping funnel (filled with a water-absorbing 3A
molecular sieve) to continue reaction, carrying out
esterification reaction for 8-10 hours while controlling the
reaction temperature at 85-90 DEG C, distilling to recover the ethanol, adding
soft water, cooling to crystallize, carrying out crude
centrifugation, decolorizing, carrying out fine
filtration, fine
crystallization and fine
centrifugation to obtain a fine product, and
drying to obtain the
ethyl gallate. The reaction procedure adopts the rectification tower and
molecular sieve for water absorption, so that the reaction time is shortened, the product yield can reach 98.0%, and the
ethyl gallate product purity is greater than 99.5%; and no water-carrying agent is needed in the reaction, thereby saving the cost and lowering the unit consumption.