A method for preparing tetrabromobenzoate ester from a tetrabromophthalic anhydride including the steps of reacting the tetrabromophthalic anhydride with a catalyst and an alcohol at a temperature that favors partial esterification over complete esterification of the tetrabromophthalic anhydride to form a tetrabromophthalate half-ester reaction mixture; and feeding the half-ester reaction mixture to at least one reactor having and maintaining a temperature that favors decarboxylation over esterification to produce a tetrabromobenzoate ester-containing product. The temperature favoring partial esterification of the tetrabromophthalic anhydride is between about 70° C. and 130° C. The temperature favoring decarboxylation over esterification is between about 190° C. and 205° C. The tetrabromobenzoate ester-containing product comprises at least about 85% tetrabromobenzoate ester. The at least one reactor may include two or more reactors connected to one another in series.