The invention relates to a method for treating waste DMF in
sucralose production, and the method is characterized by comprising the following steps: (1) feeding waste DMF discharged from the bottom of a deacidification
tower into a vacuum rectification
tower for vacuum rectification, feeding non-condensable gas extracted from the top of the rectification
tower into a
methanol rectification tower for rectification again, and feeding
methanol recovered by rectification into a reaction rectification tower for reaction; (2) feeding an acidic
azeotrope extracted from the lower part of the reduced-pressure rectifying tower into a reactive rectifying tower; controlling the volume ratio of the acidic
azeotrope to
methanol to be 1: (0.9-1.5), returning reaction liquid at the bottom of the
reactive distillation tower to the
vacuum distillation tower, and returning a mixture of methanol and
methyl acetate distilled from the top of the
reactive distillation tower to the methanol
distillation tower. The method has the advantages that the generated
methyl acetate is removed through
reactive distillation, the reaction is promoted to proceed forwards, and the yield is increased;
acetic acid contained in the raw materials is used as a catalyst, so that the problem of inactivation does not need to be worried about, and excessive
decomposition of DMF is avoided; the prepared
methyl acetate is high in purity, the product DMF is high in purity, and the production cost of
sucralose is reduced.