Method for separating and recovering alkylene glycol monoalkyl ether, method for recycling liquid waste from processing of resist composition, and method for recycling resist composition processing liquid

The present invention provides a method for separating and recovering, with a high purity and at a high recovery rate, alkylene glycol monoalkyl ether from a solvent mixture containing: alkylene glycol monoalkyl ether; carboxylic acid ester corresponding thereto; and other solvents. By adding an alkali compound to a solvent mixture that contains: alkylene glycol monoalkyl ether (first solvent); alkylene glycol monoalkyl ether carboxylic acid ester (second solvent) corresponding to the alkylene glycol monoalkyl ether (first solvent); and a solvent (third solvent) other than the alkylene glycol monoalkyl ether (first solvent) and the alkylene glycol monoalkyl ether carboxylic acid ester (second solvent), the alkylene glycol monoalkyl ether carboxylic acid ester (second solvent) is saponified and converted into alkylene glycol monoalkyl ether (first solvent). Thereafter, the alkylene glycol monoalkyl ether (first solvent) is recovered by distillation. 本发明提供，从含有烷撑二醇单烷基醚及其对应的羧酸酯，且包含其他溶剂的溶剂混合物中以高纯度且高收率分离回收烷撑二醇单烷基醚的