METHOD OF COLLECTING VALUABLE COMPOUNDS FROM FLOW OCCURRED BY PURIFICATION OF METHYL METHACRYLATE

PROBLEM TO BE SOLVED: To provide a method of extracting and collecting selected compounds such as methacrylic acid and 2-methacrylamide (MAM) from a flow occurred by purification of methyl methacrylate (MMA) or methacrylic acid (MAA) in a conventional acetone cyanohydrin (ACH) pathway process, and to provide a method of further conversion.SOLUTION: A residual material flow is separated into an overhead flow and an organic residual flow containing MAA, MAM and a heavy compound, the organic residual material flow is applied to extraction by a water-containing solvent to separate MAA and MAM from the heavy compound, an aqueous extraction agent containing MAA and MAM and an organic raffinate flow containing the heavy compound are formed, then the aqueous extraction agent is contacted with methanol or water to convert to MMA or MAA respectively. Methyl α-hydroxy isobutyrate (α-MOB) is collected from the overhead flow, or the overhead flow containing the α-MOB is applied to a chemical reaction to convert to MAA product and the like.