| 摘要 |
PURPOSE:To purify methacrylic acid, by distilling or evaporating a crude aqueous solution of methacrylic acid obtained by the catalytic vapor-phase oxidation of isobutylene, etc., extracting methacrylic acid from the residue with a water- insoluble organic solvent, and contacting the extract liquid with an aqueous solution of a bisulfite. CONSTITUTION:Methacrylic acid is produced by the catalytic vapor-phase oxidation of isobutylene, t-butanol, methacrolein or isobutyl-aldehyde. The reaction product gas containing methacrylic acid and discharged from the oxidation reactor is cooled and condensed to obtain an aqueous solution of methacrylic acid, and the solution is distilled or evaporated to remove the low-boiling components in the solution. Methacrylic acid is extracted from the residue with an essentially water-insoluble organic solvent (e.g. benzene, toluene, etc.), and the obtained extract liquid is made to contact with an aqueous solution of a bisulfite (preferably alkali metal salt or ammonium salt) to purify methacrylic acid. EFFECT:The process is economical.
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