SYNTHESIS OF METHACRYLIC ACID FROM ALKYL METHACRYLATE BASED ON METHACROLEIN Russian patent published in 2020 - IPC C07C67/39 C07C67/44 C07C51/09 C07C69/54 C07C57/04 

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of producing alkyl methacrylates, especially MMA and methacrylic acid, based on methacrolein, which have been subjected to oxidative esterification at the second step of the method. Methacrolein is obtained in general from C₂- and C₄-links. Method of producing alkyl methacrylates and methacrylic acid involves process steps: a) synthesis of methacrolein in reactor I, b) oxidative esterification of methacrolein with alcohol and oxygen to obtain alkyl methacrylate in reactor II, c) removing excessive amount of methacrolein and at least partially removing alcohol with subsequent optional treatment with acid and optional separation of phases of composition containing alkyl methacrylate, d) separating the composition containing alkyl methacrylate and optionally methacrylic acid, with feeding water as an organic phase from the aqueous phase in extraction step I, e) reacting at least a portion of alkyl methacrylate with water to obtain methacrylic acid in reactor III, f) transferring a composition containing methacrylic acid and alkyl methacrylates obtained in process step e) to extraction stage I, and g) separating methacrylic acid from alkyl methacrylate at separation step M.

EFFECT: method is characterized by the advantage that alkyl methacrylate and methacrylic acid can be obtained in a simple way with high output and with high degrees of purity or in form of a mixture, or in form of separated product streams; in particular, the method according to the present invention is characterized by a significant advantage, especially a ratio of the required methacrylic acid and alkyl methacrylate, in particular MMA, wherein products can be freely adjusted in a wide range and vary by means of chemical technology and operating parameters.

15 cl, 3 dwg, 1 tbl, 3 ex