METHOD OF PRODUCING N-METHYL-PARA-PHENETIDINE Russian patent published in 2017 - IPC C07C209/24 C07C217/68 

FIELD: chemistry.

SUBSTANCE: alkylation of para-anisidine with formalin is carried out separately, simultaneously feeding them into a mixer located in the reactor just before the catalytic reduction zone, forming intermediate azomethine-4-methoxy-(N-phenylmethanimine, in the liquid phase. Resulting azomethine is then reduced on a hydrogenating catalyst at a temperature of 20-120°C, in a hydrogen medium at elevated pressure, followed by isolation of the desired product. Starting para-anisidine is used as a solution in a solvent selected from the group: ethanol, methanol, isopropanol. The alkylation process can be carried out batchwise or continuously. When alkylating, as a rule, stabilisers are used in the form of tertiary aliphatic amines in an amount of 1-10 moll. % of the loading of para-anisidine. Typically, tertiary aliphatic amines selected from the group: triethylamine, tetramethylethylenediamine, diisopropylethylamine, dimethylbenzylamine, diazabicyclooctane, tripropylamine, aqueous solution of trimethylamine are used. The stabiliser is introduced into the reactor when charging the hydrogenating catalyst and/or feeding para-anisidine. The hydrogenation catalyst is used as a suspension in a solvent selected from the group: ethanol, methanol, isopropanol, or as a fixed bed. The isolation of N-methyl-para-anisidine is carried out by rectification. The stabiliser from the catalyst is isolated by simple distillation or rectification with subsequent reuse.

EFFECT: increasing the yield.

10 cl, 1 tbl, 15 ex