METHOD FOR PRODUCING (POLY)METHYLENEDIANILINE (OPTIONS) AND METHOD FOR PRODUCING (POLY)POLYMETHYLENE DIISOCYANATE Russian patent published in 2023 - IPC C07C209/78 C07C211/50 C07C263/10 C07C265/14 C08G18/76 

FIELD: chemical industry.

SUBSTANCE: obtaining (poly)methylenedianiline (pMDA) with a reduced content of N-formyl-MDA, constituting no more than 0.05% or no more than 0.02%. Options of the method for producing (poly)methylenedianiline (pMDA) are claimed, including the following steps: (1) obtaining hydrochloric acid pMDA; (2) neutralization of hydrochloric pMDA, including the interaction of an aqueous solution of the neutralizing agent and hydrochloric pMDA from step 1 and phase separation; (3) treating the pMDA-containing organic phase obtained after phase separation in step 2 with an aqueous solution of a neutralizing agent and separating the phases; (4) washing the organic phase containing pMDA obtained in step 3 with water; (5) distillation of volatile components from pMDA to obtain a distillation residue, moreover, the interfacial tension in step 3 is not more than 10 mN/m, but not less than 10 ^-5 mN/m. The invention also relates to a method for producing (poly)polymethylene diisocyanate (pMDI) by the method of phosgenation of pMDA, obtained by the methods of its production claimed in the present invention.

EFFECT: lowering the content of N-formyl-4,4'-MDA at the pMDA step below 0.05%, as well as improving the quality of pMDI, namely: reducing the content of residual chlorine and improving the color index, as well as, additionally, reducing the amount of used excess of a neutralizing agent, which improves the technical, economic and environmental performance of the process.

12 cl, 2 dwg, 2 tbl, 6 ex