Process for producing isocyanates

Patent metadata

Field	Value
Publication number	US-2023312462-A1
Application number	US-202118023747-A
Country	US
Kind code	A1
Filing date	Aug 23, 2021
Priority date	Sep 1, 2020
Publication date	Oct 5, 2023
Grant date	—

Abstract

The invention relates to a process for producing isocyanates by reacting the corresponding amines with phosgene in the liquid phase, comprising: (a) mixing an amine comprising feed stream, a phosgene comprising feed stream and optionally an inert solvent; (b) reacting the amine with phosgene in a first reaction section to obtain an intermediate reaction mixture comprising isocyanate, carbamoyl chlorides, amine hydrochlorides and unreacted phosgene; (c) cleaving the carbamoyl chlorides and remove phosgene from the intermediate reaction mixture in a second reaction section to obtain an isocyanate comprising crude product, (d) optionally working-up the crude product; wherein reacting (b) is carried out such that the intermediate reaction mixture comprises 1.7 to 5 mol-% solid amine hydrochlorides based on the molar amount of amine fed into the process.

First claim

1 .- 11 . (canceled)

12 . A process for producing isocyanates by reacting the corresponding amines with phosgene in the liquid phase, comprising:
(a) mixing an amine comprising feed stream, a phosgene comprising feed stream and optionally an inert solvent; (b) reacting the amine with phosgene in a first reaction section to obtain an intermediate reaction mixture comprising isocyanate, carbamoyl chlorides, amine hydrochlorides and unreacted phosgene; (c) cleaving the carbamoyl chlorides and remove phosgene from the intermediate reaction mixture in a second reaction section to obtain an isocyanate comprising crude product, (d) optionally working-up the crude product; wherein reacting (b) is carried out such that the intermediate reaction mixture comprises 1.7 to 5 mol-% solid amine hydrochlorides based on the molar amount of amine fed into the process.

13 . The process according to claim 12 , wherein the amount of amine hydrochlorides in the intermediate reaction mixture is adjusted by controlling the excess of phosgene fed into the reaction.

14 . The process according to claim 12 , wherein the amount of amine hydrochlorides in the intermediate reaction mixture is adjusted by controlling the amount of inert solvent.

15 . The process according to claim 12 , wherein the inert solvent is selected such that the solubility of the amine is reduced if the amount of solid amine hydrochlorides falls below a predetermined value and the solubility of the amine is increased if the amount of solid amine hydrochlorides rises above a predetermined value.

16 . The process according to claim 12 , wherein the amount of amine hydrochlorides in the intermediate reaction mixture is adjusted by controlling the temperature of the feed streams into the first reaction section and/or the reaction in the first reaction section.

17 . The process according to claim 12 , wherein the amount of amine hydrochloride in the intermediate reaction mixture is adjusted by controlling the amount of hydrogen chloride in the phosgene comprising feed stream.

18 . The process according to claim 12 , wherein the amount of amine hydrochloride in the intermediate reaction mixture is adjusted by controlling the mixing rate of the feed streams.

19 . The process according to claim 12 , wherein the amount of amine hydrochloride in the intermediate reaction mixture is adjusted by controlling the pressure during the reaction (b).

20 . The process according to claim 12 , wherein the amount of solid amine hydrochloride in the intermediate reaction mixture is determined by diluting a partial stream of the intermediate reaction mixture with solvent and counting the particles in the diluted partial stream.

21 . The process according to claim 12 , wherein the amine is diphenylmethanediamine (MDA), polyphenylene-polymethylene polyamine (PMDA), toluene diamine (TDA), hexamethylenediamine (HDA) or isophorone diamine (IPDA).

22 . The process according to claim 12 , wherein the first reaction section is operated in a residence time reactor.

Assignees

• Basf Se

Inventors

• Josch Jan Pablo
• Hinrichs Matthias
• Ferbitz Jens
• Thiele Kai
• Mattke Torsten
• Maixner Stefan

Classifications

• C07C263/10 Primary

  by reaction of amines with carbonyl halides, e.g. with phosgene · CPC title

• C07C269/04

  from amines with formation of carbamate groups · CPC title

• C07C265/14

  containing at least two isocyanate groups bound to the same carbon skeleton · CPC title

• C07C271/04

  Carbamic acid halides · CPC title