# US 8,772,535 B2 · Process for preparing isocyanates > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,772,535 B2 - Document ID: US8772535B2 - Status: Granted - Kind: B2 - Application number: 13/442,401 - Filed: 2012-04-09 - Published: 2012-08-02 - Granted: 2014-07-08 - Earliest claimed: 2006-10-26 - Assignees: BASF SE - Applicants: Ralf Boehling; Sven Kueber; Stefan Maixner; Eckhard Stroefer; Jochem Henkelmann; Georg Krug; Werner Bolz - Inventors: Ralf Boehling; Sven Kueber; Stefan Maixner; Eckhard Stroefer; Jochem Henkelmann; Georg Krug; Werner Bolz - Web page: https://patentgrep.com/patent/US8772535B2 ## CPC - C07C 263/10: by reaction of amines with carbonyl halides, e.g. with phosgene - B01J 2219/00038: Processes in parallel - B01J 2219/00869: Microreactors placed in parallel, on the same or on different supports - C07C 2601/14: The ring being saturated - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS ## Abstract Process for preparing isocyanates by phosgenation of amines, wherein phosgene and amine are brought into contact in at least 2 mixing chambers connected in parallel. ## Claims ### Claim 1 A process for preparing isocyanates by phosgenation of amines, comprising: mixing phosgene and an amine together to form a reaction mixture in at least 2 mixing chambers connected in parallel, with the mixing chambers being part of a reaction space or representing the reaction space, wherein the volume of each individual mixing chamber is in the range from 0.01 cm3 to 1 liter, and reacting the amine with the phosgene at a temperature in the range of from 230 to 270° C. and at a pressure in the range from 20 to 100 bar, the residence time of the reaction mixture is in the range of from 0.1 to 2 s. ### Claim 2 (depends on 1) The process according to claim 1, wherein the phosgene and the amine are fed through separate inlets into each of the mixing chambers. ### Claim 3 (depends on 1) The process according to claim 1, wherein microstructured mixing chambers are employed as mixing chambers. ### Claim 4 (depends on 1) The process according to claim 1, wherein said mixing chambers are selected from the group consisting of laminar diffusion mixers, multilamination mixers, micromixers having structured walls, split-recombine mixers, free-jet mixers and nozzles. ### Claim 5 (depends on 3) The process according to claim 3, wherein the mixing chambers are formed of Hasteloy and/or glass. ### Claim 6 (depends on 1) The process according to claim 1, wherein a phosgene stream and an amine stream are each split into a plurality of individual streams and the individual streams are fed into the mixing chambers, with each mixing chamber having at least one phosgene inlet and at least one amine inlet. ### Claim 7 (depends on 1) The process according to claim 1, wherein, after mixing of the phosgene with the amine in the mixing chambers, the streams from the individual mixing chambers are brought together. ### Claim 8 (depends on 1) The process according to claim 1, wherein the amine is introduced into the mixing chambers at a temperature in the range of from 230 to 270° C. ### Claim 9 (depends on 1) The process according to claim 1, wherein the amine is introduced into the mixing chambers as a mixture with an inert organic solvent in an amount of 5 to 90% by weight, based on the total weight of amine and solvent. ### Claim 10 (depends on 1) The process according to claim 1, wherein amine and phosgene are fed into the mixing chambers in a molar ratio of amine to phosgene in the range from 1:2 to 1:20. ### Claim 11 (depends on 1) The process according to claim 1, wherein the phosgene is introduced into the mixing chambers at a temperature in the range of from 240 to 270° C. ### Claim 12 (depends on 1) The process according to claim 1, wherein the reaction mixture is cooled after a residence time in the range of from 0.1 to 2 s at a temperature in the range of from 230 to 270° C. to a temperature in the range from 40° C. to 180° C. ### Claim 13 (depends on 1) The process according to claim 1, wherein the reaction mixture is cooled after a residence time in the range of from 0.1 to 2 s at a temperature in the range of from 230 to 270° C. by at least 50° C. in less than 1 s by depressurizing the reaction mixture by at least 20 bar. ### Claim 14 (depends on 12) The process according to claim 12, wherein the temperature of the reaction mixture changes by less than 20° C. during the residence time in the range of from 0.1 to 2 s. ### Claim 15 (depends on 1) The process according to claim 1, wherein said amine reactant is selected from the group consisting of 2,2′-, 2,4′- and/or 4,4′-diaminodiphenylmethane (MDA), 2,4- and/or 2,6-toluenediamine (TDA), 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane (isophoronediamine, IPDA) and/or hexamethylenediamine (HDA). ### Claim 16 (depends on 1) The process according to claim 1, wherein the amine is present in the liquid phase during the phosgenation reaction. ### Claim 17 (depends on 1) The process according to claim 1, wherein a solvent is mixed with said phosgene and amine reactants. ### Claim 18 (depends on 17) The process according to claim 17, wherein the isocyanate reaction product is purified by removing phosgene, HCl and solvent from the isocyanate at a temperature of <150° C. and, after removal of the phosgene, at a temperature of #190° C., separating solvent from the isocyanate, and subsequently separating the isocyanate by distillation at pressures ranging from 2 to 50 mbar and temperatures ranging from 150 to 250° C. ### Claim 19 (depends on 1) The process according to claim 1, wherein the reaction of the amine with the phosgene is conducted to form the isocyanates in a single stage reaction. ### Claim 20 (depends on 1) The process according to claim 1, wherein the reaction of the amine with the phosgene is conducted in a single stream in the reaction space. ### Claim 21 (depends on 1) The process according to claim 1, wherein the reaction of the amine with the phosgene is completed in a single pass-through a reaction space consisting of the mixing chambers connected in parallel. ### Claim 22 (depends on 1) The process according to claim 1, wherein the reaction of the amine with the phosgene is conducted in mixing chambers or reaction spaces each having the same volume. ### Claim 23 (depends on 1) The process according to claim 1, wherein the reaction of the amine with the phosgene is conducted in mixing chambers or reaction spaces all of which are connected in parallel. ### Claim 24 (depends on 1) The process according to claim 1, wherein the reaction of the amine with the phosgene is conducted under pressure until the reaction is complete. ### Claim 25 (depends on 1) The process according to claim 1, wherein during the contacting the amine and the phosgene from the parallel mixing chambers are brought together.