| 摘要 |
<p>#CMT# #/CMT# Producing diisocyanate comprises reacting corresponding diamines with stoichiometric excess of phosgene in at least a reaction zone, where: the reaction condition is selected in such a way that at least the reaction components diamine, diisocyanate and phosgene are in gasiform at these conditions; and the reaction zone is loaded with a diamine- and a phosgene containing gas stream; the chlorine portion in the phosgene stream before the mixing with the amine containing stream is less than 1000 wt.ppm and/or the bromine fraction in the phosgene containing stream is less than 50 wt.ppm. #CMT# : #/CMT# Independent claims are included for: (1) use of phosgene with a content of molecular chlorine of less than 1000 wt.ppm in a gas phase phosgenation; and (2) use of phosgene with a content of molecular bromine of less than 50 wt.ppm in a gas phase phosgenation. #CMT#USE : #/CMT# The method is useful for the production of diisocyanate (claimed). #CMT#ADVANTAGE : #/CMT# In the method, material embrittlements of the reaction wall of the production plant can be minimized due to the removal of chlorine. #CMT#ORGANIC CHEMISTRY : #/CMT# Preferred Process: The diamine containing- and/or phosgene containing gas stream are added with at least an inert medium, so that the gas volume of inert medium to amine and/or to phosgene is more than 0.001-30. The reaction of phosgene with diamine room takes place at an absolute pressure of more than 0.1 bar to less than 20 bar and at a temperature of more than 200[deg] C to 600[deg] C. The average contact time of the reaction mixture is 0.001 seconds to less than 5 seconds. The fresh phosgene with a portion of molecular chlorine (more than 2 wt.ppm) is conducted before reaction with the amine to a rectification column for the separation of chlorine from phosgene. Preferred Components: The molar ratio of phosgene to amino groups is 1.1:1-20:1. The stream in the reaction room shows a Bodenstein number of more than 10. The fraction of hydrochloric acid in the phosgene containing stream, after an optional mixing of fresh phosgene and before the mixing of the amine containing stream, is at least less than 15 wt.%. The inert medium is chlorobenzene. The isocyanate is 1,6-diisocyanatohexane, 1-isocyanato-3,3,5-trimethyl-5-(isocyanatomethyl)cyclohexane, 4,4'-di(isocyanatocyclohexyl)methane and 2,4-/2,6-toluylenediisocyanate-isomer mixture. The rectification column component is a mixture of hydrochloric acid and phosgene and optionally inert-medium. #CMT#EXAMPLE : #/CMT# No suitable example given.</p> |
