Patent ID: 8829232
Filing Date: 2014-09-09
Classification: C07C

Abstract:
1. A process for preparing isocyanates, the process comprising reacting at least one amine with a phosgene in a liquid phase, optionally in the presence of at least one inert medium, to form an isocyanate, wherein: the at least one amine and the phosgene are first mixed in a mixing chamber to produce a reaction mixture which is then fed to a reactor; the at least one amine is added through a coaxial orifice arranged coaxially to the mixing chamber and the phosgene is added through a first feed orifice and a second feed orifice situated in at least a first plane and a second plane, respectively, arranged at right angles to the axis of the mixing chamber, or the phosgene is added through the coaxial orifice arranged coaxially to the mixing chamber and the at least one amine is added through the first feed orifice and the second feed orifice situated in at least the first plane and the second plane, respectively, arranged at right angles to the axis of the mixing chamber; the first plane is arranged in an upstream of the coaxial orifice and the second plane is arranged in a downstream of the coaxial orifice; the mixing chamber comprises a diameter constriction at a downstream end thereof, such that the reaction mixture is backmixed by the diameter constriction; the diameter constriction at the downstream end of the mixing chamber is configured with an angle (α) ranging from 10 to 80° relative to the axis of the mixing chamber; and a mean residence time of the reaction mixture in the mixing chamber is not more than 18.5 ms.