| 摘要 |
The invention relates to a process for preparing isocyanates by reacting the corresponding amines with phosgene in the gas phase, optionally in the presence of an inert medium, in which the amine is evaporated in an evaporator to give an amine-comprising gas stream, the phosgene is mixed into the amine-comprising gas stream, and the amine and the phosgene are converted to the isocyanate in a reactor, wherein the temperature of surfaces in contact with the gaseous amine is kept above the dew point limit of the amine-comprising gas stream. The invention further relates to an apparatus for preparing isocyanates by reacting the corresponding amines with phosgene in the gas phase, comprising an evaporator to evaporate the amine and a reactor in which the reaction is effected, and means of connection of evaporator and reactor, wherein surfaces which can come into contact with gaseous amine are provided with a coating which is not wetted by amine or have an averaged roughness depth Rz to DIN ISO 4287 of not more than 10 μm, and/or the apparatus has no dead spaces or thermal bridges. |
