Process and apparatus for preparing isocyanates

Abstract

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 phosgene and amine are first evaporated and then superheated further to reaction temperature, and the superheated phosgene and amine are mixed and fed to a reactor in which the phosgene and the amine are converted to the isocyanate, wherein the residence time of the phosgene at temperatures greater than 300° C. is not more than 5 s, and/or the temperature of heat transfer surfaces in contact with phosgene is not more than 20 K above the phosgene temperature to be established. The invention further relates to an apparatus for preparing isocyanates by reacting the corresponding amines with phosgene in the gas phase.

Dependencies are inferred from the claim text.