Process for the production of phosgene with simultaneous generation of steam
AssigneeBayer Aktiengesellschaft
InventorsHeinz Sauer, Helmut F. Porkert, Dietrich Liebsch
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Abstract
Phosgene is produced by reacting chlorine and an excess of carbon monoxide in the presence of activated charcoal in a two stage process. In the first stage, the chlorine and carbon monoxide are reacted in a tubular reactor containing activated charcoal at a temperature above 250.degree. C. until 95 to 98% chlorine has reacted. The reaction gases are cooled to a temperature of from 50.degree. to 120.degree. C. and then introduced into a second reactor maintained at 50 to 100.degree. C. where the phosgene-forming reaction is completed. The phosgene leaving the second reactor has a residual chlorine content of less than 50 ppm. The heat generated during phosgene formation is used to produce steam.
Claims8
A process for the production of phosgene having a residual chlorine content of less than 50 ppm comprising
- (a) reacting chlorine with an excess of carbon monoxide at a temperature above 250.degree. C. in a first tubular reactor in which the tubes have an internal diameter no greater than 50 mm and are made of a material selected from nickel, high alloyed chromium/nickel steel and chromium/nickel/molybdenum steel which reactor contains granular activated charcoal having a grain size of about 3 to 10 mm, a compression resistance of more than 18 kilopond and a benzene absorption capacity above 40 wt. % to form phosgene until 95 to 98% of the chlorine is reacted,
- (b) removing heat generated in the reactor used in (a) by means of a heat carrier which is removed from the reactor,
- (c) condensing and/or cooling the heat carrier while generating steam,
- (d) removing the phosgene-containing gas from the first tubular reactor,
- (e) cooling the gas of (d) to a temperature of from 50.degree. to 120.degree. C.,
- (f) transferring the cooled gas of (e) to a second reactor containing granular activated charcoal which second reactor is maintained at a temperature of from 50.degree. to 100.degree. C. and
- (g) completing the phosgene-forming reaction until the phosgene has a residual chlorine content of less than 50 ppm (volume).
Dependencies are inferred from the claim text.