METHOD FOR PRODUCING ISOCYANATES

摘要

The invention relates to a method for producing an isocyanate by reacting the corresponding primary amine with phosgene in a reactor (100) which comprises at least one reaction zone (110) and a quenching zone (120) arranged below said reaction zone, having the following steps: (i) introducing a gaseous amine flow (1) and a gaseous phosgene flow (2) into the reactor (100) and reacting the flows in the reaction zone (110) into a product gas flow (3) comprising isocyanate and hydrogen chloride and optionally excess phosgene; (ii) introducing the product gas flow (3) into the quenching zone (120), in which the product gas flow is cooled by injecting a quenching liquid (4) via at least one quenching nozzle (200) such that a liquid flow (5) comprising the quenching liquid (4) and isocyanate and a gaseous flow (6) comprising hydrogen chloride and optionally phosgene are obtained; and (iii) separating the isocyanate from the liquid flow (5) obtained in step (ii); wherein the temperature Tw*, of the wall of the reaction zone (110) directly above the quenching zone (120) is kept at a value which lies maximally 4.0%, preferably maximally 2.0%, below the maximum temperature, Twmax, of the wall of the reaction zone, said maximum temperature being specified in Kelvin.

主权项

1. A method for producing an isocyanate by reacting the corresponding primary amine with phosgene in a reactor which comprises at least one reaction zone and a quenching zone arranged below the reaction zone, comprising:
(i) introducing a gaseous amine stream and a gaseous phosgene stream into the reactor and reacting the mixture in the reaction zone to form a product gas stream comprising isocyanate and hydrogen chloride; (ii) introducing the product gas stream into the quenching zone in which the product gas stream is cooled by spraying in a quench liquid via at least one quench nozzle in such a manner that a liquid stream comprising quench liquid and isocyanate is obtained; and (iii) isolating the isocyanate from the liquid stream obtained in step (ii); wherein the temperature of the wall of the reaction zone immediately above the quenching zone is maintained at a value which is at most 15% below the maximum temperature in Kelvin of the wall of the reaction zone.