US 2026/0242333 A1Published application

Method and device for producing isocyanates

AssigneeCovestro Deutschland AG

InventorsRuediger Borrmann, Dieter Schade, Frank Richter, Tim Loddenkemper

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Abstract

The invention relates to a method for producing isocyanates via gas-phase phosgenation of the corresponding amines in a phosgenation system, in which, in particular, problems due to the formation of deposits in apparatus of the phosgenation system, e.g. in particular the reaction section, during the initial operation (start-up) of the method are preferably avoided. The invention also relates to a device for carrying out the method according to the invention, and to a method for starting up a phosgenation system.

Claims20

Dependent claims

A process for producing isocyanates by gas phase phosgenation comprising:

(a) at least one phosgene stream apparatus (20) for provision of a gaseous phosgene stream optionally comprising, in addition to phosgene, an inert substance in the phosgene stream,
(b) optionally one inert substance stream apparatus for provision of an inert substance stream,
(c) at least one amine stream apparatus (10) for provision of a gaseous amine stream optionally comprising, in addition to amines, an inert substance in the amine stream,
(d) a phosgenation reactor (1) for mixing of the streams from (a) to (c) and reaction of the amine stream with the phosgene stream,
wherein the phosgenation plant is started up by running through the following steps:
(A) charging the phosgenation reactor (1) with the gaseous phosgene stream and optionally the inert substance stream, and then continuously feeding the gaseous phosgene stream and any inert substance stream into the phosgenation reactor (1),
(B) continuously feeding the amine stream into the phosgenation reactor (1),
wherein step (B) comprises a startup phase, a subsequent reduction phase and a production phase that follows the reduction phase, wherein, during the startup phase, the amine stream comprises at least one first amine and optionally a second amine other than the first amine, and the proportion by mass of the first amine in the totality of amines in the amine stream which is fed to the phosgenation reactor (1) is at least 90.0% by weight, then this proportion by mass is reduced during the reduction phase to 85.0% by weight or less, and then this proportion by mass is maintained in the production phase, wherein, during the startup phase, the reduction phase and the production phase, the remainder of the totality of the amines in the amine stream absent from 100% by weight is formed by the second amine and optionally to an extent of not more than 1% by weight of further organic amines other than the first and second amines, and wherein
the first amine is 1,6-diaminohexane (HDA), 1-amino-3,5,5-trimethyl-5-aminomethyl-cyclohexane (IPDA), bis(p-aminocyclohexyl)methane (PACM) or mixtures thereof;
and
the second amine is 1,5-diaminopentane (PDA), 1,3-bis(aminomethyl)benzene (m-XDA), 1,4-bis(aminomethyl)benzene (p-XDA), 1,2-bis(aminomethyl)cyclohexane (1,2-BAC), 1,3-bis(aminomethyl)cyclohexane (1,3-BAC), 1,4-bis(aminomethyl)-cyclohexane (1,4-BAC), tetramethylxylylenediamine (TMXDA), 2,5 bis(aminomethyl)bicyclo[2.2.1]heptane (2,5-NBDA), 2,6 bis(aminomethyl)bicyclo[2.2.1]heptane (2,6-NBDA), neopentane-diamine, 2,4,4-trimethylhexamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1-methyl-2,6-diaminocyclohexane and/or 1-methyl-2,4-diaminocyclohexane (collectively or individually H6TDA), 2,5-diamino-2,5-dideoxy-1,4:3,6-dianhydrosorbitol (ISODA), 2,5-diamino-2,5-dideoxy-1,4:3,6-dianhydromannitol (MANDA) and 2,5-diamino-2,5-dideoxy-1,4:3,6-dianhydroiditol (IDDA) or mixtures thereof.

8 more elements

A process for startup of a phosgenation plant comprising:

(a) at least one phosgene stream apparatus (20) for provision of a gaseous phosgene stream optionally comprising, in addition to phosgene, an inert substance in the phosgene stream;
(b) optionally one inert substance stream apparatus for provision of an inert substance stream;
(c) at least one amine stream apparatus (10) for provision of a gaseous amine stream optionally comprising, in addition to amines, an inert substance in the amine stream;
and
(d) a phosgenation reactor (1) for mixing of the streams from (a) to (c) and reaction of the amine stream with the phosgene stream;
wherein the phosgenation plant is started up by running through the following steps:
(A) charging the phosgenation reactor (1) with the gaseous phosgene stream and optionally the inert substance stream, and then continuously feeding the gaseous phosgene stream and any inert substance stream into the phosgenation reactor (1),
(B) continuously feeding the amine stream into the phosgenation reactor (1),
wherein step (B) comprises a startup phase, a subsequent reduction phase and a production phase that follows the reduction phase, wherein, during the startup phase, the amine stream comprises at least one first amine and optionally a second amine other than the first amine, and the proportion by mass of the first amine in the totality of amines in the amine stream which is fed to the phosgenation reactor (1) is at least 90.0% by weight, then this proportion by mass is reduced during the reduction phase to 85.0% by weight or less, and then this proportion by mass is maintained in the production phase, wherein, during the startup phase, the reduction phase and the production phase, the remainder of the totality of the amines in the amine stream absent from 100% by weight is formed by the second amine and optionally to an extent of not more than 1% by weight of further organic amines other than the first and second amines, and
the first amine is 1,6-diaminohexane (HDA), 1-amino-3,5,5-trimethyl-5-aminomethylcyclohexane (IPDA), bis(p-aminocyclohexyl)methane (PACM) or mixtures thereof;
and
the second amine is 1,5-diaminopentane (PDA), 1,3-bis(aminomethyl)benzene (m-XDA), 1,4-bis(aminomethyl)benzene (p-XDA), 1,2-bis(aminomethyl)cyclohexane (1,2-BAC), 1,3-bis(aminomethyl)cyclohexane (1,3-BAC), 1,4-bis(aminomethyl)-cyclohexane (1,4-BAC), tetramethylxylylenediamine (TMXDA), 2,5bis(aminomethyl)bicyclo[2.2.1]heptane (2,5-NBDA), 2,6 bis(aminomethyl)bicyclo[2.2.1]heptane (2,6-NBDA), neopentanediamine, 2,4,4-trimethylhexamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1-methyl-2,6-diaminocyclohexane and/or 1-methyl-2,4-diaminocyclohexane (collectively or individually H6TDA), 2,5-diamino-2,5-dideoxy-1,4:3,6-dianhydrosorbitol (ISODA), 2,5-diamino-2,5-dideoxy-1,4:3,6-dianhydromannitol (MANDA) and 2,5-diamino-2,5-dideoxy-1,4:3,6-dianhydroiditol (IDDA) or mixtures thereof.

9 more elements

Dependencies are inferred from the claim text.

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Abstract

A process for producing isocyanates by gas phase phosgenation comprising:

(a) at least one phosgene stream apparatus (20) for provision of a gaseous phosgene stream optionally comprising, in addition to phosgene, an inert substance in the phosgene stream,
(b) optionally one inert substance stream apparatus for provision of an inert substance stream,
(c) at least one amine stream apparatus (10) for provision of a gaseous amine stream optionally comprising, in addition to amines, an inert substance in the amine stream,
(d) a phosgenation reactor (1) for mixing of the streams from (a) to (c) and reaction of the amine stream with the phosgene stream,
wherein the phosgenation plant is started up by running through the following steps:
(A) charging the phosgenation reactor (1) with the gaseous phosgene stream and optionally the inert substance stream, and then continuously feeding the gaseous phosgene stream and any inert substance stream into the phosgenation reactor (1),
(B) continuously feeding the amine stream into the phosgenation reactor (1),
wherein step (B) comprises a startup phase, a subsequent reduction phase and a production phase that follows the reduction phase, wherein, during the startup phase, the amine stream comprises at least one first amine and optionally a second amine other than the first amine, and the proportion by mass of the first amine in the totality of amines in the amine stream which is fed to the phosgenation reactor (1) is at least 90.0% by weight, then this proportion by mass is reduced during the reduction phase to 85.0% by weight or less, and then this proportion by mass is maintained in the production phase, wherein, during the startup phase, the reduction phase and the production phase, the remainder of the totality of the amines in the amine stream absent from 100% by weight is formed by the second amine and optionally to an extent of not more than 1% by weight of further organic amines other than the first and second amines, and wherein
the first amine is 1,6-diaminohexane (HDA), 1-amino-3,5,5-trimethyl-5-aminomethyl-cyclohexane (IPDA), bis(p-aminocyclohexyl)methane (PACM) or mixtures thereof;
and
the second amine is 1,5-diaminopentane (PDA), 1,3-bis(aminomethyl)benzene (m-XDA), 1,4-bis(aminomethyl)benzene (p-XDA), 1,2-bis(aminomethyl)cyclohexane (1,2-BAC), 1,3-bis(aminomethyl)cyclohexane (1,3-BAC), 1,4-bis(aminomethyl)-cyclohexane (1,4-BAC), tetramethylxylylenediamine (TMXDA), 2,5 bis(aminomethyl)bicyclo[2.2.1]heptane (2,5-NBDA), 2,6 bis(aminomethyl)bicyclo[2.2.1]heptane (2,6-NBDA), neopentane-diamine, 2,4,4-trimethylhexamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 1-methyl-2,6-diaminocyclohexane and/or 1-methyl-2,4-diaminocyclohexane (collectively or individually H6TDA), 2,5-diamino-2,5-dideoxy-1,4:3,6-dianhydrosorbitol (ISODA), 2,5-diamino-2,5-dideoxy-1,4:3,6-dianhydromannitol (MANDA) and 2,5-diamino-2,5-dideoxy-1,4:3,6-dianhydroiditol (IDDA) or mixtures thereof.

8 more elements