Iridium-Containing Catalysts, Their Production and Use

Abstract

A process is described for producing a catalyst composition comprising an iridium component dispersed on a support. In the process, silica-containing support is treated with an iridium compound and an organic compound comprising an amino group to form an organic iridium complex on the support. The treated support is then heated in an oxidizing atmosphere at a temperature of about 325° C. to about 475° C. to partially decompose the organic metal complex on the support. The treated support is then heated in a reducing atmosphere at a temperature of about 350° C. to about 500° C. to convert the partially decomposed organic iridium complex into the desired iridium component.

1 . A process for producing a catalyst composition comprising an iridium component dispersed on a support, the process comprising:
 a) treating a silica-containing support with at least one iridium compound and at least one organic compound comprising an amino group to form a treated support comprising an organic iridium complex on the support;   b) heating the treated support in an oxidizing atmosphere at a temperature of about 325° C. to about 450° C. to partially decompose the organic iridium complex on the support to form a partially decomposed organic iridium complex; and   c) heating the treated support in an reducing atmosphere at a temperature of about 350° C. to about 500° C. to convert the partially decomposed organic iridium complex into the iridium component.   
     
     
         2 . The process of  claim 1 , wherein the at least one organic compound in step (a) is selected from an (i) amino acids and (ii) compounds comprising an amino group and an alcohol group. 
     
     
         3 . The process of  claim 1 , wherein the partially decomposed organic iridium complex retains between 10 and 95% by weight of the dry weight attributed to the organic iridium complex prior to partial decomposition. 
     
     
         4 . The process of  claim 1 , wherein the partially decomposed organic iridium complex exhibits one or more infra-red absorption bands between 2100-2200 cm −1  that are not present in the organic complex before partial decomposition. 
     
     
         5 . The process of  claim 1 , wherein the organic compound in step (a) comprises an aliphatic amine containing one or more hydroxyl groups. 
     
     
         6 . The process of  claim 1 , wherein the organic compound in step (a) comprises a hydroxyalkylamine. 
     
     
         7 . The process of  claim 6 , wherein the hydroxyalkylamine comprises one or more of: methanolamine, di-methanolamine, tri-methanolamine, ethanolamine, di-ethanolamine, tri-ethanolamine, butanolamine, di-butanolamine, tri-butanolamine, propanolamine, di-propanolamine, dimethylethanolamine, di-isopropylethanolamine, methyldiethanolamine, dimethylamino-2-propanol, and tri-propanolamine. 
     
     
         8 . The process of  claim 1 , wherein the organic compound in step (a) comprises tri-ethanolamine. 
     
     
         9 . The process of  claim 1 , wherein the organic compound in step (a) comprises an amino acid. 
     
     
         10 . The process of  claim 9 , wherein the amino acid comprises arginine. 
     
     
         11 . The process of  claim 1 , wherein heating step (b) comprises heating the treated support to a temperature of about 375° C. to about 425° C. 
     
     
         12 . A catalyst composition produced by the process of  claim 1 . 
     
     
         13 . A method for converting a cyclic aliphatic hydrocarbon to acyclic alkane or alkene comprising contacting the cyclic aliphatic hydrocarbon under ring-opening conditions with a catalyst, wherein the catalyst is produced by a method comprising:
 a) treating a silica-containing support with an iridium compound and a organic compound comprising an amino group to form a treated support comprising an organic iridium complex on the support;   b) heating the treated support in an oxidizing atmosphere at a temperature of about 325° C. to about 450° C. to partially decompose the organic iridium complex on the support to form a partially decomposed organic iridium complex; and   c) heating the treated support in an reducing atmosphere at a temperature of about 350° C. to about 500° C. to convert the partially decomposed organic iridium complex into the iridium component.   
     
     
         14 . The process of  claim 13 , wherein the at least one organic compound in step (a) is selected from an (i) amino acids; and (ii) compounds comprising an amino group and an alcohol group. 
     
     
         15 . The process of  claim 13 , wherein the partially decomposed organic iridium complex retains between 10 and 95% by weight of the dry weight attributed to the organic iridium complex prior to partial decomposition. 
     
     
         16 . The process of  claim 13 , wherein the cyclic aliphatic hydrocarbon is methylcyclopentane. 
     
     
         17 . The process of  claim 13 , wherein the partially decomposed organic iridium complex exhibits one or more infra-red absorption bands between 2100-2200 cm −1  that are not present in the organic complex before partial decomposition. 
     
     
         18 . The process of  claim 13 , wherein the organic compound in the treating step (a) comprises an aliphatic amine containing one or more hydroxyl groups. 
     
     
         19 . The process of  claim 13 , wherein the organic compound in the treating step (a) comprises a hydroxyalkylamine. 
     
     
         20 . The process of  claim 19 , wherein the hydroxyalkylamine comprises one or more of: methanolamine, di-methanolamine, tri-methanolamine, ethanolamine, di-ethanolamine, tri-ethanolamine, butanolamine, di-butanolamine, tri-butanolamine, propanolamine, di-propanolamine, dimethylethanolamine, di-isopropylethanolamine, methyldiethanolamine, dimethylamino-2-propanol, and tri-propanolamine. 
     
     
         21 . The process of  claim 13 , wherein the organic compound in the treating step (a) comprises tri-ethanolamine. 
     
     
         22 . The process of  claim 13 , wherein the organic compound in the treating step (a) comprises an amino acid. 
     
     
         23 . The process of  22 , wherein the amino acid comprises arginine. 
     
     
         24 . The process of  claim 13 , wherein the heating step (b) comprises heating the treated support to a temperature of about 375° C. to about 425° C. 
     
     
         25 . A process for producing cyclohexylbenzene, the process comprising:
 (i) contacting benzene and hydrogen in the presence of a hydroalkylation catalyst under hydroalkylation conditions effective to form a hydroalkylation reaction product stream comprising cyclohexylbenzene, cyclohexane, methylcyclopentane, and benzene;   (ii) separating at least a portion of the hydroalkylation reaction product stream into a C 6 -rich stream comprising benzene, cyclohexane, and methylcyclopentane and a cyclohexylbenzene-rich stream;   (iii) producing a first reaction product stream comprising the step of contacting at least a portion of the C 6 -rich stream with a first catalyst comprising at least one support and at least one metal component and the contacting being conducted under conditions to convert at least a portion of the methylcyclopentane to at least one paraffin wherein the first catalyst is produced by a method comprising:   a) treating a silica-containing support with an iridium compound and an organic compound comprising an amino group to form a treated support comprising an organic iridium complex on the support;   b) heating the treated support in an oxidizing atmosphere at a temperature of about 325° C. to about 450° C. to partially decompose the organic iridium complex on the support to form a partially decomposed organic iridium complex; and   c) heating the treated support in a reducing atmosphere at a temperature of about 350° C. to about 500° C. to convert the partially decomposed organic iridium complex into the iridium component;   (iv) producing a second reaction product stream comprising the step of contacting at least a portion of the first reaction product stream with a second catalyst comprising at least one support and at least one metal component and under conditions effective to convert at least a portion of the cyclohexane to benzene;   (v) separating at least a portion of the second reaction product stream produced in producing step (iv) into a benzene recycle stream and a paraffins-rich stream comprising 2-methylpentane and 3-methylpentane; and   (vi) recycling at least a portion of the benzene recycle stream to the contacting step (i).