Claims
- 1. In a process for the hydrogenation of a crude methylene bridged polyphenylamine feed containing oligomers to produce the corresponding methylene bridged polycyclohexylamine counterpart in the presence of a rhodium hydrogenation catalyst at a temperature and for a time sufficient to effect hydrogenation of the phenyl ring to the cyclohexyl ring, said methylene bridged-polyphenyl amine feed represented by the formula: ##STR2## wherein R is H.sub.1, C.sub.1-6 alkyl, C--O--R.sub.3, where R.sub.3 is C.sub.1-4 alkyl, CH.sub.2 NH.sub.2, R.sub.1 and R.sub.2 are H or C.sub.1-6 alkyl, x is 1-4, y is 0 to z with the sum being at least 1, provided that x+y is not greater than 5, and z is from 0 to 3
- pretreating the crude methylene bridged polyphenylamine feed via an initial hydrogenation in the presence of hydrogen and a hydrogenation catalyst consisting essentially of ruthenium under conditions sufficient to at least partially hydrogenate the feed, and then
- catalytically hydrogenating the methylene bridged polyphenylamine in a secondary hydrogenation zone containing rhodium catalyst for producing the corresponding methylene bridged polycyclohexylamine counterpart.
- 2. The process of claim 1 wherein said initial hydrogenation is carried out using ruthenium as the hydrogenation catalyst.
- 3. The process of claim 2 wherein said initial hydrogenation is carried out at at temperature from 130.degree. to 220.degree. C. and for a time from about 10 to 120 minutes.
- 4. The process of claim 3 wherein the ruthenium, as metal, is present in an amount of from 0.0005 to 10% by weight as metal of the methylene bridged polyphenylamine.
- 5. The process of claim 4 wherein each x is 1 and each y is 1.
- 6. The process of claim 5 wherein R.sub.1 and R.sub.2 are hydrogen.
- 7. The process of claim 6 wherein R is hydrogen or methyl.
- 8. The process of claim 7 wherein z is 0.
- 9. The process of claim 8 wherein R is hydrogen.
- 10. The process of claim 9 wherein the catalytic hydrogenation of the methylene bridged polyphenylamine to methylene bridged polycyclohexylamine is carried out using rhodium where the rhodium is present in an amount of from 0.001 to 10% by weight as metal of the methylene bridged polyphenylamine.
- 11. The process of claim 10 wherein ruthenium is added to the rhodium in the secondary hydrogenation zone and the ratio of rhodium to ruthenium is from about 2-12 weight parts rhodium per weight part ruthenium.
- 12. The process of claim 4 wherein said methylene bridged polyphenylamines are selected from the group consisting of methylenedianiline; 3,3'-dimethyl-4,4'-diaminodiphenylmethane; 3,3'5,5'-tetramethyl-4,4'diaminodiphenylmethane, 3,3'6,6'-tetramethyl-4,4'-diaminodiphenylmethane; 3,3'-di-tert-butyl-4,4'-diaminodiphenylmethane; 3,3'-dimethyl5,5'-di-tert-butyl-4,4'-diaminodiphenylmethane; N,N'-dimethyl-4,4'-diaminodiphenylmethane; and tetramethyl-4,4'-diaminodiphenylmethane.
- 13. The process of claim 12 wherein said methylene bridged polyphenylamine is methylenedianiline.
- 14. The process of claim 12 wherein said methylene bridged polyphenylamine is 3,3'4,4'-diaminodiphenylmethane.
- 15. The process of claim 12 wherein said methylene bridged polyphenylamine is 3,3'-di-tert-butyl-4,4'-diaminodiphenylmethane.
- 16. The process of claim 12 wherein said methylene bridged polyphenylamine is 3,3'6,6'-tetramethyl-4,4'-diaminodiphenylmethane.
Parent Case Info
This is a continuation of application Ser. No. 07/175,010 filed Mar. 30, 1988 now abandoned.
US Referenced Citations (11)
Foreign Referenced Citations (1)
Number |
Date |
Country |
066212 |
May 1982 |
EPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
175010 |
Mar 1988 |
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