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US 5,344,987 AGranted
Process for preparing diphenylamines
AssigneeBayer Aktiengesellschaft
InventorsOtto Immel, Gerhard Darsow, Hans-Josef Buysch
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Abstract
Optionally substituted diphenylamines can be obtained by reacting optionally substituted anilines with optionally substituted cyclohexanones over a supported catalyst at 200.degree.-450.degree. C. and 0.1-20 bar, the supported catalyst containing one or more metals having a dehydrogenating action selected from the group Ru, Pd, Os, Ir, Pt, Fe, Co, Ni, Re, Mn, Cu, Ag, Cr and Ce.
Claims20
A process for preparing a diphenylamine of the formula ##STR4## in which R.sup.1, R.sup.2, R.sup.3 and R.sup.4 denote, independently of one another, hydrogen, C.sub.1 -C.sub.4 -alkyl or C.sub.1 -C.sub.4 -alkoxy,
- wherein an aniline of the formula ##STR5## is reacted with a cyclohexanone of the formula ##STR6## which may be present mixed with recycled reaction products, in the formulae the radicals R.sup.1 to R.sup.4 having the above meaning and aniline and cyclohexanone being present in a molar ratio of 1:4-6:1 over a supported catalyst containing 0.05-5% by weight, based on the total weight of the catalyst, of one or more metals having a dehydrogenating action, in the gaseous phase at 200.degree.-450.degree. C. and at 0.1-20 bar, and the metal(s) is/are selected from the group consisting of Ru, Pd, Os, Ir, Pt, Fe, Co, Ni, Re, Mn, Ce, Cu, Ag and Cr.
Dependencies are inferred from the claim text.