Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Patent
1999-04-05
2000-08-29
Barts, Samuel
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
564462, 502313, 502330, 502332, 502333, 502334, C07C20700
Patent
active
061111406
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to catalysts comprising a support optionally doped with oxides, hydroxides and hydrated oxides of the rare earths and of manganese onto which support Ru and Pd are applied and which are treated with alkaline compounds of the alkali or alkaline earth metals and are characterized in that they contain no halogen, and a process for preparing cycloaliphatic amines by hydrogenation of the corresponding aromatic precursors in the presence of the catalysts of the invention.
It is known that aromatic amines can be hydrogenated in various ways using various catalysts. However, the development of the relevant technology teaches that it is very difficult to solve all problems which occur, for example unsatisfactory conversion, lack of selectivity caused by hydrogenolysis or condensation to form relatively high molecular weight compounds, insufficient space velocities, activity and operating life of the catalysts, sufficiently well for industrial purposes. This is shown by the many proposals which have been made on this subject over the course of time.
When Ni and Co catalysts were first employed (GB 969 542), it was soon found that supported noble metals are better catalysts (DE-AS [German Published Specification] 1 106 319). However, deaminations and condensations to form polymers, the latter particularly in the hydrogenation of polyamines, were observed, so that the reactions were restricted to low temperatures and relatively long reaction times. In addition, it was observed that NH.sub.3 formed in the condensation impairs the activity of the noble metals (J. Org. Chem. 29, 3082-4 (1964), EP 324 984). On the other hand, addition of NH.sub.3 makes it possible to restrict the condensation to relatively high molecular weight products. Attempts have also been made to control the high exothermicity of the hydrogenation and the associated temperature increases and by-product formation by addition of solvents (NL 6 709 040, EP 67 058) or by hydrogenation at low pressure in the gas phase (FR 1 530 477).
The addition of basic compounds such as alkalis to Ru catalysts has been found to be advantageous. This enabled the formation of polymers to be limited (U.S. Pat. No. 3,636,108, EP 53 818).
It was later found that Ru in the presence of oxides or hydroxides of Cr and Mn gives catalysts which have a greater activity and selectivity and make it possible to use smaller amounts of catalyst and carry out a hydrogenation in the absence of NH.sub.3 (DE-AS [German Published Specification] 2 502 893, DE-AS [German Published Specification] 2 502 894). An additional treatment of such Ru--Cr--Mn catalysts with alkalis leads to longer operating lives and greater insensitivity of the catalysts to impurities in the starting material (EP 1 425).
Hydrogenation using Pd instead of Ru has been proposed repeatedly, but condensation occurs preferentially (dicyclohexylamine from aniline: EP 503 347) so that NH.sub.3 again has to be added to avoid it (EP 53 818).
The use of Ru and Pd together on a Cr--Mn-doped or alkalized support offers an advantage if long catalyst operating lives are to be achieved. However, condensation again occurs to a considerable degree and is reduced only at very low temperatures (EP 324 983, EP 324 984). Such catalysts are, for example, suitable for the flexible preparation of mixtures of cyclohexylamine and dicyclohexylamine.
A further advance in respect of selectivity and the formation of primary amines at high conversions is achieved by using Ru on RE-Mn-doped supports (RE=rare earths). For example, cyclohexylamine is obtained in a selectivity of up to 97% at 110.degree. C. (EP 351 661, EP 476 359).
However, all known catalysts and processes still had disadvantages in respect of conversion, selectivity to primary amines, operating life of the catalysts, necessity of using NH.sub.3, etc. A serious problem in catalyst beds for the continuous trickle-phase hydrogenation is the tendency of all Ru catalysts to catalyze deaminations and hydrogenolysis of the molecule
REFERENCES:
patent: 3636108 (1972-01-01), Brake
patent: 4049584 (1977-09-01), Weissel
patent: 4161492 (1979-07-01), Weissel
patent: 4186145 (1980-01-01), Weissel
patent: 4429155 (1984-01-01), Goetz et al.
patent: 4496666 (1985-01-01), Pesa et al.
patent: 4943549 (1990-07-01), Immel et al.
patent: 4952549 (1990-08-01), Immel et al.
patent: 4960941 (1990-10-01), Vedage et al.
patent: 5023226 (1991-06-01), Immel et al.
patent: 5245082 (1993-09-01), Immel et al.
patent: 5322965 (1994-06-01), Immel et al.
patent: 5360934 (1994-11-01), Vedage et al.
patent: 5386060 (1995-01-01), Immel et al.
Journal of Org. Chem., vol. 29, Sep.-Dec. 1964, pp. 3082-3084.
Chem. Abstracts, vol. 120, Abstract No. 54237x, Sep. 1993.
Chem. Abstracts, vol. 71, Abstract No. 60833e, Jan. 1968.
Buysch Hans-Josef
Darsow Gerhard
Immel Otto
Langer Reinhard
Barts Samuel
Bayer Aktiengesellschaft
Eyl Diderico van
Gil Joseph C.
LandOfFree
Ru--Pd halogen-free catalyzers and method for producing cycloali does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Ru--Pd halogen-free catalyzers and method for producing cycloali, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Ru--Pd halogen-free catalyzers and method for producing cycloali will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1251563