Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1998-11-30
2000-02-29
Shippen, Michael L.
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C07C 3508
Patent
active
060311401
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to a continuous process for preparing isocamphyl-cyclohexanols from isocamphyl-guaiacol or isocamphyl-phenol by hydrogenation with hydrogen at elevated temperature and elevated pressure using support-free reduced molded bodies made of compressed powders of cobalt, manganese and copper (hydr)oxides and, optionally, of (hydr)oxides of alkaline earth metals.
BACKGROUND OF THE INVENTION
Isocamphyl-cyclohexanols are constituents of the industrially produced sandalwood perfumes, which are composed of synthetic mixtures of various terpenecyclohexanol isomers. Industrial sandalwood perfumes replace natural sandalwood oil in soaps, cosmetic products and perfume compounds.
As starting compounds for the isocamphyl-cyclohexanols, for example, the isocamphyl-guaiacols can be prepared in a known manner by reacting camphene with guaiacol with the aid of acidic catalysts, for example borontrifluoride and acetic acid; the isocamphyl-guaiacols are then converted into the isocamphyl-cyclohexanols by hydrogenation of the aromatic nucleus and cleavage of the methoxy group.
The reactions proceed according to the following equation: ##STR1## X=OCH.sub.3 or H ##STR2##
It is already known to hydrogenate alkylation mixtures of camphene and catechol (US 4 014 944) or camphene and guaiacol (DE-A 2 921 139) with hydrogen over Raney nickel to form the desired isocamphyl-cyclohexanols.
Without exception, these processes of the prior art proceed discontinuously using powdered catalysts by the suspension process.
In the case of powdered catalysts, the following difficulties exist: (1) to activate said catalysts in a controlled and uniform manner, (2) to circulate powdered catalysts with the aid of special sludge pumps and (3) to separate powdered catalysts from the reaction product quantitatively. Sludge pumps are, after all, subject to a high mechanical loading. The quantitative removal of powdered catalysts is furthermore expensive because it requires a coarse filtration and a fine filtration using equipment with switching facility. Furthermore, there is a great risk that the catalysts quickly lose their activity as a result of these additional operations and therefore furthermore cause high catalyst consumptions. In addition, powdered catalysts can only be loaded to a limited extent and can be freed from the reaction products only with difficulty, which makes their working-up difficult.
There was therefore the requirement to prepare highly loadable, acid-resistant and long-life catalysts for preparing isocamphyl-cyclohexanols, which catalysts should be free of complicated support systems and therefore capable of being worked up again.
SUMMARY OF THE INVENTION
Surprisingly, the problem described can be solved with the aid of support-free fixed-bed catalysts which can be obtained by reduction of molded bodies made of compressed metal (hydr)oxide powders.
The invention consequently relates to a continuous process for preparing isocamphyl-cyclohexanols from compounds which have the carbon skeleton of the isocamphyl-guaiacols or isocamphyl-phenols by hydrogenation with hydrogen at elevated temperature and elevated pressure, which process comprises using as catalysts support-free molded bodies which are obtainable by reduction of molded bodies made of compressed powders of cobalt, manganese and copper (hydr)oxides and optionally one or more (hydr)oxides of the alkaline earth metals.
For the catalysts to be used according to the invention, the Co proportions should be 40 to 65% by weight, the Mn proportions 10 to 20% by weight, the Cu proportions 0.1 to 0.5% by weight and, optionally, the alkaline earth metal proportions (with a plurality in the total) 0.2 to 5% by weight of the total (hydr)oxide powder (calculated as metal in each case). The remainder to 100% by weight is oxygen for the compounds present in oxidic form. Such a catalyst does not in fact need to contain (hydr)oxides of the alkaline earth metals; preferably, however, it contains at least one (hydr)oxide of the alkaline earth m
REFERENCES:
patent: 4014944 (1977-03-01), Hall et al.
patent: 4245124 (1981-01-01), Bauer et al.
Chem Abstract, vol. 51, No. 21, Nov. 10, 1957, Abstract No. 17107CL.A. Kheifits.
Darsow Gerhard
Niemeier Wilfried
Bayer Aktiengesellschaft
Cheung Noland J.
Gil Joseph C.
Shippen Michael L.
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