Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2002-10-15
2004-01-13
Wilson, James O. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S346000, C568S354000, C568S835000, C568S836000, C556S042000, C556S056000, C556S057000, C556S113000, C556S137000, C556S150000
Reexamination Certificate
active
06677490
ABSTRACT:
The invention relates to a process for the preparation of an alcohol/ketone mixture by decomposition of an alkyl hydroperoxide.
It relates more particularly to the preparation of a cyclohexanol/cyclohexanone mixture by decomposition of cyclohexyl hydroperoxide in the presence of a heterogeneous catalysis.
Among these organic hydroperoxides, cyclohexyl hydroperoxide is prepared by the oxidation of cyclohexane. It results, by catalytic decomposition, in cyclohexanone and cyclohexanol.
Industrial processes for the production of these cyclohexanol/cyclohexanone mixtures are of very great economic importance as they make possible access to the manufacture of chemicals on a large scale, such as adipic acid. These processes are described in an extensive literature, both scientific articles and patents.
The conventional industrial process consists of an oxidation of cyclohexane by air, making it possible to obtain a mixture of compounds, including cyclohexyl hydroperoxide (CHHPO), alcohols, ketones and acids. Cyclohexyl hydroperoxide is converted to a cyclohexanol/cyclohexanone mixture by various reactions, such as hydrogenation or decomposition.
The decomposition of organic hydroperoxides and in particular of cyclohexyl hydroperoxide (CHHPO) can first of all be carried out by homogeneous catalysis, that is to say in the presence of a catalyst dissolved in the reaction medium. Thus, Patent FR-A-1 580 206 discloses the oxidation of a cycloalkane in the liquid phase, followed by heating the solution thus obtained of the cycloalkyl hydroperoxide in the cycloalkane in the presence of a soluble chromium derivative as catalyst. Likewise, the articles in the Journal of the American Chemical Society (1985), 107, pages 3534 to 3540, or in the Journal of Molecular Catalysis (1988), 48, pages 129 to 148, describe the use of organic salts, such as cobalt octanoate, or of complexes dissolved in the organic liquid phase where the reaction takes place or in an aqueous phase in contact with the said organic phase.
This decomposition of cyclohexyl hydroperoxide can also be carried out by neutralization of the acids present in the medium with an alkaline hydroxide and in the presence of metal salts, such as those disclosed in U.S. Pat. Nos. 4,720,592 and 4,238,415. However, the yield in the production of the cyclohexanol/cyclohexanone mixture is not very high and numerous byproducts are also formed.
U.S. Pat. No. 3,925,316 discloses a process for the decomposition of cyclohexyl hydroperoxide in the presence of homogeneous catalysts composed of soluble vanadium, ruthenium or molybdenum compounds. Other catalytic systems based on pairs of different metals present in the form of soluble compounds are disclosed, for example in U.S. Pat. Nos. 3,401,193, 3,987,100 and 4,551,553.
The decomposition of hydroperoxides in the presence of a homogeneous catalyst has a number of disadvantages. Thus, large amounts of catalyst are entrained and are finally re-encountered either in the product prepared or in the effluents. It is not easy to recover this catalyst and it is therefore necessary to again add fresh catalyst. In addition, the presence of metals, essentially heavy metals, in the effluents is not very favourable to the environment and it is essential to avoid it as far as possible.
A proposal has been made, in attempting to overcome these disadvantages, to carry out this decomposition by heterogeneous catalysis, that is to say in the presence of a catalyst which is not dissolved in the reaction medium.
Thus, U.S. Pat. No. 4,173,587 discloses the use of an insoluble rhenium compound in the decomposition of cumene hydroperoxide.
Patent EP-A-0 492 807 also discloses the preparation of phenol and of acetone from cumyl hydroperoxide in the presence of a zeolite catalyst of mordenite or faujasite type chosen from zeolites Y, thermally stabilized dealuminated zeolites Y, zeolites Y exchanged with rare earth metals, in particular with lanthanum salts, or with transition metals, in particular with cobalt or nickel salts, and zeolites Y treated with fluorides.
In these cases, the metals are again not sufficiently attached to the support and partial dissolution in the reaction medium takes place during the use of the catalysts.
U.S. Pat. No. 4,543,427 discloses the preparation of a cyclohexanol/cyclohexanone mixture which consists in treating a cyclohexyl hydroperoxide with a supported catalyst comprising from 2 to 30% by weight, expressed as cobalt element, of a cobalt oxide deposited or absorbed on a zeolite support. This catalyst is not stable and a significant amount of the metal compound dissolves in the reaction medium. The problems mentioned above for the homogeneous catalyst are then encountered.
Before this, U.S. Pat. No. 2,851,496 disclosed the use of metals from Group VIII, such as cobalt deposited on an alumina, a silica, carbon or kieselguhr, as catalysts for the decomposition of cyclohexyl hydroperoxide. However, this catalyst has a reduced lifetime.
Patent EP 659 726 discloses a process for the preparation of an alcohol/ketone mixture by decomposition of an alkyl hydroperoxide in the presence of a metal immobilized on a support in the presence of an aqueous phase and of a basic compound. The support is a metal oxide, such as TiO
2
or ZrO
2
, on which is deposited a manganese, iron, cobalt and nickel or copper compound.
U.S. Pat. No. 5,298,665 also discloses the use of a catalyst composed of a metal compound deposited on or attached to a support. The compounds of the following metals: cobalt, chromium, vanadium, molybdenum, ruthenium, titanium, manganese and iron, are mentioned as metal compound. The support is a metal oxide chosen from silica, alumina or titanium oxide. This support comprises, at its surface, aromatic or aliphatic amino groups. This catalyst is used to convert an alkyl hydroperoxide to a mixture of alcohol and of ketone.
The catalysts described above have a limited lifetime because, in the majority of cases, the metal element is partially dissolved in the medium, the catalysis mainly being carried out by the dissolved fraction. The supported catalyst becomes exhausted in catalytically active metal and the mixture of ketones/alcohols produced comprises the dissolved metal fraction as harmful impurity.
Patent Application WO-A-94/08932 provides, in order to overcome the disadvantages of the heterogeneous catalysts mentioned above, for the decomposition of organic hydroperoxides to be carried out in the presence of a molecular sieve comprising aluminium and/or silicon and/or phosphorus oxides and a catalysing metal incorporated in the crystal matrix of the said molecular sieve. It seems that the active metal of these heterogeneous catalysts experiences virtually no elution. However, while the problem of elution of the catalyst into the reaction medium thus appears to be solved, it emerges from the patent application itself that the catalyst is rapidly deactivated, which results in the need for reactivation by separation of the catalyst and calcination. In the context of an industrial operation of such a process, it is clear that it is prohibitive to have to frequently separate the catalyst from the reaction medium in order to reactivate it.
One of the aims of the present invention is to overcome these disadvantages by providing a process for the manufacture of a mixture of alcohols and of ketones from an alkyl hydroperoxide comprising a heterogenous catalyst in which the cycle time and lifetime of the catalyst are high and with the reduction of an alcohol/ketone mixture not comprising or comprising a very small amount of metal element used as catalyst.
To this end, the invention provides a process for the manufacture of a mixture of alcohols and/or of ketones by decomposition of an alkyl hydroperoxide in the presence of a catalyst comprising a catalytically active metal element immobilized on a solid support, the said metal element being chosen from the group consisting of the elements belonging to Groups IB to VIIB or VIII of the Periodic Classification (CAS version), including the family o
Clark James
Fache Eric
Macquarrie Ducan
Price Peter
Rafelt John
Burns Doane Swecker & Mathis L.L.P.
Rhodia Polyamide Intermediates
Wilson James O.
Witherspoon Sikarl A.
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