Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Patent
1995-04-19
1998-04-14
Cintins, Marianne M.
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
502350, 502351, C07C 5500, B01J 2300
Patent
active
057390762
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to catalyst systems and their use for the oxidation of organic compounds and in particular to the selective oxidation of organic compounds particularly aliphatic compounds and alkyl aromatic compounds. A particularly useful feature is their performance as ring opening catalysts. In a preferred embodiment the invention is concerned with the oxidation of saturated hydrocarbon chains.
Saturated organic compounds are difficult to oxidise and despite attempts to develop methods and techniques for their controlled or selective oxidation techniques using mild conditions with relatively high yields are only known for the conversion of butane via butenes into maleic anhydride, furthermore the known processes use homogenous and sometimes hazardous catalysts requiring complex separation techniques. An example of such processes are given in Catalysis Today Vol. I Nos. 5 of October 1987 relative to the selective catalytic oxidation of butane to maleic anhydride involving dehydrogenation and oxidation of the resulting intermediate olefin, the article in Tetrahedron Vol. 31 pages 777-784 concerning the oxidation of cyclohexane with molecular oxygen and the article in the Journal of the CHEM. SOC. CHEM. COMMUN. 1987 page 1487 and Journal of Molecular Catalysis 44 (1988) pages 73-83. The direct oxidation of saturates to introduce functional groups such as ketones and alcohols using a heterogeneous catalyst system would be extremely attractive.
PCT patent application number GB 8901328 describes the use of catalysts based on crystalline synthetic material comprising silicon and titanium oxides and are characterised by an infra red absorption band at around 950 cm.sup.-1 to 960 cm.sup.-1 and typically of the general formula:
These catalysts known as TS-1 and TS-2 are typically prepared in the absence of aluminium from a mixture containing a source of silicon oxide, a source of titanium oxide, a nitrogenated organic base and water as described in United Kingdom Patent 2071071 which is concerned with the catalysts themselves or by the dealumination of ZSM-5 and reaction with titanium tetrachloride vapour as described by B. Kraushaar and J. H. C. Van Hoof in Catalysis Letters 1 (1988) pages 81-84. The catalysts may contain small amounts of other metals such as aluminium, gallium and iron (as described in European Patent Application 0226258).
More recently aluminium containing titanium silicalites have been reported for example in EP 0293950 and in Zeolites 12 (1992) 135-137. In this case, the catalysts exhibit both oxidising and acidic catalytic activities.
In EP 0230949 the treatment of TS-1 catalyst with neutralising agents (e.g. alkaline compounds is reported). The examples given in the patent show that TS-1 catalyst treated with alkaline compounds give better yields of epoxides and lower amounts of by-products when they are used as catalysts for the epoxidation of olefins by H.sub.2 O.sub.2. It is suggested that the applied treatments have a neutralising effect on the catalyst's acidity, and thus prevent the catalyst to initiate undesirable side reactions.
Both TS-1 and TS-2 catalysts contain pores with a diameter of .+-.5.5 .ANG.. This limits their application to reactions of relatively small substrates, which can easily enter these pores. For example, in paraffin oxidation, n-hexane is oxidized more easily than cyclohexane, and the reactivity of different paraffins decreases with increasing carbon-number and increasing branching. In order to have suitable catalysts for the oxidation of larger organic substrates, the synthesis of larger pore titanium containing zeolites is highly desirable.
Recently, the synthesis of a titanium containing zeolite isomorphous to zeolite Beta has been reported (J. Chem. Soc. Chem. Comm. 1992 (8) 589-590). In the described synthesis method low concentrations of aluminium (Si/Al=192) are used for the preparation of the synthesis mixture. Like TS-1 and TS-2, the titanium containing zeolite Beta is characterised by an IR absorption at .+-
REFERENCES:
patent: 4490565 (1984-12-01), Chang et al.
patent: 4927525 (1990-05-01), Chu
patent: 5412122 (1995-05-01), Saxton et al.
Journal of the Chemical Society, vol. 8, May 1992, Camblor et al., "Synthesis of a Titaniumsilicoaluminate Isomorphous to Zeolite Beta and its Application as a Catlayst for the Selective Oxidation of Large Organic Molecules", pp. 589-590.
Manel Dekker Inc. publisher of "Characterization of Heterogenous Catalysts" by Chemical Industries, vol. 15, Chpt. 4, 1984.
Morrison and Boyd, Organic Chemistry, Chapter 19, 3rd Edition, pp. 635 and 11988, 1973.
Buskens Philip Luc
Huybrechts Diane Renata Cornelia
Martens Luc Roger Marc
Mathys Georges Marie Karel
Cintins Marianne M.
Exxon Chemical Patents Inc.
Hunt John F.
Jones Dwayne C.
Mahon John J.
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