Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Patent
1991-04-03
1992-08-25
Garvin, Patrick P.
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
502163, 502167, B01J 3106
Patent
active
051419114
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to new oxidation catalysts comprising of synthetic metalloporphyrins immobolized on insoluble supports.
BACKGROUND OF THE INVENTION
The use of synthetic metalloporphyrins as catalysts for liquid-phase oxidation reactions has for a number of years been the subject of numerous publications, for example those illustrated by Mc. Murry, J. T. Groves in "Cytochrome P. 450; Structure, Mechanism and Biochemistry" Plenum, New York, 1986, pp 1-28.
These publications have revealed the important part played by the proximal ligand in the control of the rate, of the chemical selectivity and of the stereochemistry of the oxidation reaction (cf. B. Meunier et al., J. Am. Chem. Soc. 106, 6668-6676; 1984). To modify the reactivity of the catalyst systems which are employed, comprising of metalloporphyrins and an oxidizing agent such as H.sub.2 O.sub.2 or peroxides, this has led the investigators to add to the reaction mixture a nitrogenous base such as pyridine or imidazole (French patent 81/23,665 of 18.12.1981), which acts as an axial ligand. However, the limitation of this method is linked with the fact that the nitrogenous base is present in excess in a highly oxidizing reaction medium, which results in an oxidation of the cocatalyst and hence in a high consumption of the nitrogenous base.
Furthermore, these oxidative processes are conducted using homogeneous catalysis, and this involves difficulties in subsequently isolating the reaction product from the reaction mixture, and also problems in recovering the catalyst and its cocatalyst with a view to reutilization.
To overcome this disadvantage it has been proposed by the Assignee herein in a pending French application No. 88/09,169 of July 1988, to work using heterogeneous catalysis with a sulfonated metalloporphyrin catalyst fixed on a support of the ion exchange resin type (Amberlite R). This solution, which is advantageous on an industrial scale, does not, however, avoid the need to add the nitrogenous base to the reaction mixture.
The objective of the present invention is oxidation catalysts which make it possible to work using heterogeneous catalysis and which, comprising the axial ligand needed for the reaction, avoid the addition of the nitrogenous base and hence its consumption during the reaction process.
The subject of the present invention is new catalysts for liquid-phase oxidation of functional organic compounds, comprising of metalloporphyrins carrying anionic groups as substituents, active in the presence of an oxidizing agent, in which the metalloporphyrin is immobolized on a support, insoluble in the liquid phase, of polymeric type comprising nitrogenous groups acting as a Lewis base. The attachment of the metalloporphyrin takes place via a covalent bond between the metal of the porphyrin and the nitrogen of the supporting polymer.
The metalloporphyrins forming part of the composition of the catalysts of the invention are all porphyrins which have an axial site which is free or which is occupied by an axial ligand which can be easily displaced by the potential coordinate. Specifically, the nitrogen of the nitrogenous group originating from the support employed and negatively charged groups (or producing such groups after ionization), which are referred to in this text by the expression anionic groups, at the periphery of the porphyrinic ligand.
The most usual anion groups in the case of the porphyrinic compounds are carboxylic acid or sulfonate functional groups.
The metalloporphyrins employed for the catalysts of the invention can be the metal complexes of porphyrins of the class of natural porphyrins containing no substituents in a meso position but at least one anionic group in the pyrrolic positions. By way of examples there may be mentioned deuteroporphyrin IX, mesoporphyrin-IX, protoporphyrin-IX, and uroporphyrins I and III.
The preferred metalloporphyrins are porphyrins which are meso-substituted by aromatic radicals. The aryl radicals themselves will carry substituents such as alkyl or ar
REFERENCES:
patent: 4800188 (1989-01-01), Shepherd
Labat Gilles
Meunier Bernard
Seris Jean-Louis
Atochem
Garvin Patrick P.
Peebles Brent M.
Societe Nationale Elf Aquitaine
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