Bimetallic clusters of the general formula [PPN]2[MRh4(CO)15] (M = Fe, Ru, or Os; PPN+ = (PPh3)2N+) are active catalysts in the presence of methanol for the carbonylation of nitrobenzene to methyl phenylcarbamate. The clusters are active even without co-catalyst, but the addition of bipy (2,2'-bipyridine) greatly enhances both rates and selectivities. In the absence of methanol the conversion was much lower, with a low selectivity in phenyl isocyanate. Interchanging Fe, Ru, and Os has a negligible effect on the activity and a moderate effect on the selectivity, with ruthenium being best. However, the monometallic rhodium cluster [Rh5(CO)15]- proved to be both more active and selective, and the monomer [Rh(CO)4]- was found to be even better. This last catalytic system has been optimized with respect to temperature, CO pressure and the bipy/Rh ratio. The influence of solvent was also examined.

[RH(CO)4]-, [RH5(CO)15]-, AND BIMETALLIC CLUSTERS AS CATALYSTS FOR THE CARBONYLATION OF NITROBENZENE TO METHYL PHENYLCARBAMATE / F. RAGAINI, S. CENINI, A. FUMAGALLI, C. CROTTI. - In: JOURNAL OF ORGANOMETALLIC CHEMISTRY. - ISSN 0022-328X. - 428:3(1992), pp. 401-408.

[RH(CO)4]-, [RH5(CO)15]-, AND BIMETALLIC CLUSTERS AS CATALYSTS FOR THE CARBONYLATION OF NITROBENZENE TO METHYL PHENYLCARBAMATE

F. RAGAINI
Primo
;
S. CENINI
Secondo
;
1992

Abstract

Bimetallic clusters of the general formula [PPN]2[MRh4(CO)15] (M = Fe, Ru, or Os; PPN+ = (PPh3)2N+) are active catalysts in the presence of methanol for the carbonylation of nitrobenzene to methyl phenylcarbamate. The clusters are active even without co-catalyst, but the addition of bipy (2,2'-bipyridine) greatly enhances both rates and selectivities. In the absence of methanol the conversion was much lower, with a low selectivity in phenyl isocyanate. Interchanging Fe, Ru, and Os has a negligible effect on the activity and a moderate effect on the selectivity, with ruthenium being best. However, the monometallic rhodium cluster [Rh5(CO)15]- proved to be both more active and selective, and the monomer [Rh(CO)4]- was found to be even better. This last catalytic system has been optimized with respect to temperature, CO pressure and the bipy/Rh ratio. The influence of solvent was also examined.
Settore CHIM/03 - Chimica Generale e Inorganica
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/192711
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