Hydroformylations third generation

The third generation process concerns the Ruhrchemie/Rhone-Poulenc process utilizing a two-phase system containing water-soluble rhodium-tppts in one phase and the product butanal in the organic phase. The process has been in operation since 1984 by Ruhrchemie (or Celanese, nowadays). The system will be discussed in section 8.2.5. Since 1995 this process is also used for the hydroformylation of 1-butene. 

Recycling experiments were performed with the second- and third-generation dendrophites. Hydroformylation of propene was carried out in toluene, followed by... 

A recent example of another class of interesting catalyst was reported by Stanley, namely a bimetallic Rh complex provided by a tetraphosphine ligand. Up to 85% ee has been achieved in the hydroformylation of vinyl carboxylates, although the applicable substrates are still limited [39]. As a bimetallic system, the chiral dithiolate-bridged dinuclear Rh complex has been described with results of up to 10% ee for styrene [40]. Addition of chiral bisphosphine to the dithiolate-Rh system improved the ee up to 55% [41],but in this case, the dissociation of the two Rh centers into monometallic species has been claimed recently [42]. In this article, emphasis is placed on the third generation Rh(I) catalyst and the earlier generations are mentioned only briefly. Excellent review articles are available on the latter topics [10,36,43,44,45,46,47,48]. 

Water-soluble metal complexes of rhodium with polyamidoamine-based (PAMAM-based) third-generation (32 terminal groups) dendrimers modified with diphenylphosphine groups have been used in two-phase hydroformylation of 1-octene and styrene. The selectivity in styrene hydroformylation with respect to isoaldehyde was much higher than in the case of trisulfonated triphenylphosphine... 

Rhodium, besides cobalt, is the only metal that is used in technical-scale hydroformylation. Because of the classification of industrial hydroformylation processes made by Cornils [1], with rhodium, the third generation, after two generations of Co-based hydroformylation, process was ushered. The first plants went on stream in the 1970s (1974 Ruhrehemie (nowadays Celanese) 1976 Union Carbide Corporation (nowadays Dow) 1978 Mitsubishi Chemical Corporation). These units operate with P-ligand-modified Rh catalysts at low... 

A water-soluble hydroformylation catalyst was developed by Xi and co-workers [65]. Third generation PAMAM dendritic ligands, with hydrophilic amine or sulfonic acid end groups, were phosphonated and the rhodium complexes thus formed were found to catalyse efficiently the hydroformylation of 1-octene and styrene, under very mild conditions. Water-soluble dendritic cobalt phthalocyanines that exhibited catalytic activities and oxidised thiols in the presence of oxygen, have been synthesised by Kimura and co-workers [66]. The catalytic activity of the phthalocyanines was influenced by a egation of the catalytic sites that results fi om strong intermolecular cohesive forces. It was proposed that steric isolation, enforced by the addition of a bulky dendritic coaf around the active phthalocyanine unit, could improve the catalytic activity. Acid terminated polyamide dendrimers were coupled to a phthalocyanine core to produce the desired water-soluble cobalt phthalocyanines, which were tested subsequently for catalytic activity and stability. The results obtained showed that the aggregation of phthalocyanines was reduced the catalytic activity was improved and the stability of the catalyst was improved by addition of the dendritic substituents. 

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