Hydrosoluble phosphine

The synthesis of many hydrosoluble phosphines was reported in M.Darensbourg, ed., Inorganic Syntheses, John Wiley Sons, New York, 1998, Vol. 32, pp. 1 13. 

Finally, the third generation, in which a liquid-liquid biphasic system is used, corresponds to the development of the Ruhrchemie/Rhone-Poulenc process. Olefins of the organic phase are converted by a rhodium complex maintained in an aqueous phase by adjunction of an hydrosoluble phosphine, the sodium salt of the meta-sulfonated triphenylphosphine [Na][TPPTS). The separation of aldehydes from the catalytic phase is then performed by a simple decantation. 

An attractive approach for the telomerization of butadiene with methanol using hydrosoluble NHC-Pd complexes was reported by Pinel and coworkers [83], In their work, they described the preparation and the use of diiFerent hydrosoluble (NHC)-Pd-based complexes a hydrosoluble imidazolinium-che-lated palladium complex and (NHC)-Pd complexes bearing one hydrosoluble phosphine ligand and one classical carbene ligand (Figure 4.27). In the presence of water, hydrosoluble (NHC)-Pd complexes were not efficient for telomerization reaction, while the latter exhibited very high activities. 

At the Rhone-Poulenc company, Kuntz has introduced hydrosoluble phosphines, which led to the development of biphasic catalytic systems. There are also colloidal hydrogenation mechanisms involving Rh and water-soluble phosphines. 

To prepare more hydrophobic starches for specific applications, the partial substitution of starch with acetate, hydroxypropyl, alkylsiliconate or fatty-acid ester groups has been described in the literature. A new route, however, consists of grafting octadienyl chains by butadiene telomerization (Scheme 3.9) [79, 82, 83], The reaction was catalyzed by hydrosoluble palladium-catalytic systems prepared from palladium diacetate and trisodium tris(m-sulfonatophenyl)phosphine (TPPTS). 

The effect of the catalyst and the hgands has not been discussed yet however, it plays an important role. For example, by replacing the classical phosphine ligands by a hydrosoluble sulfonated triphenylphosphine (TPPTS), Safi and Sinou carried out a reaction with butadiene monoxide and ethyl acetoacetate in a two-phase aqueous-organic medium.f The recycled water layer containing the catalyst could be reused with very high efficiency for a second reaction. As a matter of fact, the corresponding ethyl ester of the 2-acetyl-6-hydroxy-4-hexenoic acid was isolated in 80% and 87% yield (Z/E = 15 85) after the first and the second reaction, respectively. 

Figure 4.27 Preparation of (a) hydrosoluble Imidazollnlum-chelated palladium catalyst and (b) mixed NHC-phosphine palladium complexes.

Sinou, D. (1986) Phosphines hydrosolubles. Syntheses et applications en catalyse. Bull. Soc. Chim. Fr., 480-6. 

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