Monosulfonated triphenylphosphine,

Hydrogenation reactions in water have been extensively studied and many of the water-solubilizing ligands described in Chapter 5 have been tested in aqueous-organic biphasic hydrogenation reactions. One of the earliest catalysts used was the water-soluble analogue of Wilkinson s catalyst, RhCl(tppms)3 (tppms = monosulfonated triphenylphosphine), but many other catalysts have since been used including [Rh(cod)(tppts)2]+, [Rh(cod)2]+ and [Rh(acac)(CO)2]+ (cod = cyclooctadiene). 

A ligand with great potential for hydroformylation of higher, terminal alkenes is monosulfonated triphenylphosphine, tppms, that was studied by Abatjoglou, also at Union Carbide [12] (section 8.2.6). In this system hydroformylation is carried out in one phase that is worked up afterwards by adding water, which gives two phases to separate catalyst and product. 

As a polar solvent for the catalyst ethylene carbonate (EC), propylene carbonate (PC) and acetonitrile were used. Tricyclohexylphosphine, triphenyl-phosphine and the monosulfonated triphenylphosphine (TPPMS) were investigated as ligands with Pd(acac)2 as the precursor. Cyclohexane, dodecane, p-xylene and alcohols (1-octanol, 2-octanol and 1-dodecanol) were tested as non-polar solvents for the product. To determine the distribution of the product and of the catalyst, the palladium precursor and the hgand were dissolved in the polar solvent and twice as much of the non-polar solvent was added. After the addition of 5-lactone, the amounts of the product in both phases was determined by gas chromatography. The product is not soluble in cyclohexane and dodecane, more than 99% of it can be found in the polar catalyst phase. With the alcohols 1-octanol, 2-octanol and dodecanol about 50 to 60% of the 5-lactone are located in the non-polar phase. With p-xylene biphasic systems can only be achieved when EC is used as the polar solvent and even in this solvent system one homogeneous phase is formed at a temperature higher than 70 °C. In a 1 1 mixture of EC and p-xylene about 50 to 60% of the product is contained in the polar phase. 

It occurred to us that ionic interactions might be a highly suitable binding motif to enforce the formation of heterobidentate ligand combinations [48[. The assembly ligand 14 /IS has been formed from the well-known TPPMS (14, monosulfonated triphenylphosphine sodium salt) and 3-(diphcnylphosphinyl)aniline hydrochloride (IS) by a simple ion-exchange reaction (Scheme 10.6). The coordination behavior ofthe ion-pair 14 /I S has been tested with various transition metal complexes. Other... 

At room temperature the Rh-catalyzed hydroformylation of butadiene [22] and of 1-pentene is possible (eq. (2)) [10 a]. In the latter case, [Rh(CO)2(acac)] in the presence of triphenylphosphine achieves slightly higher turnover frequencies (TOF) as compared to reactions in toluene. The product ratio of Ao-aldehyde was not influenced by the solvent. The use of the monosulfonated triphenylphosphine (tppms), however, reduced the activity of the catalyst drastically although its use allowed a more efficient recycling of the catalyst [10 a]. 

The use of triphenylphosphine as ligand led to acceptable rates in ILs, but with high rhodium leaching into the organic phase. Recourse to sulfonated phosphines such as monosulfonated triphenylphosphine retained the catalyst in the ionic liquid phase but decreased its activity significantly. This drawback was surmounted by the use of 47 (Table 1.5), which was derived from a simple cation metathesis reaction between TPPTS (37) and 1-butyl-2,3-dimethylimi-dazolium chloride [bdmim][Cl] in acetonitrile. 

TPPMS - m-monosulfonated triphenylphosphine. base = aniline Tp hydrotrispyrazolylborates... 

The corresponding complexes with molybdenum and palladium have been prepared particularly, the Suzuki and Sonogashira reactions have been examined using the protonated form [PhP(GuaH)2, and the results in the latter reaction show better yields than with monosulfonated triphenylphosphine [14]. 

To our knowledge, the only industrial application of the water-soluble catalyst for the hydroformylation of ( functionalized olefins has been developed by Kuraray [11]. In this process, oct-7-en-Tal is hydroformylated into 1,9-nonanedial by using a rhodium catalyst and the monosulfonated triphenylphosphine (cf. also Section 2.4.4.2). 

The sulfonation of triphenyl phosphine with fuming sulfuric acid can give three possible products monosulfonated triphenylphosphine (TPPMS), disulfonated triphenylphosphine (TPPDS), and TPPTS 1, depending on the reaction conditions (Figure 9). Using this method many sulfonated aryl phophines have been prepared (2b,... 

Sulfonated triphenylphosphine [TPPTS (triphenylphosphine, m-trisulfonated) tri(m-sulfophenyl)phosphine] (II-l) and monosulfonated triphenylphosphine [TP-PMS (triphenylphosphine, monosulfonated) 3-(diphenylphosphino)benzenesul-fonic acid] (II-2) are commercially available ligands and their sodium salts are water-soluble [15]. The Na salt of the ligand TPPTS is very soluble and may be too soluble in water, hence moderately soluble TPPMS is preferred. Another water-soluble phosphine is 2-(diphenylphosphinoethyl)trimethyl ammonium halide (II-11) [16]. A number of other water-soluble phosphines are now known (Table 1.2). Pd complexes, coordinated by these phosphines, are soluble in water, and Pd-catalyzed reactions can be carried out in water, which is said to have an accelerating effect in some catalytic reactions. 

The oxidation of monosulfonated triphenylphosphine with nitric oxide and nitrous acid was investigated in aqueous solution. The possible interconversion of phosphine chalcogenides was studied in the presence of Pd(0) catalyst. The reaction of a phosphine selenide with sulfur takes place via the phosphine that was separated as the Pd(II)complex. ... 

When investigating the aqueous-phase bicarbonate hydrogenation with ruthenium and rhodium complexes, Benyei and J06 observed certain activity for the reverse reaction, that is, formate decomposition. [RuCl2(mTPPMS)2]2 (mTPPMS = meta-monosulfonated triphenylphosphine) decomposed sodium formate and formic acid (41), while RhCl(mTPPMS)3 slowly decomposed calcium formate and promoted calcium carbonate precipitation (42). 

---