Hydroformylation water-soluble rhodium-phosphine complex

For instance, catalysis in liquid/liquid two phases is generally referred to as biphasic catalysis and has widened the practical scope of homogeneous catalysis the catalyst is present in one liquid phase, while reactants and products are present in the other liquid phase. Thus, the catalyst can be separated by simple phase separation. Celanese is operating a 300 000 t/a plant for propylene hydroformylation using a water-soluble rhodium phosphine complex in a biphasic mode of operation at the Ruhrchemie site in Oberhausen [142],... 

The hydroformylation of propene to form butyralde-hyde invariably produces some isobutyraldehyde at the same time (reaction 1.21).216 One of the best processes uses a water-soluble rhodium phosphine complex to produce 94.5% of the former and 4.5% of the latter.217 The products form a separate layer that is separated from the water. Rhodium is expensive so it is important to lose as little as possible. In 10 years of operation by Rhone-Poulenc-Ruhrchemie 2 million metric tons of butyralde-hyde have been made with the loss of only 2 kg of rhodium. The process is 10% cheaper than the usual one. Higher olefins are not soluble enough in water to work well in the process. The process does work for omega-alkenecar-boxylic acids such as 10-undecenoic acid, where a 97 3... 

An example of a large scale application of this concept is the Ruhrchemie/ Rhone Poulenc process for the hydroformylation of propylene to n-butanal, which employs a water-soluble rhodium(I) complex of trisulfonated triphenyl-phosphine (tppts) as the catalyst [103]. The same complex also functions as the catalyst in the Rhone Poulenc process for the manufacture of the vitamin A intermediate, geranylacetone, via reaction of myrcene with methyl acetoacetate in an aqueous biphasic system (Fig. 1.35) [104]. 

Fell, B., Schobben, C. and Papadogianakis, G. (1995) Hydroformylation of homologous C0-alkenecarboxylate esters with water soluble rhodium carbonyl/tertiary phosphine complex catalyst systems. J. Mol. Catal. A Chem., 101, 179. 

Researchers have worked to alleviate the problems of separation and corrosion in processes such as the oxo process by designing catalysts that are confined in a separate phase from the reactants (see Section 14.2.4). A commercially successful approach for propene hydroformylation resulted from preparation of water-soluble rhodium complex catalysts by sulfonation of the phenyl rings of the triphenyl phosphine ligands. The catalyst is used in a reactor with two liquid phases the propene is concentrated in the organic phase and the catalyst in the aqueous phase near the interface. The CO -I- H2 is bubbled into a mixed reactor, and the two-phase liquid product flows to a settler the organic product flows to downstream separation devices, and the aqueous phase with the catalyst is recycled to the reactor. 

Cuprous chloride tends to form water-soluble complexes with lower olefins and acts as an IPTC catalyst, e.g., in the two-phase hydrolysis of alkyl chlorides to alcohols with sodium carboxylate solution [10,151] and in the Prins reactions between 1-alkenes and aqueous formaldehyde in the presence of HCl to form 1,3-glycols [10]. Similarly, water-soluble rhodium-based catalysts (4-diphenylphosphinobenzoic acid and tri-Cs-io-alkylmethylam-monium chlorides) were used as IPTC catalysts for the hydroformylation of hexene, dodecene, and hexadecene to produce aldehydes for the fine chemicals market [152]. Palladium diphenyl(potassium sulfonatobenzyl)phosphine and its oxide complexes catalyzed the IPTC dehalogenation reactions of allyl and benzyl halides [153]. Allylic substrates such as cinnamyl ethyl carbonate and nucleophiles such as ethyl acetoactate and acetyl acetone catalyzed by a water-soluble bis(dibenzylideneacetone)palladium or palladium complex of sulfonated triphenylphosphine gave regio- and stereo-specific alkylation products in quantitative yields [154]. Ito et al. used a self-assembled nanocage as an IPTC catalyst for the Wacker oxidation of styrene catalyzed by (en)Pd(N03) [155]. 

Several new water-soluble phosphines were prepared for hydroformylation catalyzed by rhodium(I) complexes. These include the sulfonated derivatives BISBIS (16), BINAS (16,139), BIPHLOPHOS (143), sulfonated XANTPHOS (144), and others (Scheme 15). Rh-BINAS showed an enormously high activity in propene hydroformylation at 125°C and 5.2 MPa syngas, TOF = 10710 h , which was about 12 times higher than that of Rh-TPPTS under the same conditions (143). At the same time, the selectivity also increased to n/iso 98/2 from 95/5. Despite these improvements, the low price and availability still favors the industrial use of [HRh(CO)(TPPTS)3] -I- excess TPPTS. 

A new homogeneous process for hydroformylation of olefins using a water-soluble catalyst has been developed (40). The catalyst is based on a rhodium complex and utilizes a water-soluble phosphine such as tri(M-sulfophenyl)phosphine. The use of an aqueous phase simplifies the separation of the catalyst and products (see Oxo process). 

A breakthrough occurred in the mid-seventies when Union Carbide and Celanese introduced Rh/phosphine catalysts in commercial processes. This catalyst is based on the work by Wilkinson s group he received the Nobel prize for his work in 1973. Rhodium-based catalysts are much more active than cobalt catalysts and, under certain conditions, at least for 1-alkenes, they are also more selective. The processes for the hydroformylation of higher alkenes (detergent alcohols) still rely on cobalt catalysis. A new development is the use of water-soluble complexes obtained through sulphonation of the Ligands (Ruhrchemie). 

Water soluble ligands greatly facilitate catalyst separation. Examples are (22-XLI)174 and (22-XLII),175 which are used in hydroformylations and hydrogenation catalysis, respectively. Rhodium complexes of the sulfonated phosphine (22-XLI) are used in the production of butyraldehyde, a large-scale process developed by Ruhrchemie/Rhone-Poulenc.174... 

Hydroformylations can be carried out in aqueous solution in the absence of hydrogen. Such a situation arises because these water-soluble phosphine-substituted rhodium complexes also catalyze the water-gas shift reaction (Eq. 32). Since carbon monoxide is a reagent in both the hydrofor-... 

Another approach to water-soluble phosphines with the emphasis on metal recycling was reported by van Leeuwen and co-workers [30], They have synthesized a number of diphosphines that, when coordinated to rhodium, form complexes having an amphiphilic character. The ligands synthesized are based on BISBI and Structures 20-22, and hydroformylation (for example) can be conducted in a homogeneous (organic) phase [30 a]. After it has been used in the hydroformylation of olefins the catalyst can be removed by acidic extraction. It was established that these novel diphosphines form active and highly selective catalysts. This amphiphilic approach, i.e., rhodium recycling abased on the extraction and re-extraction principle, will be discussed in more detail in Section 7.5. 

Enhanced catalytic activity has also been observed for the hydroformylation of oct-l-ene and dec-l-ene with water-soluble phosphine-caltK[4]arene—rhodium complexes (Figure 32). " These organometallic compounds behave, not only as homogeneous metal catalysts but also as inverse phase-transfer catalysts, that is, they perform a dual functional catalysis. The olefin is believed to be included in the hydrophobic cavity and to simultaneously interact with a catalytic transition metal center coordinated to the phosphine moieties. 

A very important process with the solvent water is the hydroformylation of propene to butyraldehydes, known as the Ruhrchemie/Rhone-Poulenc process. The reaction is catalyzed by a rhodium complex containing the water-soluble ligand triphenyl-phosphine trisulfonate (TPPTS) (see Section Lower Alkenes [6-11]). 

In the first stage, 1-butene is preferentially converted to valeraldehyde. This takes place in a low-pressure process, in which the catalyst used is a rhodium complex compound containing water-soluble phosphines as ligands. A solubilizer is also added. In the second stage, the 2-butene not converted in the first stage is hydroformylated with a cobalt catalyst. Part of the valeraldehyde obtained is then hydrogenated to amyl alcohol [109]-[111]. 

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