Tetradecene-1, hydroformylation

Two new phosphines, tris[p-(10-phenyldecyl)phenyl]phosphine and 2,2 -bis di [p-(10-phenyldecyl)phenylphosphinomethyl]-l,T-biphenyl were successfully synthesized and sulfonated in H2S04. The resulting water soluble surface active phosphines were applied to the rhodium catalyzed hydroformylation of higher alkenes. It is found that these two ligands are not only excellent for octene hydroformylation, but catalyze tetradecene hydroformylation under biphasic conditions as well. Rates and selectivities are superior to TPPTS-modified rhodium catalysts under the same reaction conditions [68]. 

The same general principles and the same phosphines (18) can be used for still another variation of catalyst recovery which was demonstrated in the hydroformylation of 1-tetradecene [143], The reaction, catalyzed by the Rh/18 catdyst, was mn in a homogeneous methanolic solution and gave slightly better results than the Rh/PPhs catalyst under identical conditions. After the reaction most of the methanol was distilled off and the remaining solution was extracted with water. The catalyst-containing aqueous phase was evaporated to dryness, the catalyst was taken up in methanol and reused. No loss of activity and selectivity was observed in three recycles. 

A few years ago, a new class of ligands namely the sulfonated phosphites (for examples see Table 7, 132, 133) was described.283 287 They show remarkable stabilities in water compared to conventional phosphites such as P(OPh)3 and rhodium catalysts modified with 132 exhibited much higher catalytic activities in the hydroformylation of 1-tetradecene than conventional Rh/P(OPh)3 or Ph/PPh3 catalysts even at lower reaction temperatures.285,286 Sulfonated phosphite ligands may play a role in the emerging field of biphasic catalysis in ionic liquids15 22 or in combination with membrane separation of the metal complexes of these bulky ligands. 

Alternatively, the Rh/15-catalysed hydroformylation of 1-tetradecene may proceed in wet micelles 478 (which are water-permeated micelles) or in reversed micelles155,389,406 with solubilisation of an aqueous microdroplet of the Rh/15 catalyst in the organic bulk phase [cf. Figure 4 (A)]. 

Virtually quantitative conversions were observed in the hydroformylation of 1-tetradecene with rhodium complexes generated from the lithium salt of tppms or the lithium (sodium) salts of 21 (Table 2 R=Ph n=3,4) and 22 (Table 2) in methanol as solvent.127,334 Catalyst recycling involved evaporation of methanol and addition of water to form a two phase system, separation of the aqueous phase, evaporation to dryness and addition of MeOH. 

Rhodium catalysts for the hydroformylation of n-tetradecene-1 were synthesized that are soluble in methanol as well as in water. After reaction took place in methanol solution, the product mixture was separated by the addition of water the aqueous phase contained the catalyst (71). Several runs with the same catalyst showed that the conversion decreased, indicating losses of rhodium. 

Ionic phosphites (triisooctylamine salts of p-sulfonated phosphorous acid triphenyl ester (TPPpS-TIOA salt) were investigated by Fell and Papadogianakis [14]. Table 3 shows a direct comparison with TPP and acetone as solvent in the hydroformylation of n-l-tetradecene. A significantly better ratio of linear/... 

The first water-soluble system specifically designed to combine both functions of a ligand and a surfactant in one molecule and applied in transition-metal-cata-lyzed conversions of highly water-insoluble substrates in micellar systems is the zwitterionic tenside trisulfoalkylated tris(2-pyridyl)phosphine, 2 (n = 0, 3, 5, 7, 9, 11) [4, 14, 72, 74]. Turnover frequencies (TOF) up to 340 h-1 were achieved in the micellar hydroformylation of 1-tetradecene to pentadecanals, according to Eq. (1), using Rh/2 catalysts at 125 °C, by fine tuning of the hydrophilic/lipophilic properties of the tenside system 2 [4, 14]. In sharp contrast, Rh/TPPTS catalysts gave only traces of pentadecanals under the same biphasic conditions. 

In order to rationalize the effect whereby the activity in the Rh/2-catalyzed hydroformylation of 1-tetradecene goes through a maximum as a function of the tail length of the surfactant 2, the model of simplified spherical (Hartley) ionic micelle [9a-c] (Figure 1) was proposed [14, 15], The core of the micelle is probably composed of the hydrophobic tail of the tenside phosphine 2 where 1-tetradecene is solubilized (Figure 1, stippled part). 

The sulfonated phosphine system 6 [28-30] was also described as possessing surfactant properties [28], However, 6 and 7 have only been applied in the hydroformylation of 1-tetradecene in methanol followed by biphasic separation of the catalyst after treatment with water [30]. 

When the alkali-metal cation of a sulfonated phosphine or phosphite is replaced by ammonium ion it is possible to devise applications in nonaqueous solvents. Al-kylammonium salts of TPPTS were reported in the first patents of Kuntz [5] and catalytic examples were given in which water alone was the solvent. More recently Fell et al. prepared a series of sulfonated phosphites including the example shown below, 1 [6], and examined these in a variety of solvents for the hydroformylation of tetradecene. Catalytic results are reported with acetone and acetophenone as the... 

Fell et al. describe the hydroformylation of tetradecene in methanol alone as the solvent. Since the standard ligand for two-phase catalysis, the sodium salt of TPPTS, is not soluble in methanol, the authors used the ligand Ph2P(CH2)4S03Na. Good activities were observed although reaction selectivity to linear products was typically 70% and a relatively high proportion of alcohol products were observed... 

Fell et al. recently published a simplified version of the above-mentioned process design of UCC in which the hydroformylation reaction of 1-tetradecene is performed homogeneously with a Rh/Li-TPPMS catalyst system in the presence of methanol. When the methanol is distilled off after almost complete conversion, the catalyst complex precipitates and can be separated by filtration or extraction with water [46],... 

Rhodium(l) complexes HRh(CO)L3 of alkali metal phenylphosphinoalkyl-sulfonates (L = 6a, n = 3,4 6c) have been used as catalysts for hydroformylation of higher olefins (e.g., n-l-tetradecene) in mefhanoHc solution. The catalyst could be recovered with loss of activity by extraction of the isolated product with water. 

Smith et al. [35] have reported a drop in the activity when the pH of the reaction medium was reduced from 6.8 to 5 for a Rh nitrate/AMPHOS catalyst system (AMPHOS = l-N,N,N-trimethylamino-2-diphenylphosphinoethane iodide). Hydroformylation of 1-tetradecene with a water-soluble Rh-NABSDPP (NABSDPP Na-butylsulfonated diphenylphosphine) catalyst gave poor rates in acidic (pH 2.5 to 6) medium. A seven- to eight-fold increase in the rates was observed when the pH was increased from 6 to 10 [36],... 

For example, hydroformylation of 1-dodecene has been carried out with a phosphabicyclononane-modified Co catalyst at 8.5 MPa syngas pressure (CO/H2 = 1 2) at 120 °C with a Co/P ratio of 1 2 to produce 55% isomeric Cj g alcohols [61]. RhClj immobilized on trioctylmethylammonium chloride operating in a multiphase Uquid system together with isooctane and water was developed for the conversion of tetradecene [62]. In more sophisticated approaches, phosphorus-modified Rh catalysts have been screened in biphasic systems, sometimes containing surface-active compounds [63]. Even internal olefins, such as (Z)-2-tridecene, have been used as substrates. Thus, by using a mixed, homogeneous Rh/Ru catalyst in a hydroformylation-hydrogenation protocol, 1-tetradecanol was obtained with a yield of 83% and with an Hb selectivity of 12 (see Section 5.2) [64]. 

Hydroformylation of 1-hexene using water soluble rhodium catalysts modified with such tenside ammonium salts of tppts afforded up to 55% C7-aldehydes (n/i=94/6). Similarly, Rh/tppts catalysts in the presence of tenside phosphonium salts e.g. Me(CH2)i3P Et3 gave 74% yield to aldehydes (TOF=186 h ) in the biphasic hydroformylation of l-tetradecene. ... 

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