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The catalytic performances of rhodium complexes with three new amphiphilic phosphine ligands, bis-(3-sodium sulfonatophenyl)-(4-tert-butylphenyl)-phosphine (3), phenyl-(3-sodium sulfonatophenyl)-(4-tert-butyl-phenyl)-phosphine (4) and bis-(4-tert-butylphenyl)-(3-sodium sulfonatophenyl) phosphine (5), in hydroformylation of 1-hexene, 1-octene and 1-dodecene have been studied. The steric attributes of free ligands are investigated by Tolman's cone angle method through geometric optimizations. The results reveal that the new phosphines are surface-active as the typical surfactants and the corresponding rhodium complexes show significant enhancements in the reaction rate and higher selectivities toward the normal aldehydes in comparison with those obtained by triphenylphosphine trisulfonate (TPPTS)- and triphenylphosphine disulfonate (TPPDS) rhodium complexes under identical conditions. [ABSTRACT FROM AUTHOR]

The solution NMR (31P and 1H) and FTIR spectroscopies were employed to investigate the structure information of water-soluble complex HRh(CO)[P(m-C6H4SO3Na)3]3 (1) [P(m-C6H4SO3Na)3: trisodium salt of tri-(m-sulfophenyl)-phosphine, TPPTS] supported on SiO2 (1/SiO2). The 31P(1H) NMR spectra showed that a pair of new twin-peak at about 31.5, 32.1 ppm while no typical twin-peak at 44.0, 44.7 ppm for the phosphorus species ascribed to the complex 1 were observed at 1/SiO2. However, the typical phosphorus peaks for the complex 1 appeared in the case of using TPPTS or Na2CO3-preimpregnated SiO2 as supports. Moreover, the immobilization caused a considerable oxidation of the liberated TPPTS to OTPPTS (OTPPTS, i.e. OP(m-C6H4SO3Na)3: trisodium salt of tri-(m-sulfophenyl)-phosphine oxide) species as evidenced by 31P(1H) NMR spectroscopy. The phosphorus-31 peaks at 31.5, 32.1 ppm at 1/SiO2 were found to be unchanged before and after the propene hydroformylation. The FTIR results revealed that the CO band appeared at about 1870 cm−1 for the 1/SiO2 catalyst, which was lower than that for the precursor complex 1. It is concluded that there exists a strong interaction between the complex 1 and the acidic support of SiO2, resulting in the deformation of the Rh–phosphine complex containing less than three TPPTS ligands, which further transformed by dehydrogenation and dimerization under evacuation to form a species likely [Rh(CO)(TPPTS)2]2 as a main surface complex species at the catalyst 1/SiO2. [Copyright &y& Elsevier]

Abstract: The TPPTS-Rh complex [TPPTS = trisodium salt of tri-(m-sulfophenyl)-phosphine, P(m-C6H4SO3Na)3], which was dissolved in the ionic liquids 1-butyl-3-methyl-imidazolium tetrafluoroborate (BMI⋅BF4), 1-butyl-3-methyl-imidazolium hexafluorophosphate (BMI⋅PF6), and 1,1,3,3-tetramethylguanidinium lactate (TMGL), was immobilized on MCM-41. The resulting supported ionic liquid-phase catalysts (SILPCs) were very active for the hydroformylation of higher olefins. The SILPCs with the regular hexagonal array of MCM-41 were structurally stable before and after the catalytic reaction, as characterized by XRD, N2 adsorption/desorption, FTIR, 31P-NMR, SEM, HRTEM, and TGA-DSC. The obtained SILPCs showed higher catalytic activity, independent of IL type, as compared with their ionic liquid–organic biphasic counterparts and the one with SiO2 as carrier. Such SILPCs could be reused several times without significant loss of activity or selectivity. [Copyright &y& Elsevier]

Addition of n-C16H33P(m-C6H4SO3Na)2(CDPPDS) to TPPTS–rhodium (TPPTS=P(C6H4-m-SO3Na)3) or TPPDS–rhodium (TPPDS=C6H5P(C6H4-m-SO3Na)2) hydroformylation catalysts proved to be beneficial both for the reaction rate and normal aldehyde selectivity. Such positive effects were not simply summarized by the results of TPPTS– or TPPDS–rhodium and CDPPDS–rhodium. Emulsion formation was minimized and initial reaction rate went through maximum at the critical micelle concentration (CMC) of CDPPDS. [Copyright &y& Elsevier]

Abstract: A biphasic catalytic system with water-soluble rhodium complexes of sulfonated (R)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (labeled as (R)-BINAPS) in ionic liquid BMI·BF4 has been developed for the asymmetric hydroformylation of vinyl acetate under mild conditions. The corresponding ruthenium complexes have been investigated for the biphasic asymmetric hydrogenation of dimethyl itaconate. The biphasic asymmetric hydroformylation of vinyl acetate provided 28.2% conversion and 55.2% enantiomeric excess when BMI·BF4–toluene was used as the reaction medium at 333K and 1.0MPa for 24h. The biphasic asymmetric hydrogenation of dimethyl itaconate in BMI·BF4– i PrOH at 333K and 2.0MPa afforded 65% enantiomeric excess with an activity similar to the homogenous analogs. Both biphasic catalytic systems with (R)-BINAPS ligand could be reused several times without significantly decrease in the activity, enantio- and regio-selectivities. The effects of properties of ionic liquid, molar ratio of ligand to rhodium, temperature, pressure and reaction time have been discussed. [Copyright &y& Elsevier]