The hydroformylation of long-chain olefins catalyzed by the water soluble rhodium complex, RhCl (CO) (TPPTS) 2, were studied in aqueous/organic biphasic system containing cationic surfactants. The addition of TPPDS as a modifier dramatically increased the regioselectivity of olefin hydroformylation. A synergistic effect of TPPTS and TPPDS on the regioselectivity was observed. The ratio of linear/branched aldehyde rose from 6.5 (without TPPDS) to 22.3 ([TPPTS]/[TPPDS]=2:1). The steric structure of hydrophilic group in the cationic surfactants exhibited an important influence on the regioselectivity. The hydrophilic group with a small steric volume was favorable for the formation of linear aldehyde. It was found that when the alkyl chain length of the higher olefin and that of the cationic surfactant were comparable (matching size), the regioselectivity for linear aldehyde was outstandingly high.

The promotional effect of cationic gemini surfactants for the hydroformylation of 1-dodecene in the organic/aqueous biphasic catalytic system is reported. Cationic gemini surfactants with a flexible spacer (G(Eth), G(But) and G(Hex)) and rigid spacer (G(Xyl)) group were used in the reaction. The critical micelle concentration (CMC) and solubilization of laurylbenzene in gemini surfactant solutions were determined. The influence of the concentration of gemini surfactants and the stirring rate on 1-dodecene hydroformylation were investigated. The reaction results showed that in the biphasic catalytic system the hydroformylation of 1-dodecene catalyzed by RhCl(CO)(TPPTS)2-TPPTS [TPPTS = tris(sodium-m-sulfonatophenyl) phosphine] in the presence of gemini surfactants occurred with higher turn over frequency (TOF) and higher regioselectivity toward linear aldehyde (L/B) than those obtained with the conventional monomeric surfactant CTAB. The phenomena could be attributed to the fact that the gemini surfactant has lower CMC and better surface tension reduction ability; moreover it could form more compact and spherocylindrical micelle in the solution. These properties would be favorable for the decrease in the phase transfer energy barrier, thereby greatly accelerating the reaction rate. Meanwhile, the more compact structure of the spherocylindrical micelle formed from gemini surfactant could construct a favorable microenvironment for the formation of linear aldehyde. The comparison of the acceleration effect of the three type surfactants (monomeric surfactant CTAB (cetyltrimethylammonium bromide), gemini surfactant G(Eth), G(But), G(Hex)), G(Xyl) as well as double chain surfactant DCMAB (di(cetylmethyl)ammonium bromide) indicated that the surfactant structure had an important effect on the reaction rate. Their promotion order is DCMAB> G(Eth)≈G(But)≈G(Hex)≈G(Xyl) > CTAB.

The enantioselective hydrogenation of ethyl pyruvate in the presence of TS-1 supported rhodium nanoclusters and chiral modifier cinchonidine, cinchonine and quinine was investigated. The results showed that cinchonidine was the best modifier and THF was an excellent solvent for the reaction. Cinchonidine and quinine not only induced the enantioselectivity, but also accelerated the reaction. The interaction between the support and rhodium nanoclusters, as well as the adsorption of modifier on the support surface played an important role in promoting the increase of the catalytic activity and enantioselectivity. Under the optimum conditions, 268 K, 7MPa of hydrogen pressure and 4.0×10−3 mol/l of cinchonidine in THF, the mole conversion of ethyl pyruvate and enantiomeric excess of R-ethyl lactate reached up to 100 and 63.1%, respectively.

Hydroformylation of 1-dodecene catalyzed by water-soluble rhodium-phosphine complex, RhCl (CO) (TPPTS)2 (TPPTS: P(m-C6 H4 SO3 Na)), in the presence of various mixed micelles was investigated. When either an anionic surfactant sodium dodecyl sulfate (SDS) or dodecylbenzonesulphonate (DBS), a nonionic surfactant Triton X-100 or Brij 35, or alcohol was added into cationic surfactant cetyl pyrindium bromide (CPB) solution, a mixed micelle formed. The decrease in critical micelle concentration (CMC) and the increase in solubilization of 1-dodecene in the mixed micelle were observed. Hydroformylation of 1-dodecene exhibited higher conversion and higher regioselectivity in the mixed micellar solution than in the single micelle of CPB. The synergistic mechanism of two different surfactants was discussed.

The hydroformylation of 1-dodecene catalyzed by RhCl (CO) (TPPTS) 2-BISBIS [TPPTS: P (m-C6 H4 SO3 Na) 3, BISBIS: sulfonated 1,1-bis (diphenylphosphino methyl)-2, 2-biphenyl] in aqueous/organic two-phase systemwas studied. The addition of cationic surfactant cetyltrimethylamonium bromide (CTAB) greatly accelerated the reaction rate and the high regioselictivity for linear aldehyde using diphosphine as ligand was attained under two-phase conditions. Both high activity (TOF: 740 h−1) and excellent regioselectivity (96.5% of 1-tridecanal) were obtained at 120℃, 2.0 MPa and [BISBIS]/[Rh] ratio of 3 in thepresence of CTAB.