Marisela Reyes

Catalytic hydrogenation of 1-hexene with RuCl2(TPPMS)3(DMSO), Part I: Aqueous biphasic system

RuCl2(TPPMS)3(DMSO) (complex I) shows good catalytic 1-hexene hydrogenation activity in toluene/water biphasic medium under moderate conditions, reaching 90% conversion in 5 hours, with good hydrogenation selectivity and low isomerization products. The effect of various parameters (temperature, H2 pressure, reaction time, substrate/catalyst ratio, added electrolytes and other additives) on the hydrogenation reaction were studied. Complex (I) shows good stability in the reaction medium and can be reused several times.

Synthesis, characterization and hydroformylation catalytic activity of a water-soluble RhCl(CO)(PySO3Na)2 complex using 1-hexene and real naphtha

In this work, we describe the synthesis and characterization of a new water soluble [RhCl(CO)(PySO3Na)2], complex (1); where [PySO3Na] is the sodium salt of p-sulfonated pyridine ligand. Complex (1) was obtained in methanol, reacting the dried sodium salt of p-sulfonated pyridine ligand with [Rh(Cl)(CO)2]2 complex under inert atmosphere. Complex (1) was characterized by FT-IR and 1H NMR techniques. Complex (1) was active in the catalytic hydroformylation of 1-hexene and real naphtha in a biphasic (water/toluene) system. The effects of reaction time, temperature and syngas pressure were studied with 1-hexene as a substrate. Formation of metallic particles was tested with a mercury drop trial, giving negative results. Reuse of the aqueous phase for several times under the same conditions showed little catalytic activity loss. Complex (1) was active for the hydroformylation reaction of 1-hexene, in the presence of thiophene compounds, showing better performance in comparison with water soluble rhodium analogues.

Biphasic catalysis with RuCl2(DMSO)(TPPMS)3

A mononuclear RuCl2(DMSO)(TPPMS)3 complex (1) (TPPMS = triphenylphosphine monosulfonate) has been synthesized. Spectroscopic analysis by i.r., u.v.–vis., 1H-, 13C-, 31P-n.m.r., cyclic voltammetry, m.s. analysis and MO calculations were in agreement with a possible octahedral structure. Biphasic (H2O/PhMe) catalytic studies have shown good olefin hydrogenation activity by the complex at moderate temperature and pressure.

Catalytic activity of RuCl2(DMSO)4 in biphasic and homogeneous systems

Water soluble RuCl2(DMSO)4 is an active catalyst precursor for 1-hexene hydrogenation in water/organic solvent biphasic systems, reaching 98% total conversion (400 psi H2, 80°C, 6 h), with n-hexane as the principal product and less of the 2-hexene isomers, favoring cis-2-hexene. It is very sensitive to O2 dissolved in water, and decomposes when halide salts or alcohols are added. The Ru complex is also active in an alcohol homogeneous phase, but less than in the biphasic system, gives a greater isomer proportion, favoring cis-2-hexene and increases with potassium halide salt additives.

Synthesis, Characterization And Biphasic Catalysiswith RuCl(η5-C5H5)(TPPMS)2

A synthetic route is reported for the water soluble complex RuCl(h5- C5H5)(TPPMS)2(1), (TPPMS = (C6H5)2P(C6H4-m-SO3Na) and characterized by UV-Vis, FTIR, 1H, 13C NMR and GC-MS. Complex 1 is a good catalytic precursor in biphasic media (toluene/ water) for 1-hexene hydrogenation under moderate reaction conditions (e.g. 500 psi H2, 100°C) giving good yields of n-hexane, and smaller amounts of cis-2-hexene and trans-2-hexene. Other organic substrates (cinnamaldehyde, crotonaldehyde, cyclohexene, acetone and butylaldehyde) are hydrogenated.