Activity In Hydroformylation Research Articles

Synthesis, characterization and evaluation of heterobimetallic Fe(II)/Rh(I) and Fe(II)/Ru(II) complexes as catalyst precursors for hydroformylation of 1-octene

Two new ferrocenyl iminopyridyl ligands, L1 and L2, have been synthesized and characterized using spectroscopic and analytical techniques. Both ligands were used to prepare new Rh(I) and Ru(II) ferrocenyl complexes 1–4. The structures of the complexes were confirmed using 1H and 13C nuclear magnetic resonance spectroscopy, high resolution electrospray ionization mass spectrometry, and infrared spectroscopy. The complexes were tested as catalysts in the hydroformylation of 1-octene. Rh ferrocenyl complexes 1 and 4 produced aldehydes under mild conditions while the Ru-ferrocenyl complexes 2 and 3 required higher temperature and pressure for effective hydroformylation to occur. The catalysts display excellent aldehyde chemoselectivity with varying regeoselectivity depending on temperature and pressure conditions employed. At high temperatures, the Rh ferrocenyl precatalysts favor formation of branched aldehydes due to increased isomerization at high temperatures. The Ru ferrocenyl precatalysts displayed less hydroformylation activity; however, the complexes show good chemoselectivity for aldehydes with no hydrogenation products formed.

Highly efficient porous organic copolymer supported Rh catalysts for heterogeneous hydroformylation of butenes

Porous organic copolymer (denoted as CPOL-BP&P) was afforded through the copolymerization of vinyl biphephos and tris(4-vinylphenyl)phosphine monomers under solvothermal conditions, and followed with impregnation method provided a highly efficient Rh/CPOL-BP&P catalyst with high activity (TOF = 11,200 h−1) and regioselectivity (the ratio of linear to branched aldehydes, l:b = 62.2) for heterogeneous hydroformylation of 1-butene. High regioselectivity was also obtained in the hydroformylation of butene mixture (2-butene: l:b = 55.8, isomeric mixture of butenes: l:b = 56.0). The Rh/CPOL-BP&P catalysts were thoroughly characterized by means of nitrogen sorption isotherms, in situ FT-IR, XPS, solid-state 31P MAS NMR, HAADF-STEM, SEM and TEM. The formation of unique coordination bonds with Rh species in the polymer skeleton was determined. Heterogeneous hydroformylation of butenes was effectively realized due to a synergetic effect between PPh3 moiety and biphephos moiety.

Hydroformylation and tandem isomerization–hydroformylation of n-decenes using a rhodium-BiPhePhos catalyst: Kinetic modeling, reaction network analysis and optimal reaction control

The rhodium-BiPhePhos catalyzed hydroformylation of n-decenes, as representative long-chain olefins, was investigated in this study experimentally and theoretically. Besides hydroformylation activity, the used catalyst enables significant double bond isomerization which is an essential side reaction. Because of this property, highly selective tandem isomerization–hydroformylation reactions that convert mixtures of n-decenes with internal double bond position to the desired terminal aldehyde undecanal are possible using the Rh-BiPhePhos catalyst. Experimentally, a reaction network analysis strategy was applied to study the coupled main and side reactions separately. Subsequently, a mechanistic kinetic model based on an extended Wilkinson-mechanism was developed that includes all relevant main and side reactions. Fitting the model to the 23 well planned experiments was possible with low deviations between model and experiment, including the tandem reaction. It was found that the tandem reaction shows completely opposite dependencies regarding temperature and synthesis gas pressure compared to the conventional hydroformylation of 1-decene, which is also covered by the model. Hence, strategies for optimal reaction performance of the (tandem isomerization-) hydroformylation were developed and presented.

ChemInform Abstract: Recent Progress in Rhodium‐Catalyzed Hydroaminomethylation

AbstractReview: [52 refs.

Aqueous biphasic hydroformylation of higher alkenes and highly efficient catalyst recycling in the presence of a polar low boiling solvent

The hydroformylation of higher alkenes under aqueous biphasic reaction conditions with a rhodium catalyst derived from BISBIS (sodium salt of sulfonated 2,2′-bis (diphenylphosphinomethyl)-1,1′-biphenyl) in the presence of a polar low boiling point solvent was studied. The addition of ethanol greatly accelerated hydroformylation, such that the turnover frequency (defined as the moles of converted alkene per mole of Rh per hour) and the selectivity for linear aldehyde were up to 2095 h−1 and 99 %, respectively. The catalytic system could be recycled for at least five runs without significant loss of activity in the aqueous biphasic hydroformylation of 1-octene; the rhodium content leaching in product mixtures detected by inductively coupled plasma atomic emission spectroscopy was < 0.1 ppm.

Rhodium complexes supported on nanoporous activated carbon for selective hydroformylation of olefins

Activated carbon with nanoporous structure, high surface area (2500m2/g) and total pore volume (2.35cm3/g) was prepared from Mango seed shell (Mangifera indica L.) via chemical activation method and used as support to impregnate active hydroformylation rhodium complexes HRhCO(PPh3)3 and Rh(acac)(CO)2. The prepared catalysts were characterized by XRD, SEM, TEM, NMR, IR, TGA, and N2 adsorption/desorption techniques. The supported catalysts have shown excellent selectivity for aldehydes (~99%) in the hydroformylation of olefins with good stability and recyclability up to 4cycles.

Effect of lengthening alkyl spacer on hydroformylation performance of tethered-phosphine modified Rh/SiO2 catalyst

Rh/SiO2 catalysts with tethered-phosphines with different alkyl spacer lengths have been prepared, tested and characterized. Lengthening the alkyl spacer of the tethered-phosphine improved the flexibility of tethered-phospine, promoted the formation of active species and enhanced the activity of hydroformylation over other tethered-phosphine modified Rh/SiO2 catalysts.

Highly active rhodium/phosphorus catalytic system for the hydroformylation of α-methylstyrene

Rhodium catalyzed hydroformylation of α-methylstyrene was investigated in the presence of monodentate phosphine ligands L1–L6. We found that the phosphine with good π-acceptability could efficiently improve the activity of the α-methylstyrene hydroformylation. The big steric hindrance of α-C in α-methylstyrene enhanced the regioselectivity towards the linear aldehyde, which resulted in 3-phenylbutanal as the predominant product (>99.0%). When tris(N-pyrrolyl)phosphine (L1) modified Rh(acac)(CO)2 was employed as the catalyst, the TOF could reach up to 5786 h−1 in the α-methylstyrene hydroformylation at relatively mild conditions (110 °C, 6 MPa).

Hydroformylation of 1-octene in Pickering emulsion constructed by amphiphilic mesoporous silica nanoparticles

An efficient and stable oil/water Pickering emulsion system was constructed for hydroformylation of 1-octene with surface modified mesoporous silica nanospheres as stabilizer and Rh-TPPTS as catalyst. Compared to the neat water–oil biphasic system, the Pickering emulsion system exhibits much higher activity (TOF: 392h−1 versus 56h−1) and aldehyde selectivity (79.0% versus 45.7%) in hydroformylation of 1-octene under non-stirring conditions due to the greatly increased interface area. It was found that dimethyloctadecylammonium group is more efficient than octadecyl group for emulsion catalytic system, which is mainly attributed to its enrichment effect for anionic Rh-TPPTS on the interface of two phases. The higher activity and aldehyde selectivity were obtained with mesoporous silica as stabilizer than with nonporous silica, which is attributed to the enhanced diffusion rate of the reactants by the mesopore and uniform distribution of Rh-TPPTS in the mesopore. The Pickering emulsion system could be easily recycled without obvious loss of activity and aldehyde selectivity.

Parameters Influencing Reactivity and Regioselectivity in the Methoxycarbonylation of Arylalkenes

Previous research showed that the steric bulk, electronic character, and bite angle of the ligand have an influence on both the catalyst activity and regioselectivity of hydroformylation and hydroesterification reactions. However, little is known in this regard about the influence of the steric and electronic environment around the double bond of the substrate. A variety of arylalkenes were therefore subjected to methoxycarbonylation to investigate the steric and electronic effects of substituents on the aromatic ring of the substrate on the regioselectivity and reactivity in the methoxycarbonylation reaction of these substrates with a Pd(II)/Al(OTf)₃/Ph₃P catalyst system.

A new biogenerated Rh-based catalyst for aqueous biphasic hydroformylation

A new bio-generated rhodium based system embedded in a peculiar polysaccharide matrix (Rh-EPS), was obtained and purified from cultures of bacterial cells of Klebsiella oxytoca DSM 29614. The product was analyzed with different techniques to obtain information on its structure–property correlation. In order to determine its catalytic activity and selectivity in the aqueous biphasic hydroformylation some olefins were chosen as model substrates, obtaining fine-good results.

Rigid, non-porous and tunable hybrid p-aminobenzoate/TiO2 materials: Toward a fine structural determination of the immobilized RhCl(Ph3)3 complex

By exchange of ligands, Wilkinson complex RhCl(PPh3)3 are immobilized on p-aminobenzoate/TiO2 with different organic loading (6, 11 and 16%). This new hybrid material exhibit a linear correlation between the ligand content of the starting TiO2 and the rhodium loading, showing the accessibility of all surfaces amines fonctions on the non-porous parent materials. 1H, 13C, and 1D, 2D INAQUEDATE refocused and J-resolved 31P solid-state NMR confirm the well-defined structure [(≡TiO)2(ɳ2-O2C–C6H4–NH2)RhCl-cis-(PPh3)2]. New immobilized catalysts show interesting activity in cyclohexene hydroformylation.

Promoting effect of Al on tethered ligand-modified Rh/SiO2 catalysts for ethylene hydroformylation

A Rh/SiO2 catalyst with excellent activity and stability for ethylene hydroformylation was developed by modifying with tethered diphenylphosphinopropyl and doped with an Al promoter. The catalyst was characterized by means of N2 adsorption/desorption isotherms, transmission electron microscope, NH3 temperature programmed desorption, Fourier transform infrared spectroscopy and solid-state nuclear magnetic resonance. Experimental results showed that the existence of the Al promoter inhibited the growth of Rh particles, increased the number of exposed Rh atoms, changed the acidity of the catalyst surface, promoted in situ formation of active species that were similar to their corresponding homogeneous counterparts, and enhanced electron density of the P atom in the phosphine ligand.

Supported homogeneous catalyst makes its own liquid phase

A catalyst designed for homogeneous catalysis is shown to generate its own liquid phase if deposited onto a support. In this way, a macroscopically heterogeneous catalyst generates a microscopically homogeneous catalytic environment by self-organization.2,2′-((3,3′-di-tert-butyl-5,5′-dimethoxy-[1,1′-biphenyl]-2,2′-diyl)-bis(oxy))bis(4,4,5,5-tetraphenyl-1,3,2-dioxaphospholane) modified rhodium complexes molecularly adsorbed onto porous silica powder show surprisingly high activity and regioselectivity in the gas-phase hydroformylation of propene to butanal, with no sign of deactivation. Operando IR investigations combined with density functional theory calculations confirm a side reaction: the aldol condensation of the butanal products. These heavier by-products accumulate inside the pores of the catalytic material. IR and gas chromatography show a direct relation between formation of enones, products of the aldol condensation, performance, and stability of the catalytic system. This demonstrates that the aldol condensation products generated in situ act as a solvent providing an ideal environment to the impregnated homogeneous catalyst.

Porous organic ligands (POLs) for synthesizing highly efficient heterogeneous catalysts.

We reported a universal route for synthesizing porous organic ligands (POLs) via solvothermal polymerization. The POLs were obtained quantitatively, showing high surface area, large pore volume, hierarchical porosity, and superior stability. The POL bearing a triphenylphosphine supported rhodium catalyst (Rh/POL-PPh3) exhibits high activity and excellent recyclability in 1-octene hydroformylation.

A theoretical study of the activity in Rh-catalysed hydroformylation: the origin of the enhanced activity of the π-acceptor phosphinine ligand

The factors governing the activity in Rh-catalyzed hydroformylation were investigated using DFT and QSAR methods.

Water‐Soluble Half‐Sandwich RuII–Arene Complexes: Synthesis, Structure, Electrochemistry, DFT Studies, and Aqueous Phase Hydroformylation of 1‐Octene

AbstractWater‐soluble mononuclear ruthenium complexes containing monodentate P‐donor ligands [1,3,5‐triaza‐7‐phosphaadamantane (PTA) and P(OMe)3], together with a mononuclear bidentate salicylaldimine ruthenium–arene complex, were synthesized from a water‐soluble dimeric ruthenium(II)–arene precursor. These complexes were used as catalyst precursors in the aqueous biphasic hydroformylation of 1‐octene. Hydroformylation reactions with these Ru‐arene complexes showed that the complexes are active hydroformylation catalyst precursors in water. The catalyst precursors convert 1‐octene into a range of products, which include aldehydes and alcohols, as well as isomerization and hydrogenation products. The less basic the ligand, the more it favoured the production of aldehydes. The relative basicity of the ligands P(OMe)3, PTA and the N,O‐chelating ligand was elucidated by cyclic voltammetry and supported by DFT calculations. The catalysts show good recyclability without a significant decrease in 1‐octene conversion. All of the catalysts could be reused three times.

Highly Active Hydroformylation Catalysts: Synthesis, Characterisation and Catalytic Performance

The phoszone ligand [(Ph2P)(bis-3,5-CF3-Ph)]NN=CH(penta-fluoro-Ph) transformed in liquid CO2 at room temperature in presence of [Rh(cod)2]OTf into [Rh(cod)(η2-P,P′-Ph2POPPh2)]OTf. Replacing the O-atom in Ph2POPPh2 by a PrN-group leads to the ligand PrN(PPh2)2 acting similarly as a bidentate ligand in [Rh(cod)(η2-P,P′-PrN(PPh2)2)]OTf. Hydroformylation of 1-octene with in situ catalysts formed by the ligands with [Rh(cod)2]OTf showed hydroformylation activities at 50 % conversion of 16,000 h−1 (PrN(PPh2)2/[Rh(cod)2]OTf) and 24,000 h−1 (phoszone/[Rh(cod)2]OTf), respectively.

Libraries of Bisdiazaphospholanes and Optimization of Rhodium-Catalyzed Enantioselective Hydroformylation

Twelve chiral bis-3,4-diazaphospholane ligands and six alkene substrates (styrene, vinyl acetate, allyloxy-tert-butyldimethylsilane, (E)-1-phenyl-1,3-butadiene, 2,3-dihydrofuran, and 2,5-dihydrofuran) probe the influence of steric bulk on the activity and selectivity of asymmetric hydroformylation (AHF) catalysts. Reaction of an enantiopure bisdiazaphospholane tetraacyl fluoride with primary or secondary amines yields a small library of tetracarboxamides. For all six substrates, manipulation of reaction conditions and bisdiazaphospholane ligands enables state-of-the-art performance (90% or higher ee, good regioselectivity, and high turnover rates). For the nondihydrofuran substrates, the previously reported ligand, (S,S)-2, is generally most effective. However, optimal regio- and enantioselective hydroformylation of 2,3-dihydrofuran (up to 3.8:1 α-isomer/β-isomer ratio and 90% ee for the α-isomer) and 2,5-dihydrofuran (up to <1:30 α-isomer/β-isomer ratio and 95% ee for the β-isomer) arises from bisdiazaphospholanes containing tertiary carboxamides. Hydroformylation of either 2,3- or 2,5-dihydrofuran yields some of the β-formyl product. However, the absolute sense of stereochemistry is inverted. A stereoelectronic map rationalizes the opposing enantiopreferences.

Characterization and parametrical study of Rh-TPPTS supported ionic liquid phase (SILP) catalysts for ethylene hydroformylation

Abstract The supported ionic liquid phase (SILP) catalysis technology was applied to continuous, gas-phase hydroformylation of ethylene. Rh-TPPTS SILP catalysts with relatively low ionic liquid loading were shown to be stable and highly activity for ethylene hydroformylation. However, the catalytic activity, BET surface area and pore morphology of the catalysts depended on the content of ionic liquid. Hence, catalysts with high ionic liquid loading content showed deactivation at high reaction temperatures, possibly caused by redistribution of ionic liquid out of the pores under these conditions.