Hydroformylation Reaction Research Articles

Unexpected selectivities in transition metal-catalyzed hydroformylation of vinyl-substituted cavitands

Platinum- and rhodium-catalyzed hydroformylation reactions were performed on tetra(vinyl)cavitand skeletons. Instead of obtaining a statistical mixture of products, the reactions proceeded with high ‘tetra-selectivities’, that is, all four vinyl groups were either hydrogenated or transformed to the branched or linear aldehydes via hydroformylation. Based on these exceptionally high chemo- and regioselectivities, a cooperation between all the four catalytic reaction centers was supposed.

Highly Active Rh Catalysts with Strong π-Acceptor Phosphine-Containing Porous Organic Polymers for Alkene Hydroformylation.

Phosphine-containing porous organic polymers (phosphine-POPs) are a kind of potential catalyst support for alkene hydroformylation. However, the synthesis of phosphine-POPs with strong π-acceptor is still a challenge. Herein, we report the synthesis of phosphine-POPs with different π-acceptor properties [POL-P(Pyr)3, CPOL-BPa&PPh3-15, and CPOL-BP&PPh3-15] and evaluated their performances as ligands to coordinate with Rh(acac)(CO)2 for hydroformylation of alkenes. We found that the Rh center with stronger π-acceptor phosphine-POPs showed better catalytic performance. Rh/CPOL-BPa&PPh3-15 with strong π-acceptor bidentate phosphoramidites showed obviously higher activity and regioselectivity (TON = 7.5 × 103, l/b = 26.1) than Rh/CPOL-BP&PPh3-15 (TON = 5.3 × 103, l/b = 5.0) with weaker π-acceptor bidentate phosphonites. Particularly, the TON of the hydroformylation reached 27.7 × 103 upon using Rh/POL-P(Pyr)3 which possessed tris(1-pyrrolyl)phosphane coordination sites. Overall, our study provides an orientation to design phosphine-POPs for hydroformylation reactions.

Towards more efficient hydroformylation of long‐chain alkenes in aqueous biphasic system using microbubbles

AbstractMicrobubbles were applied for the first time to enhance the aqueous biphasic hydroformylation of long‐chain alkenes. The gas–liquid–liquid multiphase hydroformylation was carried out using 1‐dodecene as model higher olefin and dihexadecyl dimethyl ammonium bromide (DDAB) as surfactant. The increasing liquid temperature resulted in the increased mean bubble size and total bubble number, but this trend became inapparent at high temperatures due to the reduced liquid viscosity. The increasing gas flow rate was favorable to increase the multiphase interfacial area, thus leading to the increasing mass transfer coefficient KLa. The conversion of 1‐dodecene reached maximum 95% in the three‐phase microemulsion system, and at a gas flow rate of 40 ml min−1. Further increasing the gas flow rate to 80 ml min−1 decreased the conversion, which was attributed to the destroyed flow field, as observed in micro‐PIV. Owing to the increased multiphase mass transfer efficiency, the application of microbubbles allowed to intensify the hydroformylation reaction with reduced reaction pressure, higher chemoselectivity, and increased turnover frequency (TOF).

Multi-phase CFD modelling for hydroformylation of 1-hexene with microbubbles

Based on the micro-bubbling process as an intensification method, an experimental study on hydroformylation of 1-hexene was carried out. Effects of different total pressures, temperatures, partial pressures and substrate concentrations on the conversion rate of olefin and normal-to-iso ratio were investigated and the reaction kinetic coefficients were determined by fitting the experimental data with the model. Using the Euler two-fluid and standard k-ε turbulence model, a computational fluid dynamics model was established to describe the multi-phase flow mass transfer and reaction of olefin hydroformylation. The simulation results were in good agreement with the experimental results. Furthermore, the effects of microbubble sizes and internal components on the overall gas holdup, mass transfer rate, turbulent mixing and reaction efficiency of the multi-phase 1-hexene hydroformylation reaction system were studied, which could be applied to the process intensification and scale-up of the various multi-phase gas-liquid hydroformylation reactions.

Osmium-catalyzed reduction processes

Catalytic reduction processes are of vital importance in organic chemistry. Numerous reactions catalyzed by palladium, rhodium, ruthenium, iridium and platinum complexes have been developed. Meanwhile, the use of osmium compounds as catalysts for reduction reactions has received surprisingly little attention, although they can effectively accelerate some processes. In some cases, osmium catalysts are superior to related ruthenium compounds both in activity of the catalytic system and in stability of the catalys <i>per se</i>. This review systematically summarizes reductive transformations catalyzed by organometallic osmium complexes. General trends in this research area followed in the literature are described and prospects in this field of chemistry are discussed. The hydrogen transfer and borrowing hydrogen reactions, hydrogenation, hydroformylation, reductive amination, and water-gas shift reactions are considered.<br> The bibliography includes 96 references

Unraveling the Origin of the Regioselectivity of a Supramolecular Hydroformylation Catalyst

AbstractSupramolecular substrate preorganization using DIMPHos ligands, which are bisphosphine ligands equipped with a carboxylate binding site, allows for control over the regioselectivity in the hydroformylation reaction. In all reported examples, the aldehyde product in which the CO was inserted farthest from the directing group, was formed in excess (for terminal alkenes the linear aldehyde). We report here an in‐depth DFT study to provide mechanistic insight into this selective transformation. These calculations show large energy differences between the different hydride migration steps of competing pathways that lead to either the linear or branched aldehyde product, in line with the experimentally found selectivity. Through the use of calculated model systems of the catalyst, it is shown that the substrate binding event itself plays an important role in determining these large energy differences. Following ditopic substrate binding, the product forming pathways that lead to the minor isomeric product is particularly disfavored by the steric repulsion between the ditopically bound substrate and the apical coordinated CO ligand.

Tandem Electrocatalytic–Thermocatalytic Reaction Scheme for CO2 Conversion to C3 Oxygenates

A two-step tandem electrochemical–thermochemical reaction scheme is demonstrated to convert CO2 into value-added C3 oxygenate molecules: CO2 was electrochemically reduced to ethylene, CO, and H2, followed by the thermochemical hydroformylation reaction to produce 1-propanol and propanal. The CO2 electrolyzer was evaluated with Cu catalysts containing different oxidation states and with modifications to the gas diffusion layer hydrophobicity, while the hydroformylation reactor was tested over a Rh1Co3/MCM-41 catalyst. In situ X-ray absorption spectroscopy showed minimal changes to the Cu and Rh catalysts in the electrochemical and thermochemical reactions, respectively. The tandem configuration achieved a total C3 oxygenate product selectivity (on a basis of reduced CO2) of ∼18%, representing over a 4-fold improvement compared to direct electrochemical CO2 conversion to 1-propanol in flow cells. Additionally, the CO2 electrolyzer was scaled to a 25 cm2 device to enhance the C3 oxygenate production rate up to 11.8 μmol min–1 and demonstrate potential scalability of the tandem system.

Total Synthesis of Clovan-2,9-dione via [3 + 2 + 1] Cycloaddition and Hydroformylation/Aldol Reaction

Here we report the total synthesis of clovan-2,9-dione via Rh-catalyzed [3 + 2 + 1] cycloaddition/hydroformylation/aldol reaction. The [3 + 2 + 1] reaction of 1-yne-vinylcyclopropane and CO was used for the generation of a 5/6 bicyclic skeleton with a bridgehead vinyl group. The hydroformylation reaction converted the congested olefin of the [3 + 2 + 1] cycloadduct to a one-carbon elongated aldehyde, which underwent in situ aldol reaction, with the carbonyl group in the [3 + 2 + 1] cycloadduct, to generate the tricyclic bridged-ring skeleton of the target molecule.

Hydroformylation-like Reactions Enable Electrochemical Pathways from CO2 to Extended Carbon Chains

Atomically precise active sites on electrode surfaces promise new chemical transformations that simultaneously exploit both the potent physical handle of applied voltage and the highly-tailored reactivity of well-defined active sites. Often, these catalysts have off-electrode analogs in biology or organometallic chemistry, and effectively leveraging these analogies requires an understanding of how catalysis at the active site is perturbed by the complex interplay of electrolyte species and electric fields at electrode interfaces. In this work, we dissect and design two atomically precise catalysts that leverage off-electrode analogies and enable an electrochemical pathway that converts CO2 to extended carbon chains.We show that a new electrified hydroformylation reaction can be used to achieve electrochemical C-C coupling. Hydroformylation is a well-studied thermochemical reaction that performs C-C coupling by appending CO to an olefin in the presence of H2 gas. We mimic homogeneous HFN catalysts on electrode surfaces using single atom-decorated nanoparticles. We show that electrochemistry can be used to circumvent the need to supply H2 as a reactant. Instead, protons, electrons, and CO can be used to hydroformylate a model substrate. Additionally, we study the electrochemical generation of CO, a necessary reactant for hydroformylation, via immobilized cobalt phthalocyanine (CoPc) catalysts. Through collecting kinetic data over a wide range of operating conditions and quantitatively comparing candidate mechanisms, we are able to demonstrate unexpected roles of both the electrolyte and applied potential on the reaction pathway.These studies build towards a more rigorous and quantitative understanding of how the many components of an electrode interface interact with and influence catalysis on atomically precise active sites. It is crucial to carve out this complexity if we wish to effectively import catalysts or design principles from other catalytic contexts onto electrified interfaces.

Silicalite-1 encapsulated rhodium nanoparticles for hydroformylation of 1-hexene

Hydroformylation has been applied in the chemical industry for decades to produce n-aldehydes from 1-olefins and syngas (a mixture of CO and H2). However, the difficulty of catalyst separation and harsh operating conditions of conventional homogeneous hydroformylation reactions have prompted researchers to explore heterogeneous catalytic strategies. In this work, a novel core-shell structured catalyst comprised of Rhodium nanoparticles (Rh NPs) homogeneously encapsulated in a silicalite-1 zeolite (Rh@S-1) is designed to realize a high activity in 1-hexene hydroformylation. The conversion of 1-hexene over the Rh@S-1 catalyst exhibits as high as 85.8%, and the ratio of n-heptanal to iso-heptanal reaches up to 2.5 at 90 °C. Multiple studies demonstrate that the outstanding catalytic activity over this core-shell structured catalyst can be explained by the highly active homogeneously dispersed Rh NPs and the distinguishable mass transfer effect of the unique and orderly micropores structure of silicalite-1 zeolite. Furthermore, by changing templating agent concentrations during the hydrothermal method, the size of the zeolite crystals can be easily controlled and is proven to be an essential factor affecting the hydroformylation performance.

Silicon Carbide Supported Liquid Phase (SLP) Hydroformylation Catalysis – Effective Reaction Kinetics from Continuous Gas‐phase Operation

AbstractThe hydroformylation reaction is one of the most important applications of homogeneous catalysis on an industrial scale with worldwide production capacities exceeding 15 Mio tons per year. Efficient catalyst immobilization becomes mandatory for such large‐scale processes. In this work, a supported liquid phase (SLP)‐type catalyst on a silicon carbide support material was applied in the continuous Rh‐bpp (bpp=biphephos) catalyzed gas‐phase hydroformylation of but‐1‐ene. A parameter variation was carried out in the pressure range from 0.5 to 3.0 bara for but‐1‐ene, 0.5 to 5 bara for H2, 0.5 to 5 bara for CO, and in the temperature range from 90 to 125 °C. Activation energies were determined for the individual reactions showing a shift in activation energy most significantly for the hydroformylation to n‐pentanal for temperatures of 110 °C and above. For all substrates the effective reaction orders were calculated and employed in a power‐law rate model giving good agreement of measured and modeled data within a ±20 % error margin. Similar results were obtained using a microkinetic model.

The catalytic mechanism of hydroformylation of 1-butene on rhodium-coordinated organic linkers in MOFs: A computational study

In this work, five different ligands for MOFs catalyzing 1-butene hydroformylation reactions were investigated using density functional theory (DFT) with heteroatoms (N, O, P) containing in the organic ligands that can chelate the catalytic metal Rh. The results show that the N/P-containing organic linkers have lower activation barriers than the carboxylate linkers (O-containing) and have potential for catalytic hydroformylation reactions. However, the N-containing catalysts have a significant defect in the selectivity of linear/branched product. The relatively low regioselectivity may be due to their weak steric effect of ligands. This work explores the strategy that MOFs fixing the single metal atom at metallolinkers for catalytic hydroformylation of 1-butene. It is of great significance for the design and construction of MOFs for hydroformylation in the future investigation.

Highly regioselective tandem hydroformylation of substituted styrene using Iminophosphine rhodium complex immobilized on carbon

With an exponential increase in fossil fuel consumption and an increasing demand for carbon-based materials, it draws the attention of researchers to seek alternative carbon sources. Herein, we report the sustainable route for the synthesis of ionic carbon from bio-derived sugarcane-waste (Bagasse) and further anchoring with iminophosphine rhodium complex (Rh@BCNP) and utilized for tandem hydroformylation reaction. The SEM analysis confirms the formation of spherical shape morphology of carbon with sizes ranging from 30-150 nm. The successful functionalization of the iminophosphine rhodium complex on the carbon surface was determined by XPS, TEM, FE-SEM, 31P NMR, 13C CP-MAS-NMR, and FTIR analysis. Furthermore, ICP-OES analysis confirms the presence of 0.307 mmoles/g of Rh and 0.484 mmoles/g of P on the carbon surface. Rh@BCNP catalyst is the best combination of triphenylphosphine ligand, imine, and rhodium metal, resulting in hybrid material with some acidic properties of carbon that favour the selectivity towards linear products. Rh@BCNP showed remarkable catalytic performance under moderate reaction conditions (80 °C, 40 bar (CO + H2)) in 5 h. This sharp divergence from other methods leading to linear amines and acetals results in a novel atom economic approach to synthesize pharmaceuticals and industrial products. The Rh@BCNP catalyst gave recyclability up to five cycles.

Reduced graphene oxide supported cobalt catalysts for ethylene hydroformylation: Modified cobalt-support interaction by rhodium

The metal-support interaction (MSI) alters the geometric morphologies, electronic properties, or distribution of metal nanoparticles, which is indeed to influence the heterogenous catalytic system. Two heterogenous ethylene hydroformylation catalysts, cobalt supported on reduced graphene oxide (RGO) with or without Rhodium (5%Rh-20%Co/RGO and 20%Co/RGO), were successfully synthesized. The effect of the MSI between Co and RGO and a MSI tuning strategy by Rh on the ethylene hydroformylation (EH) were investigated. CoO nanorods was present in fresh Rh-Co/RGO, while only CoO nano-particles were formed in fresh Co/RGO. Rh enhanced the reducibility of the cobalt species. After reduction and the ethylene hydroformylation reaction, Co2C was formed in spent Rh-Co/RGO, while a mixture of Co and CoO were present in the spent Co/RGO. Co2C grew to a large flat plane structure in spent Rh-Co/RGO, while Co and CoO formed smaller nano-particles in spent Co/RGO. The changes of the geometric morphologies and the phases of the active species made by the Rh-Co-RGO interaction significantly enhance the activity of the CO and the selectivity for the production of the C3 oxygenates. A Model on how the nanoparticles distributed on the RGO were hypothesized.

Metal–organic framework ZIF-8 loaded with rhodium nanoparticles as a catalyst for hydroformylation

Porous metal–organic framework ZIF-8 materials containing incorporated rhodium (Rh@ZIF-8) and rhodium chloride (RhCl3@ZIF-8) nanoparticles were obtained and tested as a catalytic reaction vessel in the reactions of hydroformylation of 1-decene and styrene. Catalytic tests with Rh@ZIF-8 showed that the selectivity and conversion of the hydroformylation reaction depended on the size of the substrate molecule. The incorporation of catalytic nanoparticles into the pores of a metal–organic framework opens up new possibilities for regioselective hydroformylation.

Rh‐Complex Supported on Magnetic Nanoparticles as Catalysts for Hydroformylations and Transfer Hydrogenation Reactions

AbstractHerein, we describe a facile protocol for the phosphine complex of Rh anchored on the ultrasmall magnetic nanoparticles for transfer hydrogenation and hydroformylation reactions. A diphenylphosphino‐ferrocenylethyl amine was conjugated with dopamine hydrochloride to form dop‐Fc, which was then anchored on the surface of magnetic nanoparticles to produce Fe3O4@dop‐Fc. The prepared materials were complexed with a Rh precursor as a catalytic center. XRD, FTIR, SEM, TEM, and XPS were used to investigate the structure and its reactivity. Rh‐complexes of Fe3O4@dop‐Fc were used to convert terminal olefin to aldehyde using syngas (CO : H2 1 : 1) under pressure, obtaining up to 99% selectivity for branched aldehyde. The wide applicability of the Fe3O4@dop‐Fc−Rh construct was tested for the selective transfer hydrogenations of nitroarene and N‐heteroarene. Particularly, quinoline was quantitatively hydrogenated to 1,2,3,4‐tetrahydroquinoline(py‐THQ) using tetrahydroxydiboron (THDB). Also, the functional group tolerance in the reduction of nitroarene and styrene was evaluated. The robustness of the catalyst was tested by reusing it for multiple cycles.

Construction of a quaternary stereogenic center by asymmetric hydroformylation: a straightforward method to prepare chiral α-quaternary amino acids.

The construction of chiral quaternary carbon stereocenters has been a long-standing challenge in organic chemistry. Particularly, α-quaternary amino acids that are of high importance in biochemistry still lack a straightforward synthetic method. We here reported a hydroformylation approach to access chiral quaternary stereogenic centers, which has been a long-standing challenge in transition metal catalysis. α,β-Unsaturated carboxylic acid derivatives undergo hydroformylation with a rhodium catalyst to generate an α-quaternary stereocenter under mild conditions. By using this method, a variety of chiral α-quaternary amino acids could be synthesized with satisfactory enantioselectivity. In-depth investigation revealed that the regioselectivity is dramatically influenced by the electronic properties of the substituents attached to the target C Created by potrace 1.16, written by Peter Selinger 2001-2019 ]]> C bond. By applying NMR and DFT analyses, the chiral environment of a rhodium/Yanphos complex was depicted, based on which a substrate-catalyst interaction model was proposed.

Complejos (η6-Arene)-tricarbonylchromium(0) complexes used in olefin hydroformylation reaction with syngas

Aldehydes are compounds with a great scientific interest in its chemical applications, especially to consider a raw material in many industrially and process for manufacturing secondary products, such as, solvents, biodegradable detergents, pharmaceuticals, surfactants, lubricants, other. In this paper we describe the use of commercial chromium carbonyl: [Cr(CO)6] (1), [Cr(CO)3(η6-C6H6)](2a), [Cr(CO)3(η6-C6H5CH3)] (2b), [Cr(CO)3(η6-C8H8O2)] (2c) y [Cr(CO)3(η6-C7H8)] (3), as catalytic precursors in hydroformylation reactions of 1-hexene and cyclohexene with syngas CO/H2 and CO2/H2 in homogeneous phase. In all cases, the reactions conditions (temperature, pressure, CO/H2 ratio, solvents, substrate/catalyst ratio) were optimized and additionally, the catalytic activity was studied employing excess ligands condition or mercury test to verify the homogeneity in the catalytic system. Under optimal conditions, a high percent yield and good selectivity for linear versus branched aldehydes, and for the CO2/H2 system, all the catalysts showed moderate conversion towards linear, branched aldehydes and alcohols with and without NaCl.

Hydroformylation of olefins by metals other than rhodium

Metal catalyzed hydroformylation of alkenes is an atom economic transformation to construct useful aldehydes and is being industrially practiced for decades. The most commonly used metal for this transformation on an industrial scale is rhodium. However, rhodium is rare, costly, and is depleting at a skyrocketing rate. Therefore, finding a suitable alternative to rhodium for metal-catalyzed hydroformylation has been on the radar of many academic and industrial researchers. This review presents the scientific advancements reported in the hydroformylation reaction using metals other than rhodium. An overview of recent progress in palladium, iridium, ruthenium, cobalt, platinum, and iron-catalyzed hydroformylation is presented. Hydroformylation of alkenes and alkynes, using syngas as well as syngas surrogates is examined. The evaluation of the current status of non-rhodium metals in hydroformylation suggests that the field is still in a nascent stage and, except cobalt, no other metal poses a significant challenge to the dominance of rhodium. Deep mechanistic understanding of rate-limiting elementary steps in the non-rhodium metals is largely missing and thus only limited success is reported. Intense research on ligand design, mechanistic understanding, and choice of non-rhodium metal precursors may change this scenario in near future.

A Highly Active N-Doped Carbon Supported CoFe Alloy Catalyst for Hydroformylation of C8 Olefins

The development of inexpensive and efficient Co-based heterogeneous catalysts for hydroformylation reactions remains an enormous challenge. In this paper, N-doped carbon supported CoFe bimetallic catalysts (CoFe/NC) are successfully synthesized through a simple thermal decomposition of a mixture of Co(acac)2 and Fe(acac)3, and melamine with activated carbon in N2 atmosphere. With the CoFe/NC-800 as the catalyst, hydroformylation of diisobutene proceeded smoothly in THF under 4 MPa syngas at 130 °C to obtain 92% conversion of diisobutene and 79.6% selectivity to isononyl aldehydes. Detailed studies revealed that the N-doped carbon supported FeCo alloy may be the active species in which nitrogen might act as ligand played an important role in improvement of catalytic performance of hydroformylation reactions. The present study provided meaningful insights into tuning the catalytic performance of non-noble metal heterogeneous catalysts for carbonylation reaction.