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The 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. [ABSTRACT FROM AUTHOR]

The supported ionic liquid phase (SILP) concept, which included thin films of ionic liquid dispersed onto porous support surfaces, was applied for the gas‐phase hydroformylation of but‐1‐ene catalyzed by Rh‐bpp (bpp=biphephos ligand) complexes. The support material silica was carefully pre‐treated by a hydrothermal procedure to induce textural changes concerning the pore size. Starting with a mean pore size of 3 nm these could be enlarged by almost a factor of 10 up to 27 nm. Different particle size fractions having the same pore size of 10±1 nm were investigated regarding the hydroformylation activity. A clear limitation by pore diffusion can be found for particles larger than 500 μm in diameter. The limitation could be minimized by enlarging the pore size. To support the data, dimensionless numbers and criteria were calculated, including Thiele‐modulus, Mears, and Weisz‐Prater. All data support the assumption that limitation occurs around 500 μm particle size if 10 nm pores are present. [ABSTRACT FROM AUTHOR]

Process intensification is a cornerstone to achieve a significant reduction in energy consumption and CO2 emissions in the chemical industry. In this context, a monolithic membrane reactor combining homogeneous catalytic gas-phase hydroformylation of but-1-ene with in situ product removal is here presented. The homogeneous supported ionic liquid-phase (SILP) catalyst consists of a Rh-biphephos complex dissolved in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C2C1Im][NTf2] and immobilized on a mesoporous silicon carbide monolith. The resulting monolith is catalytically active and selective towards linear aldehyde formation, but the accumulation of aldehyde products and high boilers in the ionic liquid leads to slow catalyst deactivation. This accumulation is suppressed when bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate is used as alternative solvent, where only marginal aldehyde accumulation and aldol formation occur. A polydimethylsiloxane (PDMS) membrane coating of the monolith increases the aldehyde-alkene ratio by an enrichment factor of 2.2 in the permeate gas compared to the retentate gas from the reactor simplifying further downstream processing. The monolithic membrane reactor loaded with SILP or SLP catalysts presents a scalable, versatile platform to achieve process intensification for diverse hydroformylation reactions as well as related gas-phase reactions. [ABSTRACT FROM AUTHOR]

A novel gas-phase process has been developed that allows direct two-step conversion of butane into pentanals with high activity and selectivity. The process consists of alkane dehydrogenation over a heterogeneous Cr/Al2O3 catalyst followed by direct gas-phase hydroformylation using advanced supported ionic liquid phase (SILP) catalysis. The latter step uses rhodium complexes modified with the diphosphite ligands biphephos (BP) and benzopinacol to convert the butane/butene mixture from the dehydrogenation step efficiently into aldehydes. The use of the BP ligand results in improved yields of linear pentanal because SILP systems with this ligand are active for both isomerization and hydroformylation. © 2014 American Institute of Chemical Engineers AIChE J, 61: 893-897, 2015 [ABSTRACT FROM AUTHOR]

Ligand-modified Rh complexes were physically adsorbed on the surface of porous silica. The resulting materials were subjected to the continuous gas-phase hydroformylation of C2 and C4 alkenes. The ligands used for catalyst modification were bidentate phosphorus ligands known from the literature, namely, sulfoxantphos ( 1) and a benzopinacol-based bulky diphosphite 2. The tested catalyst materials were active and, in particular, selective as in comparable homogeneous liquid-phase experiments. Long-term stability experiments over 1000 h on stream showed minor deactivation. A significant increase in the catalyst mass after the reaction was detected by weighing and thermogravimetric analysis. By using headspace-GC-MS, the mass increase could be attributed to high-boiling compounds, which are formed in situ during the catalytic reaction itself and accumulate inside the pores of the support. Evidence is given that the initially physisorbed catalyst complexes dissolve in the high-boiling aldol side-products, which are suitable solvents for the active catalyst species and provide a liquid-phase environment held by capillary forces on the support. [ABSTRACT FROM AUTHOR]

The article offers the authors' insights on the aspects of the catalytic hydroaminomethylation in a gas-phase reaction with supported ionic liquid phase (SILP) materials. The authors investigates ethylene hydroaminomethylation with synthesis gas and diethylamine. They also analyzed the impact of ionic liquid coatings on Rh-Xantphos catalyst performance. They conclude that SILP materials are ideal catalyst materials for hydroformylation tandem reaction.

The concept of supported ionic liquid phase (SILP) catalysis has been established in recent years by our group and others. Its application in continuous catalytic gas-phase processes provides a very attractive way to bridge the gap between homogeneous and heterogeneous catalysis. In this contribution, we extend SILP hydroformylation catalysis to reactions with a highly diluted, technical C4 feed containing 1.5 % 1-butene, 28.5 % 2-butenes, and 70 % of inert n-butane. To obtain the desired product, n-pentanal, the Rh-biphephos catalyst system was immobilized in the SILP system to allow for consecutive isomerization/hydroformylation activity. The resulting SILP catalyst material converted up to 81 % of the reactive butenes, with a residence time of 155 s in the reactor. An n-pentanal selectivity greater than 92 % was realized for more than 500 h time-on-stream in the continuous gas-phase reaction. Post-reaction NMR studies revealed no significant loss of the phosphite ligand through ligand oxidation during the reaction. [ABSTRACT FROM AUTHOR]

The supported ionic liquid phase (SILP) catalysis technology was applied to gas-phase hydroformylation of 1-butene using sulfoxantphos 1 modified rhodium complexes. Kinetic experiments were performed in a fixed bed reactor and compared to a gradient-free gas-phase loop reactor (Berty type). The influence of substrate concentration, temperature and syngas pressure was determined. Data from fixed bed and Berty reactor were found to be in good agreement with respect to activation energy and reaction order. Ex-situ NMR studies of fresh and used SILP catalysts confirmed that the ligand remained intact after prolonged time on stream. [Copyright &y& Elsevier]

The article discusses the catalyst and process developments of room temperature ionic liquids' (RTILs) hydroformylation reaction. Topics including development of novel ionic liquids, ligands that meet with the requirements of biphasic catalysis, effect of hydrogen, carbon monoxide, and 1-buitene gas solubility in ionic liquids during catalysts in hydroformylation are discussed.

The hydroformylation of 7-tetradecene with Co-TPPTS was studied in microemulsions as reaction media at various temperatures, pressures and surfactant concentrations. The influence of metal concentration and ligand excess on activity and selectivity has been investigated. The use of cobalt based catalysts resulted in isomerization of the internal double bond of 7-tetradecene to yield more than 50% terminal aldehydes. A change in the selectivity for linear aldehydes at different temperatures and metal to ligand ratios indicates a shift in the equilibrium between modified and unmodified cobalt species. [Copyright &y& Elsevier]

Water soluble rhodium catalyst complexes are highly active in a microemulsion system stabilized by technical grade surfactants of the alkyl-polyglycolether type. At temperatures around 120 °C and pressures of 100 bar internal alkenes are hydroformylated with high regioselectivity. 7-Tetradecene as model alkene was effectively hydroformylated in microemulsions with high reaction rates yielding 2-hexyl-nonal. Under the reaction conditions applied the equilibria between different catalytically active complexes are shifted towards the unmodified HRh(CO)3. Easy catalyst recycling of the water soluble modified complex is possible when the equilibrium is shifted back under work-up conditions. [Copyright &y& Elsevier]

Biphasic hydroformylation using water-soluble rhodium catalysts is advantageous with regard to catalyst recovery and product separation. Higher olefins cannot be converted due to their immiscibility with water. The 1-dodecene as model alkene was successfully hydroformylated in microemulsions with reaction rates higher than in a two-phase system. Technical grade polyglycolether type surfactants were used for the preparation of the microemulsions. Suitable microemulsions were found for carrying out hydroformylation reactions at different temperatures. Catalyst recovery can be achieved by phase separation followed by ultrafiltration. [Copyright &y& Elsevier]

[Display omitted] • Wall-flow channeled monoliths with trimodal pore-size distribution. • SiC monoliths with core-skin hierarchical macroporosity allow membrane coating. • Homogeneous loading of SiO 2 or Al 2 O 3 nanoparticles into the SiC macropores. • Texture defined by SiC porosity, nanoparticle composition, size and load, and calcination temperature. • Efficient Rh-catalyst immobilization, hydroformylation integrated membrane reactor feasible. Monolithic support materials with the mechanical resistance and thermal conductivity of SiC as well as tunable surface chemistry and textural properties were developed for their use in catalytic membrane reactors. After heat treatment, the extruded SiC monoliths have a monomodal distribution of macropores of a few μm in diameter depending on the particle size of the starting material. A macroporous, defect-free, smoother skin was applied onto the external wall using a solution of sub-micrometer SiC particles. These monoliths with skin could be coated successfully with molecularly selective membranes, and thus have application in membrane reactor processes. Finally, metal oxide nanoparticles were infiltrated into the macropores to modify the surface texture and chemistry, allowing the immobilization of liquid phase catalysts. The resulting multimodal distribution of pore sizes could be tuned by the choice of SiC and oxide particle sizes, number of wash-coats and calcination temperature. Mesopores created between nanoparticles had diameters of roughly 40 % of those of the nanoparticles. Small macropores, between 10−1000 nm, were also created, with bigger size and volume at higher calcination temperatures due to the metal oxide particles contraction. The developed materials were validated as support for PDMS membranes and for continuous gas-phase hydroformylation of 1-butene using Rh-diphosphite catalysts. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]