Kinetics of hydroformylation of 1-octene in ionic liquid-organic biphasic media using rhodium sulfoxantphos catalyst

Biphasic hydroformylation of 1-octene was performed using rhodium sulfoxantphos catalyst dissolved in [BuPy][BF4] ionic liquid. Preliminary experiments proved this system to retain the catalytic complex within the ionic liquid phase and to maintain a high selectivity towards the linear aldehyde (n:iso ratio of 30) over several cycles. Process parameter investigation showed a first order dependence of the initial rate with respect to the catalyst and 1-octene concentrations, but a more complex behavior with respect to hydrogen (fractional order) and carbon monoxide partial pressures (inhibition at high pressures). Different mathematical models were selected based on the trends observed and evaluated for data fitting. Also, rate models were derived from a proposed mechanism, using Christiansen matrix approach. To calculate concentrations of substrates in the catalytic phase as required by this kinetic modeling, solubility measurements were preformed for the gases (pressure drop technique), as well as for 1-octene and n-nonanal (thermogravimetry analysis)

Synthesis of polyesteramides by a new palladium catalyzed carbonylation–polycondensation reaction

This is the published version. Copyright © The Royal Society of Chemistry 2001Alternating polyesteramides are prepared by palladium catalyzed carbonylation–polycondensation reactions of aromatic diiodides and aminohydroxy compounds in the presence of an organic base

Hydroformylation of 1-Octene Using [Bmim][PF6]−Decane Biphasic Media and Rhodium Complex Catalyst: Thermodynamic Properties and Kinetic Study

A chemical reaction engineering approach is reported to investigate the biphasic hydroformylation of 1-octene using [bmim][PF6] ionic liquid. It is based both on a process parameter investigation (temperature, concentrations, and pressures) and a thermodynamic study of the reaction medium (gas−liquid and liquid−liquid equilibria). Initial rate data show complex behavior with respect to operating parameters and are best described by a rate equation based on a mechanistic model. Complete reaction scheme including isomerization is then modeled accounting from the time dependent concentration of the organic substrates measured in organic phase and recalculated in ionic liquid phase from liquid−liquid equilibria

Mass transfer assessment and kinetic investigation of biphasic catalytic systems

Efficient catalyst recovery and recycling is still a major challenge for the development of homogeneous catalysis. In the 80’s, the concept of biphasic catalysis, in which the catalyst is confined into a solvent immiscible with the products, has opened new perspectives for transition metal complex driven homogeneous catalysis, after the industrial success of the Ruhrchemie/Rhone-Poulenc process operating the rhodium-catalyzed hydroformylation of propene in water. However, the low solubility of long-chain a-olefins has limited the scope of hydrosoluble catalysts for this reaction. To overcome this problem, various strategies have been developed since then, which consist in replacing water by a more suitable solvent or using additives/ligands able to increase the substrate solubility or create a favorable microenvironment in the aqueous phase. Apart from the screening/tailoring of solvent and ligand, the determination of an adequate kinetic model and the assessment of the mass transfer role is of great importance for the design and optimization of the multiphase reaction system. This presentation gives an account of collaborative works between chemical engineering and chemistry teams to address these issues for two different biphasic catalysis approaches: catalyst immobilization in ionic liquids and use of amphiphilic polymer ligands. The hydroformylation of oct-1-ene by rhodium complexes was selected as model reaction for the developed methodology. This includes the thermodynamic study of the complex reaction medium (gas-liquid and liquid-liquid equilibria), the thorough investigation of the effect of process parameters to evaluate the location of the catalytic act and the interfacial mass transfer resistance, the discrimination and identification of intrinsic kinetic models (derived from elementary reaction steps) and their coupling with (gas-liquid) mass transfer under low stirring conditions. In the first example, the role of the ionic liquids as solvents for biphasic catalysis was specified, by characterizing the solubility of both gaseous and organic substrates, and a detailed kinetic model was able to accurately describe the time-concentration profiles of reactants and products (1-octene,internal octenes, n-nonanal and branched aldehydes) measured in the organic phase. TOF values could be further improved (up to 560 h-1) by supporting the ionic liquid phase onto a silica gel support. In the second example, the proof of concept of cross-linked micelles as efficient supports for aqueous phase catalysis was established, demonstrating that the reaction occurs within the nano-objects with fast exchange with the organic phase. The study also provided clues for their optimization: a low functionalization degree and a nanogel structure embedding the phosphine moieties were proved to improve the catalytic activity and reduce the metal leaching, respectively. These innovative ligands yielded TOF in the range of 350 to 650 h-1 and linear/branched aldehyde ratios between 3 and 6. The Rh loss could be reduced to 0.1 ppm with adequate pH and temperature conditions

Hydrocarbonylation of methyl acetate using a homogeneous Rh(CO)Cl(PPh<SUB>3</SUB>)<SUB>2</SUB> Complex as a catalyst Precursor: kinetic modeling

The kinetics of hydrocarbonylation of methyl acetate to ethylidene diacetate (EDA) using the Rh(CO)Cl(PPh3)2/PPh3/MeI catalyst system was studied in a temperature range of 433-463 K. Concentration-time profiles were obtained for different reaction conditions such as concentrations of methyl acetate, methyl iodide, and catalyst and partial pressures of CO and hydrogen. Rate equations were proposed on the basis of a reaction mechanism with [Rh(CO)2I2]- as the catalytically active species. Activation energies for acetic anhydride (Ac2O) and EDA formation were found to be 80.72 and 91.79 kJ/mol, respectively. A semibatch reactor model was developed, and the effect of the carbon-monoxide-to-hydrogen ratio on the conversion of methyl acetate and selectivity to EDA is discussed

Hydroformylation of 1,4-diacetoxy-2-butene using HRh(CO)(PPh<SUB>3</SUB>)<SUB>3</SUB> tethered on alumina as a catalyst: kinetic study

Hydroformylation of 1,4-diacetoxy-2-butene (DAB) was studied using [HRh(CO)(PPh<SUB>3</SUB>)<SUB>3</SUB>] complex catalyst tethered on alumina using phosphotungstic acid (PTA) as an anchoring agent, with the aim to understand the product distribution, selectivity, and intrinsic kinetics. It was observed that with the tethered heterogeneous catalyst a simultaneous hydroformylation followed by deacetoxylation steps was possible, which is relevant for combining two steps in the sequence of synthesis of vitamin-A intermediate [2-formyl-4-acetoxy butene (FAB)]. <SUP>31</SUP>P cross-polarization magic angle spinning nuclear magnetic resonance (CP MAS NMR) and infrared (IR) instrumental techniques were found be the most effective techniques to establish the catalyst structure and true heterogeneity. On the basis of the spectroscopic evidence, we postulate the loss of a PPh<SUB>3</SUB> group during tethering to give HRh(CO)(PPh<SUB>3</SUB>)<SUB>2</SUB>-PTA-Al<SUB>2</SUB>O<SUB>3</SUB> as a heterogeneous complex catalyst. Experimental data on the concentration-time and CO/H<SUB>2</SUB> consumption-time profiles were obtained and the effects of DAB concentration, CO partial pressure, H<SUB>2</SUB> partial pressure, and catalyst loading were studied in a 50 mL stirred batch reactor over a temperature range of 338-358 K. The analysis of solid-liquid-gas mass transfer effects was investigated to ensure that the reaction was operating in the kinetic regime. Various models were developed, and the best model was chosen by a model discrimination procedure. The agreement between the model prediction and the experimental data was found to be excellent. The activation energies for the hydroformylation and deacetoxylation steps were found to be 42.5 and 80.2 kJ/mol

Biphasic hydroformylation of 1,4-diacetoxy-2-butene: a kinetic study

Hydroformylation of 1,4-diacetoxy-2-butene was studied using a water-soluble Rh complex catalyst prepared in situ from [Rh(COD)Cl]<SUB>2</SUB> complex and trisodium salt of tri-(m-sulfophenyl)phosphine (TPPTS) in a biphasic system. The sequence of addition of catalyst precursor, ligand, and reactant/solvent showed a significant effect on leaching of Rh from aqueous to organic phase, and hence, the procedure was optimized to develop a nonleaching and stable biphasic catalyst system. The only hydroformylation product (1,4-diacetoxy-2-formyl butane, DAFB) formed was found to deacetoxylate completely to 2-formyl-4-acetoxybutene (FAB), thus allowing a one-pot synthesis of FAB, an important intermediate for Vitamin A. Experimental data on the concentration-time and CO/H<SUB>2</SUB> consumption-time profiles were obtained, and the effects of DAB concentration, CO partial pressure, H<SUB>2</SUB> partial pressure, and catalyst concentration were studied in a stirred batch reactor over a temperature range of 338-358 K. The effect of aqueous phase holdup on the initial rate of hydroformylation and analysis of gas-liquid and liquid-liquid mass transfer effects were also investigated to identify the reaction rate data operating in a kinetic regime. A rate equation based on the known hydroformylation reaction mechanism was used to fit the experimental rate data and to evaluate kinetic parameters. The agreement between the model prediction and the experimental data was found to be excellent. The activation energy was calculated as 30.1 kJ/mol. The biphasic catalyst system reported here is not only efficient for catalyst-product separation but also provides a tandem synthesis of Vitamin A intermediate, FAB

Hydroesterification of 2-vinyl-6-methoxynaphthalene using palladium complexes containing chelating nitrogen ligands

Hydroesterification of 2-vinyl-6-methoxynaphthalene (VMN) to methyl ester of 6-methoxy naphthyl propionic acid (ester of naproxen) has been investigated using palladium complexes containing the chelating N&#8745;O and N&#8745;N ligands (pyridine-2-carboxylate, 2-acetylpyridine, 2-pyridine-carboxaldehyde, and bipyridine) as catalysts. Palladium complex containing 2-acetylpyridine as the ligand was found to be superior to other Pd-complexes. Both acid and halide promoters were necessary for high activity and selectivity. As an acid promoter, benzenesulfonic acid was found to be more effective compared to p-toluenesulfonic acid. Formation of ether 2-methoxy-6-(1-methoxyethyl)naphthalene and a polymer of VMN was observed in all the reactions. It was observed that active catalytic species generated during carbonylation reaction was responsible for the polymer formation. The effect of various parameters such as solvents, CO pressure, and alcohols on the catalytic activity as well as the selectivity was investigated. The turnover frequency using the complex Pd(acpy)(PPh3)(OTs)2 (acpy = 2-acetylpyridine) catalyst was found to be 42 h-1, which is the highest for the hydroesterification of VMN