Supported Liquid Phase Research Articles

Supported liquid phase catalysis in selective oxidation

The application of supported liquid-phase catalysis (SLPC) to selective oxidation examples is discussed to provide valuable alternatives to the purely homogeneous or heterogenous processes. Specific examples discussed are the Wacker type ethylene oxidation on heterogenous catalysts and the vinyl acetate production by ethylene acetoxylation. The potential industrial application of SLPC for these oxidations and the possible extensions of this technology to other oxidation processes are also discussed.

Poly(ethylene glycol) Supported Liquid Phase Synthesis of Biaryls

Poly(ethylene glycol) Supported Liquid Phase Synthesis of Biaryls

Solvent‐Anchored Supported Liquid Phase Catalysis: Polyoxometalate‐Catalyzed Oxidations

Solvent‐Anchored Supported Liquid Phase Catalysis: Polyoxometalate‐Catalyzed Oxidations

REACTION ENGINEERING OF CHEMICAL PCBs DECHLORINATION: AN EXPERIMENTAL APPROACH

Abstract This paper deals with the application of some chemical reaction engineering principles in order to develop a supported liquid phase reagent (SLPR) able to dechlorinate PCBs contained in highly viscous media. The reagent consists of polyethyleneglycols containing a dissolved base and a radical initiator. Recently this mixture was proposed as CDP(R) (Chemical Dechlorination Process) for PCBs detoxification. In this paper are reported several experimental tests designed to optimise configuration of reagents on inert support to dechlorinate the PCBs contained in the transformer oil. The main results are: the evaluation of optimum reagent load on support, the set up of dechlorination kinetics of commercial PCBs as AROCLOR 1260 in transformer oil tested in the 50-2500 ppm range. SLPR was tested in a “fixed-bed” as well as in “slurry” reactor configurations. The above results were used to design two mobile plants for on-site treatments.

ChemInform Abstract: Studies on the Stability of Supported Liquid Phase Catalysts.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Reaktions‐ und verfahrenstechnische Aspekte der Heterogenisierung homogen‐katalysierter Synthesen

AbstractReaction and process engineering aspects of transforming homogenous catalytic syntheses into heterogeneous processes. In order to avoid the separation of the catalyst in homogeneous catalytic processes, the preparation of supported phase catalysts has attracted widespread attention in recent years. Most interest has focussed on the immobilization of transition‐metal complexes on solid supports for catalyzing carbon monoxide and olefin reactions. After a survey of the development of solid supported phase (SSP)‐ and supported liquid phase (SLP)‐catalysts two reactions in which SSP‐catalysts have been applied are considered in detail: The carbonylation of methyl acetate to acetic anhydride and the stereoselective hydrogenation of 2‐acylaminocinnamic acid to (S)‐phenylalanine, a derivative of L‐DOPA. In order to discuss the favourable characteristics and the disadvantages of SSP‐catalysts, they are compared to soluble catalysts. Furthermore, the design of both processes is discussed.

Supported liquid phase reactor (SLPR) for PCBs in oil decontamination

Polyethyleneglycols containing a dissolved based and a radical initiator are supported on a solid carrier in a fixed bed reactor. This formulation is able to degrade chemically stable polychlorinated diphenyls (PCBs) dissolved in transformer oil in a continuous process. This short report concerns with the results of laboratory and on-site applications of chemical PCBs degradation by SLPR.

The industrial hydroformylation of olefins with rhodium-based supported liquid phase catalyst (SLPC): Part VI. general predesign of a large-scale SLPC Plant for the hydroformylation of propylene

The application of a rhodium-based catalyst dissolved in triphenylphosphine and condensed into α-alumina is studied for use in the industrial hydrofo The main conclusions regarding the outlay of a plant with a production of 20 000 tons of aldehydes per year are: (1) The volume necessary for the rhodium-containing reactor is 18.6m 3. (2) The best type of reactor is a multitube fixed bed. (3) If the conditions are chosen optimally (the degree of catalyst loading is 0.163, the [Rh]-concentration is 100 mole m −3, the ratio of propyle (4) The maximum degree of propylene conversion is 0.35. (5) Calculations with a pseudo-homogeneous reactor model show that with a cooling temperature of 95 °C a reactor consisting of 311 tubes with a lengt

The industrial hydroformylation of olefins with rhodium-based supported liquid phase catalyst (SLPC): Part V. The formation of 2-ethyl-2-hexenal and propane: extrinsic catalyst poisoning

Hydridocarbonyltris(triphenylphosphine)-rhodium(I) dissolved in liquid triphenyl-phosphine and capillary condensed into the pores of a porous support i The extent of the side reactions, hydrogenation to propane and aldolization to 2-ethyl-2-hexenal, is studied. The hydrogenation does not occur in the t Although impurities in propylene such as acetylene and methylacetylene do not have any effect on catalyst poisoning, propadiene does. Hence the use of

Theoretical foundation of cluster formation in supported liquid-phase catalysts

Despite the widespread use of supported liquid phase catalysts (SLPC) in industrial practice, the basic phenomenon of liquid dispersion which affects the diffusion rates of reaching components and gas-liquid interfacial area, is not well understood. The paper identifies the associated problems and formulates a model for the pore structure of real catalysts based on intersecting cylinders to study the effects of capillary forces. The formation of liquid clusters of dimensions larger than the pore dimensions and their subsequent effects on the performance of SLPC can be studied using this model. The model provides a basis for manipulating parameters that can reduce such cluster formation.

The industrial hydroformylation of olefins with a rhodium-based supported liquid phase catalyst (SLPC): III. The kinetics of propylene hydroformylation catalyzed by the rhodium-based supported liquid phase catalyst

Hydridocarbonyltris(triphenylphosphine)-rhodium(I), dissolved in triphenylphosphine and capillary condensed in the pores of α-Al 2O 3, was studied as a catalyst for hydroformylation of propylene. The activity and selectivity for n-butyraldehyde were measured in the range 90 – 110 °C. Even up to a degree of conversion of 25 mol.% propylene no deactivation was found at 110 °C. Varying the partial pressures of hydrogen, carbon monoxide and propylene gave the reaction orders. With respect to propylene the order is 1.57. The other reaction orders are smaller than 0.1. The stability of the catalyst depends mainly on the partial pressure of CO. At p CO = 0.180 MPa the catalyst is stable. The activation energy is then 70.6 kJ mol −1. The selectivity to n-butyraldehyde is increased by lowering p CO. The lowest ratio of n-butyraldehyde to the isoproduct is 14.

The industrial hydroformylation of olefins with a rhodium-based supported liquid phase catalyst (SLPC): II. Influence of the degree of liquid loading on the catalytic performance of the rhodium-based supported liquid phase catalyst

Ethylene was hydroformylated with a rhodium-based liquid phase catalyst supported on α-Al 2O 3. Triphenylphosphine was the ligand in the catalyst. The effect of the degree of liquid loading on the catalytic performance was investigated for the range δ = 0.05 – 0.80. A stable activity level, which was highly dependent on the type of α-Al 2O 3, was reached in 24 h on-stream time. The experiments were carried out at relatively large Rh concentrations of up to 100 mol Rh m −3. For some supports the maximum value led to deactivation. A concentration of 50 mol Rh m −3 resulted in better stability. The deactivation was probably caused by the formation of aldol products which leached out the catalyst.

The industrial hydroformylation of olefins with a rhodium-based supported liquid phase catalyst (SLPC): IV: Heat-transfer measurements in a fixed bed containing alumina SCS9 particles

Heat transfer measurements have been carried out to investigate the technical use of a rhodium-based catalyst which is capillary condensed in porous α-Al 2O 3. Empirical correlations have been found for the effective thermal conductivity and the wall heat-transfer coefficient in a tubular fixed bed consisting of α-Al 2O 3 particles. These parameters are only dependent on the Reynolds number. The correlation found for the thermal conductivity is in satisfactory agreement with that reported by Coberly and Marshall. The wall heat-transfer coefficient resembles that obtained by de Wasch and Froment.

The industrial hydroformylation of olefins with a rhodium-based supported liquid phase catalyst: I: Description of the catalyst system, catalyst characterization and preparation, together with some orienting hydroformylation experiments with propyl

Hydridocarbonyltris(triphenylphosphine)-rhodium(I) (RhHCO(PPh 3) 3), dissolved in liquid triphenylphosphine and immobilized in a porous support b The hydroformylation reaction proceeds in the following way for propylene: CH 3CHCH 2 + CO + H 2 → CH 3CH 2CH 2CHO In order to assess the industrial applicability of the above-mentioned catalyst a number of support materials were investigated. The influence of the r It is concluded that supports based on α-alumina show the best results if these are pure and have an inert surface. SCS9 and SA5202 and also an exper In the range 25 – 100 (mol Rh) (m 3 PPh 3) −1 the reaction rate is first order with respect to the rhodium concentration. The selectivity The degree of propylene conversion can be as high as 16.8% without an adverse effect on the catalyst performance. In this range of degrees of conversio

The thermal and chemical stability limits of supported liquid phase rhodium catalysts in the hydroformylation of propene

A study is made of the thermal deactivation of Supported Liquid Phase Rhodium Catalysts (Rh-SLPC) during the hydroformylation of propene to linear and branched butanal. Thermal deactivation is observed above 403 K, and is attended by the formation of triphenylphosphine oxide. The influence on catalytic performance of the intentional admixture of triphenylphosphine oxide to triphenylphosphine in the Rh-SLPC is studied. Furthermore, catalyst poisoning by water is examined.

Adsorptive withdrawal of RhHCO(PPh 3) 3 in supported liquid phase hydroformylation catalysts

In supported liquid-phase catalysts the degree of pore filling may strongly influence the catalytic activity. This is the case, for instance, when dealing with supported liquid-phase rhodium catalysts in which the complex RhHCO(PPh 3) 3, dissolved in PPh 3, is dispersed in the pores of inorganic support materials such as silica and alumina. One of the factors which may cause an increase or decrease in the activity per unit weight of rhodium is the variable extent of adsorptive complex withdrawal at the liquid-solid interface in the pores. The amount of complex adsorbed (the percentage of dissolved complex withdrawn from the liquid PPh 3 by adsorption) appears to depend, among other factors, strongly on the degree of pore filling 5, which varies from zero (empty pores) to one (totally filled pores). In view of the foregoing, we determined the adsorption isotherms of RhHCO(PPh 3) 3, dissolved in PPh 3, on various support materials such as silica, various crystallographic modifications of alumina, and on porous Amberlite, type XAD-2. Most isotherms are measured at 90 °C, very near to the temperature at which the catalysts are applied. The nature of the adsorptive bond is discussed; in some cases physical adsorption is involved, in others there is strong evidence for chemisorption of the complex on the support. The question of how completely the adsorbed complexes are catalytically eliminated will be dealt with in a forth-coming article.

Supported liquid phase hydroformylation catalysts containing rhodium and triphenylphosphine. Effects of additional solvents and kinetics

Catalysts contaning hydridocarbonyltris(tripenylphosphine)rhodium (I), HRh(CO)(PPh 3) 3, and excess PPh 3 supported on silica show some modification in behaviour (hydroformylation of propene) if additional solvents are present. At high phosphine loadings the effect is to increase the overall rate of reaction and to reduce the regioselectivity for n-butanal production. At low phosphine loadings both the rate and regioselectivity are increased for small additions of other solvents (except Ph 3PO 4) but thereafter further increase in rate is accompanied by a fall in regioselectivity. It is believed that these result illustrate the distinction between chemical and physical roles played by the PPh 3 in these catalysts. The kinetics of hydroformylation can be reasonably described by a power rate law of the form r 1 = k 1 P G C 3 P b CD P c H 1 exp(− E 1/ RT) where r 1 is the overall rate of propene consumption. Analogous expressions for rates of production of n-butanal ( r 2) and isobutanal ( r 3 are presented. In all cases the values of the parameters typified by k 1, a, b, c and E 1 are given for the reaction conditions employed. The influences of phosphine loading on the kinetic parameters are discussed in terms of an increasing tendency of PPh 3 to become highly mobile at sufficiently high loadings. The choice of support (non-porous microspheroids or microporous gel) is largely without influence on the catalytic behaviour.

Hydroformylation of 1-hexene with supported liquid phase catalyst (SLPC) RhHCO(P φ3) 3

Hydroformylation of 1-hexene with supported liquid phase catalyst (SLPC) RhHCO(P φ3) 3

Comparison of the activity of homogeneous catalysts in liquid phase without solvent and as supported liquid phase catalysts (SLPC)

Abstract The hydrogenation of ketones and aldehydes has been carried out at 160 °C and pH1 = 15 bar with the homogeneous catalyst RuCl2(CO)2(P∅3)2 both in solution, and in the gas phase with supported liquid-phase catalysts (SLPC). It is shown that, in the gas phase, hydrogenation of reactants with boiling points near the reaction temperature is possible. In the liquid phase, catalyst activity varies from 1.15 to 60 min−1 and in the gas-phase reaction from 3 to 8.16 min−1. In the liquid-phase hydroformylation of 1-hexene with RhHCO(P∅3)3, the catalyst activity at 120 °C is 250 min−1 with linear/branched product ratio ( n i ) = 5.4. In the gas-phase reaction the activity is only 1.7 min−1 but n i = 46. The boiling point of the product, heptanal, is 35 °C higher than the reaction temperature. Therefore, gas-phase reactions with supported liquid-phase catalysts are not limited to reactants which give only low-boiling point products.

Gas phase hydroformylation of allyl alcohol with supported liquid phase rhodium catalysts

Hydridocarbonyltris(triphenylphosphine)rhodium(I), dissolved in triphenylphosphine or in tri-p-tolylphosphine and capillary-condensed in the pores of a support material, is successfully applied in the heterogeneous gas phase hydroformylation of allyl alcohol. Very high selectivities for 4-hydroxybutyraldehyde are obtained. No sign of catalyst deactivation was observed even after 250 h of testing. The undesired side reaction of allyl alcohol to propionaldehyde is caused by the catalytic action of both the support material and the rhodium complex. By the use of silica with a low aluminium content and of phosphine-rich rhodium complexes, this problem is circumvented. The kinetics of the hydroformylation of allyl alcohol are studied; they differ from those found for propylene with SLP catalysts.