- Email: [email protected]
Gas-liquid-liquid reaction using water soluble catalyst
Chemical
Engineering
Science.
Vol. 47, No. 9-l
1, pp. 2689-2694,
1992. 0
printed in Great Britain.
GAS-LIQUID-LIQUID I. HABLOT*, *
ooo9-2509/92 $5.00+0.00 1992 pergamon Press Ltd
REACTION USING WATER SOLUBLE CATALYST J. JENCK+, G. CASAMA-ITA*.
H. DELMAS*
Ecole Nationale Sup&ieure d’IngCnieursde Genie Chimique URA CNRS 192, chemin de la Loge F-3 1078 TOULOUSE Cedex’
+ RhOne Poulenc Industrialisation.Centre d’Indust.rialisationde D&ines 24, avenue Jean-JauresF-6915 1 DECINES CHARPIEU CCdex ABSTRACT
Industrialapplications of homogeneous catalysis by precious metal complexes are limited due to the difficult recovery or regeneration of such catalysts. By using water soluble phosphorous ligands, the catalytic complex can be kept in aqueous phase. The major drawback, a drastic reduction of the effective reaction rate, has been overcome by adding a cosolvent. Water-octene-cosolvent equilibrium has been estimated (UNIFAC) in order to select a convenient cosolvent, i.e. increasing significantly the octene concentration in the aqueous phase without losing catalyst in the organic phase. Similar thermodynamic prediction of liquid-gas equilibria has then been performed, showing only moderate effects of the cosolvent. Due to ligands oxidation by water, catalyst stability must be improved by increasing the concentration of phosphorous ligands. Then initial kinetics, derived without any mass transfer limitations, showed first order reaction rates with respect to hydrogen and octene-1 in the aqueous phase. Complete kinetics of parallel hydrogenation and isomerisation have been analysed, using step by step liquid-liquid and liquid-gas equilibria accounting for octene consumption. INTRODUCTION Selective hydrogenation, hydroformylation or carbonylation can be performed by using complexes of transition metals, especially rhodium, ruthenium or cobalt. However, the homogeneous catalytic processes development is limited by the uneasy separation or recovery of these very expensive catalysts. Better than supported catalysis, an alternative solution consists in using water soluble phosphorous ligands in order to keep the catalytic complex in the aqueous phase. So, the reaction involves a three-phase system which includes : - a dispersed gas phase, - a continuous aqueous phase containing the catalytic complex - an organic phase which contains substrateand products of reaction. Preliminar experiments resulted in dramatic reductions of the effective reaction rates, which were supposed to be due to the very low solubility of the organic reagents in the catalytic aqueous phase. So, in the case of octene-1 hydrogenation, the thermodynamic limitations of the liquid-liquid-gas reaction system were first analysed and then, the kinetic study could be performed. THERMODYNAMICS Octene solubility in the catalytic phase In order to increase octene concentration in the reaction phase, addition of a cosolvent, i.e. a product soluble in both water and octene, must be intended; but the need of cosolvent for hydrogenation reaction in a gas-liquid-liquid system was not clearly proved in previous works. For instance, in the case of cyclohexene hydrogenation using the preformed complex 2689
I. HABLOT et al.
2690
,
F12
[RhCl(dpm)g], Dror and Manassen (1977) found that the reaction depends on the alkene solubility in the aqueous phase and that a cosolvent is necessary, while on the contrary, for Borowski et aL, (1978) the reaction occurs at the interface and so no cosolvent must be added. Facing this contradiction, preliminary experiments on the octene hydrogenation carried out without cosolvent led to very low reaction rates : the conversion of octene-1 in octane was about 1% after one hour. On the contrary, when adding cosolvents much higher reaction rates were obtained. The main limitation of the reaction rate was then clearly related to the very low octene solubility in the aqueous catalytic phase where the reaction is taking place. According to Mac Auliffe (1966) the weight fraction of octene is 2.7 lo-6 kg/kg of water. In order to investigate the influence of a cosolvent on octene solubility in the aqueous phase, liquid-liquid equilibria were predicted by a thermodynamic model (Hablot, 1991) which firstly consists of the combination of Unifac group contribution method and Uniquac equation (L-e Lann et al., 1988) and secondly of the use of Prophy (Joulia et aZ_, 1987), a simulation software of thermodynamic and equilibria properties between phases. This model allowed to determine the composition of every component in both phases in equilibrium and was validated with experimental data obtained by Nowakowska et aZ. (1956). Liquid-liquid equilibria were then determined for many water-cosolvent-octene mixtures. Two types of ternary diagrams were schematically obtained depending on the slope of tie lines (Hablot et u1., 1990) : - type A : ethanol, acetonitrile, ethylene glycol, n-propylamine, acetone . . . In this case, there is more octene in the aqueous phase than water in the organic phase - type B : THF, cyclohexanol, propanol, n-butylamine .. . . Here, on the contrary, there is more water in the organic phase than octene in the aqueous phase. High water concentrations in the organic phase could result in significant catalyst losses, therefore only cosolvents of type A were selected. These cosolvents enhance considerably the octene concentration in the aqueous phase (Figure 1). For example, adding about as much cosolvent as water can increase octcnc concentration in a ratio up to 10,000. In addition, these cosolvents carry pratically no water in the organic phase and thus, even with the very pessimistic assumption of equal RhIwater ratio in the two liquid phases, less than 1 ppm rhodium would be lost in the organic phase . octene concentration * 102(mol/kg)
1 10 80 60 40 cosolvent content (8 weight) Figure 1 : octene solubility in the aqueous phase with different cosolvents 0
20
F12
Gas-liquid-liquid
reaction using water soluble catalyst
2691
Hydrogenation reactions were carried out with different convenient cosolvents showing that a cosolvent is necessary to obtain a significant initial reaction rate, but no clear correlation between initial reaction rates and octene concentration in the aqueous phase could be deduced. Acomplete analysis should also require the estimation of hydrogen concentration in the catalytic phase. Hydrogen solubility in the aqueous phase First, a correlation for hydrogen solubility in a single component was set up. This correlation permits to determine hydrogen solubility as well in non polar as in polar solvents and leads to very good agreement between estimated values and experimental data. This method has been successfully generalized to various water-organic solvent mixtures as follows
where
- LnX&i = LnfAL(O. lma)
+ vA (q - ~A)~/RT
PI2 = @,- a2)2/RT According to the type of solvent (non polar, polar non associated or polar associated solvents), the solubility parameter of hydrogen aA is different (Hablot, 1991). The comparison between the estimated solubility and the only experimental data (Linke and Seidell, 1958) found in the literature and concerning a mixture of water-ethanol is presented on Figure 2. The average deviation is less than 4%. hydrogen solubility * 10’ (molkg) 50 40
a
/
experimental values model
30 20 10 ethanol content (weight 96) 0 Figure 2 : hydrogen solubility in water-ethanol mixtures (P=O.l MPa) The calculation of hydrogen concentration in water-cosolvent mixtures using another cosolvent than ethanol proved that adding a cosolvent does not highly increase hydrogen solubility in the aqueous phase. The hydrogen concentration in the catalytic phase is much less varying with the cosolvent fraction than the octene concentration. Furthermore, with significant addition of a cosolvent, the hydrogen molar concentration in the reaction phase at atmospheric pressure is much lower than octene molar concentration.
2692
I. HABLOT
FL2
eral.
only way to significantly increase hydrogen solubility in the aqueous catalytic phase, is then, according to Henry’s law, to raise hydrogen pressure as shown on Figure 3. The
25
solubility * 10 2 (mol/kg) 1
20 15 10 5 0
0
10
20
30
40
50
60
ethanol content (mass %) Figure 3 : pressure effect on hydrogen solubility, comparison with octene concentration
KINETICS Equipment and experimental conditions : The reaction was carried out in a 570 cm3 high pressure autoclave (39 MPa) fitted with a diving tube for sampling during reaction. Semi-batch operation was selected, the gas being introduced at constant flowrate. The liquid-liquid and liquid-gas dispersions were achieved by a gas inducer of Rushton type. In all runs presented here, ethanol was used as a cosolvent, the temperature was 50°C and the stirring was proved sufficient (2500 tr/mn) to avoid any mass transfer limitations. The catalytic complex is formed in situ from [RhCl(Cod)]2 and TPPTS. The resulting complex was found to be very unstable due to phosphine oxidation. It was decomposed progressively in very effective colloi’dal rhodium (Larpent et aZ., 1987). In order to reduce this decomposition, a large excess of phosphine was added to the aqueous phase. Satisfactory stabilization was achieved with a phosphorous/rhodium molar ratio equal to 16. Influence of reagents concentrations : Various ethanol contents were used for hydrogenation reaction, involving consequently different octene concentrations in the aqueous phase. The amounts of octane formed for these effective octene concentrations are presented on Figure 4a. Then, keeping the same ethanol content and therefore the same octene concentration in the catalytic phase, the hydrogen pressure was varied from 3 to 10 MPa (Figure 4b). The initial kinetics, derived without liquid-liquid and liquid-gas mass transfer limitations, led approximately to first order with respect to dissolved hydrogen and water solubilized octene.
Gas-liquid-liquid
F12 Kinetic
reactiun using water soluble catalyst
2693
model :
The reaction of octene- 1 hydrogenation involved parallel octene- 1 isomerisation which had to be taken into account. Different reaction schemes, lumping all octene-1 isomers, were tested. These models account for octene consumption and so octane and isomers formation. For this, the thermodynamic liquid-liquid model was used at each time step to determine octene, octane and isomers amounts in the aqueous and organic phases. The concentrations in the organic phase were used to calculate the reaction rate at the following step. Kinetic parameters optimization was then performed for different reaction schemes, using the time dependant concentrations together with liquid-liquid equilibria. As major features, it can be concluded that isomerisation is not a reversible reaction but it depends on hydrogen pressure, the partial orders with respect to hydrogen and octene-1 are close to one and hydrogenation of isomers is negligible.The selected sheme is then : octene-1
+
H2
kl_
octane
%
octene isomers
k2
octene- 1 %aXale
a
-I
r1 = k, (C*)l
%lXtane c*=110moVoI3 a
, = 0 P=lOMPa
l
/
r2
=
(s*$
k, (C*>’ (s*)’
C’ = 110moum3
0
P=lOMt?a
a
l
10
P=Q@iI
C* 55AmoUm3l0
0
,
0
P=3MPa
C*= 28.5molhn3
~w0 20 10 30 Figure 4b : influence of hydrogen pressure Figure 4a : influence of octene concentration in on octane formation. aqueous phase on octane formation. Comparison between experimental values and calculations based on step by step liquid-liquid equilibria 0
% isomers P=
37
IOMPa
C* = 110 moYm3
2-
C* = 55.6 molhn3 l-
C* = 28.5 molhn3
0
10
20
30
Figure 4c : influence of octene concentration on isomers formation. Comparison between experimental values and calculations based on step by step liquid-liquid equilibria.
2694
I. HABLOT
et al.
Fi2
comparison between experimental data and the optimized model is presented on Figures 4a and 4c, with various octene concentrations in the aqueous phase, and on Figure 4b ,with various hydrogen pressures.
The
Future work will be devoted to hydroformylation. much more promising from an industrial point of view and also relative to the catalyst stability, which is highly improved by CO ligands. After choosing a convenient cosolvent and deriving the intrinsic kinetics in strongly stirred reactor, a complete analysis will require separate investigations on two unusual mass transfer phenomena, liquid-liquid transfer in presence of a dispersed gas phase and gas-liquid transfer with a dispersed second liquid phase. NOTATIONS octene concentration in the aqueous phase (at liquid-liquid equilibrium) cyclooctadiene fugacity of hypothetical liquid hydrogen at 0. 1MPa rate constant reaction rate hydrogen concentration in the aqueous phase (at gas-liquid equilibrium) triphenylphosphine meta trisulfonate molar volume of hydrogen molar volume of component i mole fraction of hydrogen in the liquid i solubility parameter of hydrogen solubility parameter of component i volume fraction of component i
E; kt ri
&PTS VA vi
REFERENCES Borowski A-F., Cole-Hamilton D.J., WiIlcinson G., Water-soluble complexes
and their use in two-phase
(1978) Dror Y., Manassen J., Hydrogenation
catalytic reactions
transition metal phosphine of oleflns, Nouv. J. Chim.. 2, 137
of olefins with rhodium-phosphine complexes, having substrate and catalyst in two different immiscible phases. An alternative method for the heterogenization of a homogeneous catalyst, J. Mol. Catal., 2,219 (1977) Hablot I., Jenck .I., Casamatta G., Delmas H., Selection of pressure and cosolvent concentration for an organic liquid-gas reaction catalysed by an aqueous phase, 2nd International Symposium : High Pressure Chemical Engineering, Erlangen (1990) Hablot I., Reaction Liquide-liquide-gaz : t?udes thernwdynamique et cine’tique d ‘une hydrogt%ation d’olk”ne cat&y&e par un complexe de coordination solubilise’ en phase aqueuse,
Thesis, Toulouse (1991) Joulia X., Koehret B., Le Lann J.M., Lambolez F., Sere Peyrigain P.. Prophy
: programme thermodynamiques et d’kquiiibres entre phases (1987) H., Rhodium(I) production during the oxidation by water of a
interactif de culcul de propri&&
Larpent C., Dabard R., Patin phosphine, Inorg. Chem., 26,2922 (1987) Le Lann J-M., Joulia X., Koehret B., A computer program for the prediction of the thermodynamics properties andphase equilibria, Int. Chem. Engng, 28.36 (1988) Linke W-F., Seidell A., Sokbilities of inorganic and metal-organic compounds, volume one, fourth edition, Van Nostrand Company, New York (1958) Mac Auliffe C., Solubility in water of para_lYTn, cycloparamn, olefin, acetylene, cycloolejin, and aromatic hydrocarbons, J. Phys. Chem., 70, 1267 (1966) Nowakowska J., Kretschmer C.B., Wiebe R., Ethyl alcohol-water with 2,2,4-trimethylpentane and with I-octene at 0 “c and 25 “C, Ind.Engng Chem., 1,42 (1956) hydrosoluble
Engineering
Science.
Vol. 47, No. 9-l
1, pp. 2689-2694,
1992. 0
printed in Great Britain.
GAS-LIQUID-LIQUID I. HABLOT*, *
ooo9-2509/92 $5.00+0.00 1992 pergamon Press Ltd
REACTION USING WATER SOLUBLE CATALYST J. JENCK+, G. CASAMA-ITA*.
H. DELMAS*
Ecole Nationale Sup&ieure d’IngCnieursde Genie Chimique URA CNRS 192, chemin de la Loge F-3 1078 TOULOUSE Cedex’
+ RhOne Poulenc Industrialisation.Centre d’Indust.rialisationde D&ines 24, avenue Jean-JauresF-6915 1 DECINES CHARPIEU CCdex ABSTRACT
Industrialapplications of homogeneous catalysis by precious metal complexes are limited due to the difficult recovery or regeneration of such catalysts. By using water soluble phosphorous ligands, the catalytic complex can be kept in aqueous phase. The major drawback, a drastic reduction of the effective reaction rate, has been overcome by adding a cosolvent. Water-octene-cosolvent equilibrium has been estimated (UNIFAC) in order to select a convenient cosolvent, i.e. increasing significantly the octene concentration in the aqueous phase without losing catalyst in the organic phase. Similar thermodynamic prediction of liquid-gas equilibria has then been performed, showing only moderate effects of the cosolvent. Due to ligands oxidation by water, catalyst stability must be improved by increasing the concentration of phosphorous ligands. Then initial kinetics, derived without any mass transfer limitations, showed first order reaction rates with respect to hydrogen and octene-1 in the aqueous phase. Complete kinetics of parallel hydrogenation and isomerisation have been analysed, using step by step liquid-liquid and liquid-gas equilibria accounting for octene consumption. INTRODUCTION Selective hydrogenation, hydroformylation or carbonylation can be performed by using complexes of transition metals, especially rhodium, ruthenium or cobalt. However, the homogeneous catalytic processes development is limited by the uneasy separation or recovery of these very expensive catalysts. Better than supported catalysis, an alternative solution consists in using water soluble phosphorous ligands in order to keep the catalytic complex in the aqueous phase. So, the reaction involves a three-phase system which includes : - a dispersed gas phase, - a continuous aqueous phase containing the catalytic complex - an organic phase which contains substrateand products of reaction. Preliminar experiments resulted in dramatic reductions of the effective reaction rates, which were supposed to be due to the very low solubility of the organic reagents in the catalytic aqueous phase. So, in the case of octene-1 hydrogenation, the thermodynamic limitations of the liquid-liquid-gas reaction system were first analysed and then, the kinetic study could be performed. THERMODYNAMICS Octene solubility in the catalytic phase In order to increase octene concentration in the reaction phase, addition of a cosolvent, i.e. a product soluble in both water and octene, must be intended; but the need of cosolvent for hydrogenation reaction in a gas-liquid-liquid system was not clearly proved in previous works. For instance, in the case of cyclohexene hydrogenation using the preformed complex 2689
I. HABLOT et al.
2690
,
F12
[RhCl(dpm)g], Dror and Manassen (1977) found that the reaction depends on the alkene solubility in the aqueous phase and that a cosolvent is necessary, while on the contrary, for Borowski et aL, (1978) the reaction occurs at the interface and so no cosolvent must be added. Facing this contradiction, preliminary experiments on the octene hydrogenation carried out without cosolvent led to very low reaction rates : the conversion of octene-1 in octane was about 1% after one hour. On the contrary, when adding cosolvents much higher reaction rates were obtained. The main limitation of the reaction rate was then clearly related to the very low octene solubility in the aqueous catalytic phase where the reaction is taking place. According to Mac Auliffe (1966) the weight fraction of octene is 2.7 lo-6 kg/kg of water. In order to investigate the influence of a cosolvent on octene solubility in the aqueous phase, liquid-liquid equilibria were predicted by a thermodynamic model (Hablot, 1991) which firstly consists of the combination of Unifac group contribution method and Uniquac equation (L-e Lann et al., 1988) and secondly of the use of Prophy (Joulia et aZ_, 1987), a simulation software of thermodynamic and equilibria properties between phases. This model allowed to determine the composition of every component in both phases in equilibrium and was validated with experimental data obtained by Nowakowska et aZ. (1956). Liquid-liquid equilibria were then determined for many water-cosolvent-octene mixtures. Two types of ternary diagrams were schematically obtained depending on the slope of tie lines (Hablot et u1., 1990) : - type A : ethanol, acetonitrile, ethylene glycol, n-propylamine, acetone . . . In this case, there is more octene in the aqueous phase than water in the organic phase - type B : THF, cyclohexanol, propanol, n-butylamine .. . . Here, on the contrary, there is more water in the organic phase than octene in the aqueous phase. High water concentrations in the organic phase could result in significant catalyst losses, therefore only cosolvents of type A were selected. These cosolvents enhance considerably the octene concentration in the aqueous phase (Figure 1). For example, adding about as much cosolvent as water can increase octcnc concentration in a ratio up to 10,000. In addition, these cosolvents carry pratically no water in the organic phase and thus, even with the very pessimistic assumption of equal RhIwater ratio in the two liquid phases, less than 1 ppm rhodium would be lost in the organic phase . octene concentration * 102(mol/kg)
1 10 80 60 40 cosolvent content (8 weight) Figure 1 : octene solubility in the aqueous phase with different cosolvents 0
20
F12
Gas-liquid-liquid
reaction using water soluble catalyst
2691
Hydrogenation reactions were carried out with different convenient cosolvents showing that a cosolvent is necessary to obtain a significant initial reaction rate, but no clear correlation between initial reaction rates and octene concentration in the aqueous phase could be deduced. Acomplete analysis should also require the estimation of hydrogen concentration in the catalytic phase. Hydrogen solubility in the aqueous phase First, a correlation for hydrogen solubility in a single component was set up. This correlation permits to determine hydrogen solubility as well in non polar as in polar solvents and leads to very good agreement between estimated values and experimental data. This method has been successfully generalized to various water-organic solvent mixtures as follows
where
- LnX&i = LnfAL(O. lma)
+ vA (q - ~A)~/RT
PI2 = @,- a2)2/RT According to the type of solvent (non polar, polar non associated or polar associated solvents), the solubility parameter of hydrogen aA is different (Hablot, 1991). The comparison between the estimated solubility and the only experimental data (Linke and Seidell, 1958) found in the literature and concerning a mixture of water-ethanol is presented on Figure 2. The average deviation is less than 4%. hydrogen solubility * 10’ (molkg) 50 40
a
/
experimental values model
30 20 10 ethanol content (weight 96) 0 Figure 2 : hydrogen solubility in water-ethanol mixtures (P=O.l MPa) The calculation of hydrogen concentration in water-cosolvent mixtures using another cosolvent than ethanol proved that adding a cosolvent does not highly increase hydrogen solubility in the aqueous phase. The hydrogen concentration in the catalytic phase is much less varying with the cosolvent fraction than the octene concentration. Furthermore, with significant addition of a cosolvent, the hydrogen molar concentration in the reaction phase at atmospheric pressure is much lower than octene molar concentration.
2692
I. HABLOT
FL2
eral.
only way to significantly increase hydrogen solubility in the aqueous catalytic phase, is then, according to Henry’s law, to raise hydrogen pressure as shown on Figure 3. The
25
solubility * 10 2 (mol/kg) 1
20 15 10 5 0
0
10
20
30
40
50
60
ethanol content (mass %) Figure 3 : pressure effect on hydrogen solubility, comparison with octene concentration
KINETICS Equipment and experimental conditions : The reaction was carried out in a 570 cm3 high pressure autoclave (39 MPa) fitted with a diving tube for sampling during reaction. Semi-batch operation was selected, the gas being introduced at constant flowrate. The liquid-liquid and liquid-gas dispersions were achieved by a gas inducer of Rushton type. In all runs presented here, ethanol was used as a cosolvent, the temperature was 50°C and the stirring was proved sufficient (2500 tr/mn) to avoid any mass transfer limitations. The catalytic complex is formed in situ from [RhCl(Cod)]2 and TPPTS. The resulting complex was found to be very unstable due to phosphine oxidation. It was decomposed progressively in very effective colloi’dal rhodium (Larpent et aZ., 1987). In order to reduce this decomposition, a large excess of phosphine was added to the aqueous phase. Satisfactory stabilization was achieved with a phosphorous/rhodium molar ratio equal to 16. Influence of reagents concentrations : Various ethanol contents were used for hydrogenation reaction, involving consequently different octene concentrations in the aqueous phase. The amounts of octane formed for these effective octene concentrations are presented on Figure 4a. Then, keeping the same ethanol content and therefore the same octene concentration in the catalytic phase, the hydrogen pressure was varied from 3 to 10 MPa (Figure 4b). The initial kinetics, derived without liquid-liquid and liquid-gas mass transfer limitations, led approximately to first order with respect to dissolved hydrogen and water solubilized octene.
Gas-liquid-liquid
F12 Kinetic
reactiun using water soluble catalyst
2693
model :
The reaction of octene- 1 hydrogenation involved parallel octene- 1 isomerisation which had to be taken into account. Different reaction schemes, lumping all octene-1 isomers, were tested. These models account for octene consumption and so octane and isomers formation. For this, the thermodynamic liquid-liquid model was used at each time step to determine octene, octane and isomers amounts in the aqueous and organic phases. The concentrations in the organic phase were used to calculate the reaction rate at the following step. Kinetic parameters optimization was then performed for different reaction schemes, using the time dependant concentrations together with liquid-liquid equilibria. As major features, it can be concluded that isomerisation is not a reversible reaction but it depends on hydrogen pressure, the partial orders with respect to hydrogen and octene-1 are close to one and hydrogenation of isomers is negligible.The selected sheme is then : octene-1
+
H2
kl_
octane
%
octene isomers
k2
octene- 1 %aXale
a
-I
r1 = k, (C*)l
%lXtane c*=110moVoI3 a
, = 0 P=lOMPa
l
/
r2
=
(s*$
k, (C*>’ (s*)’
C’ = 110moum3
0
P=lOMt?a
a
l
10
P=Q@iI
C* 55AmoUm3l0
0
,
0
P=3MPa
C*= 28.5molhn3
~w0 20 10 30 Figure 4b : influence of hydrogen pressure Figure 4a : influence of octene concentration in on octane formation. aqueous phase on octane formation. Comparison between experimental values and calculations based on step by step liquid-liquid equilibria 0
% isomers P=
37
IOMPa
C* = 110 moYm3
2-
C* = 55.6 molhn3 l-
C* = 28.5 molhn3
0
10
20
30
Figure 4c : influence of octene concentration on isomers formation. Comparison between experimental values and calculations based on step by step liquid-liquid equilibria.
2694
I. HABLOT
et al.
Fi2
comparison between experimental data and the optimized model is presented on Figures 4a and 4c, with various octene concentrations in the aqueous phase, and on Figure 4b ,with various hydrogen pressures.
The
Future work will be devoted to hydroformylation. much more promising from an industrial point of view and also relative to the catalyst stability, which is highly improved by CO ligands. After choosing a convenient cosolvent and deriving the intrinsic kinetics in strongly stirred reactor, a complete analysis will require separate investigations on two unusual mass transfer phenomena, liquid-liquid transfer in presence of a dispersed gas phase and gas-liquid transfer with a dispersed second liquid phase. NOTATIONS octene concentration in the aqueous phase (at liquid-liquid equilibrium) cyclooctadiene fugacity of hypothetical liquid hydrogen at 0. 1MPa rate constant reaction rate hydrogen concentration in the aqueous phase (at gas-liquid equilibrium) triphenylphosphine meta trisulfonate molar volume of hydrogen molar volume of component i mole fraction of hydrogen in the liquid i solubility parameter of hydrogen solubility parameter of component i volume fraction of component i
E; kt ri
&PTS VA vi
REFERENCES Borowski A-F., Cole-Hamilton D.J., WiIlcinson G., Water-soluble complexes
and their use in two-phase
(1978) Dror Y., Manassen J., Hydrogenation
catalytic reactions
transition metal phosphine of oleflns, Nouv. J. Chim.. 2, 137
of olefins with rhodium-phosphine complexes, having substrate and catalyst in two different immiscible phases. An alternative method for the heterogenization of a homogeneous catalyst, J. Mol. Catal., 2,219 (1977) Hablot I., Jenck .I., Casamatta G., Delmas H., Selection of pressure and cosolvent concentration for an organic liquid-gas reaction catalysed by an aqueous phase, 2nd International Symposium : High Pressure Chemical Engineering, Erlangen (1990) Hablot I., Reaction Liquide-liquide-gaz : t?udes thernwdynamique et cine’tique d ‘une hydrogt%ation d’olk”ne cat&y&e par un complexe de coordination solubilise’ en phase aqueuse,
Thesis, Toulouse (1991) Joulia X., Koehret B., Le Lann J.M., Lambolez F., Sere Peyrigain P.. Prophy
: programme thermodynamiques et d’kquiiibres entre phases (1987) H., Rhodium(I) production during the oxidation by water of a
interactif de culcul de propri&&
Larpent C., Dabard R., Patin phosphine, Inorg. Chem., 26,2922 (1987) Le Lann J-M., Joulia X., Koehret B., A computer program for the prediction of the thermodynamics properties andphase equilibria, Int. Chem. Engng, 28.36 (1988) Linke W-F., Seidell A., Sokbilities of inorganic and metal-organic compounds, volume one, fourth edition, Van Nostrand Company, New York (1958) Mac Auliffe C., Solubility in water of para_lYTn, cycloparamn, olefin, acetylene, cycloolejin, and aromatic hydrocarbons, J. Phys. Chem., 70, 1267 (1966) Nowakowska J., Kretschmer C.B., Wiebe R., Ethyl alcohol-water with 2,2,4-trimethylpentane and with I-octene at 0 “c and 25 “C, Ind.Engng Chem., 1,42 (1956) hydrosoluble