Hydroformylation of oct-1-ene by supported aqueous phase catalysis: Influence of catalytic complex and preparation method of the supports
U. J. Jáuregui-Haza* 1, A. M. Wilhelm2, H. Delmas2
1Centro de Química Farmacéutica, Apdo. 16042, C. Habana, Cuba. E-mail: ulises@cqf.co.cu
2Ecole Nationale Supérieure d'Ingénieurs de Génie Chimique, 18 chemin de la Loge, 31078 Toulouse, France
*Author to whom correspondence should be addressed
Abstract Four silica samples were evaluated as supports in the hydroformylation of oct-1-ene by Supported Aqueous Phase Catalysis (SAPC) using [Rh2(µ-StBu)2(CO)2(TPPTS)2] and [Rh(COD)Cl]2/TPPTS as catalysts. Adsorption studies of the [Rh(COD)Cl]2/TPPTS complex from aqueous solutions on the supports were carried out at 25 °C. The isotherms obtained were correlated by several models, among which the Fowler-Guggenheim/Jovanovic-Freundlich equation was found to be the most satisfactory. The influence of the nature of catalytic complex and of the methods for supporting the catalyst on the silica conversion was also studied.
Keywords Supported Aqueous-Phase Catalysis (SAPC); Hydroformylation; Oct-1-ene; Silica; Rhodium
1. Introduction
The recent development of Supported Aqueous Phase
Catalysis (SAPC) opened the way to hydroformylate very
hydrophobic alkenes such as octene, dicyclopentadiene
or oleyl alcohol with water-soluble catalysts (Arhancet et
al., 1989). But SAPC is still used with empirical rules,
because the mechanisms governing the interactions
between complex, water and solid surface are not well
elucidated. For this reason, it is necessary to study in
depth the adsorption of water soluble ligands and
catalytic complexes onto inorganic supports, as an
important step in the preparation of catalyst-support
complex and the understanding of these catalytic
properties. Recently, the adsorption of aqueous solutions
of benzenesulfonic acid, 3, 3', 3''-phosphinidynetris-,
trisodium salt (TPPTS), the most used hydrosoluble
ligand in biphasic catalysis, and di (µ-tertiobutylthiolato)
dicarbonyl, bis (benzenesulfonic acid, 3, 3', 3''-
phosphinidyne-tris-, trisodium salt) dirhodium ([Rh(µ-
tBu)(CO)(TPPTS)]2 or C1, M.W.= 1577.04) on different
silica supports was reported (Jáuregui-Haza et al.,
2001a). Although C1 and di (1,5 cyclo-octadiene)
dichloro dirhodium, benzenesulfonic acid, 3, 3', 3''-
phosphinidyne-tris-, trisodium salt
([Rh(COD)Cl]2/TPPTS2 or C2, M.W. = 1629.93) had
been used for hydroformylating oct-1-ene by biphasic
catalysis or SAPC (Chaudhari et al., 1995; Deshpande et
al., 1996; Kalck et al., 1998; Jáuregui-Haza et al.,
2001b), it was necessary to obtain the adsorption
isotherms for this second complex and to compare the
performances of these two supported catalysts in the
same operating conditions.
On the other hand, several methods have been used
for preparing the SAP catalysts. According to the
preparation procedure, the methods can be classified into
two groups : i) indirect method, when the support is first
impregnated with the hydrosoluble catalytic complex,
then dried and rehydrated before use (Arhancet et al.,
1989, 1990, 1991a; Choplin et al., 1998; Guo et al.,
1991; Horvath, 1990) ; ii) direct method : the support,
catalytic complex and water are mixed at the same time
in the reaction system (Arhancet et al., 1991b; Kalck et
al., 1998). In general, the best conversions of
hydroformylation of alkenes by SAPC have been
obtained when the SAP catalyst was prepared by indirect
method.
This paper deals with the hydroformylation of oct-1-
ene by SAPC using C1 and C2 and four silica samples as
supports. Adsorption studies of the C2 from aqueous
solutions on the supports were carried out at 25 °C; the
influence of the method of preparation of the supported
catalyst was also investigated. Finally, the catalytic
performances of this catalyst were evaluated and
compared to those of C1.
2. Experimental section
TPPTS was supplied by Rhône-Poulenc. The
complex C1 was synthesized as reported before (Kalck
et al., 1988). The other chemicals and solvents were
purchased from Aldrich and SDS, and used without
further purification. All the reactions and adsorption
experiments were carried out under an inert atmosphere
(Argon or Nitrogen).
Four supports were used to prepare SAP catalysts: the
Sipernat silica samples DS22 and DS50 (from Degussa)
and two SDS silica samples (S60 and S200). Their BET surface area, pore volume, and average pore sizes were
measured by nitrogen sorptometry, using a NOVA-1000
version 3.70 analyser. Particle size measurements were
obtained on a Mastersizer MALVERN S. Table 1 shows
the physical properties of the adsorbents.
The adsorption essays were carried out as described
elsewhere (Jáuregui-Haza et al., 2001a). A fixed amount
of silica (0.5 g) and 6 mL of an aqueous solution of C2 were placed in a 50 mL glass-stoppered flask and shaken
at 100 rpm for 24 hours in a thermostated oscillating bath
(JULABO-SW-20C). The aqueous solutions of C2 were
prepared in deaerated water. The initial concentrations of
solutions were in the range of 8.4 10-5 -0.549 g/g of
solution, which includes the concentration ranges
reported in the works on SAPC and biphasic catalysis
(Arhancet et al., 1989, 1990, 1991; Chaudhari et al.,
1995; Deshpande et al., 1996; Dos Santos et al., 1998;
Guo et al., 1991; Herrmann and Kohlpainter, 1993;
Horvath, 1990; Kuntz, 1981; Monteil, 1993). Preliminary
experiments had shown these adsorption processes
reached equilibrium within 12 hrs. Each experiment was
duplicated under identical conditions. The concentration
of Rh in the aqueous phase was determined by atomic
absorption spectrometry (328.1 or 343.5 nm) with a
VARIAN AA275 spectrometer.
The SAP catalysts were prepared by direct and
indirect methods. In the second case, the impregnation
step involved adsorption of an aqueous solution of C1 or C2 as described above, followed by the drying of the
support under reduced pressure at 40°C during 24 hrs.
Catalytic tests were carried out in a 150 mL stainless
steel stirred autoclave heated by a thermostatic oil bath.
In a typical run, 2.26x10-5 mol of C1 or C2, an excess of
TPPTS (P/Rh = 6, Jáuregui-Haza et al., 2001b), 2.3 g of
the support, 57 mL of toluene, 2.55x10-2 mol of oct-1-ene
and the amount of permuted water necessary to reach the
desired hydration percentage (Jáuregui-Haza et al.,
2001b) were used. The reactor was pressurized with 5 bar
of an equivalent mixture of hydrogen and carbon
monoxide and heated to 80 °C. After 3 hrs, unless
otherwise stated, the gas mixture feed was stopped and
the reactor was cooled down to room temperature. Then,
the reactor was depressurized and the liquid and solid
phases were separated by filtration. The organic phase
was analyzed by gas phase chromatography on a Carlo
Erba HRGC 5160 chromatograph equipped with a flame
ionization detector and a capillary column Alltech
Econopac FFAP (30 m; 0.53 mm; 1.2 µm), Tdet = 200 °C,
PH2 = 0.45 bar.
3. Results and discussion
3.1 Adsorption isotherms
Experimental results of equilibrium adsorption isotherms of C2 are plotted in Fig. 1 (experimental data available by request). The average relative error on the measured concentration in the liquid phase was 4.05 % (with a higher value of 6.97 %). In the same figure, for comparison, the adsorption isotherms obtained previously (Jáuregui-Haza et al., 2001a) for C1 are also shown. In general, high capacities are obtained for both complexes on all supports. The adsorption capacity is higher for C1 than for C2 and for the both complexes it increases with an increase in total pore volume of the support (DS22 < S200 < DS50 < S60). The differences in adsorption capacity might be explained by the differences in molecular size of C1 and C2 as well as by the possible different interactions between the ligands and support surface.
Different isotherm models have been used to correlate isotherm data for C2: the Langmuir model (Langmuir, 1916), for homogeneous surfaces without lateral interactions; the model (Fowler and Guggenheim, 1965), for homogeneous surfaces with lateral interactions; the Jovanovic-Freundlich model (Quiñones and Guiochon, 1996), for heterogeneous surfaces without lateral interactions and the Fowler-Guggenheim/Jovanovic- Freundlich model (Quiñones and Guiochon, 1998), for heterogeneous surfaces with lateral interactions. The equations of these four isotherm models are displayed in Tab. 2.
Fitting of the adsorption isotherm models to the experimental data was performed using a corrected Newton algorithm. The procedure calculates the values of the isotherm parameters which minimize the average standard error of estimation (SEE):
![]() |
(1) |
where are the elements of the vector
containing the given experimental adsorbed phase
concentrations at equilibrium,
are the corresponding
theoretical values calculated by the model and n is the
number of data points.
The selection of the most adequate model was
performed using Fisher's test. The model selected
exhibited the highest value of the Fisher parameter Fcalc (Ajnazarova and Kafarov, 1985):
![]() |
(2) |
where is the mean value of the vector
and l is the number of adjusted parameters of the model.
Table 3 summarizes the results of the nonlinear
regression analysis. In general, the agreement of the
models with the data is good as SEE and Fcalc values
show. The Fowler-Guggenheim/Jovanovic-Freundlich
model was found to best fit C2 data, while Fowler's
model was found to be the most satisfactory for C1
(Jáuregui-Haza et al., 2001a). Figure 1 shows the
comparison between experimental adsorption data and
calculated values.
The increase of adsorption capacity whith icreasing porosity, could be explained by the possible adsorbateadsorbate interaction (Jaroniec and Madey, 1998). In this sense, both Fowler and Fowler-Guggenheim/Jovanovic- Freundlich equations, behave rather similarly (Tab. 3). The obtained values of χ show the importance of adsorbate-adsorbate interactions in the sorption process. It is well known, that positive values of χ imply that attraction forces between molecules predominate in the adsorbed layer (Fowler and Guggenheim, 1965). Regarding the surface heterogeneity, we can observe that the parameter ν in Jovanovic-Freundlich and Fowler- Guggenheim/Jovanovic-Freundlich models is close to unity for all supports. When the heterogeneity parameter is equal to unity, as for the systems studied, adsorption takes place on homogeneous surface.
3.2 Catalytic tests
From the best obtained model of adsorption isotherm, the needed initial concentration of the Rh-complex in aqueous solution was calculated for preparing SAP catalyst by the indirect method as described in the experimental section. Figure 2 shows the results of catalytic tests for both Rh-complexes when the indirect method of preparation of the SAP catalyst was used. The experimental average relative errors for the conversion and linearity were 5.24 % and 4.12 %, respectively. Regarding the conversion, C1 is more performance than C2. However, the linearity of the product, expressed as the percentage of lineal aldehyde out of the total amount of obtained isomers, was not dependent of the nature of Rh-complex. The influence of physical properties of the supports on the performance of oct-1-ene hydroformylation was discussed elsewhere (Jáuregui- Haza et al., 2001b). According to the size of pores SAPC could take place either at the surface of the pores, as described by Arhancet et al. (1990) and Horvath (1990), or at the external surface of the particle with a storage of TPPTS and catalytic complex in the filled pores. When the pores are full filled the SAPC can operate efficiently onto the external surface, stabilising the conversion in a relatively wide range of support hydration (Jáuregui- Haza et al., 2001b).
Fig. 2 .- Influence of the nature of Rh-complex on conversion and linearity for oct-1-ene hydroformylation after 3 hrs
reaction (white: [Rh(COD)Cl]2/TPPTS2; black: [Rh(µ-StBu)(CO)(TPPTS)]2; *significant difference for p < 0.05).
Figure 3 displays the influence of the preparation method of SAP catalyst on the conversion and linearity with C1. The indirect method resulted better than direct method only for the support S60, being the conversion statistically different for both methods. Considering that direct method is of easier implementation than the indirect one, the use of the first procedure is recommended with C1 for the hydroformylation of oct- 1-ene with the studied silica supports.
Fig. 3 .- Influence of the preparation method of SAP catalysts on conversion and linearity with [Rh(µ-StBu)(CO)(TPPTS)]2
after 3 hrs reaction (white: direct method, black: indirect method, * significant difference for p < 0.05)
In the case of C2, the hydroformylation did not take place after three hours when SAP catalyst was prepared by the direct method. A complementary experiment, carried out with DS22 support for 18 h, yielded a 4.6 % conversion with this complex, whereas with the C1, the conversion was 87.9 %. This behavior can be explained by the kinetics of formation of C2 from solid [Rh(COD)Cl]2 and TPPTS. Total dissolution of [Rh(COD)Cl]2 in the presence of TPPTS occurs after 30 min. When the direct method is used for the preparation of SAP catalyst, water adsorption onto silica might take place faster than complex formation, affecting the course of the reaction. Therefore, this method is not recommended for C2.
4. Conclusions
Adsorption studies of the [Rh(COD)Cl]2/TPPTS
complex from aqueous solutions on the four silica
supports at 25 °C showed a high capacity of adsorption
on all supports, related to the total pore volume of the
support. The isotherms were correlated by several
models, among which the Fowler-
Guggenheim/Jovanovic-Freundlich equation was found
to be the most satisfactory.
On the other hand, the catalytic activity of the SAP
catalyst prepared by the direct or the indirect method was
higher with [Rh(µ-StBu)(CO)(TPPTS)]2 complex than
with [Rh(COD)Cl]2/TPPTS.
Finally, the direct method for preparing SAP catalyst
with [Rh(COD)Cl]2/TPPTS is not recommended due to
the apparent slow kinetics of [Rh(COD)Cl]2 dissolution
in water whereas it gives good results (as good as the
indirect method) with [Rh(µ-StBu)(CO)(TPPTS)]2 complex .
Acknowledgements
The authors thank Prof. Philippe Kalck and Dr. Michel Dessoudeix for helping in the synthesis and characterization of [Rh(µ-StBu)(CO)(TPPTS)]2 ; Dr. Béatrice Biscans and Prof. Fernand Rodriguez for helping in characterization of silica ; DEGUSSA for the samples of silica and Rhône-Poulenc for the TPPTS. U.J.J.H. expresses his gratitude to ALFA-Programme of the European Community and INP-ENSIGC for the financial support of his travel and stay at the ENSIGC.
References
1. Ajnazarova, S. L.; Kafarov, V. V. Metodi Optimisatsi
Eksperimenta v Khimicheskoy Teknologui; Vishaia
Shkola: Moscow (1985).
2. Arhancet, J. P.; Davis, M. E.; Hanson, B. E. "Supported
Aqueous-Phase Rhodium Hydroformylation
Catalysts. 1. New Methods of Preparation". J.
Catal., 129, 94-99 (1991a).
3. Arhancet, J. P.; Davis, M. E.; Hanson, B. E. "Supported
Aqueous-Phase Rhodium Hydroformylation
Catalysts. 2. Hydroformylation of linear, terminal
and internal olefins". J. Catal., 129, 100-105
(1991b).
4. Arhancet, J. P.; Davis, M. E.; Merola, S. S.; Hanson, B.
E. "Hydroformylation by supported aqueous-phase
catalysis: a new class of the heterogeneous catalysts".
Nature, 399, 454-455 (1989).
5. Arhancet, J. P.; Davis, M. E.; Merola, S. S.; Hanson, B.
E. "Supported Aqueous-Phase Catalysts". J. Catal.
121, 327-339 (1990).
6. Chaudhari, R. V.; Bhanage, B. M.; Deshpande, R. M.;
Delmas, H. "Enhancement of interfacial catalysis in
a biphasic system using catalyst-binding ligands".
Nature, 373, 501-503 (1995).
7. Choplin, A.; Dos Santos, S.; Quignard, F.; Sigismondi,
S.; Sinou, D. "Palladium(0) allylic alkylation in a
two-phase system or with a supported aqueous
phase catalyst". Catal. Today, 42, 471-478 (1998).
8. Deshpande, R. M.; Purwanto; Delmas, H.; Chaudhari,
R. V. "Kinetics of hydroformylation of 1-octene
using [Rh(COD)Cl]2-TPPTS complex catalyst in a
two-phase system in the presence of a cosolvent". Ind. Eng. Chem.Res., 35, 3927-3933 (1996).
9. Dos Santos, S.; Tong, Y.; Quignard, F.; Choplin, A.;
Sinou, D.; Dutasta, J. P. "Supported Aqueous-Phase
Palladium Catalysts for the Reaction of Allylic
Substitution: Towards and Understanding of the
Catalytic System". Organometallics, 17, 78-89
(1998).
10. Fowler, R.; Guggenheim, E. A., Statistical
Thermodynamics, Cambridge Univ. Press:
Cambridge (1965).
11. Guo, I.; Hanson, B. E.; Tóth, I.; Davis, M. E. "Hydroformylation
of 1-hexene with Pt(m-
C6H4SO3Na)3)2Cl2 and its tin chloride analogue on
a controlled-pore glass". J. Mol. Catal., 70, 363-
368 (1991).
12. Herrmann, W. A; Kohlpainter, C. W. "Water-Soluble
Ligands, Metal Complexes, and Catalysts:
Synergism of Homogeneous and Heterogeneous
Catalysis". Angew. Chem. Int. Ed. Engl., 32, 1524-
1544 (1993).
13. Horvath, I. T. "Hydroformylation of Olefins with the
Water Soluble HRh(CO)[P(m-C6H4SO3Na)3]3 in
Supported Aqueous-Phase. Is it Really Aqueous ?" Catal. Lett., 6, 43-48 (1990).
14. Jaroniec, M.; Madey, R. Physical Adsorption on
Heterogeneous Solids; Elsevier: Amsterdam, 1998.
15. Jáuregui-Haza, U. J.; Wilhelm, A. M.; Delmas;
Canselier, J. P. "Adsorption of benzenesulfonic
acid, 3, 3', 3''-phosphinidynetris-, trisodium salt
and di (µ-tertiobutylthiolato) dicarbonyl, bis
(benzenesulfonic acid, 3, 3', 3''-phosphinidynetris-,
trisodium salt) dirhodium from aqueous
solutions on silica". J. Chem. Eng. Data, 46, 281-
285 (2001a).
16. Jáuregui-Haza, U. J.; Dessoudeix, M.; Kalck, Ph.;
Wilhelm, A. M.; Delmas, H. "Multifactorial
analysis in the study of hydroformylation of oct-1-
ene using supported aqueous phase catalysis".
Catalysis Today, 66, 297-302 (2001b).
17. Kalck, Ph.; Escaffre, P.; Serein-Spirau, F.; Thorez, A.;
Besson, B.; Coleuille, Y.; Perron, R. "Watersoluble
dinuclear rhodium complexes as catalytic
precursors for the hydroformylation of alkenes in a
two phases system". New J. Chem., 12, 687-690
(1988).
18. Kalck, Ph.; Miquel, L.; Dessoudeix, M. "Various
approaches to transfers improvement during biphasic
catalytic hydroformylation of heavy alkenes".Catalysis Today, 42, 431-440 (1998).
19. Kuntz,E. U. S. Patent 4,248,802 to Rhône-Poulenc
Chimie de Base (1981).
20. Langmuir, I. "Constitution and Fundamental Properties
of Solids and Liquids. I. Solids". J. Am. Chem.
Soc., 38, 2221-2295 (1916).
21. Monteil, F. Carbonylation de l'Oct-1-ène et du
Bromobenzene Catalysée par des Complexes
Hydrosolubles du Palladium ou du Rhodium; Thèse
de Doctorat de l'INP: Toulouse (1993).
22. Quiñones, I.; Guiochon, G. "Derivation and Application
of a Jovanovic-Freundlich Isotherm Model for
Single-Component Adsorption on Heterogeneous
Surfaces". J. Colloid Interface Sci., 183, 57-67
(1996).
23. Quiñones, I.; Guiochon, G. "Extension of a Jovanovic-
Freundlich Isotherm Model to Multicomponent
Component Adsorption on Heterogeneous
Surfaces". J. Chromatogr. A., 796, 15-40 (1998).
Received: April 5, 2001.
Accepted for publication: May 22, 2001.
Recommended by Subject Editor G. Meira.