Ind. Eng. Chem. Res. 2007, 46, 4415-4420
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Kinetics of Tricyclopentadiene Hydrogenation over Pd-B/γ-Al2O3 Amorphous Catalyst Ji-Jun Zou, Zhongqiang Xiong, Xiangwen Zhang,* Guozhu Liu, Li Wang, and Zhentao Mi Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin UniVersity, Tianjin, 300072, People’s Republic of China
The kinetics of tricyclopentadiene hydrogenation to tetrahydrotricyclopentadiene over Pd-B/γ-Al2O3 amorphous catalyst has been studied in a stirred semibatch reactor over a range of temperatures (353-413 K), hydrogen pressures (1.0-3.5 MPa), initial feed concentrations (0.2-0.4 mol/L), and catalyst concentrations (0.605.33 g/L). The reaction is found to be a consecutive reaction with 14,15-dihydrotricyclopentadiene as the intermediate product. Analysis verifies that the kinetic experiments are conducted in the absence of mass transfer resistance. An Eley-Rideal kinetic model is formulated with the assumption that single-site adsorbed organic species are saturated by hydrogen dissolved in the liquid phase and the surface reaction is ratedetermining. This model can accurately fit the experimental data in the ranges studied and correctly explain the observed tendencies. The kinetic parameters are obtained by minimizing the error between the model predications and the experimental results. The activation energies for the first and second step reactions are 11.11 kJ/mol and 34.71 kJ/mol, respectively. The kinetic model provides a useful tool for the reactor design and performance estimation of amorphous Pd catalysts. Introduction Tricyclopentadiene (TCPD) has two unsaturated bonds, with one in the norbornene ring and the other in the cyclopentene ring. The catalytic hydrogenation of TCPD is of both industrial and scientific interest. First, the hydrogenation product, namely, tetrahydrotricyclopentadiene (THTCPD), is regarded as a potential high-energy density fuel that can provide more propulsive energy for aircrafts than traditional liquid fuels with equal volume.1-4 Because it can significantly promote the performance of aircrafts, the synthesis of high-energy density fuel has attracted increasing interest. Second, unsaturated multi-ring compounds are widely used in many fields like pharmaceutical chemistry. Results from TCPD hydrogenation can provide useful information for the hydrogenation of these unsaturated multiring compounds. Compared with single-ring or non-ring compounds, the hydrogenation of multi-ring compounds is more difficult becaues of the steric hindrance of multi-ring structures. It has been shown that nickel catalysts have very low activity for TCPD hydrogenation. Pt and Pd catalysts can catalyze the reaction, but the activities still need to be improved.1-4 Therefore, it is necessary to explore more active hydrogenation catalysts. Amorphous catalysts have attracted much attention because of their superior activity in hydrogenation reactions. The short-range ordering structures of amorphous catalysts can provide highly active and selective sites. The mostly studied Ni amorphous catalysts have exhibited excellent activity for the hydrogenation of many liquid organics. However, the reports on amorphous Pd catalysts are very limited, and more work is required to demonstrate their potential. An amorphous Pd-B/SiO2 catalyst for nitrobenzene hydrogenation was first reported in 2000.5 Then, its microRaman spectroscopy characterization was reported.6 Later, a PdB/γ-Al2O3 amorphous catalyst was reported for anthraquinone hydrogenation.7 It has also been reported that supported Pd reduced with glow discharge plasma shows some amorphous * To whom correspondence should be addressed. Fax: 86-2227402604. E-mail address:
[email protected].
characteristics.8 To the authors’ knowledge, the hydrogenation kinetics over amorphous Pd catalysts has not been reported. Previously, we have prepared a Pd-B/γ-Al2O3 amorphous alloy catalyst that exhibited excellent thermal stability and activity for TCPD hydrogenation in the liquid phase.9,10 This result suggests that amorphous Pd is the ideal catalyst for the hydrogenation of multi-ring compounds. In this work, the kinetics of TCPD hydrogenation was studied over a range of operating conditions in a stirred semibatch reactor in the absence of mass transfer resistance. An Eley-Rideal kinetic model was formulated on the basis of observed tendencies. It is found that the model fits the experimental results very well. The result may provide a useful tool for process design and performance estimation of amorphous Pd catalysts. Experimental Section Catalyst and Materials. Pd-B/γ-Al2O3 amorphous alloy catalyst was prepared by the following procedures. γ-Al2O3 powders (Tianjin Chemical Engineering Design Institute, 100120 mesh) were calcined at 550 °C for 2 h and then impregnated with diluted PdCl2 (Xian Kaili Chemical Engineering Company) solution. The initial amount of Pd was defined as 0.4 wt %. After being dried at 120 °C for 2 h, the catalysts were precalcined at 300 °C for another 2 h. Then they were reduced by adding a threefold amount (molar basis) of KBH4 solution (0.2 M) dropwise under gentle stirring in an ice-water bath. The stirring was stopped until no obvious bubbles were observed. The resulting black solid powders were washed thoroughly with oxygen-free distilled water until no Cl- ions were detected in the solution. Finally they were washed with pure alcohol. The resulting catalysts were kept in alcohol for further use. The amount of Pd supported on the catalysts was 0.36 wt % as determined by inductively coupled plasma spectrometry (ICPOES, Vista-MPX). The specific surface area was 190.2 m2/g as measured using N2 physical adsorption (Quantachrome Nova2000) with a multi-plot method. TCPD used for the hydrogenation reaction was prepared by the oligomerization of dicyclopentadiene and then distillation
10.1021/ie0700359 CCC: $37.00 © 2007 American Chemical Society Published on Web 05/23/2007
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Scheme 1. Hydrogenation of TCPD to THTCPD
to diminish the un-reacted feedstock according to previous report.4 The purity of TCPD was >96% as determined by GC. Analytic reagent-grade cyclohexane (Tianjin Dawenxigui Reagent Company) was used as the solvent without any treatment. Experimental Apparatus. Hydrogenation reactions were conducted in a 250 mL mechanically agitated reactor system. The reactor was a commercial unite (Xintai Chemical Equipment Co., Weihai, China) made of 316 stainless steel equipped with an external band heater. The error of reaction temperature was controlled within (1 K through regulating the input power using a PID temperature controller. The agitation speed was controlled by a magnetic stirrer and measured by a digital tachometer. The gas inlet, gas release valve, cooling water feed line, sample pipe, and valve were made of 316 stainless steel and located on the cover of the reaction vessel. Experimental Procedure. To conduct the hydrogenation experiment, catalyst powders were added into the autoclave, sealed, and purged with nitrogen at 323 K for 30 min to displace air and alcohol vapors. Then a 150 mL mixture of TCPD and cyclohexane was introduced into the reactor via a syringe pump. After that the reactor was flushed with hydrogen for 30 min to exclude nitrogen and heated to a defined temperature under slow agitation (100 rpm). Then the agitation speed was quickly increased to the defined value with hydrogen introduced from the bottom of liquid. The reaction was regarded to begin when the hydrogen pressure reached the defined value. During the experiment, the total reactor pressure was maintained constant by continuously supplying the consumed hydrogen. The reactant sample was withdrawn using a microsyringe through a dip tube containing a solid filter with a manually operated valve at regular intervals. When the reaction was finished, the system was purged with nitrogen and cooled to ambient temperature. Components of the samples were determined with HP-5971 GC-MS equipped with an HP-5 capillary column (0.53 mm × 30 m). Their concentrations were analyzed using a GC (HP 4890, FID) equipped with the same HP-5 capillary column. Results and Discussion Hydrogenated Products and Reaction Pathway. Besides the completely hydrogenated product (THTCPD), hydrogenated intermediates including 14,15-dihydrotricyclopentadiene (14,15-DHTCPD) and 1,2-dihydrotricyclopentadiene (1,2-DHTCPD) were also detected by MS. However, the concentration of 1,2DHTCPD is less than 0.15 wt % for all experiments, which approaches the detection limit of GC analysis. This suggests that the reaction pathway through 1,2-DHTCPD rarely happens. Thus it was neglected in the kinetic analysis, and in the following sections DHTCPD refers to 14,15-DHTCPD. The hydrogenation pathway of TCPD can be simply described as shown in Scheme 1. During the hydrogenation reaction, the TCPD concentration decreases quickly. The DHTCPD concentration rapidly reaches the highest value and thereafter slowly decreases, whereas the THTCPD concentration slowly rises up with reaction time. This suggests that the first step reaction easily takes place but the second one occurs with difficulty, which will be demonstrated by the following kinetic analysis.
Figure 1. Effect of stirring speed on the yield of THTCPD (mc ) 5.3 g/L; T ) 413 K; pH2 ) 3.5 MPa; [TCPD]0 ) 0.3 mol/L).
Verification of Kinetic Conditions. In gas-liquid-solid catalytic hydrogenation, the reaction rate may be influenced by external and intraparticle mass-transfer resistance. For kinetic study, these mass-transfer effects must be eliminated by choosing suitable process parameters. The reaction rate for TCPD hydrogenation to DHTCPD is very high, which is generally completed in less than 10 min. Therefore, the relationship between the THTCPD concentration and stirring speed was studied as shown in Figure 1. With the same reaction time, the THTCPD concentration rises up with the increase of stirring speed, and it does not change any more when the stirring speed is beyond 900 rpm. This indicates that the external mass transfer resistance has been eliminated. Therefore, all the experiments were conducted with a stirring speed of 1000 rpm. It is difficult to verify the effect of intraparticle mass transfer by changing the diameter of catalyst particles. So a classical Weisz-Prater criterion is used to determine whether the diameter of the present catalyst could cause significant intraparticle mass transfer effect.11
(ηφ2)TCPD < (ηφ2)H2 )
robsFcdp2 < 1 × 10-3 4DeCH2
where the upper limitation of particle size is 0.07 mm; De is with order of magnitude of 10-6 m2/s. For all the experimental conditions the ηφ2 values are less than 10-3, indicating that the intraparticle mass transfer effect can be neglected. Gas-liquid and solid-liquid interfacial mass-transfer coefficients for H2 and TCPD under a stirring speed of 1000 rpm were also estimated using the correlations developed by Jadhav and Pangarkar12 and Yawalkar et al.,13 respectively. The maximum mass-transfer rates, estimated as the product of the mass-transfer coefficient and bulk liquid-phase concentration, are at least 10 times higher than the reaction rates. This calculation verifies that the mass-transport resistances across phase boundaries are negligible under the present experimental conditions. Analysis of Initial Rate. Experiments over a range of catalyst concentration and hydrogenation pressures were carried out to analyze the initial hydrogenation rate, with the attempt to get some insight into the reaction kinetics. Because the hydrogenation of TCPD to DHTCPD is very fast, the reactions for initial rate analysis were conducted at relatively low temperature (353 K). To obtain the initial rate of first step (r1,0), the concentration-time data of TCPD were fitted by the first-order decay model from which the initial rates were calculated by differentiation at time t ) 0. The concentration-time data of
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Figure 3. Experimental and predicted concentration-time curves at different reaction temperatures (mc ) 5.3 g/L; pH2 ) 2.5 MPa; [TCPD]0 ) 0.3 mol/L; solid line, model predicted).
Figure 2. Effect of hydrogen pressure on initial reaction rate (mc ) 1.6 g/L; T ) 353 K; [TCPD]0 ) 0.3 mol/L).
THTCPD were fitted with the sigmoidal (Boltzmann) model to obtain the initial rate of second step (r2,0). It is found that both initial rates (r1,0 and r2,0) exhibit a first-order dependence on the catalyst concentration. This not only confirms that the reaction is the free of mass transfer resistance but also suggests that the reaction involves a single adsorbed species.14 Figure 2 shows the linear relationships between the initial reaction rates and the pressure of hydrogen. It is clear that both steps are first-order with respect to the hydrogen pressure. Because the concentration of hydrogen dissolved in the liquid phase is linearly dependent on the pressure, the result give hints that it is hydrogen dissolved in the liquid phase that takes part in the hydrogenation reaction. Kinetic Experimental Data. Detailed hydrogenation experiments were carried out with different reaction temperatures (383-413 K), initial TCPD concentrations (0.2-0.4 mol/L), and hydrogen pressures (2.0-3.5 MPa). The effects of the three factors on the hydrogenation reaction were assessed to obtain further information on the reaction kinetics. Figure 3 shows the effect of temperature on the reaction. In the range studied, the TCPD concentration decays quickly, and a conversion of 98% is obtained within 10 min, again indicating that the first hydrogenation step takes place easily. Increasing the temperature can improve the reaction rate, but the effect is limited. The second step takes a much longer time, suggesting that this reaction occurs with difficulty because of the steric hindrance of the cyclopentene ring. The DHTCPD concentration decreases more quickly, and the THTCPD concentration correspondingly rises more quickly at higher temperature. The maximum DHTCPD concentration decreases with the increase of reaction temperature, indicating that high temperature favors the second-step reaction more significantly. Figure 4 shows the effect of hydrogen pressure on the hydrogenation reaction. Increasing the pressure can accelerate the reaction, and the effect on the second step is more obvious.
Figure 4. Experimental and predicted concentration-time curves at different hydrogen pressures (mc ) 5.3 g/L; T ) 413 K; [TCPD]0 ) 0.3 mol/L; solid line, model predicted).
Figure 5. Experimental and predicted concentration-time curves at different initial TCPD concentrations (mc ) 5.3 g/L; T ) 403 K; pH2 ) 2.5 MPa; solid line, model predicted).
Specifically, the DHTCPD concentration decreases and the THTCPD concentration increases more quickly when the hydrogen pressure increases, respectively. The maximum DHTCPD concentration is not influenced by the hydrogen pressure. This means that the hydrogen pressure has equal effect on both steps, in agreement with the result of initial rate studies. Figure 5 shows the effect of initial TCPD concentration on the hydrogenation reaction. It is clear that the initial TCPD concentration has no significant effect on the rate for TCPD hydrogenation to DHTCPD; thus, the first step reaction is zeroorder with respect to the TCPD concentration. The maximum DHTCPD concentration increases with the initial TCPD con-
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TCPD* + H2 T DHTCPD*
(R1)
DHTCPD* + H2 T THTCPD*
(R2)
For a sparingly soluble gas such as hydrogen in organic liquid, Henry’s law can be used to describe the liquid-phase hydrogen concentration as [H2] ) HH2pH2. Then, assuming the surface reaction steps as rate-limiting, the reaction rates are given by
Figure 6. Plots of ln r2 vs ln[DHTCPD] (mc ) 5.3 g/L; T ) 403 K; pH2 ) 2.5 MPa; [TCPD]0 ) 0.3 mol/L).
centration, but the time needed to reach the maximum value is also increased. Kinetic Model. The initial rate studies and kinetic experiments show three important tendencies. First, the reaction involves single adsorbed species. Second, the reaction is firstorder with respect to the hydrogen pressure. Third, the first step is zero-order with respect to the initial TCPD concentration. To analyze the dependence of the second step on the DHTCPD concentration, the concentration-time data of THTCPD in Figure 5 were fitted with the sigmoidal model, and the reaction rate was obtained by the differentiation method. Figure 6 shows the relationship between ln r2 and ln[DHTCPD]. The reaction shows a tendency from first- to zero-order with respect to [DHTCPD]. This confirms that it is DHTCPD absorbed on the catalysts surface, not free DHTCPD in the liquid phase, that participates in the reaction. It also indicates that the reaction kinetics cannot be explained by a simple power-law empirical model.15 In fact, the average relative error of this model is higher than 43.0%. The kinetics of TCPD hydrogenation has not been reported; there is no literature about hydrogenation kinetics over amorphous Pd catalysts, either. To develop a suitable kinetics model, various Langmuir-Hinshelwood models with single- or dualsite adsorption of organic species and dissociation adsorption of hydrogen were used to fit the experimental data. However, neither model gives a satisfied result. Therefore, an Eley-Rideal type model is chosen to describe the reaction mechanism with the assumption that the surface reaction is rate-controlling. The hydrogenation of dicyclopentadiene over Pd/Al2O3 catalysts has been reported.16,17 The Eley-Rideal type model was used, and the single-site adsorption of organic species fitted the experimental data better than the double-site adsorption model. Because TCPD and dicyclopentadiene are both oligomers (triand dimers, respectively) of cyclopentadiene, there would be similarities in the adsorption mechanism of them. Therefore, the organic species in this work were also assumed to be adsorbed on a single site. The kinetic model can be formulated with the following steps.
r1 ) k1[TCPD*]pH2
(1)
r2 ) k2[DHTCPD*]pH2
(2)
The surface species concentrations can be obtained from equilibrium of adsorption-desorption
[TCPD*] ) KTCPD[TCPD][*]
(3)
[DHTCPD*] ) KDHTCPD[DHTCPD][*]
(4)
[THTCPD*] ) KTHTCPD[THTCPD][*]
(5)
Summarization of the catalyst surface adsorption sites yields
*t ) [*] + [TCPD*] + [DHTCPD*] + [THTCPD*]
(6)
Then we obtain
[*] )
*t 1 + KTCPD[TCPD] + KDHTCPD[DHTCPD] + KTHTCPD[THTCPD]
(7)
Therefore, the following kinetic expressions are obtained by substituting eqs 3-7 into eqs 1-2
θ)
r1 ) k1KTCPDθ[TCPD]pH2
(8)
r2 ) k2KDHTCPDθ[DHTCPD]pH2
(9)
1 1 + KTCPD[TCPD] + KDHTCPD[DHTCPD] + KTHTCPD[THTCPD]
(10)
where
ki ) ki,0 exp(-Ei/RT)
(11)
KA ) KA,0 exp(∆HA/RT)
(12)
The kinetics expressions can be incorporated into the differential model describing the variations of liquid-phase species in the reactor
d[TCPD] ) -r1 mc dt
(13)
TCPD + * T TCPD*
(A1)
d[DHTCPD] ) r1 - r 2 mc dt
(14)
DHTCPD + * T DHTCPD*
(A2)
d[THTCPD] ) r2 mc dt
(15)
THTCPD + * T THTCPD*
(A3)
accompanied with the initial conditions
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[TCPD] ) [TCPD]0, [DHTCPD] ) [THTCPD] ) 0 at t ) 0 (16) Kinetic Parameters. The experimental data obtained under a temperature of 353-413 K, hydrogen pressure of 1.0-3.5 MPa, catalyst concentration of 0.60-5.33 g/L, and initial TCPD concentration of 0.2-0.4 mol/L were used to estimate the kinetic parameters of the formulated model. The calculation algorithm is as follows. First, the best-fit values of the kinetic parameters were obtained at different temperatures by the no-constraint SIMPLEX algorithm. Then the average values of the above kinetic parameters were used as the initial values to fit the concentration-time data of all experimental sets by numerically integrating the differential mass balance equations (eqs 1316) with the fourth-order Runge-Kutta method. The computed values were compared with the experimental data to calculate the error function L
Q)
∑l ∑ ∑ m n L
Q)
M N
(
)
m,n Cm,n exp - Ccal
Cm,n exp
2
Table 1. Kinetics Parameters Determined from Experimental Data
(Cexp * 0)
(17.1)
M N
∑l ∑ ∑ m n
Figure 7. Comparison between the calculated and the experimental concentrations for the overall experimental points.
m,n 2 (Cm,n (Cexp ) 0) exp - Ccal )
(17.2)
parameter
k1
k2
KTCPD
KDHTCPD
KTHTCPD
preexponential coefficient (ki,0, Ki,0)a reaction activation energy or adsorption heat (kJ/mol)
40.48
26.03
33.47
21.85
37.90
11.11
34.72
3.11
5.89
3.85
a
where L is the number of experiments involving M species, with concentrations measured at N reaction times. The error was minimized using the Levernberg-Marquardt algorithm. Finally, the kinetic parameters were obtained with the minimum error. The curves in Figures 3-5 show the model predicated concentration-time curves of some data. It can be seen that the model fits these experimental data very well. Furthermore, a comparison of all the experimental points and their corresponding predicated values is plotted in Figure 7. It is clear that the predications compare well with the experimental data, with the average absolute error less than 0.01 mol/L and the average relative error less than 13.0%. This indicates that the formulated kinetic model can accurately fit the result of the TCPD hydrogenation reaction. The obtained kinetic parameters are summarized in Table 1. The activation energies for the first and second step are 11.11 kJ/mol and 34.71 kJ/mol, respectively. The kinetic model and parameters determined in this work are very useful to understand the reaction behavior. For example, the higher activation energy of the second step confirms that the DHTCPD hydrogenation to THTCPD occurs relatively difficultly. In addition, the reaction temperature has a more significant effect on this step. Specifically, increasing the temperature can improve the selectivity toward THTCPD rather than toward DHTCPD, which explains why the maximum DHTCPD concentration decreases with the temperature. This model also confirms that the maximum DHTCPD concentration is not influenced by the hydrogen pressure because the ratio of r1/r2 is independent of pH2. The above analysis demonstrates that the kinetic model predicts the experimental tendencies correctly. Conclusions The reaction kinetics of TCPD hydrogenation over Pd-B/γAl2O3 amorphous catalyst has been studied with the mass transfer resistance being eliminated. The reaction is a consecutive reaction with 14,15-dihydrotricyclopentadiene as the major intermediate product. An Eley-Rideal kinetic model involving single-site adsorbed organic species and dissolved hydrogen is
For units, please see Nomenclature.
formulated. The model can accurately predict the reaction behavior for the range studied. The activation energy for the first and second step reaction is 11.11 kJ/mol and 34.71 kJ/ mol, respectively. The developed kinetic model may provide a useful tool for process design and performance estimation of amorphous Pd catalysts. Acknowledgment The support of the Programme of Introducing Talents of Discipline to Universities (No. B06006) and fundamental research project of COSTIND (No. A1420060192) is greatly appreciated. Nomenclature [A] ) molar concentration of reactant or species A, mol/L De ) effective diffusivity, m2/s dp ) diameter of catalyst particle, m Ei ) activation energy of ith step reaction, kJ/mol ∆HA ) adsorption heat for organic species A, kJ/mol HH2 ) Herrry’s law constant for gas H2, mol/(L‚MPa‚min) KA ) adsorption rate constant for organic species A, L/mol KA,0 ) preexponential coefficient of adsorption rate constant for organic species A, L/mol ki ) rate constant of ith step reaction, mol/(gcat‚MPa‚min) mc ) catalyst concentration, g/L pH2 ) hydrogen pressure, MPa ri ) rate of the ith reaction, mol/(gcat‚min) ri,0 ) initial rate of the ith reaction, mol/(gcat‚min) robs ) observed reaction rate, mol/(gcat‚min) R ) ideal gas constant, kJ/(mol‚K) T ) temperature, K t ) time, min Greek Letters and Symbols θ ) surface concentration of vacancy site ηφ2 ) observable modulus for hydrogen and TCPD Fc ) density of the catalyst, kg/m3
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* ) number of vacancy catalyst surface sites *t ) total number of catalyst surface sites Literature Cited (1) Chung, H. S.; Chen, C. S.; Kremer, R. A.; Boulton, J. R. Recent developments in high-energy density liquid hydrocarbons fuels. Energy Fuels 1999, 13 (3), 641-649. (2) Boulton, J. R.; Kremer, R. A. Oligomers of cyclopentadiene and process for making them. U.S. Patent, 5,446,222, 1995. (3) Burdette, G. W.; Schneider, A. I. Exo-tetrahydrotricyclopentadiene, a high density liquid fuel. U.S. Patent, 4,401,837, 1983. (4) Xiong, Z.; Mi, Z.; Zhang, X. Study on the oligomerization of cyclopentadiene and dicyclopentadiene to tricyclopentadiene through the Diels-Alder reaction. React. Kinet. Catal. Lett. 2005, 85, 89-97. (5) Yu, X.; Wang, M.; Li, H. Study on the nitrobenzene hydrogenation over a Pd-B/SiO2 amorphous catalyst. Appl. Catal., A 2000, 202, 17-22. (6) Wang, G.; Yu, X.; Li, H.; Zhang, Z. Micro-Raman spectroscopy of Pd-B/SiO2 amorphous alloy catalyst. J. Raman Spectrosc. 2000, 31, 10511055. (7) Ding, T.; Qin, Y.; Ma, Z. Study on the Pd-B/γ-Al2O3 amorphous alloy catalyst. Chin. Chem. Lett. 2003, 14 (3), 319-322. (8) Zou, J.-J.; Zhang, Y.-P.; Liu, C.-J. Reduction of supported noblemetal ions using glow discharge plasma. Langmuir 2006, 22 (26), 1138811394. (9) Xiong, Z.; Mi, Z.; Zhang, X. A Pd-B/γ-Al2O3 amorphous alloy catalyst for hydrogenation of tricyclopentadiene to tetrahydrotricyclopentadiene. Catal. Commun. 2007, 8, 571-575.
(10) Zou, J.-J.; Xiong, Z.; Wang, L.; Zhang, X.; Mi, Z. Preparation of Pd-B/γ-Al2O3 amorphous catalyst for the hydrogenation of tricyclopentadiene. J. Mol. Catal. A: Chem. 2007, 271, 209-215. (11) Jere, F. T.; Jackson, J. E.; Miller, D. J. Kinetics of the aqueousphase hydrogenation of L-Alanine to L-Akaninol. Ind. Eng. Chem. Res. 2004, 43 (13), 3297-3303. (12) Jadhav, S. V.; Pangarkar, V. G. Particle-liquid mass transfer in mechanically agitated contactors. Ind. Eng. Chem. Res. 1991, 30 (11), 24982503. (13) Yawalkar, A. A.; Heesink, A. B. M.; Versteeg, G. F.; Pangarkar, V. G. Gas-liquid mss transfer coefficient in stirred tank reactors. Can. J. Chem. Eng. 2002, 80 (5), 840-848. (14) Wilhite, B. A.; McCready, M. J.; Varma, A. Kinetics of phenylacetylene hydrogenation over Pt/γ-Al2O3 catalyst. Ind. Eng. Chem. Res. 2002, 41 (14), 3345-3350. (15) Vaidya, P. D.; Mahajani, V. V. Kinetics of liquid-phase hydrogenation of furaldehyde to furfuryl alcohol over a Pt/C catalyst. Ind. Eng. Chem. Res. 2003, 42 (17), 3881-3885. (16) Liu, G.; Mi, Z.; Wang, L.; Zhang, X. Kinetics of dicyclopentadiene hydrogenation over Pd/Al2O3 catalyst. Ind. Eng. Chem. Res. 2005, 44 (11), 3846-3851. (17) Chou, S. H.; Chen, S. C.; Tan, C. S.; Wang, W. H. Hydrogenation of dicyclopentadiene in trickle-bed reactor. J. Chin. Inst. Chem. Eng. 1997, 28 (3), 175-182.
ReceiVed for reView January 8, 2007 ReVised manuscript receiVed April 13, 2007 Accepted April 19, 2007 IE0700359
