Skip to main content
Log in

Kinetics of toluene hydrogenation—integrating a dynamic approach regarding catalyst activity

Reaction Kinetics, Mechanisms and Catalysis Aims and scope Submit manuscript

Abstract

Gas phase toluene hydrogenation is investigated over Pt/Al2O3 catalyst with temperature ranging from 75 to 125 °C and at atmospheric pressure. Strong activity variations are observed during long duration experiments. These variations are thoroughly investigated and a mechanistic model is proposed with dynamic adsorption activity of the reactants, used to explain the decrease in catalyst activity. This model considers competitive adsorption behaviour of the reactants and dissociative adsorption of hydrogen. Such a model can also be used to explain the strong metal-support interaction (SMSI) effect induced by the catalyst support. The decrease in activity after temperature maxima as previously observed can also be addressed by the approach presented. A comparison of activity variation at different residence times i.e. 20–50 kgcat·s·mol−1 and different hydrogen and toluene partial pressures is also simulated.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11

Abbreviations

i :

Stoichiometric constant

j :

Stoichiometric constant

\({\mathbb{C}}\) :

Sites on platinum (mol·kgcat −1)

C :

Concentration of species (mol·m−3)

k :

Rate parameters for hydrogenation reaction

P :

Partial pressures (Pa)

r :

Reaction rate

S :

Sites offered by support (mol·kgcat −1)

T :

Temperature (K)

t :

Time (s)

Tol :

Toluene

α:

Hydrogen reaction order

Γ:

Deactivation factor

*:

Species adsorbed on platinum

s :

Species adsorbed on support

d :

Order of deactivation

ad, H2:

Hydrogen adsorption

adTol:

Toluene adsorption

d, H2:

Hydrogen desorption

dTol:

Toluene desorption

H2 :

Hydrogen

Tol :

Toluene

t :

Total

References

  1. Wang J, Wan W (2009) Int J Hydrogen Energy 34:235–244

    Article  CAS  Google Scholar 

  2. Das D, Veziroglu TN (2001) Int J Chem Reactor Eng 26:13–28

    CAS  Google Scholar 

  3. Saeys M, Reyniers MF, Thybaut JW, Neurock M, Marin GB (2005) J Catal 236:129–138

    Article  CAS  Google Scholar 

  4. Keane MA, Patterson PM (1996) J Chem Soc Faraday Trans 92:1413–1421

    Article  CAS  Google Scholar 

  5. Orozco JM, Webb G (1983) Appl Catal 6:67–84

    Article  CAS  Google Scholar 

  6. Rousset JL, Stievano L, Cadete Santos Aires FJ, Geantet C, Renouprez AJ, Pellarin M (2001) J Catal 197:335–343

    Article  CAS  Google Scholar 

  7. Kaufmann TG, Kaldor A, Stuntz GF, Kerby MC, Ansell LL (2000) Catal Today 62:77–90

    Article  CAS  Google Scholar 

  8. Klvana D, Chaouki J, Kusohorsky D, Chavarie C (1988) Appl Catal 42:121–130

    Article  CAS  Google Scholar 

  9. Gaidai NA, Kazantsev RV, Nekrasov NV, Shulga YuM, Ivleva IN (2002) React Kinet Catal Lett 75:55–61

    Article  CAS  Google Scholar 

  10. Kazantsev RV, Gaidai NA, Nekrasov NV, Tenchev K, Petrov L, Lapidus AL (2003) Kinet Catal 44:529–535

    Article  CAS  Google Scholar 

  11. Lin SD, Vannice MA (1993) J Catal 143:563–572

    Article  CAS  Google Scholar 

  12. Lindfors LP, Salmi T, Smeds S (1993) Chem Eng Sci 48:3813–3828

    Article  CAS  Google Scholar 

  13. Thybaut JW, Saeys M, Marin GB (2002) Chem Eng J 90:117–129

    Article  CAS  Google Scholar 

  14. Lin SD, Vannice MA (1993) J Catal 143:554–562

    Article  CAS  Google Scholar 

  15. Rahaman MV, Vannice MA (1991) J Catal 127:267–275

    Article  CAS  Google Scholar 

  16. Rahaman MV, Vannice MA (1991) J Catal 127:251–266

    Article  CAS  Google Scholar 

  17. Wang J, Huang L, Li Q (1998) Appl Catal A Gen 175:191–199

    Article  CAS  Google Scholar 

  18. Levenspiel O (1999) Chemical reaction engineering, 3rd edn. Wiley, New York

    Google Scholar 

  19. Masloboishchikova OV, Khelkovskaya-Sergeeva EG, Bogdan VI, Vasina TV, Kustov LM (2006) Russ J Phys Chem 80:646–652

    Article  Google Scholar 

  20. Castaño P, Arandes JM, Pawelec B, Luis J, Fierro G, Gutierrez A, Bilbao J (2007) Ind Eng Chem Res 46:7417–7425

    Article  Google Scholar 

  21. Chupin J, Gnep N, Lacombe S, Guisnet M (2001) Appl Catal A Gen 206:43–56

    Article  CAS  Google Scholar 

  22. Bartholomew CH (2001) Appl Catal A Gen 212:17–60

    Article  CAS  Google Scholar 

  23. Hallenbeck PC, Ghosh D (2009) Trends Biotechnol 27:5

    Article  Google Scholar 

  24. Lindfors LP, Salmi T (1993) Ind Eng Chem Res 32:34–42

    Article  CAS  Google Scholar 

  25. Mamède AS, Giraudon JM, Löfberg A, Leclercq L, Leclercq G (2002) Appl Catal A Gen 227:73–82

    Article  Google Scholar 

  26. Gaidai NA, Gudkov BS, Aliev KhKh, Kiperman SL (1992) Kinet Katal 33:370–374

  27. Keane MA, Patterson PM (1999) Ind Eng Chem Res 38:1295–1305

    Article  CAS  Google Scholar 

  28. Bond GC (2005) Metal-catalysed reactions of hydrocarbons. Springer, New York

    Google Scholar 

  29. Briens C, Piskorz J, Berruti F (2008) Int J Chem Reactor Eng 6:1–49

    Google Scholar 

  30. Wang J, Wan W (2009) Int J Hydrogen Energy 34:3313–3323

    Article  CAS  Google Scholar 

  31. Ali AGA, Ali LI, Aboul-Fotouh SM, Aboul-Gheit AK (1998) Appl Catal A Gen 170:285–296

    Article  CAS  Google Scholar 

  32. Slioor RI, Kanervo JM, Keskitalo TJ, Krause AOI (2008) Appl Catal A Gen 344:183–190

    Article  CAS  Google Scholar 

  33. Slioor RI, Kanervo RI, Krause AOI (2008) Catal Lett 121:24–32

    Article  CAS  Google Scholar 

  34. El-Hajj A, Karaki S, Al-Husseini M, Kabalan KY (2004) Spreadsheets Educ 1:217–229

    Google Scholar 

Download references

Acknowledgments

We are thankful to Government of Pakistan (Higher Education Commission) for supporting this research work through a doctoral grant to Aqeel Ahmad TAIMOOR.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Isabelle Pitault.

Appendix

Appendix

Internal diffusion resistance

Simple mass balance across the pore length yields the following equation

$${ \frac{d^2C_A}{dx^2} }= {- \frac{r^\prime}{{\mathcal{D}}_e} }$$
(13)

where

$$ r' = {\frac{rW}{V}}$$
(14)

let \(t = 0\,\therefore\,\varphi = 1\) so, from empirical model:

$$ r = k{P_{\text {H}_2}}^{0.5}{P_{\text {Tol}}}^{0.1}{\mathbb{C}}_t $$
(15)

Also, from the ideal gas law

$$ C_A = {\frac{P_A}{RT}} $$
(16)

By combining Eqs. 1316:

$$ {\frac{d^2P_{\text {Tol}}}{dx^2} }= {-\frac{WRTk{P_{{\text {H}}_2}}^{0.5}{P_{\text {Tol}}}^{0.1}{\mathbb{C}}_t}{V{\mathcal{D}}e} }$$
(17)

By applying boundary conditions, i.e.

$$ x = L \Rightarrow \frac{dP_{\text {Tol}}}{dx} = 0 \quad {\hbox{and}} \quad x = 0 \Rightarrow P_{\text {Tol}} = {P^S}_{\text {Tol}} $$

and integrating Eq. 17:

$$ {\frac{{\mathcal{D}}eV({{P^S}_{\text {Tol}}}^{1.9} - {P_{{\text {H}}_2}}^{1.9})} {1.71WRTk{P_{{\text {H}}_2}}^{0.1}{\mathbb{C}}_t}} = {-\frac{L^2}{2}} $$
(18)

where:

L :

 = \({\frac{200 \times 10^{-6}}{6}} = 3.33 \times 10^{-5}\,\hbox{m} \)

W :

 = 0.002 kgcat

C t :

 = 4.33 × 10−2 mol

k :

 = \(7.8 \times 10^{-3}\exp\,{{\frac{-21.48}{T}}}\,\hbox{s}^{-1}\,\hbox{kPa}^{-0.6}\)

\(P_{{\text {H}}_2}\) :

 = 45585 Pa

T :

 = 348 K

R :

 = 8.314 J·K−1·mol−1

V :

 = 0.003 m3

\({\cal D}e\) :

 = \( 5\cdot 10^{-5} {\text{m}^{2}} \cdot{\text{s}^{-1}}\)

\(\triangle\hbox{P}\) is found negligible by calculating from Eq. 17.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Taimoor, A.A., Pitault, I. Kinetics of toluene hydrogenation—integrating a dynamic approach regarding catalyst activity. Reac Kinet Mech Cat 102, 263–282 (2011). https://doi.org/10.1007/s11144-010-0270-3

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11144-010-0270-3

Keywords

Navigation