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Towards a molecular understanding of shape selectivity


Shape selectivity is a simple concept: the transformation of reactants into products depends on how the processed molecules fit the active site of the catalyst. Nature makes abundant use of this concept, in that enzymes usually process only very few molecules, which fit their active sites. Industry has also exploited shape selectivity in zeolite catalysis for almost 50 years, yet our mechanistic understanding remains rather limited. Here we review shape selectivity in zeolite catalysis, and argue that a simple thermodynamic analysis of the molecules adsorbed inside the zeolite pores can explain which products form and guide the identification of zeolite structures that are particularly suitable for desired catalytic applications.

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Figure 1: Hydroisomerization and hydrocracking of n -decane.
Figure 2: Schematic representation of the free-energy model.
Figure 3: Zeolite screening by computer.


  1. 1

    Corma, A. Inorganic solid acids and their use in acid-catalyzed hydrocarbon reactions. Chem. Rev. 95, 559–614 (1995)

    CAS  Article  Google Scholar 

  2. 2

    Corma, A. From microporous to mesoporous molecular sieve materials and their use in catalysis. Chem. Rev. 97, 2373–2419 (1997)

    CAS  Article  Google Scholar 

  3. 3

    Auerbach, S. M., Carrado, K. A. & Dutta, P. K. (eds) Handbook of Zeolite Science and Technology (Marcel Dekker, New York, 2004)

    Google Scholar 

  4. 4

    van Santen, R. A. & Neurock, M. Molecular Heterogeneous Catalysis: A Conceptual and Computational Approach (Wiley-VCH, Weinheim, 2006)

    Book  Google Scholar 

  5. 5

    Froment, G. F. Kinetics of the hydroisomerization and hydrocracking of paraffins on a platinum containing bifunctional Y-zeolite. Catal. Today 1, 455–473 (1987)

    CAS  Article  Google Scholar 

  6. 6

    Weisz, P. B. & Frilette, V. J. Intracrystalline and molecular-shape-selective catalysis by zeolite salts. J. Phys. Chem. 64, 382 (1960)

    CAS  Article  Google Scholar 

  7. 7

    Degnan, T. F. The implications of the fundamentals of shape selectivity for the development of catalysts for the petroleum and petrochemical industries. J. Catal. 216, 32–46 (2003)

    CAS  Article  Google Scholar 

  8. 8

    Weitkamp, J., Ernst, S. & Puppe, L. in Catalysis and Zeolites (eds Weitkamp, J. & Puppe, L.) 327–376 (Springer, Berlin, 2001)

    Google Scholar 

  9. 9

    Yashonath, S., Thomas, J. M., Nowak, A. K. & Cheetham, A. K. The siting, energetics and mobility of saturated hydrocarbons inside zeolitic cages: methane in zeolite Y. Nature 331, 601–604 (1988)

    CAS  Article  ADS  Google Scholar 

  10. 10

    June, R. L., Bell, A. T. & Theodorou, D. N. Molecular dynamics of butane and hexane in silicalite. J. Phys. Chem. 96, 1051–1060 (1992)

    CAS  Article  Google Scholar 

  11. 11

    Smit, B. & Siepmann, J. I. Simulating the adsorption of alkanes in zeolites. Science 264, 1118–1120 (1994)

    CAS  Article  ADS  Google Scholar 

  12. 12

    Smit, B. & Maesen, T. L. M. Commensurate ‘freezing’ of alkanes in the channels of a zeolite. Nature 374, 42–44 (1995)

    CAS  Article  ADS  Google Scholar 

  13. 13

    Beerdsen, E., Smit, B. & Dubbeldam, D. Molecular simulation of loading dependent slow diffusion in confined systems. Phys. Rev. Lett. 93, 248301 (2004)

    CAS  Article  ADS  Google Scholar 

  14. 14

    Dubbeldam, D., Calero, S., Maesen, T. L. M. & Smit, B. Incommensurate diffusion in confined systems. Phys. Rev. Lett. 90, 245901 (2003)

    CAS  Article  ADS  Google Scholar 

  15. 15

    Jacobs, P. A., Martens, J. A., Weitkamp, J. & Beyer, H. K. Shape-selectivity changes in high-silica zeolites. Faraday Discuss. Chem. Soc. 72, 353–369 (1981)

    Article  Google Scholar 

  16. 16

    Schenk, M., Smit, B., Vlugt, T. J. H. & Maesen, T. L. M. Shape selectivity in alkane hydroconversion. Angew. Chem. Int. Edn Engl. 40, 736–738 (2001)

    CAS  Article  Google Scholar 

  17. 17

    Schenk, M. et al. Inverse shape selectivity revised. Angew. Chem. Int. Edn. Engl. 41, 2500–2502 (2002)

    Article  Google Scholar 

  18. 18

    Santilli, D. S., Harris, T. V. & Zones, S. I. Inverse shape selectivity in molecular sevies: Observations, modelling, and predictions. Microporous Mater. 1, 329–341 (1993)

    CAS  Article  Google Scholar 

  19. 19

    Schenk, M. et al. Shape selectivity through entropy. J. Catal. 214, 88–99 (2003)

    CAS  Article  Google Scholar 

  20. 20

    Calero, S. et al. The selectivity of n-hexane hydroconversion on MOR-, MAZ- and FAU-type zeolites. J. Catal. 228, 121–129 (2004)

    CAS  Article  Google Scholar 

  21. 21

    Maesen, T. L. M., Calero, S., Schenk, M. & Smit, B. Understanding cage effects in the n-alkane conversion on zeolites. J. Catal. 237, 278–290 (2006)

    CAS  Article  Google Scholar 

  22. 22

    Maesen, Th. L. M. et al. The shape selectivity of paraffin hydroconversion on TON-, MTT- and AEL-type Sieves. J. Catal. 188, 403–412 (1999)

    CAS  Article  Google Scholar 

  23. 23

    Dubbeldam, D., Calero, S., Maesen, T. L. M. & Smit, B. Understanding the window effect in zeolite catalysis. Angew. Chem. Int. Edn Engl. 42, 3624–3626 (2003)

    CAS  Article  Google Scholar 

  24. 24

    Rosenbaum, J. M. & Howell, R. L. Dewaxing process. European Patent Application No. 1037956. (1999)

  25. 25

    Chen, N. Y., Schlenker, J. L., Garwood, W. E. & Kokotailo, G. T. TMA-offretite. Relationship between structural and catalytic properties. J. Catal. 86, 24–31 (1984)

    CAS  Article  Google Scholar 

  26. 26

    Duhoux, E. et al. Process to prepare a lubricating base oil and its use. European Patent Application No. 1791931. (2006)

  27. 27

    Murphy, W. J. et al. Improved molecular sieve containing hydrodewaxing catalysts. US Patent Application No. 2006/0073962. (2006)

  28. 28

    Benazzi, E., Guillon, E. & Martens, Y. Catalyst and its use for improving the pour point of hydrocarbon feedstocks. European Patent Application No. 2004/0290680. (2004)

  29. 29

    Maesen, T. L. M., Beerdsen, E. & Smit, B. Dewaxing process using zeolites MTT and GON. US Patent Application No. 2007/0029229. (2007)

  30. 30

    Rozanska, X. et al. A periodic DFT study of isobutene chemisorption in proton-exchanged zeolites: dependence of reactivity on the zeolite framework structure. J. Phys. Chem. B 107, 1309–1315 (2003)

    CAS  Article  Google Scholar 

  31. 31

    Clark, L. A., Sierka, M. & Sauer, J. Computational elucidation of the transition state shape selectivity phenomenon. J. Am. Chem. Soc. 126, 936–947 (2004)

    CAS  Article  Google Scholar 

  32. 32

    Calero, S. et al. A coarse-graining approach for the proton complex in protonated aluminosilicates. J. Phys. Chem. B 110, 5838–5841 (2006)

    CAS  Article  Google Scholar 

  33. 33

    Garcia-Perez, E. et al. A computational method to characterize framework aluminum in aluminosilicates. Angew. Chem. Int. Edn Engl. 46, 276–278 (2007)

    CAS  Article  Google Scholar 

  34. 34

    Earl, D. J. & Deem, M. W. Toward a database of hypothetical zeolite structures. Ind. Eng. Chem. Res. 45, 5449–5454 (2006)

    CAS  Article  Google Scholar 

  35. 35

    Thomas, J. M. & Klinowski, J. Systematic enumeration of microporous solids: towards designer catalysts. Angew. Chem. Int. Edn Engl. 46, 7160–7163 (2007)

    CAS  Article  Google Scholar 

  36. 36

    Auerbach, S. M., Ford, M. H. & Monson, P. A. New insights into zeolite formation from molecular modeling. Curr. Opin. Colloid Interf. Sci. 10, 220–225 (2005)

    CAS  Article  Google Scholar 

  37. 37

    Baerlocher, Ch. & McCusker, L. B. Database of Zeolite Structures〉 (Structure Commission of the International Zeolite Association, IZA-SC)

  38. 38

    Vlugt, T. J. H. & Schenk, M. Influence of framework flexibility on the adsorption properties of hydrocarbons in the zeolite silicalite. J. Phys. Chem. B 106, 12757–12763 (2002)

    CAS  Article  Google Scholar 

  39. 39

    Demontis, P. & Suffritti, G. B. Structure and dynamics of zeolites investigated by molecular dynamics. Chem. Rev. 97, 2845–2878 (1997)

    CAS  Article  Google Scholar 

  40. 40

    Frenkel, D. & Smit, B. Understanding Molecular Simulations: From Algorithms to Applications 2nd edn (Academic Press, San Diego, 2002)

    MATH  Google Scholar 

  41. 41

    Siepmann, J. I. & Frenkel, D. Configurational-bias Monte Carlo: A new sampling scheme for flexible chains. Mol. Phys. 75, 59–70 (1992)

    CAS  Article  ADS  Google Scholar 

  42. 42

    Frenkel, D., Mooij, G. C. A. M. & Smit, B. Novel scheme to study structural and thermal properties of continuously deformable molecules. J. Phys. Condens. Matter 4, 3053–3076 (1992)

    Article  ADS  Google Scholar 

  43. 43

    Rosenbluth, M. N. & Rosenbluth, A. W. Monte Carlo simulations of the average extension of molecular chains. J. Chem. Phys. 23, 356–359 (1955)

    CAS  Article  ADS  Google Scholar 

  44. 44

    Siepmann, J. I., Karaborni, S. & Smit, B. Simulating the critical properties of complex fluids. Nature 365, 330–332 (1993)

    CAS  Article  ADS  Google Scholar 

  45. 45

    Siepmann, J. I., Martin, M. G., Mundy, C. J. & Klein, M. L. Intermolecular potentials for branched alkanes and the vapour liquid equilibria of n-heptane, 2-methylhexane, and 3-ethylpentane. Mol. Phys. 90, 687–693 (1997)

    CAS  Article  ADS  Google Scholar 

  46. 46

    Dubbeldam, D. et al. Force field parametrization through fitting on inflection points in isotherms. Phys. Rev. Lett. 93, 088302 (2004)

    CAS  Article  ADS  Google Scholar 

  47. 47

    Krishna, R., Smit, B. & Vlugt, T. J. H. Sorption-induced diffusion-selective separation of hydrocarbon isomers using silicalite. J. Phys. Chem. A 102, 7727–7730 (1998)

    CAS  Article  Google Scholar 

  48. 48

    Morell, H. et al. Structural investigation of silicalite-I loaded with n-hexane by X-ray diffraction, Si-29 MAS NMR, and molecular modeling. Chem. Mater. 14, 2192–2198 (2002)

    CAS  Article  Google Scholar 

  49. 49

    Yu, M., Falconer, J. L. & Noble, R. D. Adsorption of liquid mixtures on silicalite-1 zeolite: A density-bottle method. Langmuir 21, 7390–7397 (2005)

    CAS  Article  Google Scholar 

  50. 50

    Dubbeldam, D. et al. United atom force field for alkanes in nanoporus materials. Phys. Chem. B 108, 12301–12313 (2004)

    CAS  Article  Google Scholar 

  51. 51

    Maesen, T. L. M., Calero, S., Schenk, M. & Smit, B. Alkane hydrocracking: shape selectivity or kinetics? J. Catal. 221, 241–251 (2004)

    CAS  Article  Google Scholar 

  52. 52

    Zones, S. I. et al. Hydrocarbon conversion using molecular sieve SSZ-75. US Patent Application 2007/0284284. (2007)

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We thank S. Calero, D. Dubbeldam, D. Frenkel, R. Krishna and M. Schenk. This work was supported by the EC through the Marie Curie EXT programme BiMaMoSi.

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Correspondence to Berend Smit or Theo L. M. Maesen.

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Smit, B., Maesen, T. Towards a molecular understanding of shape selectivity. Nature 451, 671–678 (2008).

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