Physisorption and Chemisorption of Linear Alkenes in Zeolites: A Combined QM-Pot(MP2//B3LYP:GULP)–Statistical Thermodynamics Study

Physisorption and chemisorption of C2–C8 linear alkenes in H–FAU, H–BEA, H–MOR, and H–ZSM-5 have been quantified up to 800 K by combining QM-Pot(MP2//B3LYP:GULP) with statistical thermodynamics calculations. The influence of the zeolite topology and the alkene CC double bond position on the alkene sorption thermodynamics is addressed on the basis of linear variations of sorption enthalpies and entropies as a function of the carbon number. The physisorption strength and entropy losses increase in the order H–FAU < H–BEA < H–MOR < H–ZSM-5. Higher physisorption strength is computed for 2-alkenes (H–MOR) and 2-, 3-, and 4-alkenes (H–ZSM-5) as compared with 1-alkenes. Protonation of physisorbed alkenes leads to significantly more stable alkoxides. In contrast to the physisorption, higher chemisorption strength does not lead to larger chemisorption entropy losses. Also, the intrinsic stability of the alkoxides, i.e., relative to gas phase H2 and graphite, only depends on the carbon number and not on the detaile...

[1]  Guy Marin,et al.  Alkene Protonation Enthalpy Determination from Fundamental Kinetic Modeling of Alkane Hydroconversion on Pt/H–(US)Y-Zeolite , 2001 .

[2]  Rajamani Krishna,et al.  United Atom Force Field for Alkanes in Nanoporous Materials , 2004 .

[3]  A. Becke.  Density-functional thermochemistry. III. The role of exact exchange , 1993 .

[4]  P. Jacobs,et al.  Alkylcarbenium Ion Concentrations in Zeolite Pores During Octane Hydrocracking on Pt/H-USY Zeolite , 2004 .

[5]  Hans W. Horn,et al.  Fully optimized contracted Gaussian basis sets for atoms Li to Kr , 1992 .

[6]  F. Keil,et al.  Molecular simulation of alkene adsorption in zeolites , 2005 .

[7]  T. Degnan,et al.  Applications of zeolites in petroleum refining , 2000 .

[8]  P. Ungerer,et al.  Development of a transferable guest?host force field for adsorption of hydrocarbons in zeolites , 2003 .

[9]  J. Lercher,et al.  Alkane sorption in molecular sieves: The contribution of ordering, intermolecular interactions, and sorption on Brønsted acid sites , 1997 .

[10]  R. Ahlrichs,et al.  Efficient molecular numerical integration schemes , 1995 .

[11]  J. Limtrakul,et al.  Alkylation of benzene with ethylene over faujasite zeolite investigated by the ONIOM method , 2004 .

[12]  G. Marin,et al.  A single-event microkinetic analysis of the catalytic cracking of (cyclo)alkanes on an equilibrium catalyst in the absence of coke formation , 2007 .

[13]  L. A. Clark,et al.  Computational elucidation of the transition state shape selectivity phenomenon. , 2004, Journal of the American Chemical Society.

[14]  P. Jacobs,et al.  Chromatographic Study of Adsorption of n-Alkanes on Zeolites at High Temperatures , 1998 .

[15]  L. A. Clark,et al.  Stable mechanistically-relevant aromatic-based carbenium ions in zeolite catalysts. , 2003, Journal of the American Chemical Society.

[16]  P. Jacobs,et al.  High-Temperature Low-Pressure Adsorption of Branched C5−C8 Alkanes on Zeolite Beta, ZSM-5, ZSM-22, Zeolite Y, and Mordenite , 1998 .

[17]  A. Schäfer,et al.  Fully optimized contracted Gaussian basis sets of triple zeta valence quality for atoms Li to Kr , 1994 .

[18]  van Ra Rutger Santen,et al.  A Periodic Structure Density Functional Theory Study of Propylene Chemisorption in Acidic Chabazite: Effect of Zeolite Structure Relaxation , 2002 .

[19]  P. Jacobs,et al.  Kinetic modeling of pore mouth catalysis in the hydroconversion of n-octane on Pt-H-ZSM-22 , 2003 .

[20]  M. Sierka,et al.  Physisorption and chemisorption of hydrocarbons in H-FAU using QM-Pot(MP2//B3LYP) calculations , 2008 .

[21]  Avelino Corma,et al.  Inorganic Solid Acids and Their Use in Acid-Catalyzed Hydrocarbon Reactions , 1995 .

[22]  Julian D. Gale,et al.  GULP: A computer program for the symmetry-adapted simulation of solids , 1997 .

[23]  Berend Smit,et al.  Molecular simulations of zeolites: adsorption, diffusion, and shape selectivity. , 2008, Chemical reviews.

[24]  Julian D. Gale,et al.  The General Utility Lattice Program (GULP) , 2003 .

[25]  Berend Smit,et al.  Energetics of n-alkanes in zeolites: a configurational-bias Monte Carlo investigation into pore size dependence , 1996 .

[26]  P. Ungerer,et al.  Development of a transferable guest-host force field for adsorption of hydrocarbons in zeolites. II. Prediction of alkenes adsorption and alkane/alkene selectivity in silicalite , 2004 .

[27]  Adsorption of n-alkanes in faujasite zeolites: molecular simulation study and experimental measurements , 2007 .

[28]  Christof Hättig,et al.  CC2 excitation energy calculations on large molecules using the resolution of the identity approximation , 2000 .

[29]  L. A. Clark,et al.  Diffusion mechanisms of normal alkanes in faujasite zeolites , 1999 .

[30]  G. Curthoys,et al.  Heats and entropies of adsorption of saturated hydrocarbons by zeolites X and Y , 1981 .

[31]  Joachim Sauer,et al.  Combining quantum mechanics and interatomic potential functions in ab initio studies of extended systems , 2000 .

[32]  Parr,et al.  Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. , 1988, Physical review. B, Condensed matter.

[33]  J. Limtrakul,et al.  The adsorption of saturated and unsaturated hydrocarbons on nanostructured zeolites (H-MOR and H-FAU): An ONIOM study , 2007 .

[34]  J. Bokhoven,et al.  Observation of a compensation relation for n-hexane adsorption in zeolites with different structures: implications for catalytic activity , 2005 .

[35]  Hans W. Horn,et al.  ELECTRONIC STRUCTURE CALCULATIONS ON WORKSTATION COMPUTERS: THE PROGRAM SYSTEM TURBOMOLE , 1989 .

[36]  Jumras Limtrakul,et al.  Application of ONIOM calculations in the study of the effect of the zeolite framework on the adsorption of alkenes to ZSM-5 , 2006 .

[37]  Guy Marin,et al.  Adsorption of C2−C8 n-Alkanes in Zeolites† , 2011 .

[38]  C. Kölmel,et al.  Combining ab initio techniques with analytical potential functions for structure predictions of large systems: Method and application to crystalline silica polymorphs , 1997 .

[39]  G. Marin,et al.  Physisorption and chemisorption of alkanes and alkenes in H-FAU: a combined ab initio-statistical thermodynamics study. , 2009, Physical chemistry chemical physics : PCCP.

[40]  Michel Waroquier,et al.  Normal Mode Analysis in Zeolites: Toward an Efficient Calculation of Adsorption Entropies. , 2011, Journal of chemical theory and computation.

[41]  Rutger A. van Santen,et al.  A Periodic DFT Study of Isobutene Chemisorption in Proton-Exchanged Zeolites: Dependence of Reactivity on the Zeolite Framework Structure , 2003 .

[42]  A. Corma,et al.  Reaction intermediates in acid catalysis by zeolites: prediction of the relative tendency to form alkoxides or carbocations as a function of hydrocarbon nature and active site structure. , 2004, Journal of the American Chemical Society.

[43]  Lalji Dixit,et al.  Heats of Adsorption of Hydrocarbons on Zeolite Surfaces: A Mathematical Approach , 1999, J. Chem. Inf. Comput. Sci..

[44]  Lubomir Benco,et al.  Physisorption and Chemisorption of Some n-Hydrocarbons at the Brønsted Acid Site in Zeolites 12-Membered Ring Main Channels: Ab Initio Study of the Gmelinite Structure , 2003 .

[45]  M. Stockenhuber,et al.  Bronsted acid and pore controlled siting of alkanes sorption in acidic molecular sieves , 1997 .

[46]  G. Bond,et al.  Compensation Phenomena in Heterogeneous Catalysis: General Principles and a Possible Explanation , 2000 .

[47]  Marek Sierka,et al.  Structure and reactivity of silica and zeolite catalysts by a combined quantum mechanics[ndash ]shell-model potential approach based on DFT , 1997 .