Calorimetric study of the absorption of n-butane and but-l-ene on a highly dealuminated Y-type zeolite and on silicalite

Thamm, H.; Stach, H.; Fiebig, W.

doi:10.1016/0144-2449(83)90192-6

Cited by 48 publications

(20 citation statements)

References 7 publications

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“…Reliable experimental data for heats of adsorption for alkenes in purely siliceous zeolites are scanty and not available for ferrierite. The most reliable result is probably the calorimetric measurement of Thamm et al,57 −49 kJ mol −1 , for the enthalpy of adsorption of but‐1‐ene in silicalite‐1, the all‐silica form of MFI. A recent configuration‐bias Monte‐Carlo simulation using an experimentally adjusted united atom force field yields −47 kJ mol −1 52.…”

Section: Resultsmentioning

confidence: 99%

Application of semiempirical long‐range dispersion corrections to periodic systems in density functional theory

2008

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Ewald summation is used to apply semiempirical long-range dispersion corrections (Grimme, J Comput Chem 2006, 27, 1787; 2004, 25, 1463) to periodic systems in density functional theory. Using the parameters determined before for molecules and the Perdew-Burke-Ernzerhof functional, structure parameters and binding energies for solid methane, graphite, and vanadium pentoxide are determined in close agreement with observed values. For methane, a lattice constant a of 580 pm and a sublimation energy of 11 kJ mol(-1) are calculated. For the layered solids graphite and vanadia, the interlayer distances are 320 pm and 450 pm, respectively, whereas the graphite interlayer energy is -5.5 kJ mol(-1) per carbon atom and layer. Only when adding the semiempirical dispersion corrections, realistic values are obtained for the energies of adsorption of C(4) alkenes in microporous silica (-66 to -73 kJ mol(-1)) and the adsorption and chemisorption (alkoxide formation) of isobutene on acidic sites in the micropores of zeolite ferrierite (-78 to -94 kJ mol(-1)). As expected, errors due to missing self-interaction correction as in the energy for the proton transfer from the acidic site to the alkene forming a carbenium ion are not affected by the dispersion term. The adsorption and reaction energies are compared with the results from Møller-Plesset second-order perturbation theory with basis set extrapolation.

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Section: Resultsmentioning

confidence: 99%

Application of semiempirical long‐range dispersion corrections to periodic systems in density functional theory

2008

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“…Besides, both diffusivity and adsorption of reactant guest molecules in zeolites are known to be highly dependent on treatment conditions such as dealumination or steaming 13. Studies about the potential influence of such treatments on hydrocarbon adsorption are frequently limited to lower‐temperatures (temperatures smaller than 350°C), and/or using less reactivity zeolites, which give data that is distant from relevant reaction conditions 14, 15, 16, 17. For instance, Denayer and Baron18 investigated the effect of chain length and branching of paraffins in the gasoline range on adsorption and diffusion in various zeolites at 275–400°C.…”

Section: Introductionmentioning

confidence: 99%

Kinetic modeling of catalytic conversion of methylcyclohexane over USY zeolites: Adsorption and reaction phenomena

Al-Sabawi¹,

Lasa²

2009

AIChE Journal

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Catalytic conversion of cycloparaffins is a complex process involving competing reaction steps. To understand this process, FCC experiments using methylcyclohexane (MCH) on USY zeolite catalysts were carried out in the mini-fluidized CREC riser simulator. Runs were developed under relevant FCC process conditions in terms of partial pressures of MCH, temperatures (450-550 C), contact times (3-7 s), catalyst-oil mass ratios (5), and using fluidized catalysts. MCH overall conversions ranged between 4 to 16 wt %, with slightly higher conversions obtained using the larger zeolite crystallites. Moreover, it was found that MCH undergoes ring opening, protolytic cracking, isomerization, hydrogen transfer and transalkylation. A heterogeneous kinetic model for MCH conversion including thermal effects, adsorption and intrinsic catalytic reaction phenomena was established. Adsorption and kinetic parameters were determined, including the heat of adsorption (À40 kJ/mol), as well as thermal and primary catalytic intrinsic activation energies, which were in the range of 43-69 kJ/mol, and 50-74 kJ/mol, respectively. V

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“…For apolar molecules, the adsorption enthalpy, reflecting the energetic interaction between the molecule and the zeolite force field, increases with decreasing pore size (Barrer and Sutherland, 1956;Thamm et al, 1983;Jänchen and Stach, 1985;Richards and Rees, 1987;Lercher, 1997, Hufton andDanner, 1993;Denayer et al, 1998;Smit and Siepmann, 1994). For apolar molecules, the adsorption enthalpy, reflecting the energetic interaction between the molecule and the zeolite force field, increases with decreasing pore size (Barrer and Sutherland, 1956;Thamm et al, 1983;Jänchen and Stach, 1985;Richards and Rees, 1987;Lercher, 1997, Hufton andDanner, 1993;Denayer et al, 1998;Smit and Siepmann, 1994).…”

Section: Introductionmentioning

confidence: 99%

The Confinement Factor: A Thermodynamic Parameter to Characterize Microporous Adsorbents

Denayer

Baron

2005

Adsorption

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Calorimetric study of the absorption of n-butane and but-l-ene on a highly dealuminated Y-type zeolite and on silicalite

Cited by 48 publications

References 7 publications

Application of semiempirical long‐range dispersion corrections to periodic systems in density functional theory

Application of semiempirical long‐range dispersion corrections to periodic systems in density functional theory

Kinetic modeling of catalytic conversion of methylcyclohexane over USY zeolites: Adsorption and reaction phenomena

The Confinement Factor: A Thermodynamic Parameter to Characterize Microporous Adsorbents

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