(A,B,C) Triplet of Infrared OH Bands of Zeolitic H-Complexes

Pelmenschikov, A. G.; Wolput, van J H M C Jos; Jänchen, J.; Santen, van Ra Rutger

doi:10.1021/j100011a031

Cited by 100 publications

(86 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These three broad bands may come from the H-bonding complex and be attributed to the perturbed OH vibration, because they are quite similar to the triplet A, B, C bands of hydroxyl group as previously reported [21,22]. Usually, for the H-bonding complex, the A-B-C pattern with broad and intense absorbance at around 2800, 2400 and 1700 cm À1 , is caused by a Femi resonance between out-of-plane deformation vibration of bridged OH group and the perturbed hydrogen bound OH group due to O-HÁÁÁX-H formation.…”

Section: Resultssupporting

confidence: 78%

New route for light olefins production from chloromethane over HSAPO-34 molecular sieve

Wei

Zhang

et al. 2005

Catalysis Today

View full text Add to dashboard Cite

Section: Resultssupporting

confidence: 78%

New route for light olefins production from chloromethane over HSAPO-34 molecular sieve

Wei

Zhang

et al. 2005

Catalysis Today

View full text Add to dashboard Cite

“…Pelmenschikov pointed out that the CN stretching frequency is an efficient probe to distinguish different adsorption sites in zeolites, in particular Lewis acid sites, terminal silanol groups, and the bridging Brønsted acid site, which will be discussed in this work. 55,56 Related work of Simperler et al obtained a ranking of seven different high silica zeolites based on the hydrogen-bond strength as a predictor of acidity. 60 In this study, the shift in the ν(OH) region will be investigated for all adsorption complexes.…”

Section: 29mentioning

confidence: 99%

Efficient Approach for the Computational Study of Alcohol and Nitrile Adsorption in H-ZSM-5

et al. 2012

View full text Add to dashboard Cite

Since many industrially important processes start with the adsorption of guest molecules inside the pores of an acidic zeolite catalyst, a proper estimate of the adsorption enthalpy is of paramount importance. In this contribution, we report ab initio calculations on the adsorption of water, alcohols, and nitriles at the bridging Brønsted sites of H-ZSM-5, using both cluster and periodic models to account for the zeolite environment. Stabilization of the adsorption complexes results from hydrogen bonding between the guest molecule and the framework, as well as from embedding, i.e., van der Waals interactions with the pore walls. Large-cluster calculations with different DFT methods, in particular B3LYP(-D), PBE(-D), M062X(-D), and ωB97X-D, are tested for their ability to reproduce the experimental heats of adsorption available in the literature (J. Phys. Chem. B 1997, 101, 3811−3817). A proper account of dispersion interactions is found to be crucial to describe the experimental trend across a series of adsorbates of increasing size, i.e., an increase in adsorption enthalpy by 10−15 kJ/mol for each additional carbon atom. The extended-cluster model is shown to offer an attractive alternative to periodic simulations on the entire H-ZSM-5 unit cell, resulting in virtually identical final adsorption enthalpies. Comparing calculated stretch frequencies of the zeolite acid sites and the adsorbate functional groups with experimental IR data additionally confirms that the cluster approach provides an appropriate representation of the adsorption complexes.

show abstract

“…Partial Hessian Vibrational Analysis. Three different interpretations 17 have been proposed to explain the experimentally observed triplet of bands at approximately 2800À3000, 2400À2600, and 1500À1700 cm À1 of alcohols adsorbed in several zeolites. 6À11 The first one assumes the formation of protonated alcohol (ROH 2 þ ) and assigns the three bands to the symmetric (ν s ) and asymmetric (ν a ) HOH stretch and (δ) HOH bending, respectively.…”

Section: Physisorption Energymentioning

confidence: 99%