Heats of Adsorption of Hydrocarbons on Zeolite Surfaces: A Mathematical Approach
IR@IIP: CSIR-Indian Institute of Petroleum, Dehradun
View Archive Info| Field | Value | |
| Creator |
Dixit,Lalji
Rao,T.S.R Prasada |
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| Date |
2010-07-20T08:53:04Z
2010-07-20T08:53:04Z 2010-07-20T08:53:04Z |
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| Identifier |
J. Chem. Inf. Comput. Sci. 1999, 39, 218-223
http://hdl.handle.net/123456789/669 |
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| Description |
The role of electronic polarizabilities in dealing with the phenomenon of molecular adsorption and catalysis
by zeolites has been discussed in this work. Making use of the principles of periodic minimal surfaces of
crystalline materials and rules of atomic connectivities of zeolite structures, an expression has been derived
to evaluate heats of adsorption of hydrocarbons interacting with the surfaces of zeolites that reads ¢H )
RMâââç + õf, where RM is the average polarizability of hydrocarbons, â and õf are the constants, and ç the
average curvature of the zeolite surface. After determining the polarizabilities of hydrocarbons by a quantum
mechanical method and establishing the magnitudes of the curvatures of surfaces of zeolites by differential
geometrical approach, the formalism has been applied to evaluate heats of adsorption of C1-C8 hydrocarbons
on the typical surfaces of MOR, FAU, ZSM-5, and silcalite zeolites. The agreement between theoretical
and experimental values of heats of adsorptions of paraffins, naphthenes, olefins, and aromatics has been
found to be very good and compares fairly well with those obtained from experimental methods as well as
derived by other theoretical methods. The applicability of the data so generated has been demonstrated in
estimating the driving force of cracking (activation energy, E) following the Evans-Polyani procedure in
the case of n-paraffins interacting with ZSM-5 surface. The data so generated has been used to explain
negative activation energy for cracking observed for n-hexadecane and higher alkanes (C16 effect).
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| Language |
en_US
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| Subject |
Adsorption
Hydrocarbons Zeolite Surface |
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| Title |
Heats of Adsorption of Hydrocarbons on Zeolite Surfaces: A Mathematical Approach
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| Type |
Article
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