The term
selectivity(
) is used to describe the relative rates of two or more competing reactions on a
catalyst. Such
competition includes cases of different reactants undergoing
simultaneous reactions or of a single reactant taking part in two or more reactions. For the latter case,
may be defined in two ways. The first of these defines a fractional
selectivity,
, for each product by the equation
The second defines relative selectivities,
, for each pair of products by
In each case,
and
are the rates of increase of the
extent of reactionsi and
j respectively, i.e.
and
,
where
and
are the extents of reactions
and
respectively.
Source:
PAC, 1976, 46, 71
(Manual of Symbols and Terminology for Physicochemical Quantities and Units - Appendix
II. Definitions, Terminology and Symbols in Colloid and Surface Chemistry. Part II:
Heterogeneous Catalysis)
on page 81
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
https://doi.org/10.1351/goldbook.
