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The term applies to either of the equations:
Math - e
Math - e
(or their logarithmic forms) where Math - text, Math - text and Math - text are constants for a given reaction series (Math - text and Math - text are called 'Brønsted exponents'), Math - text and Math - text are catalytic coefficients (or rate coefficients) of reactions whose rates depend on the concentrations of HA and/or of A . Math - text is the acid dissociation constant of the acid HA, Math - text is the number of equivalent acidic protons in the acid HA, and Math - text is the number of equivalent basic sites in its conjugate base A. The chosen values of Math - text and Math - text should always be specified. (The charge designations of H and A are only illustrative.) The Brønsted relation is often termed the 'Brønsted catalysis law' (or the 'Catalysis Law'). Although justifiable on historical grounds, this name is not recommended, since Brønsted relations are known to apply to many uncatalysed and pseudo-catalysed reactions (such as simple protondron ). The term 'pseudo-Brønsted relation' is sometimes used for reactions which involve nucleophilic catalysis instead of acid–base catalysis. Various types of Brønsted parameters have been proposed such as Math - text, Math - text, Math - text for leaving group, nucleophile and equilibrium constants, respectively.
Source:
PAC, 1994, 66, 1077 (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1091
PAC, 1996, 68, 149 (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 154
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Cite as: IUPAC Compendium of Chemical Terminology, Electronic version, http://goldbook.iupac.org/B00746.html.
Transformed and rewritten from PDF version (entry http://www.iupac.org/goldbook/B00746.pdf)
by: Miloslav Nic, Jiri Jirat, Bedrich Kosata, ICT Prague, Czech Republic
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