If an acid or base is present in nearly constant concentration throughout a reaction in solution (owing to buffering or the use of a large excess), it may be found to increase the rate of that reaction and also to be consumed during the process. The acid or base is then not a @C00876@ and the phenomenon cannot be called @C00874@ according to the well-established meaning of these terms in chemical kinetics, although the @M03804@ of such a process is often intimately related to that of a catalysed reaction. It is recommended that the term pseudo-@C00874@ be used in these and analogous cases (not necessarily involving acids or bases). For example, if a @B00744@ accelerates the @H02902@ of an ester to a carboxylic acid and an alcohol, this is properly called acid @C00874@, whereas the @A00051@, by the same acid, of @H02902@ of an amide should be described as pseudo-@C00874@ by the acid: the 'acid pseudo-@C00876@' is consumed during the reaction through formation of an ammonium ion. The terms 'general acid pseudo-@C00874@' and 'general base pseudo-@C00874@' may be used as the analogues of @G02609@ and @G02610@. The term 'base-promoted', 'base-accelerated' or 'base-induced' is sometimes used for reactions that are pseudo-catalysed by bases. However, the term '@P04877@' also has a different meaning in other chemical contexts.
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1153 [Terms] [Paper]