New applications of recurrent relations: precalculation of p K a values of substituted alkanecarboxylic acids

The series of substituted alkanecarboxylic acids including insertion homologues of ω‐substituted acids X(CH 2 ) n CO 2 H ( n  ≥ 1) and isomers that differ in the position of substituents X in the alkyl fragments, k ‐X(C n H 2 n )CO 2 H ( n  = const ≥ 1, 1 ≤  k  ≤  n  + 1) is the sub‐group most poorly characterized by their acidity constants, p K a , comparing with the acids of the other sub‐groups. When the experimental data for such compounds are unavailable, the precalculated estimates should be taken into consideration. The p K a values for such acids can be calculated using the single first‐order recurrent relation, p K a ( n  + 1) =  a p K a ( n ) +  b , using p K a values of other (usually the simpler and, consequently, better characterized) homologues and/or isomers of the same series. This algorithm results from the unique mathematical properties of recurrent relations in chemistry. Copyright © 2014 John Wiley & Sons, Ltd.