A Cellular Automata Model of Acid Dissociation

Abstract

A dynamic cellular automata model that simulates the dissociation of an organic acid in solution is described. In the model, acids are represented by a novel cell type in which one face corresponds to the dissociating carboxylic acid group and the remaining faces represent the anionic portion of the acid. Simulations are described that analyze the effects of variable acid strength, changes of solvent temperature, and environmental influences, such as the presence of cosolutes and other acids. Several general features of acid dissociation in solution are replicated by the model and some additional aspects are examined. As a rule, additional solutes depress acid dissociation, the effect being greatest when the added cosolute is lipophilic, as might occur, for example, in a biological system. In mixtures of two different acids, the dissociation of each is suppressed, the weaker acid experiencing the greater suppression.