Investigation of dissolution kinetics for high rates of dissolution

A procedure was developed for investigating the dissolution of crystals that rub against a substrate with the solvent, whereby the process becomes significantly intensified. A theory of the method is presented. The kinetics of dissolution of azobenzene in alcohol at different rates of substrate motion, normal loads on the crystal, and temperatures is investigated. It is shown that a diffusion-kinetic regime of dissolution is realized under these conditions. An estimate of the kinetic dissolution coefficient (K 1–15 cm/sec) yields a high value that does not agree with the concepts of the tangential mechanism, and indicates a normal mechanism of the process. The probable mechanism of crystallization of azobenzene from alcohol is tangential, and there is no quantitative reversibility of the crystallization and dissolution.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 18–24, December, 1970.