Abstract
Reaction between DAHG and organic acid, i.e., salicylic acid, trichloroacetic acid, monochloroacetic acid, or formic acid, was examined and the following results were obtained. 1. Three stages of the reaction, i.e., the initial, the main, and the final stages, were observed with the progress of dissolution of DAHG in acid. 2. The initial stage is concerned with the rapid increase of pH, which was considered to be due primarily to the adsorption of acid by DAHG and also to the dissolution of aluminum ion on the surface of DAHG. 3. The rate of dissolution of DAHG at the main stage was in accordance with equation (2). 4. The order of the reaction with respect to the hydrogen ion was influenced by the dissociation constant. 5. The effect of anion on the apparent rate constant, K2, was condiered to be a specific property of that anion and not applicalbe to any generalization. 6. The estimated activation energy was 23, 000∼25, 000 calories, indicating that the reaction between DAHG and organic acid might be chemically controlled. 7. At the final stage, corresponding to the reaction in the higher pH region than about 4, the increase of aluminum ion was ceased apparently.
