Kinetics of aluminum can dissolution in sec-butyl alcohol for aluminum sec-butoxide

A kinetic study of dissolution reaction of Al can was conducted for the synthesis of aluminum sec-butoxide (ASB). With the Al can scraps and sec-butyl alcohol (SBA) as reactants, the reaction was examined at the condition of 3 mol SBA/mol Al of stoichiometric ratio, adding 10−3 mol HgI2/mol Al for catalyst and no agitation at the reaction temperature ranging from 80 to 100 °C. After the dissolution of 24 h at 100 oC, the reaction gave a 75% yield. A two-stage dissolution mechanism was proposed in which the dissolution rate is determined first by a chemical reaction and then by ash layer diffusion as the previous dissolution kinetics for the synthesis of AIP (Aluminum iso-propoxide) (Yoo, S.-J.,Yoon,H.-S., Jang, H.D., Lee,M.-J., Lee, S.-I.,Hong, S.-T., Park,H.S., 2007a. Dissolution kinetics of aluminum can in isopropyl alcohol for aluminum isopropoxide. Chem. Eng. J. 133, 79–84.). On the basis of the shrinking core model with the shape of flat plate, the first dissolution rate of Al can was controlled by chemical reaction. The concentration of SBA was largely changed during the dissolution reaction because it was added the stoichiometric ratio to the reactor. Therefore it was included as an integral term of the reaction time. By using the Arrhenius expression, the apparent activation energy of the first chemical reaction step was determined to be 200.5 kJ mol−1. In the second stage, the dissolution rate is controlled by diffusion control through the ash layer. The apparent activation energy of the second step was determined to be 101.8 kJ mol−1.