Preparation and extraction properties of microcapsules containing tri-n-octyl amine as core material.

Microcapsules containing tri-n-octyl amine as core material were prepared by in situ polymerization of styrene and divinylbenzene over a wide range of relevant preparation conditions. The extraction equilibrium and extraction rate of propionic acid in aqueous phase were investigated by using the microcapsules. The extraction equilibrium of propionic acid/tri-n-octyl amine in a suspended microcapsules system was well consistent with that in a liquid-liquid system. From the experimental results, the rate-determining step was concluded to be the pore diffusion of propionic acid through the porous film of microcapsules. The activation energy was found to be 34.6 kJ/mol. The extraction rate decreased with increase in monomer concentration, divinylbenzene/styrene weight ratio and average diameter of microcapsules.