A gas phase method for the generation of aqueous submicron suspensions of poorly water soluble organic substances

This work presents a novel process for the production of vapor-borne submicron organic particles and their transfer into an aqueous environment. A mixture of water and the organic substance is totally evaporated in a micro-structured evaporator. In a second step, the hot vapor mixture is rapidly cooled down inside a quench cooler so that the organic component gets into a supersaturated state and fine particles are formed due to homogenous nucleation. The rapid cooling is realized by the injection of liquid water into the hot vapor atmosphere. The liquid water evaporates and thereby cools down the vapor mixture. Water as one component of the vapor mixture remains in the vapor phase and acts as a carrier for the generated organic particles. The generation of the aqueous suspension is realized by the total condensation of the water vapor atmosphere directly after the quench cooler. The condenser is continuously supplied with surfactant solution. This prevents agglomeration as soon as the particles get transferred from the vapor into the liquid environment. The process has been realized successfully in a lab-scale plant. First results with Tocopheryl acetate and Myristyl myristate as model substances are presented in this work.