Abstract
Recently, microreactors have attracted considerable attention in homogeneous reaction system. For the crystallization in microreactor, however, the channel blockage is a key issue for the continuous operation. In this study, the crystallization of calcium carbonate (CaCO3), which was selected as a model reaction, was carried out in liquid flow along the microchannel. As a result, the channel blockage occurred instantaneously due to the deposition of particles to the channel wall. In order to prevent the channel blockage, novel designed microreactor was fabricated to obtain the particles in droplets. Soybean oil was introduced into microchannel as a continuous phase. A droplet was formed by a coalescence of Na2CO3 solution and CaCl2 solution at the tip of nozzles and then the nucleation and the crystal growth of CaCO3 particles were observed in the droplet. In this system, CaCO3 particles could be formed continuously without channel blockage. This novel microreactor was applied to the synthesis of Ag nanoparticles. When the Ag nanoparticles were synthesized in the microreactor, the particle agglomeration was more suppressed and the distribution of particle size became narrower as compared with the particles produced in a beaker.
