Development of Catalytic Microreactors by Non-aqueous Microencapsulation Method

Despite the greater selectivity and reactivity in homogeneous catalysis compared to heterogeneous catalysis, processes performed by heterogeneous catalysis are more desirable, owing to facile recovery and low costs. The latent monumental potential in the bridging of both types of catalysis has encouraged the development of numerous methods for heterogenization of homogeneous catalysts. As a valuable emerging term, the homogeneous-heterogeneous principle is regarded as the best possible conjunction of both catalytic routes, where green processes with low economic cost and highly desired efficiency can be manifested.

Recently, we developed a new heterogenization method based on non-aqueous microencapsulation.. In this method, the catalyst is encapsulated within silica or polyurea microcapsules by applying either non-aqueous sol-gel processes or interfacial polymerization principles. Both preceded by the preparation of oil-in-oil (O/O) emulsion by dispersing a polar organic phase such as polyethylene glycol (PEG) in a non-polar organic solvent containing a proper surfactant. The catalyst is dissolved in the polyethylene glycol phase. At the end of this process, microreactors of silica or polyurea containing in the core the a solubilized catalyst are obtained. The characterization of these microreactors and their catalytic activity in different organic transformations will be presented.