Narrow channel microreactors have been evaluated for the reaction of immiscible liquid-liquid systems. In order to stimulate rapid interphase mixing and mass transfer, alternating slugs of organic and aqueous phases were generated at a "T" piece and flowed down an etched channel in a glass substrate. The detailed flow behavior was recorded photographically. Finally, some benzene and toluene nitration experiments were performed in stainless steel and PTFE capillary tubing in order to explore the industrial potential of microreactors for chemical production.