Conventionally, ZIF-8 particles have been prepared in batch solvothermal reactors, imposing limitations on the stability to achieve large-scale, rapid, and reproducible synthesis. In this study, ZIF-8 nanoparticles with narrow particle size distribution were produced continuously in a tubular reactor by a novel solvojet process, which combined solvothermal reaction for nucleation and vaporization-induced solid-liquid reaction for crystal growth and facet development. The size and morphology of the product ZIF-8 nanoparticles were significantly affected by the reaction temperature and residence time. With increasing reaction temperature from 120 degrees C to 180 degrees C, the average particle size decreased from 155 nm to 35 nm. The mechanism of crystal formation by continuous solvo-jet process was studied. Furthermore, gas separation properties of the product ZIF-8 nanoparticles were investigated by the adsorption of various gases. (C) 2014 Elsevier B.V. All rights reserved.