Abstract <p>The extractive desulfurization of the light vacuum gas oil has been investigated in a mini-channel reactor. The influence of operating and geometrical parameters of mini-channel on the flow pattern of two immiscible phases and efficiency of a sulfur extraction from a petroleum product has been studied. Using <i>N</i>-methyl-2-pyrrolidone as a solvent, it was possible to remove up to 50% of sulfur from light vacuum gas oil in a mini-channel within 20–50 s. The extraction efficiency of benzo- and dibenzothiophene homologues from petroleum feedstock was investigated in mini-channels of various internal diameter (0.5, 1, and 1.6 mm) and length (from 10 to 300 сm) within the range of total flow velocities of 0.01–0.1 m/s. Different flow configurations (slug, slug-drop, annular, wavy annular) were observed in the mini-channel. It was shown that the values of a sulfur extraction efficiency for the slug and annular flow regimes were close for the same retention time. However, compared to the slug flow, the volumetric mass transfer coefficient for the annular flow regime decreased significantly as the mini-channel length (retention time) increased. In total, 75% of sulfur compounds can be extracted from light vacuum gas oil by a multi-stage extraction in a mini-channel.</p>