The kinetic laws of mass transfer under conditions of spontaneous interfacial convection are investigated and it is shown that the intensity of interfacial convection through a spherical phase boundary increases the mass transfer coefficient ~10 times. Of crucial importance are phase resistances due to the physicochemical properties of the substances and solvents carried (viscosity, distribution coefficient, interfacial tension gradients, chemical reactions occurring in phases, etc.). It is shown that the gradients of temperature and concentration in the drop and in the external flow are comparable with the corresponding gradients in the continuous medium and in the drop volume.