Monte-Carlo simulations have been performed in lattice systems. Mass transfer across liquid-liquid interfaces has been investigated in these systems. The occurrence of small micro droplets in the close vicinity of the interface has been observed. Based on these micro droplets disordered convections are explained on a microscopic level which are generally called Marangoni instabilities. The pronounced influence of convection due to the micro droplets on mass transfer is discussed. The distinct difference between diffusive and fluid dynamic Marangoni instabilities is derived.