This research suggests a linear analysis of the stability of non-stationary absorption of concentrated gases in an immobile liquid, where a basic flow is induced as a result of a natural convection and a non-linear mass transfer. A specter of disturbances that lead to a stable dissipative structure with a high mass transfer doefficient has been found. The disturbance amplitude is determined by experimental data for the mass transfer rate in absorption of pure CO2 in a stagnant water column. It has been shown that conditions for the occurrence of the Marangoni effect do not exist. The theoretical results have a good agreement with the experimental data.