A mathematical model has been developed to describe the disordering kinetics of a condensed monolayer adsorbed at the electrochemical interface, It is assumed, that the disordering process is linked to the presence of defects in the condensed him. In the case of a perfectly smooth electrode, like a mercury drop, the only defects present in the film orginate from its formation by a 2D nucleation and growth process, so that the film can be viewed as an arrangement of linear and point defects. The model is restricted to the case where the disordering starts from lines and corresponds to the progressive shrinkage of patches having the same size. The rate of disorder propagation is considered as time dependent, this dependence being expressed as a function of the surface energy and the line tension. The expression for the surface coverage of the disordered film as a function of time is modulated by two parameters. The validation of the model is based on experimental results obtained by chronocoulometry for the disordering of a coumarin monolayer at the mercury/electrolyte interface.