Percolation-dependent Reaction Rates in the Etching of Disordered Solids
  A prototype statistical model for the etching of a random solid is investigated in order to assess the influence of disorder and temperature on the dissolution kinetics. At low temperature, the kinetics is dominated by percolation phenomena, and the percolation threshold determines the global reaction time. At high temperature, the fluctuations of the reaction rate are Gaussian, whereas at low temperature they exhibit a power law tail due to chemical avalanches. This is an example where microscopic disorder directly induces non-classical chemical kinetics. 
K. M. Kolwankar, M. Plapp and B. Sapoval