Results are presented of direct numerical simulations of a two-dimensional temporally developing high speed mixing layer under the influence of a second-order non-equilibrium chemical reaction of the type A + B→Products+Heat. Simulations arc performed with different magnitudes of the convective Mach number and with different chemical kinetics parameters for the purpose of examining the isolated effects of the compressibility and the heat released by the chemical reaction on the structure or the layer, A full compressible code is developed and utilized, so that the coupling between mixing and chemical reaction is captured in a realistic manner.