Liquid-solid phase transformation of a two-component system (1,2-1,4 chloronitrobenzenes) held inside porous materials

The liquid-solid phase changes of a perfect solution (1,2-1,4 chloronitrobenzenes) held inside porous materials of known textural characteristics have been studied by using a DSC technique.When the pores are saturated with the condensate, the successive steps of equilibrium crystallization depend on whether the porous volume can be filled or not with the eutectic liquid.By varying the amount and initial composition of the solution used, the composition of the condensate which crystallizes inside the biggest pores of a given porous material, can be adjusted. By measuring the corresponding temperature, it is then possible to determine the phase diagram of the binary system in a given state of division.The equilibrium curves are similar to those of bulk binary systems for the two considered states of division. They are all the more shifted towards lower temperatures as the capillary condensate is more finely divided.The temperature shift depends on the composition, like the ratio of the solution-crystal 1,2 (or 1,4) interfacial tension to the partial volumic entropy of transition of the 1,2 (respectively 1,4) component.