Investigation of cocrystallization of para-36ClIC6H4 impurity with paraI2C6H4 in the system of vapour-solid

Cocrystallization of the mixture of para-36ClIC6H4 with crystals of para-I2C6H4 with 0.5-2 mol.% mixture in the system is studied under static conditions. The values of thermodynamically equilibrium coefficient of cocrystallization Dx103 which characterizes the distribution of mixture between a vapour phase and a diluted solid solution for temperatures 50,60,70,80 and 90 deg C are found to be 4.0+-1.5, 6.8+-2.0, 9.4+-3.0, 18.7+-5.0 and 19.3+-5.0 respectively. It is established that equilibrium mixture distribution in the above system is mainly achieved due to recrystallization processes. The experimentally found dependence lgD on 1/T (T-temperature, K) has been used to find the value of differences of potential energies of molecules of the main component (ΔE''sub(sld.sol.)) and the mixture (ΔE'sub(sld. sol.)) in the forming diluted solid solution (ΔE''sub(sld.sol.)-ΔE'sub(sld.sol.)=-4.19 kkal/mol.). The conclusion is made that the ΔE'sub(sld.sol.)=-16.65 kkal/mol value in this solid solution is close to the energy of the crystal lattice of pure para-ClIC6H4 (ΔE=-16.25 kkal/mol). Estimating prognosis of D values for systems with para-dihaloidbenzols is carried out. The conclusion is made on the perspective use of cocrystallization out of the gaseous phase for separation and purification of some para-dihaloidbenzols