Disclosed are compositions and systems having utility in numerous situations, including in particular solvent cleaning systems, as well as refrigerant lubricants and/or compatibilizing agents, and to methods which utilize such compositions and systems. More particularly, the present invention in preferred aspects is directed to solvents, blowing agents, heat transfer fluids and compatibilizing agents comprising the compound 3-chloro-1,1,1,6,6,6-hexafluoro-2,4-hexadiene. In particular, this invention provides a method for the production of the compound of Formula I, 3-chloro-1,1,1,6,6,6- hexafluoro-2,4-hexadiene,comprising reacting 1,1,1,3,3-pentachloropropane with hydrogen fluoride in the presence of a catalyst, in a reactor.