1,1,2,3-Tetrachloropropene is used in producing 2,3,3,3-Tetrachloropropene. 2,3,3,3-Tetrachloropropene may be useful as heat transfer compns., aerosol propellants, foaming agents, blowing agents, solvents, cleaning agents, carrier fluids, displacement drying agents, buffing abrasion agents, polymn.