Octachloropropane

Octachloropropane, also known as perchloropropane, is a chlorocarbon with the formula C₃Cl₈ and structural formula Cl₃C−CCl₂−CCl₃. It is a derivative of propane (C₃H₈) where all hydrogen atoms are replaced by chlorine. The compound is a clear white crystalline solid at room temperature with a hexagonal crystal structure that can deform plastically under mechanical stress without losing its structure.

First synthesized in 1875 by Krafft and Merz, octachloropropane was later noted for its unique crystal properties by McCrone in 1949. Its use as a model for studying crystal deformation in minerals was developed by Win D. Means and Marc W. Jessel in the 1980s.

Production methods involve reacting partially chlorinated propane with iodine trichloride, chlorine at high pressure, or light-activated chlorine. Temperatures must remain below 200°C to prevent further reactions yielding carbon tetrachloride or hexachloroethane.

In chemical reactions, octachloropropane reacts with aluminum in diethyl ether to produce unsaturated perchlorocarbons such as hexachloropropene (C₃Cl₆). These reactions yield various isomers with distinct melting points and structures.

Applications include its use as a model for studying plastic deformation of crystalline minerals and rocks. It is also used in metal separation, reacting with niobium pentoxide, tantalum pentoxide, and titanium dioxide to produce corresponding chlorides. As a pesticide, it was marketed under the brand name HRS-1622 but proved ineffective despite its toxicity to housefly larvae.

Environmental concerns highlight octachloropropane as a contaminant in carbon tetrachloride production and waste from aluminum etching in integrated circuit factories.