Carbon Tetraiodide - Properties, Synthesis, Uses

Properties, Synthesis, Uses

CI₄ is slightly reactive towards water, giving iodoform and I₂. Otherwise it is soluble in nonpolar organic solvents. It decomposes thermally and photochemically to tetraiodoethylene, I₂C=CI₂. Its synthesis entails AlCl₃-catalyzed halide exchange, which is conducted at room temperature:

CCl₄ + 4 EtI → CI₄ + 4 EtCl

The product crystallizes from the reaction solution.

CI₄ is used as an iodination reagent, often upon reaction with base. Ketones are converted to 1,1-diiodoethenes upon treatment with PPh₃ and CI₄. Alcohols are converted in and to iodide, by a mechanism similar to the Appel reaction. In an Appel reaction carbon tetrachloride is used to generate the chloride from alcohols.