Reaction LXII.—Direct reduction of Halogen Compounds

Reaction LXII. Direct Reduction of Halogen Compounds. (J. C. S., 

154 47, 200.)—A very useful method for the preparation of hydrocarbons, more especially of aliphatic hydrocarbons, consists in replacing the halogen atom of a halogen compound by an atom of hydrogen. 

The reducing agents usually employed are phosphorus and hydriodic acid, or the zinc-copper or the aluminium-mercury couple. The couples have the advantage of readily yielding a pure gas, and are of wide application. 

For the preparation of zinc-copper couples in alloy form, see O. S., XII., 87. 

Methane can be prepared from methyl iodide or chloroform, etc., ethane from ethyl iodide, propane from propyl and isopropyl iodides, and so on. 

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