If dry chlorine is passed into strong alcohol to saturation, the mixture being at first cooled and afterwards heated slowly to 100°, the alcohol is chlorinated, the final product being a crystalline mixture of chloral hydrate, chloral alcoholate, and trichloroacetal. On distilling the crystalline product with sulphuric acid, chloral is obtained. With bromine, the corresponding product, bromal, is given. Alcohol distilled from bleaching powder yields chloroform. This reaction is usually explained as one in which both oxidation and chlorination proceed simultaneously, aldehyde being first produced by oxidation, and then ultimately converted into trichloroaldehyde or chloral, CCl3.CHO. The latter substance reacts with the calcium hydroxide present, yielding chloroform and calcium formate: -

2CC13.CHO + Ca(OH)2 == 2CHC13 + CaH1(CO2)2.

1 Zeitsch. Elektrochem., 1909, 15, 846.