Preparation and Physical Properties of Alkyl Halides:

Preparation Alkenes can be considered with hydrogen halides (HCl, HBr, and HI) or halogens (Cl₂ and Br₂) to provide alkyl halides and dihaloalkanes correspondingly. A very helpful method of preparing alkyl halides is to treat an alcohol along with a hydrogen halide (HX= HCl, HBr, or HI). The reaction acts best for tertiary alcohols. Primary and secondary alcohols can be transformed to alkyl halides much more effectively by treating them with thionyl chloride (SOCl₂) or phosphorus tribromide (PBr₃). The circumstances are less acidic and less probable to cause acid-catalyzed rearrangements.