Halogenation of Alcohols

[rickjames]

I have three isomers of an alcohol: 1-butanol, 2-butanol, 2-methyl-2-propanol and all three are mixed with 12 mol HCl. Now is this a halogenation reaction or hydrohalegenation reaction? And also how can intermolecular forces explain this. Doing the experiment, 2-methyl-2-propanol turns instantly cloudy, 2-butanol experience a tiny colour change and 1-butanol does not react. Any ideas?

[budullewraagh]

the -OH group is protonated by the HCl to form -OH2+

the -OH2+ group is an excellent leaving group and so Cl- displaces it via backside nucleophilic substitution.