The invention relates to a process for preparing haloalkanes by reaction of alcohol with hydrogen halide, wherein the reaction of the alcohol with the hydrogen halide occurs in the presence of an ionic liquid at a temperature which is above 100° C. for at least part of the time and, at least at the time of the commencement of the reaction, the water content is not more than 25 mol % based on the amount of liquid, where the ionic liquid is not octyltrimethylammonium chloride.
A compound having the general formula (I):
−
O
3
S—R
1
—V
1
—R
2
—V
2
wherein R
1
is a hydrocarbon radical comprising C
1
to C
10
main chain carbon atoms, wherein hydrogen atoms bonded to the main chain carbon atoms are optionally substituted; R
2
is a hydrocarbon radical comprising 6 to 20 main chain carbon atoms, wherein hydrogen atoms bonded to the main chain carbon atoms are optionally substituted; V
1
is a saturated or unsaturated, monocyclic or bicyclic ring system comprising 5 to 9 ring atoms, wherein at least 2 ring atoms are nitrogen atoms forming the same cyclic moiety; and V
2
is a moiety comprising a carboxyl group and an unsaturated carbon-carbon bond.