Preparation of 4-bromobutanol (US Patent 7629345):
Preparation of 4-bromobutanol (US Patent 7629345):
Tetrahydrofuran (12.5 g, 173 mmol) was charged under N2 in a
reactor cooled to 5-10C. HBr (7.0 g, 86.5 mmol) was added slowly
and stirred for 4.5 h at 5-10C The mixture was diluted with 22.5 ml
water and pH adjusted to 5-7 with 27.65% NaOH solution at 5-10C.
The solution is extracted twice with DCM (13.25 g), dried over
MgSO4 and evaporated. Crude 4-bromobutanol (10.3 g, 66.9 mmol) is
obtained in a yield of 77%
Preparation of 4-bromobutanol (US Patent 4107122):
To a 1-liter reactor, equipped with thermometer and condenser,
there were added 99.6 g. (1.02 moles) maleic anhydride, 162 g.
(2.25 moles) tetrahydrofuran and 4 g p-toluenesulfonic cid.
Hydrogen bromide (177.4 g., 2.19 moles) was added subsurface over a
period of 1.75 hours while the temperature was held at
approximately 70 C.
