One of most popular method for oxidation of alcohol to aldehyde or ketone is Parikh-Doering oxidation (SO₃.py/DMSO) and method for preparation of SO3.Py complex was described delow:

Chemical reagents

-Chlorosulfonic acid

-dry Pyridine

-dry CH₂Cl₂

Methodology (modified from original method)

         To a stirred solution of  dry pyridine (64.57 mL, 0.8 mol) in dry CH₂Cl₂ (150 mL) was added dropwise chlorosulfonic acid (26.3 mL,0.4 mol) over 2 hours. Then, the white percipitate was filterd and washed with ice-cold water (2x100 mL), acetone (50 mL) and ether (50 mL).  The resulting precipitate was dired under vacumn.

Note

-SO₃PY is sensitive to water.