Oxidation of Aerosols
2027
EXPERIMENTAL
Preparation of PSCC
Chlorosulfonic acid (23 ml) is added dropwise to a stirred solution of
pyridine (64 ml) in chloroform (100 ml) at −5◦C. The reaction mixture
is stirred at the same temperature for 20 min. Pyridinium sulfonate
chloride is formed as a white solid and separated. This solid (4.25 g)
is dissolved in 2 ml of water, and CrO3 (2 g) is added and stirred for
30 min at room temperature. An orange-red solution is obtained. The
reaction mixture is then cooled in an ice bath (0–5◦C). The yield of
C5H5NSO3H [CrO3Cl] is found to be 91%. The extend of the oxidation
is determined via proton nuclear magnetic resonance (1H NMR) and
gas chromatography (GC) (Table I).
General Experimental Procedure for the Application
of PSCC as an Oxidizing Agent
To a stirred solution of PSCC (5 mmole) in CH2Cl2 (10 ml), a solution
of alcohol (5 mmole) in CH2Cl2 (10 ml) is added in one portion. Stir-
ring is continued for 30 min to give a yellow solution. The progress
of the reaction is monitored by thin layer chromatography (TLC) (ethyl
acetate-hexane (1:9)). After completion of the reaction, dry diethyl ether
(50 ml) is added to the reaction mixture.
The whole mass is shaken well. The organic layer is decanted, and
the residue is washed with dry diethyl ether (3 × 20 ml). The combined
organic layers are passed through a short pad of celite. This is to trap the
reduced chromium. The product of oxidation is also washed thoroughly
with dietyl ether (3 × 10 ml). The solvent is removed in a rotavapor
under reduced pressure.∗
REFERENCES
[1] J.-D. Lou and Z.-N. Xu, Tetrahedron Lett., 43, 6095 (2002).
[2] M. N. Bhattacharjee, M. K. Chaudhuri, and S. Purkayastha, Tetrahedron, 43, 5389
(1987).
∗1H NMR, 13C NMR, IR, and UV spectra were entirely consistent with the assigned
structure of PSCC. Selected data are as follows: 1H NMR (90 MHz, CH3CN): δ = 7.9 (m,
2H, m-CH), 8.5 (m, 1H, p-CH), 8.8 (m, 2H, o-CH), 13C NMR (90 MHz, CH3CN): δ = 127.33
(2C, m-CH), 141 (1C, p-CH), 178 (2C, o-CH); IR ν(KBr): 954 (s, Cr-O), 921 (s, Cr-O), 435
(m, Cr-Cl), 1150–1250 (s, SO3) 1440–1640 (originating due to the pyridinium solfonate
cation); UV(CH3CN): 350–400 (CrCl), 256–260 (originating due to the pyridinium so-
fonate cation).
Elemental analysis data for the PSCC is found as follows: Cr, 17.6%; C, 20.5%; N, 4.80%;
H, 1.95%. Calculated: Cr, 17.65%; C, 20.37%; N, 4.75%; H, 1.83%.
Kassaee
