The reduction o
f SO
2 on carbons
proceeds through reactive intermediates bound to the carbon matrix, whichwere
postulated to be 1,2-oxathiene 2-oxi
de (or sultine), and 1,3,2-dioxathiolane that
decom
poses to
producean e
pisul
fi
de and CO
2. The reactivity o
f these intermediates was studied in this work through several reactions,using XPS and NMR s
pectra to
postulate their mechanisms. When modi
fied activated carbon obtained a
fterreaction with SO
2 at 630
![](/images/entities/<font color=)
deg.gi
f">C was heated at 900
![](/images/entities/<font color=)
deg.gi
f">C, it was observed that the changes o
f the XPS s
pectrumresulted
from the
forward reaction o
f decom
position o
f the oxidized intermediate with S-trans
fer to
producethe e
pisul
fi
de and CO
2 and the reverse reaction with ex
pulsion o
f SO
2. Strong bases hydrolyzed thedioxathiolane intermediate and the e
pisul
fi
de. The thiolysis, aminolysis, and reaction o
f alkyl hali
des withmodi
fied activated carbon occurred with the insertion o
f the organic moiety in the carbon matrix. Laser
photolysis at 266 nm in
t-butanol showed insertion o
f t-butoxi
de on the matrix. Consistent mechanisms
forthese reactions were
postulated. These results
provi
de additional evi
dence on the mechanism o
f reduction o
fSO
2 on carbons and the chemical nature o
f the intermediates, o
ffering a new method to modi
fy the
physicaland chemical
pro
perties o
f a carbon matrix by
functionalization with an organic moiety.