The reduction of
SO
2 on carbon
s proceed
s through reactive intermediate
s bound to the carbon matrix, whichwere po
stulated to be 1,2-oxathiene 2-oxide (or
sultine), and 1,3,2-dioxathiolane that decompo
se
s to producean epi
sulfide and CO
2. The reactivity of the
se intermediate
s wa
s studied in thi
s work through
several reaction
s,u
sing XPS and NMR
spectra to po
stulate their mechani
sm
s. When modified activated carbon obtained afterreaction with SO
2 at 630
s/entitie
s/deg.gif">C wa
s heated at 900
s/entitie
s/deg.gif">C, it wa
s ob
served that the change
s of the XPS
spectrumre
sulted from the forward reaction of decompo
sition of the oxidized intermediate with S-tran
sfer to producethe epi
sulfide and CO
2 and the rever
se reaction with expul
sion of SO
2. Strong ba
se
s hydrolyzed thedioxathiolane intermediate and the epi
sulfide. The thioly
si
s, aminoly
si
s, and reaction of alkyl halide
s withmodified activated carbon occurred with the in
sertion of the organic moiety in the carbon matrix. La
serphotoly
si
s at 266 nm in
t-butanol
showed in
sertion of
t-butoxide on the matrix. Con
si
stent mechani
sm
s forthe
se reaction
s were po
stulated. The
se re
sult
s provide additional evidence on the mechani
sm of reduction ofSO
2 on carbon
s and the chemical nature of the intermediate
s, offering a new method to modify the phy
sicaland chemical propertie
s of a carbon matrix by functionalization with an organic moiety.