5278
drogen atoms attain almost complete equivalence in the molecular ion of toluene, and that a single 13Catom in position a 2or 13 , 4 - ~ r2, as shown in the present workis lost statistically in the path leading to C6H6+ions. Carbon-I3 label retentions in the C6H5+ion (eq 1) derived from toluene-a,l-l3C2(1)314further indicated that - H.
C?Hs.+
- CzHz
+C?H7+ + m* = 46.4
I
VI
.J l2%+
CjHs+
(1)
the tropylium ion formed is best represented as one in which the carbon atoms have all lost positional identity related to their toluene origin, Le., a randomized tropylium ion (11). The latter may arise (a) by a series of
VI1
@+
VI
+
VI1
C6H6+ions should be formed if path b alone is operative. However, label retentions shown in Table I reveal the Table I. High-Resolution Mass Spectral Peaks ~~
I
I1
I11
rv
(3) I
