The reaction of d0-, 1, l-d2-, 2,2-d2- and 4,4,4-d3-l-butanethiols with H and D atom have been investigated at room temperature, under 530 and 2660 Pa, using a conventional discharge flow apparatus. Butane and 1-butene were produced mainly. Small amounts of ethylene, propylene, x propane, and ethane were also detected (Table 1). Relative amount of butane increased slightly as conversion increased, while that of 1-butene decreased (Figs. 1 and 2). The decrease of 1-butene could be accounted for by secondary reactions with H/D atom (Table 2). The numer of D atoms in unreacted thiols was unaffected by the reaction. The number of D atoms in butane remained unchanged with that in the substrate thiols when the reaction was carried out with H atom, but it increased precisely by one when reacted with D atom (Table 3). The number of D atoms in 1-butene remained unchanged in the reaction of d0-, 1, l-d2- and 4,4,4-d3-l-butanethiols, irrespective of the reaction partner, H or D atom. But one D atom was lost in 1-butene from 2,2-d2-l-butanethiol (Table 4). Deuterium distribution in butane and 1-butene can be, explained by abstraction and addition reaction between butyl radical and H/D atom. However, the amount of 1-butene can not be explained only by these reactions, since the abstraction/addition ratio is estimated to be small, ca. 0.05 (Table 5). The D atom distribution and relative amount of 1-butene were taken in support for concomitant elimination of mercapto group and hydrogen at the second position from the substrate thiols. From these results, the following scheme is proposed.
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