Abstract: | Only a minor yield of sulfur dioxide positive ions is eliminated from the meso- and dl-hydrobenzoin cyclic sulfite molecules under electron bombardment. Among the principal fragmentation products for both sulfites are very similar yields of ions with m/e 154 and 126, which contain sulfur most probably attached to a phenyl ring. Positive ions apparently corresponding to those of diphenylacetaldehyde, desoxybenzoin, and stilbene are minor products of the positive-ion fragmentation process of the sulfites. These three compounds along with sulfur dioxide are the products of the pyrolysis of the sulfites at 240-250°. The principal product from the meso-sulfite is desoxybenzoin, and from the dl-sulfite it is diphenylacetaldehyde. Mechanistic details are discussed. |