Stereospecific Addition of Hydrogen to Fumaric Acid in irradiated Single Crystals of Succinic Acid

Abstract

Pooley and Whiffon1 reported an interesting proton–deuteron exchange reaction of the primary radical HOOCCHβHβ′CHαCOOH (or DOOCCHβHβ′CHαCOOD)2 in an irradiated crystal of succinic acid. By means of an electron spin resonance technique, they detected DOOCCDβ Hβ′CHCOOD in addition to the primary species, but they did not detect DOOCCHβ Dβ′CHCOOD, nor DOOCCH2CDCOOD (hyperfine splitting constant for Hβ is larger than that for Hβ′2). It was shown later3,4, however, that formation of this DOOCCDβHβ′CHCOOD species is associated with an unidentified impurity in the crystal; the impurity is too low in concentration to be detected with ordinary experimental techniques. During the present investigation it was found that fumaric acid behaved quite similarly to the impurity: in a crystal of succinic acid which contained 0.001 mole fraction of fumaric acid, the ratio was found to be 0.2, that is, the same as the ratio found in the impure crystal3.