| Title:  1,1-Diphenyl-2-picrylhydrazyl (Free Radical) CAS Registry Number:  1898-66-4 CAS Name:  2,2-Diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl Additional Names:  DPPH Literature References:  Prepn:  Goldschmidt, Renn, Ber. 55B, 628 (1922); Lyons, Watson, J. Polym. Sci. 18, 141 (1955); Arbuzov, Valitova, Zh. Obshch. Khim. 27, 2354 (1957).  Structure:  Poirier et al., J. Org. Chem. 17, 1437 (1952). Properties:  Large, dark violet prisms from benzene + petr ether, mp 127-129° (dec).  mp also reported as 132-133°. Melting point:  mp 127-129° (dec); mp also reported as 132-133° Use:  Analytical reagent for reducing substances:  Schenck et al., Tetrahedron Lett. 1967, 193.  |