IMPROVED SYNTHESES AND COMPLETE CHARACTERIZATION OF SOME POLYCHLORONAPHTHALENES

Improved methods of preparation are reported for the following isomeri cally pure polychloronaphthalenes: 1,2,3,4,5,6,7- and 1,2,3,4,5,6,8-he ptachloro; 1,2,3,4,5,6-, 2,3,4,5,6,7-, and 1,2,4,5,6,7-hexachloro; 2,3 ,4,5,6-pentachloro; plus the mixture of 1,2,3,4,6,7- and 1,2,3,5,6,7-h exachloro isomers. Sufficient quantities of these environmentally ubiq uitous materials have been obtained so that for the first time complet e physicochemical data are presented that unambiguously characterize t hese compounds. Also included is an X-ray crystallographic analysis of 2,3,4,5,6,7-hexachloronaphthalene which crystallized in the space gro up P212121 with cell dimensions: a = 11.2187 (13), b = 14.7768 (22), a nd c = 6.898 (3). The structure was determined by direct methods and w as refined by a full-matrix least-squares calculation to give a final R value of 0.034 for 944 unique reflections with I/sigma(I) > 2.5.