IMPROVED SYNTHESES AND COMPLETE CHARACTERIZATION OF SOME POLYCHLORONAPHTHALENES

Improved methods of preparation are reported for the following isomerically pure polychloronaphthalenes: 1,2,3,4,5,6,7- and 1,2,3,4,5,6,8-heptachloro; 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-hexachloro isomers. Sufficient quantities of these environmentally ubiquitous materials have been obtained so that for the first time complete physicochemical data are presented that unambiguously characterize these compounds. Also included is an X-ray crystallographic analysis of 2,3,4,5,6,7-hexachloronaphthalene which crystallized in the space group P212121 with cell dimensions: a = 11.2187 (13), b = 14.7768 (22), and c = 6.898 (3). The structure was determined by direct methods and was 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.