Homogeneous initiation of aromatic nucleophilic substitution in a polyhaloarene-sodium sulfide-dipolar aprotic solvent system

The polycondensation of polyhaloarenes with sodium sulfide in a medium of dipolar aprotic solvents provides the most widespread method for the synthesis of polyarylene sulfides. The authors have established that the presence of the solid phase Na/sub 2/S x 9H/sub 2/O is not sufficient condition for the initiation of the polycondensation of polyhaloarenes with sodium sulfide, and the authors showed that the initiation of this reaction under homogeneous conditions is possible. For the case of hexafluorobenzene by means of /sup 19/F NMR spectroscopy the authors established the formation of disubstituted products in its reaction with a blue solution of Na/sub 2/S x 9H/sub 2/O in 1-methyl-2-pyrrolidinone. For the investigation the authors used recrystallized Na/sub 2/S x 9H/sub 2/O, freshly distilled solvents, and chromatographically pure polyhaloarenes. The /sup 19/F NMR spectra were determined on a JEOL FX-900 spectrometer with a working frequency for /sup 19/F of 84.25 MHz (internal standard C/sub 6/F/sub 6/, delta -162.9 ppm relative to CFCl/sub 3/).