Metathesis degradation of polymers obtained by grignard‐wurtz reaction of partially α‐brominated 1,4‐polybutadiene

Abstract1,4‐Polybutadiene was partially brominated at the methylene groups with N‐bromosuccinimide. Then, by means of Grignard‐Wurtz reactions, the following substituents were introduced: isopropyl, butyl, pentyl, cyclohexyl, phenyl, 4‐methylphenyl, 4‐ethylphenyl, 3,4‐dimethylphenyl, 4‐isopropylphenyl, 4‐fluorophenyl, 3‐trifluorophenylmethyl, 4‐chlorophenyl, benzyl, 2‐methylbenzyl, and 4‐methylbenzyl. The modified polymers (ca. 20% of the units substituted) were degraded to low molecular products with E‐4‐octene in the presence of the catalyst WCl6/(CH3)4Sn. The degradation products were separated by gas chromatography and identified by mass spectrometry. Isomeric substituents, isomeric units, and isomeric segments in the polymers could be distinguished. — In Grignard‐Wurtz reactions, transfer reactions with toluene as solvent and simultaneous reactions with two Grignard reagents (4‐methylphenyl and 4‐methylbenzyl compounds) were also investigated.