ISOMERIZATION IN HYDROGENATION OF 1,4-POLYBUTADIENES BY DIIMIDE FROM TOLUENESULFONYL HYDRAZIDE

In the reported experiments, 1,4-polybutadiene was hydrogenated by in situ generated diimide obtained in the process of heating toluenesylfonyl hydrazide in xylene. The course of the reaction was studied by 13C-NMR spectroscopy. In this study particular attention has been given to isomerization. Experimental data are presented which show that the remaining double bonds in the partially hydrogenated cis-1,4-PBC and trans-1,4-PBD have mixed cis/trans structural units with trans at higher concentration. It remains to be established, however, as indicated previously, whether the isomerization is a part of the hydrogenation reaction itself or it is just a side reaction caused by the presence of the reactants, reaction products, or even some traces of impurities in the hydrogenation medium.