The hydrogenation of HO‐terminated telechelic polybutadienes in the presence of a homogeneous hydrogenation catalyst based on tris(triphenylphosphine)rhodium chloride

The hydrogenation kinetics of multiple bonds in HO‐terminated telechelic polybutadienes was investigated using two types of these prepolymers prepared by the anionic and radical polymerization. The rate of addition of hydrogen to the π‐bonds of these polydienes in the presence of tris(triphenylphosphine) rhodium chloride as a homogeneous hydrogenation catalyst was determined by the chemical structures of the starting polydienes, their concentration in the solvent, the partial hydrogen pressure, the concentration of the catalyst, and the temperature. The effect of kinetic parameters given above on the rate of hydrogenation reaction can be interpreted in the sense of Wilkinson's reaction mechanism of the hydrogenation of alkenes in the presence of the Rh(I)‐complex. Due to the predominant 1,2‐structural units, the anionic prepolymer reacted twice as quickly with hydrogen (k = 0.093 mol−1 dm3 s−1) compared with the radical prepolymer (k = 0.045 mol−1 dm3 s−1). During the hydrogenation of multiple bonds there is a partial loss of hydroxy groups in modified telechelic prepolymers; the extent of this reaction depends on reaction conditions of the hydrogenation reaction.