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Hydrogenation of Low Molecular Weight Polymers in Ionic Liquids and the Effects of Added Salt
Author(s) -
MacLeod S.,
Rosso R. J.
Publication year - 2003
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200202203
Subject(s) - chemistry , tppts , catalysis , ionic liquid , nitrile , polybutadiene , polymer chemistry , polymer , natural rubber , triphenylphosphine , salt (chemistry) , nitrile rubber , tetrafluoroborate , organic chemistry , copolymer , rhodium , hydroformylation
Abstract The biphasic hydrogenations of a number of polymeric materials, polybutadiene (PBD), nitrile‐butadiene rubber (NBR) and styrene‐butadiene rubber (SBR), were investigated in a toluene/ N,N′‐ butylmethylimidazolium tetrafluoroborate, (BMI + BF 4 − ) system with a water‐soluble analogue of Wilkinson's catalyst, RhCl(TPPTS) 3 (TPPTS=triphenylphosphine, trisulfonated) at 100 °C and 3.1 MPa. The catalyst shows reasonable activity within ionic liquids with PBD although it was necessary in the case of NBR and SBR to add water as a co‐solvent to solubilize the catalyst within the ionic media. Both the extent of hydrogenation and the ratio of the internal 1,4‐olefins to vinyl 1,2‐olefins were monitored. A clear preference for the external olefins was observed even within NBR and SBR where functionalization on the polymer might enhance the degree of hydrogenation of the internal olefins. The effect of adding NaCl to the PBD system was also investigated. The addition of salt decreases the activity of the catalyst but has no effect on the preference for the hydrogenation of vinyl olefins.