| 摘要 |
A process is claimed for the telomerisation of conjugated dienes with polyols in the presence of a Pd catalyst. The diene is reacted with a conc. aq. soln. of the polyol (10-90%), the Pd catalyst being associated with a ligand which aids solubility in the aq. medium. Pref., the polyol is a non-reducing mono-, di- or tri- saccharide - a non-reducing sugar, more pref. sucrose, trichalose or a 1-12C alkyl glucoside. Alternatively it may be a polyol resulting from hydrogenation of a sugar e.g. sorbitol, xylitol, erythrite, maltitol, lactitol and palatinate, or a prod. resulting from dehydration of a hydrogenated sugar i.e. sorbitan or isosorbitan. The di-ene component is a 4-10C conjugated diene - more pref. butadiene, isoprene or piperylene. The Pd catalyst is a Pd(II) salt - associated with a water sol. phosphine - or a Pd(O) deriv. associated with a non-coordinating ligand and a water sol. phosphine: the phosphine is more pref. triphenyl-phosphine trisulphonate (Na salt) (TPPTS). ADVANTAGE - The process avoids loss of dienes by dimerisation or telomerisation with the solvent, which were disadvantages of former processes, using a sec. or tert. alcohol as solvent. The new process uses water as the solvent. Comparable amts. of catalyst are used compared with previous techniques. |
