Application of carbonate solvents in the telomerisation of butadiene with carbon dioxide

This contribution describes the synthesis of the delta-lactone 2-ethylidene-6-heptene-5-olide from the reactants 1,3-butadiene and carbon dioxide in carbonate solvents. Palladiumbis(acetyl acetonate) in combination with the ligand triphenylphosphine is used as homogeneous catalyst. At a reaction temperature of 60-100 degrees C yields of the delta-lactone up to 50% can be achieved in a reaction time of 4 h. The use of green solvents like carbonates in this reaction is new, as mainly toxic nitrile solvents such as acetonitrile are known from literature till now. In this work we examined in detail the application and the influence on the selectivity of linear carbonates (dimethyl and diethyl carbonate), cyclic carbonates (ethylene carbonate, propylene carbonate and butylene carbonate) and glycerol carbonate esters in the telomerisation of butadiene with carbon dioxide. (C) 2006 Elsevier B.V. All rights reserved.