E. Mizushima et al., Palladium-catalysed carbonylation of aryl halides in ionic liquid media: high catalyst stability and significant rate-enhancement in alkoxycarbonylation, GREEN CHEM, 3(2), 2001, pp. 76-79
Palladium-catalysed carbonylation of aryl halides with alcohols or NEt2H pr
oceeds in ionic liquid media (1-butyl-3-methylimidazolium tetrafluoroborate
or hexafluorophosphate). The catalyst/ionic liquid mixture could be recycl
ed, after separation of the product by either distillation or extraction wi
th ether. Carbonylation with alcohols forming benzoates was greatly acceler
ated by the use of ionic liquid.