Small amounts of SO3H-functionalised room temperature synthesized ionic liquids efficiently dehydrate aqueous xylose to furfural under microwave heating at mild reaction conditions. The RT-ionic liquid catalysts were also found to be effective catalysts for the two step one-pot simultaneous hydrolysis and dehydration of a lignocellulosic waste biorefinery-derived syrup enriched in C5 sugar oligomers.
18 June 2007 in European Journal of Inorganic Chemistry
In this paper we report on a comparative study of the non-alternating CO–C2H4 copolymerization catalyzed by neutral PdII complexes with the phosphine–sulfonate ligands bis(o-methoxyphenyl)phosphinophenylenesulfonate and bis(o-methoxyphenyl)phosphino-ethylenesulfonate. The former ligand, featuring a lower skeletal flexibility, has been found to form more active catalysts as well as produce polyketones with higher molecular weight and higher extra-ethylene incorporation. Operando high-pressure NMR studies have allowed us to intercept, for the first time, PdII(phosphine–sulfonate) β-chelates in the non-alternating copolymerization cycle, while model organometallic reactions have contributed to demonstrate that PdII (phosphine–sulfonate) fragments do not form stable carbonyl complexes. The opening of the β-chelates has been found to be a viable process by either comonomer, which contrasts with the behaviour of PdII (chelating diphosphine) catalysts for the perfectly alternating copolymerization.