New dicationic and monocationic palladium complexes with 2,2'-bipyridine ligands bearing perfluorinated ponytails have been prepared and used as catalysts for CO/4-tert-butylstyrene (TBS) and CO/styrene (ST) copolymerization in supercritical carbon dioxide (scCO2) and in CO2-expanded liquids. Best catalytic performances were achieved carrying out the copolymerization in carbon dioxide expanded substrates in the presence of 2,2,2-trifluoroethanol (TFE). The dicationic systems with 5,5’-substituted ligands [Pd(N-N)2][X]2 generated the most active and productive catalysts with up to 532 g copolymer CP/g Pd•h for CO/TBS and led to polyketones with high molecular weight and narrow polydispersity (molecular weight up to Mw = 692000 for CO/ST; Mw/Mn = 1.2-3.3). MALDI-TOF mass spectrometry analysis of copolymer end groups revealed that the main initiation and termination steps involved the insertion of the alkene into the Pd-H bond and the -H-elimination on the Pd-alkyl bond, respectively

The catalytic hydrocarboxylation of linear alkenes to carboxylic acids using supercritical carbon dioxide as a solvent was studied. High selectivities in acids have been obtained. The best results were achieved when adding a perfluorinated surfactant to the reaction mixture (93 % conversions and ca.

Hydroformylation of 1-octene in supercritical carbon dioxide was performed using new soluble rhodium-phosphite catalytic systems. A high conversion and selectivity in the corresponding aldehydes were obtained. The ligands were synthesised and its coordination to Rh(I) complexes was studied. The reactivity of rhodium precursors with these ligands towards CO and H 2 was analyzed by high pressure IR and NMR spectroscopies.

The presence of peracetylated β‐cyclodextrin in the reaction medium allowed for an increase in the solubility of rhodium species modified by alkyl P‐donor ligands in the catalytic hydroformylation of 1‐octene in supercritical carbon dioxide. These results were explained by considering an interaction between the peracetylated β‐cyclodextrin and the P‐donor ligands.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

The palladium catalysed hydroesterification of linear alkenes to obtain carboxylic esters in supercritical carbon dioxide is studied for the first time. Palladium complexes with phosphines containing -CF 3 groups are used as catalyst precursors. For 1-hexene, conversions into the corresponding methyl esters up to 67% were obtained using [PdCl 2 (PhCN) 2 ]/P(3,5-CF 3 C 6 H 4 ) 3 .