Repositori URV

Identificador: TDX:843

Handle: https://hdl.handle.net/20.500.11797/TDX843

Autors:
Aghmiz, Ali

Resum:
New catalysts for the carbonylation and hydrogenation of alkenes in homogeneous biphasic systemsThe work entitled 'New catalysts for the carbonylation and hydrogenation of alkenes in homogeneous and biphasic systems' consists of three chapters:Chapter I: This chapter studies the hydroformylation and hydrocarboxylation of alkenes in aqueous and perfluorinated biphasic systems. In particular:1) The hydroformylation of vinylarenes in aqueous biphasic systems with rhodium complexes and sulfonated diphosphines. The sulfonated diphosphines used are the achiral diphosphines 1,3-bis [(di-m-sulfonatophenyl)phosphino]propane (dpppts) and 1,4-bis [(di-m-sulfonatophenyl)phosphino]butane (dppbts), and the chiral sulfonated diphosphines (S,S)-2,4-bis [di(m-sulfonatophenyl)phosphino]pentane ((S,S)-BDPPTS) and (R,R)-1,2-bis [di (m-sulfonatophenyl)phosphinomethyl]cyclobutane ((R,R)-CBDTS). In this study it was observed that the activity of the catalytic systems depends on the pH of the medium. In basic medium, these systems are active because [RhH(CO)2(P-P)] species are formed, which are precursors of the active species [RhHCO(P-P)]. In neutral medium, however, these species are not formed, which leads to a drastic decrease in activity.2) The hydroformylation in perfluorinated biphasic systems with rhodium /P(C6H4-p-OCH2C7F15)3 (L1). Those systems are active in the hydroformylation of 1-octene and the results are similar to those obtained with triphenylphosphine in homogeneous systems, which means that the group O-CH2 minimizes the electroattractive effects of the perfluorinated chain on the phosphorus atom of the ligand. The catalytic phase was recycled up to three times with the same activity and selectivity of the system. 3) The hydrocarboxylation of styrene and other vinyl arenes i