CHIRAL Rh/SiO2 CATALYSTS FOR ENANTIOSELECTIVE HYDROGENATION REACTIONS. THE ROLE OF (S,S)-DIPAMP AS CHIRAL MODIFIER AND STABILIZER ON METALLIC NANOPARTICLES SYNTHESIS

Mella, Claudio; Avila, Mauricio; Sanchez, Ariel; Marzialetti, Teresita; Reyes, Patricio; Ruiz, Doris

Abstract

Rhodium nanoparticles were successfully stabilized by the (S, S)-1,2-ethanediylbis[(2-ethoxyphenyl) phenylphosphine] ((S,S)-DIPAMP) deposited on SiO2 prepared by a facile reduction and impregnation method. The chiral catalysts obtained were efficient for the enantioselective hydrogenation reactions of prochiral compounds. The catalysts synthesized from [Rh(mu-OMe)(COD)](2) in the presence of different amounts of a ligand used as chiral stabilizer, showed good metal dispersion. As shown by TEM, the metal particle size ranged between 1 and 2 nm using stabilizer and 9.1 nm was achieved without chiral ligand. Other techniques were used to characterize the chiral catalysts such as X-ray diffraction (XRD), electron diffraction, thermogravimetric analysis (TGA) and N-2 adsorption-desorption isotherms. (S,S)-DIPAMP was used as the stabilizer of metal particles to prevent growing and agglomeration, and it also acts as chiral modifier inducing enantioselectivity in the asymmetric hydrogenation of 3,4-hexanodione (HD), ethyl pyruvate (EP), ketopantolactone (KP), and acetophenone (AP). Under specific conditions such as 25 degrees C, 40 bar of H-2 and substrate/Rh= 100, 1% Rh-(S,S)-DIPAMP/SiO2 chiral catalysts showed excellent catalytic performance with conversion and enantiomeric excess (ee) levels up to 99% and 54% respectively.

Más información

Título según WOS: CHIRAL Rh/SiO2 CATALYSTS FOR ENANTIOSELECTIVE HYDROGENATION REACTIONS. THE ROLE OF (S,S)-DIPAMP AS CHIRAL MODIFIER AND STABILIZER ON METALLIC NANOPARTICLES SYNTHESIS
Título de la Revista: Journal of the Chilean Chemical Society
Volumen: 58
Número: 4
Editorial: Sociedad Chilena de Química
Fecha de publicación: 2013
Página de inicio: 2125
Página final: 2130
DOI:

10.4067/S0717-97072013000400050

Notas: ISI