TY - JOUR
T1 - Immobilised chiral inducer on Pt-based mesoporous titanate nanotubes as heterogeneous catalysts for enantioselective hydrogenation
AU - Campos, Cristian H.
AU - Torres, Cecilia C.
AU - Osorio-Vargas, Paula
AU - Mella, Claudio
AU - Belmar, Julio
AU - Ruiz, Doris
AU - Fierro, José L.G.
AU - Reyes, Patricio
N1 - Funding Information:
The authors thank CONICYT for the financial support (FONDECYT GRANT 1061001, FONDECYT Initiation GRANT 11121631, FONDECYT postdoctoral 3140130 and 3140157) and REDOC.CTA doctoral network. P.A. Osorio-Vargas thanks MECESUP for doctoral fellowship.
PY - 2015/1/1
Y1 - 2015/1/1
N2 - A new series of chiral porous titanate nanotubes (TNTs) containing (-)-11-trimethoxysilyl-cinchonidine (TMS-CD) moieties were synthesized via direct surface anchorage. These hybrid solids were used as supports for Pt (1 wt%) catalysts and evaluated in heterogeneous enantioselective hydrogenation of 1-phenyl-1,2-propanodione. The supports and catalysts were characterized by a variety of techniques including TGA, N2 adsorption isotherms, solid state NMR (13C and 29Si), XRD, HR-TEM, DRIFTs and XPS. For the best system the hydrogen pressure, solvent effects and recycles were studied. The maximum enantiomeric excess (ee) and the turnover frequency obtained under optimized conditions with 1% Pt/TNT-CD were 37% (at 15 wt% nominal content of TMS-CD) and 165 min-1 (at 10 wt% nominal content of TMS-CD), respectively. The variation of H2 pressure and solvent affects both the activity and enantioselectivity due to the substrate adsorption on the metal active sites. Additionally, these heterogeneous catalysts can also be easily recycled and reused for three times without the loss of activity and enantioselectivity. After the 3rd cycle, catalyst deactivation due to the leaching of Pt nanoparticles and modifier hydrogenation in the feed was detected.
AB - A new series of chiral porous titanate nanotubes (TNTs) containing (-)-11-trimethoxysilyl-cinchonidine (TMS-CD) moieties were synthesized via direct surface anchorage. These hybrid solids were used as supports for Pt (1 wt%) catalysts and evaluated in heterogeneous enantioselective hydrogenation of 1-phenyl-1,2-propanodione. The supports and catalysts were characterized by a variety of techniques including TGA, N2 adsorption isotherms, solid state NMR (13C and 29Si), XRD, HR-TEM, DRIFTs and XPS. For the best system the hydrogen pressure, solvent effects and recycles were studied. The maximum enantiomeric excess (ee) and the turnover frequency obtained under optimized conditions with 1% Pt/TNT-CD were 37% (at 15 wt% nominal content of TMS-CD) and 165 min-1 (at 10 wt% nominal content of TMS-CD), respectively. The variation of H2 pressure and solvent affects both the activity and enantioselectivity due to the substrate adsorption on the metal active sites. Additionally, these heterogeneous catalysts can also be easily recycled and reused for three times without the loss of activity and enantioselectivity. After the 3rd cycle, catalyst deactivation due to the leaching of Pt nanoparticles and modifier hydrogenation in the feed was detected.
KW - 1-Phenyl-propane-1,2-dione
KW - Chiral supports
KW - Enantioselective hydrogenation
KW - Titanate nanotubes catalysts
UR - http://www.scopus.com/inward/record.url?scp=84949121162&partnerID=8YFLogxK
U2 - 10.1016/j.molcata.2014.11.026
DO - 10.1016/j.molcata.2014.11.026
M3 - Article
AN - SCOPUS:84949121162
SN - 1381-1169
VL - 398
SP - 190
EP - 202
JO - Journal of Molecular Catalysis A: Chemical
JF - Journal of Molecular Catalysis A: Chemical
ER -