Effect of the carbon nanotube basicity in Pd/N-CNT catalysts on the synthesis of R-1-phenyl ethyl acetate

Abstract

Catalytic activities of palladium catalysts supported on activated carbon and carbon nanotubes were investigated in the one-pot synthesis of R-1-phenylethyl acetate in combination with an immobilized lipase in toluene. Palladium catalysts on carbon nanotubes with nitrogen-containing surface groups were prepared by incipient wetness impregnation. The basic N-CNT support was synthesized by post-treating oxidized CNTs in gaseous NH3 at high temperature, prior to Pd addition. The basic character of the support was adjusted by controlling the temperature of the posttreatment step. The results showed that the desired product yield was enhanced over palladium catalysts with the lowest basicity.

One-dimensional nitrogen-containing carbon nanostructures

“…Sahin et al [476] prepared NCNT/Pd catalysts using the incipient wetness impregnation technique. Noble metalcoated NCNTs were also produced on oxidized silicon substrates using catalytic CVD from an aerosol containing droplets of a solution of ferrocene and an acetylacetonate salt of a noble metal (Pt, Ru or Pd) in CH 3 CN [477].…”

“…N-doping was confirmed to lead to the improved selectivity towards the C=C bond hydrogenation and high stability of the catalysts. Moreover, Pd/NCNTs catalyst was used for the synthesis of R-1-phenyl ethyl acetate [476], while Pd/NCNFs was used for (Z)-selective partial hydrogenation of internal alkynes [581]. Chen et al [283] showed that Pd NPs supported on NCNTs show narrower size distribution, compared to the ones deposited over O-functionalized CNTs.…”

Palladium catalysts supported on N-functionalized hollow vapor-grown carbon nanofibers: The effect of the basic support and catalyst reduction temperature

“…The maximum yield of (R)-1-phenylethyl acetate over Entry 2.0 was 35% at 98% conversion of acetophenone corresponding to 36% selectivity over 312.5 mg of Pd-catalyst in combination with 62.5 mg of immobilized lipase. The desired product yield was improved by using Pd-N-VGCF catalysts comparing to the yields obtained with Pd on active carbon as the maximal yield reported for the latter catalyst was 15% at 66% conversion of acetophenone [35]. In addition for one pot reaction with Pd on ac-tive carbon the major product was ethyl benzene due to the acidic character of the support.…”