Metal-Free H2 Activation for Highly Selective Hydrogenation of Nitroaromatics Using Phosphorus-Doped Carbon Nanotubes.
ACS Appl Mater Interfaces
; 12(1): 654-666, 2020 Jan 08.
Article
in En
| MEDLINE
| ID: mdl-31808342
ABSTRACT
We reported that phosphorus-doped carbon nanotubes (P-CNTs), showing metal-like properties, can efficiently promote metal-free hydrogenation of nitrobenzene (1a) to aniline (2a) using molecular hydrogen (H2) as a reducing reagent under very mild conditions with a reaction temperature of only 50 °C. The kinetics of 1a hydrogenation over P-CNT reveals that the hydrogenation rate of 1a is a first-order dependence on the H2 pressure and the P-CNT loading level, and a zero-order dependence on 1a concentration, demonstrating the rate-determining step of H2 adsorption and activation over P-CNT. The activation energy of P-CNT-catalyzed 1a hydrogenation is 43 ± 3 kJ mol-1 with the turnover frequency around 3.60 ± 0.12 h-1 at 50 °C. In addition to 1a, the general applicability of the P-CNT-promoted metal-free hydrogenation process is further demonstrated by applying various functionalized nitroaromatics with wide industrial interest. The P-CNT shows both excellent yields and selectivities to hydrogenation with respect to reducible, labile, and strong leaving groups on the nitroaromatics molecules. The stability and reusability of the P-CNT demonstrate up to eight-time recycling without evident loss of activity and selectivity. In addition to hydrogenation, metal-free catalytic transfer hydrogenation of 1a is achieved with P-CNT using diverse hydrogen sources, including hydrazine hydrate (N2H4·H2O), carbon monoxide/water (CO/H2O), and formic acid/triethylamine (HCOOH/Et3N).
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
ACS Appl Mater Interfaces
Journal subject:
BIOTECNOLOGIA
/
ENGENHARIA BIOMEDICA
Year:
2020
Document type:
Article
Affiliation country:
China