Creat membership Creat membership
Sign in

Forgot password?

Confirm
  • Forgot password?
    Sign Up
  • Confirm
    Sign In
Creat membership Creat membership
Sign in

Forgot password?

Confirm
  • Forgot password?
    Sign Up
  • Confirm
    Sign In
Collection
For ¥0.57 per day, unlimited downloads CREATE MEMBERSHIP Download

toTop

If you have any feedback, Please follow the official account to submit feedback.

Turn on your phone and scan

home > search >

Liquid phase hydrogenation of nitrobenzene

Author:
Turáková, Mária   Salmi, Tapio   Er?nen, Kari   W?rn?, Johan   Murzin, Dmitry Yu.   Králik, Milan  


Journal:
Applied Catalysis A: General


Issue Date:
2015


Abstract(summary):

Highlights

Pd/C catalyst was tested in liquid phase hydrogenation of nitrobenzene in methanol.

Detailed analysis of the reaction mixture was performed using RP-HPLC.

Kinetic regime was attained at 30–70 °C temperature and 2–4 MPa pressure range.

Nitrobenzene attack by hydrogen is the rate determining step.

A complex reaction mechanism involving the intermediate Phsingle bond NOH has been suggested.

Abstract

Hydrogenation of nitrobenzene (NB) was carried out in methanol solutions (initial concentration 0.8 mol l−1) over a Pd/C catalyst (3 wt.% of Pd; reaction mixture contained 2.2 mg Pd l−1) over the pressure range of 2–4 MPa and temperature 30–70 °C in a laboratory scale batch reactor. Zero order kinetics was observed at hydrogen pressures above 2 MPa Under applied experimental conditions the apparent activation energy was 35 ± 1 kJ mol−1. A detailed analysis of the reaction mixture inspired the hypothesis that a C6H5–NO(H) moiety is formed on the catalyst surface and it undergoes further condensation to azoxybenzene (AOB) releasing water. However, very low concentrations of azobenzene (AB) and hydrazobenzene (HAB) in the reaction mixture indicate that the reaction route to the formation of aniline by hydrogenation of AOB to AB, hydrazobenzene (HAB) and subsequent hydrogenolysis to AN is of low probability. Hydrogenolysis of AOB to C6H5–NO(H) and C6H5–N(H), where the latter is hydrogenated to AN, is more likely. Based on the experimental observations a new reaction scheme for the heterogeneous catalytic hydrogenation of NB was proposed.

Graphical abstract



Page:
66-76


VIEW PDF

The preview is over

If you wish to continue, please create your membership or download this.

Create Membership

Similar Literature

Submit Feedback

This function is a member function, members do not limit the number of downloads