Process for reducing aromatic nitro compounds with supported catalyst

Patent metadata

Field	Value
Publication number	US-11712680-B2
Application number	US-202217820111-A
Country	US
Kind code	B2
Filing date	Aug 16, 2022
Priority date	Mar 20, 2019
Publication date	Aug 1, 2023
Grant date	Aug 1, 2023

Abstract

A supported catalyst having rhodium particles with an average diameter of less than 1 nm disposed on a support material containing magnetic iron oxide (e.g. Fe 3 O 4 ). A method of producing the supported catalyst and a process of reducing nitroarenes to corresponding aromatic amines employing the supported catalyst with a high product yield are also described. The supported catalyst may be recovered with ease using an external magnet and reused.

First claim

The invention claimed is:

1. A process of reducing an aromatic nitro compound to an aromatic amine compound, the method comprising:
mixing the aromatic nitro compound with a hydrogen transfer reagent in the presence of a supported catalyst and a solvent to form a reaction mixture; and
heating the reaction mixture thereby forming the aromatic amine compound;
wherein the supported catalyst comprises:
a support material comprising Fe 3 O 4 ; and
a catalytic material comprising rhodium disposed on the support material;

wherein the catalytic material is in the form of subnanoparticles having an average particle size of 0.2-0.99 nm;
the rhodium is present in an amount of 1-20 wt % relative to a total weight of the supported catalyst; and
the support material is devoid of Al 2 O 3 .

2. The method of claim 1 , wherein the Fe 3 O 4 in the supported catalyst is in the form of nanospheres.

3. The method of claim 2 , wherein the nanospheres have an average particle size of 5-25 nm.

4. The method of claim 1 , wherein the rhodium in the supported catalyst is present in an amount of 4-10 wt % relative to a total weight of the supported catalyst.

5. The method of claim 1 , wherein the supported catalyst has a BET surface area in a range of 100-180 m 2 /g.

6. The method of claim 1 , wherein the supported catalyst has a saturation magnetization value in a range of 50-75 emu/g.

7. The process of claim 1 , wherein the hydrogen transfer reagent is tetrahydroxydiboron.

8. The process of claim 1 , wherein the supported catalyst is present in an amount of 1-50 g/mol relative to a molar amount of the aromatic nitro compound.

9. The process of claim 1 , wherein the reaction mixture is heated at a temperature of 30-80° C.

10. The process of claim 1 , wherein the reaction mixture is heated for 0.5-300 minutes.

11. The process of claim 1 , wherein the solvent is water.

12. The process of claim 1 , wherein the aromatic nitro compound is at least one selected from the group consisting of nitrobenzene, 2-nitrotoluene, 3-nitrotoluene, 4-nitrotoluene, 3-nitroaniline, 4-nitroanisole, 1,3-dimethyl-2-nitrobenzene, 2-nitrophenol, 4-nitrophenol, and 1-chloro-4-nitrobenzene.

13. The process of claim 1 , wherein the aromatic amine compound is at least one selected from the group consisting of aniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 1,3-diaminobenzene, 4-methoxyaniline, 2,6-dimethylaniline, 2-aminophenol, 4-aminophenol, and 4-chloroaniline.

14. The process of claim 1 , which has an aromatic amine compound yield of 35-99.9 mole % relative to a molar amount of the aromatic nitro compound.

15. The process of claim 1 , further comprising:
separating the supported catalyst from the aromatic amine compound; and
reusing the supported catalyst.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Shaikh M Nasiruzzaman
• Aziz Md Abdul

Classifications

• B01J35/70

  characterised by their crystalline properties, e.g. semi-crystalline (catalysts comprising carbon B01J21/18; molecular sieves B01J29/00) · CPC title

• B01J35/45

  Nanoparticles · CPC title

• B01J2235/30

  Scanning electron microscopy; Transmission electron microscopy · CPC title

• B01J35/393

  Metal or metal oxide crystallite size · CPC title

• B01J2235/00

  Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties · CPC title