Methods of reducing dinitrogen

Patent metadata

Field	Value
Publication number	US-2022396491-A1
Application number	US-202017775417-A
Country	US
Kind code	A1
Filing date	Dec 3, 2020
Priority date	Dec 3, 2019
Publication date	Dec 15, 2022
Grant date	—

Abstract

The invention provides a method of reducing dinitrogen to produce at least one haloamine compound, the method comprising: contacting a cathode comprising a dinitrogen-activating electrocatalytic composition with an electrolyte; providing dinitrogen, a reducible source of halogen and a source of hydrogen for reaction at the cathode; and applying a potential at the cathode sufficient to reduce the dinitrogen on the dinitrogen-activating electrocatalytic composition in the presence of the reducible source of halogen and the source of hydrogen, thereby producing at least one haloamine compound.

First claim

1 . A method of reducing dinitrogen to produce at least one haloamine compound, the method comprising:
contacting a cathode comprising a dinitrogen-activating electrocatalytic composition with an electrolyte; providing dinitrogen, a reducible source of halogen and a source of hydrogen for reaction at the cathode; and applying a potential at the cathode sufficient to reduce the dinitrogen on the dinitrogen-activating electrocatalytic composition in the presence of the reducible source of halogen and the source of hydrogen, thereby producing at least one haloamine compound.

2 . The method according to claim 1 , wherein the reducible source of halogen and the source of hydrogen are provided in the electrolyte for reaction at the cathode.

3 . The method according to claim 1 , wherein the halogen is chlorine and the at least one haloamine compound comprises at least one selected from the group consisting of NCl 3 , NHCl 2 and NH 2 Cl.

4 . The method according to claim 1 , wherein the reducible source of halogen comprises at least one selected from the group consisting of hypochlorite anion (OCl − ), hypochlorous acid (HOCl) and dichlorine (Cl 2 ).

5 . The method according to claim 1 , wherein the potential is in the range of +250 mV to −500 mV relative to the reversible hydrogen electrode (RHE).

6 . The method according to claim 1 , wherein the reducible source of halogen is dissolved in the electrolyte at a concentration of at least 1×10 −5 mol/litre.

7 . (canceled)

8 . The method according to claim 1 , wherein the electrolyte is an acidic aqueous electrolyte.

9 . The method according to claim 1 , wherein the electrolyte comprises a solution of halide.

10 . The method according to claim 9 , wherein the halide concentration is at least 0.05 mol/litre.

11 . The method according to claim 1 , further comprising producing the reducible source of halogen by oxidising a halide anion in the electrolyte at an anode, wherein the reducible source of halogen is transported in the electrolyte from the anode for reaction with the reduced dinitrogen.

12 . (canceled)

13 . The method according to claim 11 , wherein the halide anion is oxidised at the anode to produce the reducible source of halogen with a faradaic efficiency of at least 20%.

14 . (canceled)

15 . The method according to claim 1 , further comprising introducing an external feed to an electrochemical cell comprising the cathode, wherein the external feed comprises at least a portion of the reducible source of halogen provided for reaction at the cathode.

16 . The method according to claim 1 , wherein the dinitrogen-activating electrocatalytic composition comprises a metallic composition.

17 . (canceled)

18 . (canceled)

19 . The method according to claim 16 , wherein the metallic composition is in the form of micro- and/or nanoparticles.

20 . (canceled)

21 . The method according to claim 1 , further comprising dissolving the dinitrogen in the electrolyte by contacting the electrolyte with dinitrogen gas at a partial pressure of between 0.7 bar and 100 bar.

22 . The method according to claim 1 , wherein the dinitrogen is converted to the at least one haloamine compound with a faradaic efficiency of at least 40%.

23 . The method according to claim 1 , further comprising recovering a product composition comprising the at least one haloamine compound from a reaction zone of an electrochemical cell in which the haloamine was produced.

24 . The method according to claim 23 , wherein at least one of the following is extant:
the product composition is an acidic aqueous composition and the haloamine compound is a chloramine compound, and wherein the method further comprises neutralising or diluting the acidic aqueous composition to increase a concentration of NH 2 Cl therein; or, the method further comprises concentrating the product composition to produce a concentrated composition of haloamine compound; or the product composition is an aqueous composition and the method further comprises extracting the haloamine compound from the aqueous composition into a non-aqueous solvent.

25 . (canceled)

26 . (canceled)

27 . The method according to claim 1 , further comprising separating the haloamine compound from the electrolyte by partitioning the haloamine compound into a gas phase.

28 . The method according to claim 1 , further comprising converting the at least one haloamine compound to ammonia (NH 3 ) or ammonium cation (NH 4 + ).

29 . The method according to claim 28 , wherein the converting comprises hydrolysing the haloamine with an acid and removing a reducible source of halogen produced as a by-product of the hydrolysing.

30 . (canceled)

31 . (canceled)

32 . A method of producing ammonia or an ammonium salt from dinitrogen, the method comprising:
contacting a cathode comprising a dinitrogen-activating electrocatalytic composition with an electrolyte; providing dinitrogen, a reducible source of halogen and a source of hydrogen for reaction at the cathode; applying a potential at the cathode sufficient to reduce the dinitrogen on the dinitrogen-activating electrocatalytic composition in the presence of the reducible source of halogen and the source of hydrogen, thereby producing at least one haloamine compound; and converting the at least one haloamine compound to ammonia or an ammonium salt.

Assignees

• Univ Monash

Inventors

• Vallana Federico M Ferrero
• Macfarlane Douglas R
• Simonov Alexandr Nikolaevich

Classifications

• C25B11/089

  Alloys · CPC title

• C25B1/26

  Chlorine; Compounds thereof (by simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine C25B1/34) · CPC title

• C01B21/091

  Chloramine, i.e. NH2Cl or dichloramine, i.e. NHCl2 · CPC title

• C25B15/081

  Supplying products to non-electrochemical reactors that are combined with the electrochemical cell, e.g. Sabatier reactor · CPC title

• C25B11/081

  the element being a noble metal · CPC title