Conversion of natural gas into clean liquid fuels

Patent metadata

Field	Value
Publication number	US-10519084-B2
Application number	US-201715789743-A
Country	US
Kind code	B2
Filing date	Oct 20, 2017
Priority date	Oct 20, 2016
Publication date	Dec 31, 2019
Grant date	Dec 31, 2019

Abstract

Provided herein are methods and systems for converting natural gas, and specifically methane, into higher-value oxycarbon products, such as methanol, methyl formate, and formic acid. The natural gas is introduced into an aqueous solution with hydroxyl radicals and reacted in ambient conditions to form the desired products in the presence of a metal catalyst. The methods described herein overcome the “over-activation” dilemma of prior art methods that lead to the formation of undesirable carbon oxide compounds. Methods and apparatus for forming hydrogen peroxide via electrolysis and for forming hydroxyl radicals from the hydrogen peroxide via reaction with ferrous ions are also provided.

First claim

The invention claimed is:

1. A method of converting methane to an oxycarbon product, the method comprising:
dissolving methane in an aqueous solution comprising hydroxyl radicals, hydrogen peroxide, and ferrous ions, the aqueous solution comprising a molar concentration ratio of the hydrogen peroxide to the ferrous ions of 1:1 to 200:1; and
reacting the methane and hydroxyl radicals in the presence of a metal catalyst having a CH 3 .−M binding energy of less than 0 eV to produce the oxycarbon product, wherein the metal catalyst comprises a metal selected from the group consisting of platinum, palladium, copper, gold, rhenium, combinations thereof, and alloys thereof.

2. The method of claim 1 , wherein the dissolving and/or reacting step is performed under ambient conditions.

3. The method of claim 1 , wherein the hydroxyl radicals are produced by Fenton's reaction between the hydrogen peroxide and ferrous ions.

4. The method of claim 3 , wherein the Fenton's reaction converts the ferrous ions to ferric ions, the method further comprising photoreducing the ferric ions to ferrous ions.

5. The method of claim 4 , wherein the step of photoreducing occurs concurrently with the step of reacting the methane and hydroxyl radicals.

6. The method of claim 1 , wherein the hydrogen peroxide is produced by water electrolysis via oxidizing water or reducing oxygen.

7. The method of claim 1 , wherein the aqueous solution has a pH of 0 to 6.

8. The method of claim 1 , wherein the oxycarbon product comprises one or more of an oxycarbon selected from the group consisting of methanol, methyl formate, formic acid, and mixtures thereof.

9. The method of claim 1 , wherein the oxycarbon product is free of carbon monoxide and aldehydes.

10. The method of claim 1 , wherein the metal catalyst does not comprise cobalt phthalocyanine.

Assignees

• Univ Wichita State
• Houtaham Farshad
• Farshad Houtaham

Inventors

• Gu Shuang
• Houtaham Farshad

Classifications

• B01J2219/24

  Stationary reactors without moving elements inside · CPC title

• B01J19/24

  Stationary reactors without moving elements inside (B01J19/08, B01J19/26 take precedence; with stationary particles B01J8/02) · CPC title

• B01J2219/0892

  involving catalytically active material · CPC title

• B01J19/122

  Incoherent waves (gamma-radiation B01J19/082) · CPC title

• C07C67/40

  by oxidation of primary alcohols · CPC title