# US 10,865,487 B2 · Electrochemical conversion of hydrocarbons

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- Number: US 10,865,487 B2
- Document ID: US10865487B2
- Status: Granted
- Kind: B2
- Application number: 15/910,112
- Filed: 2018-03-02
- Published: 2019-03-14
- Granted: 2020-12-15
- Earliest claimed: 2013-10-31
- Assignees: ExxonMobil Chemical Patents Inc.
- Applicants: ExxonMobil Chemical Patents Inc.
- Inventors: Walter Weissman; Sumathy Raman; Mark A. Greaney
- Web page: https://patentgrep.com/patent/US10865487B2

## CPC

- C25B 3/25: Reduction
- B01D 53/326: {in electrochemical cells}
- C07C 2/06: of alkenes, i.e. acyclic hydrocarbons having only one carbon-to-carbon double bond
- C07C 5/03: of non-aromatic carbon-to-carbon double bonds
- C07C 29/04: by hydration of carbon-to-carbon double bonds
- C08F 2/00: Processes of polymerisation
- C25B 3/00: Electrolytic production of organic compounds
- C25B 3/07: Oxygen containing compounds
- C25B 3/23: Oxidation (halogenation C25B3/27)
- C25B 3/29: Coupling reactions
- C25B 15/02: Process control or regulation
- B01D 2257/7022: Aliphatic hydrocarbons
- Y02C 20/30: of perfluorocarbons [PFC], hydrofluorocarbons [HFC] or sulfur hexafluoride [SF6]
- C25B: ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR (anodic or cathodic protection C23F13/00; single-crystal growth C30B)
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- Y02C: CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]

## Abstract

An electrochemical conversion method for converting at least a portion of a first mixture comprising hydrocarbon to C2+ unsaturates by repeatedly applying an electric potential difference, V(τ1), to a first electrode of an electrochemical cell during a first time interval τ1; and reducing the electric potential difference, V(τ1), to a second electric potential difference, V(τ2), for a second time interval τ2, wherein τ2≤τ1. The method is beneficial, among other things, for reducing coke formation in the electrochemical production of C2+ unsaturates in an electrochemical cell. Accordingly, a method of reducing coke formation in the electrochemical conversion of such mixtures and a method for electrochemically converting carbon to C2+ unsaturates as well as an apparatus for such methods are also provided.

## Claims

### Claim 1

An electrochemical conversion method, comprising:
(a) providing an electrochemical cell, the electrochemical cell comprising a first electrode, a second electrode, and at least one membrane located therebetween;
(b) providing a first mixture comprising >1.0 wt. % hydrocarbon based on the weight of the first mixture to the first electrode of the electrochemical cell;
(c) applying an electric potential to the cell to establish an electric potential difference V1, across the cell during a first time interval, the first time interval having a duration τ1;
(d) changing the applied electric potential to (i) establish a second electric potential difference, V2, across the cell for a second time interval τ2, and (ii) produce C2+ unsaturates proximate to the first electrode, wherein V2 is more negative or less positive than V1, τ2<τ1, and τ1 is in the range of from 1×10−1° sec. to 1.0 sec.; and
(e) repeating steps (c) and (d).

### Claim 2 (depends on 1)

The method of claim 1, wherein step (c) and/or step (d) are carried out in the substantial absence of oxygen, the hydrocarbon is methane, and wherein the process further comprises conducting at least a portion of the C2+ unsaturates away from the first electrode at a rate >1.0×10−7 mole min·−1 cm−2 for >100.0 minutes.

### Claim 3 (depends on 1)

The method of claim 1, wherein during at least step (c) the first mixture is exposed to a temperature in the range of from 1.0×102° C. to 5.0×102° C. at a pressure in the range of from 0.1 bar to 100.0 bar.

### Claim 4 (depends on 1)

The method of claim 1, further comprising conducting an oxygen-containing mixture to the second electrode during at least step (c), the oxygen-containing mixture comprising ≥10.0 wt. % molecular oxygen, based on the weight of the oxygen-containing mixture, and conducting water away from the second electrode.

### Claim 5 (depends on 1)

The method of claim 1, wherein the first electrode and/or the second electrode comprises ≥1.0 wt. % of at least one noble metal.

### Claim 6 (depends on 1)

The method of claim 1, wherein a current density through the membrane during step (c) achieves a value in the range of from 1.0 mA cm−2 to 100.0 mA cm−2.

### Claim 7 (depends on 1)

The method of claim 1, wherein V1 is in the range of from 0.1 to 20 volts.

### Claim 8 (depends on 1)

The method of claim 1, wherein V1 and V2 satisfy at least one of: (i) V1>0, V2>0, and V2=A1⋅V1, wherein A1 is in the range of from about 0.00 to about 0.99; (ii) V1≥0 and V2<0; or (iii) V1<0, V2<0, and |V2|=A2|V1|, wherein A2≥1.01.

### Claim 9 (depends on 1)

The method of claim 1, wherein τ2 is in the range of from 0.01 ⋅τ1 to 0.9⋅τ1.

### Claim 10 (depends on 1)

The method of claim 1, further comprising a step of oligomerization, polymerization, hydroxylation, or hydrogenation of at least a portion of the C2+ unsaturates.

### Claim 11 (depends on 1)

The method of claim 1, wherein, the first electrode is an anode and the second electrode is a cathode.

### Claim 12 (depends on 1)

The method of claim 1, wherein applying an electric potential to the cell includes applying an external positive voltage to the first electrode.