United Technologies Converts CO2 to Formic Acid

United States Patent: 4921585

We trust that you recall some of earlier reports, wherein it was seen that the major US Department of Defense contractor, United Technologies, and their Hamilton Standard division, have been participating in the US Department of Defense efforts to synthesize liquid hydrocarbon fuels from Carbon Dioxide.

 

Their work, as we earlier documented, extends even to filing for a United States Patent on a conceptual "Fuel Production Ship", wherein Carbon Dioxide, extracted from the environment, would be combined with Hydrogen, electrolyzed from ocean water, to synthesize liquid hydrocarbon fuels for other ships of the Navy fleet at sea.

Herein, we see that United Technologies posits that other useful compounds, specifically Formic Acid, can also be made from Carbon Dioxide.

 

The technology, and it's product, might not at first seem all that exciting. However, following our excerpts from the above link to this United States Patent, we include a brief report from the US Naval Research Laboratory, and some further explanation, which might serve to clarify it's true importance.

 

As follows:

 

"United States Patent 4,921,585 - Electrolysis Cell and Method of Use

 

Date: May, 1990

 

Inventor: Trent Moller, CT

 

Assignee: United Technologies Corporation, CT

 

Abstract: The present invention discloses an improved solid polymer electrolysis cell for the reduction of carbon dioxide. The improvement being the use of a cathode having a metal phthalocyanine catalyst which results in the suppression of the formation of hydrogen during the reduction process and the subsequent improved conversion efficiency for carbon dioxide.(and) an improved electrolysis cell useful in the production of oxygen and the reduction of carbon dioxide.

 

(I)t is intended as a primary use that the electrolysis cell be used with water as the fuel. This would permit the electrolytic decomposition of water to form oxygen ... while supplying the hydrogen ions for the carbon dioxide reduction.

 

The improvement comprises the selection of the cathode material (which) will improve the conversion efficiency of carbon dioxide in the presence of hydrogen ions to organic compounds. The most prevalent reaction is the reduction of carbon dioxide to formic acid ... . 

However, several other reactions may also be enhanced through the use of this cathode such as production of methanol, formaldehyde, glycolic acid, and methane. One or more of these materials will be generated at the cathode depending on the current density at which the cell is operated and other operating parameters of the electrolysis cell including the reactants."

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Again, although United Technologies notes that both Methanol and Methane can be co-produced in, perhaps, minor amounts by the efficient electrolytic process, from Carbon Dioxide, it is actually the Formic Acid that they are after in this technology.

 

And, although Formic Acid does have documented, and valuable, applications, such as in fuel cells, the following report from the US Naval Research Laboratory, with our comments appended, might help to explain really why Formic Acid was the target product:

 

ScienceDirect - Journal of Electroanalytical Chemistry : The electrochemical conversion of carbon dioxide into methanol : : Th

 

"The Electrochemical Conversion of Carbon Dioxide into Methanol: The Formic Acid Reduction Step

 

Date: September, 1984

 

Author(s): M.H. Miles, et. al.

 

Affiliations: Research Department, Naval Weapons Research Center, China Lake, CA

 

Abstract: Various studies have shown that the electrode reduction of CO2 in water using metal electrodes yields formic acid as the main product. Recent publications have generated conflicting claims regarding the further reduction of formic acid to methanol using TiO2 electrodes. Our cyclic voltammetric studies using TiO2, Ti, In, Ag, Pt and other electrodes at a fixed pH in mildly acidic NaClO4 solutions show an increase in the cathodic current when NaCOOH is added. The current increases linearly with the concentration of the NaCOOH added if the pH is kept constant; this suggests that formic acid participates in the reduction reaction. Closer examinations, however, that include constant potential coulometry studies show that the HCOOH/HCOO equilibrium is involved and that H3O+ rather than HCOOH is reduced. Undissociated HCOOH molecules aid the cathodic reaction by serving as a conveyor of protons to the electrode surface. The positively charged protons complexed with one more water molecules are electrochemically reduced at more positive potentials than neutral water molecules. Investigations using salts of other weak acids such as NaC2H3O2 and Na2HPO4 in acidified solutions gave results similar to those obtained using NaCOOH."

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We know that might appear as a lot of abbreviated gibberish. However, our consultants tell us that what it all means is that using Formic Acid, dissolved in Water, reduces the energy needed - and through chemical participation otherwise facilitates the reaction - to electrolyze more Carbon Dioxide, also dissolved in that Water, into the nearly-precious Methanol, which, we remind you, can be converted, via ExxonMobil's "MTG"(r) process, into Gasoline.

 

Moreover, Methanol, as we've previously documented for you, is an excellent raw material for use in the synthesis of a wide variety of plastics.

 

Further, Methanol, again as we've documented, is also specified in some Carbon Dioxide "scrubber" technologies as an efficient solvent to use in removing Carbon Dioxide from industrial exhaust gasses.