New Catalyst Converts CO2 to Useful Synthetic Chemicals
10 October 2008
Researchers at RIKEN in Japan have developed a new copper catalyst that allows carbon dioxide to be converted into a variety of functionalized carboxylic acid derivatives—versatile synthetic chemicals. A paper on their work was published earlier this year in the journal Angewandte Chemie International Edition.
Industry has used carbon dioxide as a chemical building block—in the manufacture of aspirin, for example—but its use is limited by the difficulty of breaking open its strong carbon-oxygen double bonds. Carbon compounds activated by lithium or magnesium are often needed to attack and incorporate carbon dioxide successfully, but these reagents are extremely reactive and quite hazardous on a large scale.
Milder, boron-based alternatives require a rhodium catalyst to speed up the reaction. Unfortunately, this catalyst tends to break down particularly sensitive chemical groups in the product.
Zhaomin Hou, of RIKEN’s Advanced Science Institute, Wako, along with colleagues Takeshi Ohishi and Masayoshi Nishiura, has now developed a copper catalyst that helps the boron compounds for the carboxylation of aryl- and alkenylboronic esters with CO2.
This makes the reaction particularly useful for building complex molecules containing several different types of chemical group, something that would not be possible with the harsh lithium reagents.
We have tried many different metal compounds, among which the copper catalyst was the best.—Zhaomin Hou
The team was also able to study exactly how the catalyst works, by isolating key molecules at various intermediate stages of the reaction. They found that the active copper catalyst first displaces the boron group from the starting molecule, forming a new copper–carbon bond. Carbon dioxide then inserts itself into this bond before the copper catalyst is finally removed, leaving behind a carboxylic acid (-CO2H) group.
Various forms of the boron compounds, known as boronic esters, are commercially available, and can also easily be prepared in the lab.
Hou notes that their method is also amenable to large-scale, commercial synthesis.
Since CO2 is a renewable carbon resource, exploration of new reactions and catalysts for its efficient use is of great importance. One of our goals is to find a catalyst that can transform CO2 in exhaust gasses of automobile vehicles or chemical plants into useful materials.—Zhaomin Hou
Ohishi, T., Nishiura, M. & Hou, Z. (2008) Carboxylation of organoboronic esters catalyzed by N-heterocyclic carbene copper(I) complexes. Angewandte Chemie International Edition 47, 5792–5795 doi: 10.1002/anie.200801857
Now all they need to determine is:
- The lifecycle cost of providing chemicals in this manner
- The long term availability of critical materials
- The Energy Return On Energy Invested (EROEI) ratio, comparing the energy costs of how those chemicals are acquired today (and into the future)
Posted by: Will S | 10 October 2008 at 07:21 AM
I hate to be cynical, but there is no way this process will contribute meaningfully to address CO2 emissions, but that is precisely how this article will be played by the media, and in fact, is being played by GCC right now.
Posted by: Jim | 10 October 2008 at 08:03 AM
From an chemical energy perspective this can never be economic as you have correctly pointed out.
Unfortunately you are also correct the Gaian religious nuts, will and do play this as a solution to their own mind-created devil, the beneficial and limited suppiles of a ntural and necessary plant fooed gas.
Idiocy can only run so long, and then it will die sof its own contradictions. Thankfully AGW is already more than one foot in the grave and will shortly join acid- rain, Y2K, epicycles and flat-earth theories in deserved oblivion.
Posted by: stas peterson | 10 October 2008 at 09:09 AM
@Jim and Stas,
I agree that this will not reduce GHG emissions. But that is not the point of the article; the objective was to use CO2 as a renewable feedstock. CO2 utilization for chemical synthesis accounts for ~110 million tons of CO2/year.
Eric Beckman (U. Pittsburgh) at the ICCDU-IX talked about this.
"Beckman discussed uses of carbon dioxide as a raw material in chemical production. This attractive option represents, unfortunately, only a small component among potential solutions to the climate change problem because human technology emits far more CO2 into the atmosphere than can be utilized as industrial products. For example, Beckman noted that if all methanol production worldwide (approximately 33 million tons) were converted to a CO2-based process, it would consume less than 1 percent of the CO2 generated by human activity. Additional targets for substitution are the production of chlorine and ammonia. The use of atmospheric CO2 as a feedstock for high-value products such as diphenyl carbonate and various isocyanates would be too small to have a significant impact on the accumulation of atmospheric CO2, but it could contribute to an industry’s profitability, which might provide an added incentive if a “cap and trade” system of CO2 credits were created. Beckman noted that CO2 reforming and synthetic biology should be especially viable areas for future research."
Researchers have also been involved in converting CO2 to fuels, this might make a more substantial impact on GHG emissions than producing fine chemicals from CO2. More on my blog about this.
Posted by: Pradeep | 10 October 2008 at 11:56 AM
Just because the world has not ended does not mean that people were wrong to be concerned. As it turns out there were real problems (problems that are now being seen in China). We knew the mechanisms behind them. We put in place emissions standards for vehicles and power plants to address those mechanisms, and those standards had the desired effect.
Have you really not heard this? Many dates were recorded with 2-digit years. Businesses were not sure what the effects would be of suddenly having dates drop back 100 years (negative accrued interest? etc.), so they spent $Billions on reprogramming databases with 4-digit years. So again, we knew that problems could arise, and we knew why. The problems were addressed. How is that idiocy or self-contradictory?
The interaction between certain gasses (architypically CO2) and various wavelengths of electro-magnetic radiation are well known. We pour huge amounts of these gasses into the atmosphere. Their atmospheric concentrations have been going up. Atmospheric models predict a warming trend as a result. We measure a warming trend. Again, where is the self-contradiction?
Posted by: NatPearre | 10 October 2008 at 12:28 PM
This is silly. Where is the energy going to from to break the C - O2 bond? I mean CO2 is generated in the first place to capture the energy. If you use the same energy to break the bond, you end up with no energy (and even a loss, due to inefficiencies). This is silly.
Posted by: Mehdi | 11 October 2008 at 12:30 AM
The energy needed to capture and re-use CO2 could easily come from renewables such as wind and solar. Wind in particular when my new quiet vertical turbines arrives.
The chemistry, regardless of source material and end product, will as NatPearre stated, require a suitable energy component to complete the cycle.
Posted by: DavidBuchanan | 11 October 2008 at 10:49 PM
"which might provide an added incentive if a “cap and trade” system of CO2 credits were created."
The entire notion of CO2 cap and trade is entirely bogus. It is an invention of (not-so) clever financial analysts designed to rip off business and enrich a small group of commodities specialists. As CO2 is a trace gas measuring less than four hundredths of one percent of atmosphere and with the rapid electrification of transport - its negative effect on anything is highly questionable.
Do not count on Wall Street commodity traders to support a CO2 fuel industry - they are out of favor these days.
Posted by: nrg nut | 13 October 2008 at 05:18 PM