Researchers transform carbon dioxide into methanol
April 16, 2009Scientists at Singapore's Institute of Bioengineering and Nanotechnology (IBN) have succeeded in unlocking the potential of carbon dioxide - a common greenhouse gas - by converting it into a more useful product.
In the international chemistry journal Angewandte Chemie, the IBN researchers report that by using organocatalysts, they activated carbon dioxide in a mild and non-toxic process to produce methanol, a widely used industrial feedstock and clean-burning biofuel.
Organocatalysts are catalysts that are comprised of non-metallic elements found in organic compounds. NHCs such as IMes (1,3-bis-(2,4,6 trimethylphenyl)imidazolylidene) are a form of organocatalysts that are stable and easily stored. They do not contain toxic heavy metals and can be produced easily without high costs.
The scientists made carbon dioxide react by using N-heterocyclic carbenes (NHCs), a novel organocatalyst. In contrast to heavy metal catalysts that contain toxic and unstable components, NHCs are stable, even in the presence of oxygen. Hence, the reaction with NHCs and carbon dioxide can take place under mild conditions in dry air.
The IBN scientists showed that only a small amount of NHC is required to induce carbon dioxide activity in a reaction. "NHCs have shown tremendous potential for activating and fixing carbon dioxide. Our work can contribute towards transforming excess carbon dioxide in the environment into useful products such as methanol," said Siti Nurhanna Riduan, IBN Senior Lab Officer, who is also pursuing her Ph.D. under the Scientific Staff Development Award at IBN, one of the research institutes of Singapore's A*STAR (Agency for Science, Technology and Research).
Hydrosilane, a combination of silica and hydrogen, is added to the NHC-activated carbon dioxide, and the product of this reaction is transformed into methanol by adding water through hydrolysis.
Yugen Zhang, Ph.D., IBN Team Leader and Principal Research Scientist, explained, "Hydrosilane provides hydrogen, which bonds with carbon dioxide in a reduction reaction. This carbon dioxide reduction is efficiently catalyzed by NHCs even at room temperature. Methanol can be easily obtained from the product of the carbon dioxide reaction. Our previous research on NHCs has demonstrated their multiple applications as powerful antioxidants to fight degenerative diseases, and as effective catalysts to transform sugars into an alternative energy source. We have now shown that NHCs can also be applied successfully to the conversion of carbon dioxide into methanol, helping to unleash the potential of this highly abundant gas."
Previous attempts to reduce carbon dioxide to more useful products have required more energy input and a much longer reaction time. They also require transition metal catalysts, which are both unstable in oxygen and expensive. Ongoing research at IBN aims to find cheap alternatives for the hydrosilane reagent so that the production of methanol can be even more cost-effective for mass industrial production.
"At IBN, we are innovating effective methods of generating clean energy using green chemistry and nanotechnology. In the face of environmental pollution, global warming and increasing demands on diminishing fossil fuel resources, we hope to provide a viable alternative energy option for industry, and effective sequestration and conversion of carbon dioxide," said IBN Executive Director. Jackie Y. Ying, Ph.D.
More information: The research was published online in the Angewandte Chemie International Edition, at this link: 10.1002/anie.200806058. IBN's report has been designated a "Hot Paper."
Source: Agency for Science, Technology and Research (A*STAR), Singapore
Mar 09, 2007 |
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There is a loss of energy in heat when the fuel is burned, plus you need hydrasilane, and then you need to add water through hydrolysis. So there is no perpetual motion going on, that's for sure. You are also assuming that methanol burns 100% releasing all the CO2 that was used to make it. I am not sure, but I am guessing that some of the methanol is not converted to CO2 when burned.
"Both methanol and ethanol burn at lower temperatures than gasoline, and both are less volatile, making engine starting in cold weather more difficult. Using methanol as a fuel in spark ignition engines can offer an increased thermal efficiency and increased power output (as compared to gasoline) due to its high octane rating (114[3]) and high heat of vaporisation. However, its low energy content of 19.7 MJ/kg and stoichiometric air fuel ratio of 6.42:1 mean that fuel consumption (on volume or mass basis) will be higher than hydrocarbon fuels. The extra water produced also makes the charge rather wet (similar to hydrogen/oxygen combustion engines)and combined with the formation of acidic products during combustion, the wearing of valves, valveseats and cylinder might be higher than with hydrocarbon burning. Certain additives may be added to motor oil in order to neutralize these acids.
Methanol, just like ethanol, contains soluble and insoluble contaminents [4]. These soluble contaminants, halide ions such as cloride ions, have a large effect on the corrosivity of alcohol fuels. Halide ions increase corrosion in two ways; they chemically attack passivating oxide films on several metals causing pitting corrosion, and they increase the conductivity of the fuel. Increased electrical conductivity promotes electric, galvanic, and ordinary corrosion in the fuel system. Soluble contaminents, such as aluminumhydroxide, itself a product of corrosion by halide ions, clog the fuel system over time.
Methanol is hygroscopic, meaning it will absorb water vapor directly from the atmosphere.[1] Because absorbed water dilutes the fuel value of the methanol (although, it suppresses engine knock), and may cause phase separation of methanol-gasoline blends, containers of methanol fuels must be kept tightly sealed."
(Source: http://en.wikiped...ne_fuel)
2 things:
1) Methanol is very toxic, is absorbed easily through the skin, and is volatile. It will probably need conversion in to another compound that is less toxic or volatile.
2) What is environmental (green house gas) impact of methanol? There will be some and there will be people saying how it shouldn't be used because of some potential impact.
Yes, it's toxic. It's used/was used as fuel in indy cars.
As for environmental effects:
"... since methanol is readily biodegradable in both aerobic (oxygen present) and anaerobic (oxygen absent) environments, methanol will not persist in the environment. The "half-life" for methanol in groundwater is just one to seven days, while many common gasoline components have half-lives in the hundreds of days (such as benzene at 10-730 days). Since methanol is infinitely soluble in water and biodegradable, methanol is unlikely to accumulate in groundwater, surface water, air or soil. (Reference: Evaluation of the Fate and Transport of Methanol in the Environment, Malcolm Pirnie, January 1999)." [Source: http://en.wikiped...Toxicity]
One use of methanol is to react it with animal or plant oils to form bio-diesel, although the environmental benefits of bio-diesel are questionable.
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