New Catalytic System for the Efficient Conversion of CO2 to Methanol
15 June 2010
Researchers at the University of Cincinnati, Ohio, report on the development of a catalytic hydroboration system for the “highly efficient” reduction of CO2 with a borane and subsequent hydrolysis of the resulting methoxyboryl species to produce methanol (CH3OH) in good yield.
A paper on their work was published online 14 June in the ACS journal Energy & Fuels.
Transforming CO2 into methane, the most reduced form of carbon, under homogeneous conditions can be accomplished using silanes as the reducing reagents. Reducing CO2 to methanol would be even more desirable for the advantages of transporting a liquid fuel rather than a gas.
Catalytic hydrosilylation of CO2 to methoxysilyl species is feasible with Ir(CN)(CO)(dppe) [dppe=1,2-bis(diphenylphosphino)ethane] at 40 °C, albeit with limited turnover numbers. More efficient hydrosilylation reactions are catalyzed by N-heterocyclic carbenes (metal-free) at ambient temperature with turnover frequencies (TOFs) as high as 25.5 h-1 (based on Si-H), and methanol is produced from the hydrolysis of the initial reduction products. The recent development of frustrated Lewis acid-base pair (FLP) chemistry has led to alternative strategies for the reduction of CO2 to the methoxide level given either H2 or H3NBH3 9 as a hydrogen source.
In this paper, we report a highly efficient nickel system for the catalytic hydroboration of CO2 to methoxyboryl species using a simple borane. The reactions operate at room temperature with TOFs [495 h-1 based on B-H] at least 1 order of magnitude higher than those of the related reactions described above.
Further studies to elucidate the mechanistic details and improve the catalytic efficiencies are in progress.
Resources
Sumit Chakraborty, Jie Zhang, Jeanette A. Krause and Hairong Guan (2010) An Efficient Nickel Catalyst for the Reduction of Carbon Dioxide with a Borane. J. Am. Chem. Soc., Article ASAP doi: 10.1021/ja103982t
If CO2 can be captured (at a very high rate) and recycled over and over again, it may be used in the power generation mix in the future.
Posted by: HarveyD | 15 June 2010 at 11:39 AM
Combine this process with the output of a Coal gasifier and a nuclear plant.. combust the resulting gases in the peaking turbines to generate electricity and recycle the CO2 (perhaps with excess power from the nuke)to make methanol.. either sell the methanol or combust it back in the gassifier to generate extra power at peak times, or perhaps when the nuke is down for maintenance. Methanol would be a lot easier to store than synthesis gas. The methanol could also be used locally for transportation.
Many nuke sites also have coal and NG burners on site, so they have the raw materials available in quantity. This is the traditional American way, make a profit with a previously discarded waste product.
Posted by: Herm Perez | 15 June 2010 at 12:11 PM
You have to get the H2 somewhere, there is NO free lunch. It is easier to work with the CO in synthesis gas than to work with CO2. You can gas shift it with steam and get more H2 from the water and sequester the CO2.
One interesting fact I came across was that it takes 30 kWh to turn CO2 into a gallon of methanol. This makes for some mighty expensive methanol and I would not recommend that we use that method. We will find a use for sequestered CO2 and in the future people may wonder why we just released it into the air.
Posted by: SJC | 15 June 2010 at 12:38 PM
and a gallon of methanol contains 16kwh of energy.. not very efficient at all. Hopefully the process can be improved.
Posted by: Herm Perez | 15 June 2010 at 04:55 PM
It is a good deal if you need liquid fuel, and if you consider how much carbon is put into the air by making ethanol from corn, instead of just growing bigger trees on the corn lands and using a little more fossil fuel it is a very good deal. At a nuclear power plant, a KWH costs less than $0.05, so it is slightly better than gasoline at $3.00. If you can use the electricity directly then you can get over 150 miles on 30 kwh ZEBRA batteries have allowed the use of long distance electric cars for over ten years, but the batteries are still expensive because not enough volume of them is being made. We can use coal to fuel cars for the next 100 years or so. There is no reason that most roads can not be electrified on the main routes and then there are the small batteries and the tiny range extenders. ..HG..
Posted by: Henry Gibson | 16 June 2010 at 12:33 AM
Most of these chemical processes seem to have a poor energy balance. IF they can reuse heat and cheap electric at nuke plants this MAY be a modest added revenue stream for nuke operators.
Posted by: sulleny | 16 June 2010 at 10:13 AM