
Aberration-corrected HAADF/STEM images of as-synthesized Rh-ZSM-5. Single rhodium cations are circled in white with proposed ball-stick model of the structure. (Lawrence F. Allard, co-author and researcher at Oak Ridge National Laboratory )
New process could lead to production of methanol or acetic acid through more energy efficient, low-cost and environmentally-friendly ways
The direct oxidation of methane—found in natural gas—into methanol at low temperatures has long been a holy grail. Now, researchers at Tufts have found a breakthrough way to accomplish the feat using a heterogeneous catalyst and cheap molecular oxygen, according to a paper published today in the journal Nature by a team led by Tufts University chemical engineers.
Methanol is a key feedstock for the production of chemicals, some of which are used to make products such as plastics, plywood and paints. Methanol also can fuel vehicles or be reformed to produce high-grade hydrogen for fuel cells.
However, the current method for producing methanol from methane- or coal-derived synthesis gas involves a multi-step process that is neither efficient nor economical in small-scale applications. As a result, methane emissions from oil wells, accounting for 210 billion cubic feet of natural gas annually, are being vented and flared, according to the U.S. Energy Information Administration. Meanwhile, the growth of hydraulic fracturing, or fracking, and the subsequent use of shale gas, the chief component of which is methane, have dramatically increased the natural gas supply in the United States, and accelerated the desire to upgrade methane into more valuable chemicals, such as through oxidation to methanol or carbonylation to acetic acid.
As a result, scientists have been seeking more efficient and less expensive ways to convert methane with a process that uses inexpensive molecular oxygen in mild conditions in which relatively low temperatures and pressures are used. The potential benefit is significant. In 2000, the availability of cheap shale gas represented just 1 percent of American natural gas supplies, while today it represents more than 60 percent.
The Tufts-led researchers found that they could use molecular oxygen and carbon monoxide for the direct conversion of methane to methanol catalyzed by supported mononuclear rhodium dicarbonyl species, anchored on the internal pore walls of zeolites or on the surface of titanium dioxide supports that were suspended in water under mild pressure (20 to 30 bar) and temperature (110 to 150° C).
The same catalyst also produces acetic acid through a different reaction scheme that does not involve methanol as an intermediate. Carbon monoxide is essential to the catalytic reaction, which is heterogeneous. Tuning the reaction to either methanol or acetic acid is possible by properly controlling the operating conditions, especially the acidity of the support. Even after many hours of reaction, there is no leaching of the catalyst in the water, the study found.
The paper’s senior author, Maria Flytzani-Stephanopoulos, Ph.D., a Distinguished Professor and the Robert and Marcy Haber Endowed Professor in Energy Sustainability in the School of Engineering at Tufts University, said the researchers were very surprised to find that carbon monoxide was necessary in the gas mixture to produce methanol.
“We attributed this to retaining the active site carbonylated,”Flytzani-Stephanopoulos said. “Interestingly, our catalyst does not carbonylate methanol. Instead, it carbonylates methane directly to acetic acid, which is a most exciting finding.”
“Although more study is needed, we are encouraged that this process holds promise for further development. Not only could it be effective in producing methanol and acetic acid directly from methane, it also could do so in a more energy efficient and environmentally friendly way than current processes,” she added.
Postdoctoral fellow JunJun Shan and doctoral student Mengwei Li, who are both first authors of the paper, prepared supported Rh catalysts through relatively simple synthesis procedures. The main focus was to atomically disperse the rhodium species, which was achieved by a special heat treatment protocol on the zeolite support and by anchoring rhodium precursor species on reduced titania assisted by UV-irradiation. The atomic rhodium state is necessary for the reaction to occur, said Shan.
Lawrence F. Allard, Ph.D., distinguished research staff member at Oak Ridge National Laboratory and a co-author of the paper, said aberration-corrected electron microscopy was crucial in supporting the research.
“The ‘direct’ imaging of single atom dispersions coupled with more standard ‘indirect’ chemical and spectroscopic methods has been a powerful combination of capabilities that allow these studies to be so successful,” Allard said.
Graph of U.S. natural gas gross withdrawals between 2000 and 2016 (Courtesy of Energy Information Administration)
Flytzani-Stephanopoulos directs the Tufts Nano Catalysis and Energy Laboratory, in the Department of Chemical and Biological Engineering, which investigates new catalyst materials for the production of hydrogen and “green” chemicals. Pioneering work from her lab has demonstrated the use of heterogeneous single metal atom catalysts for reactions of interest to fuel processing, and to commodity and value-added chemicals production, with improved yields and reduced carbon footprint, while using precious metals sustainably and more efficiently.
Learn more: Researchers discover breakthrough process for directly converting methane to methanol
The Latest on: Methane to methanol
[google_news title=”” keyword=”methane to methanol” num_posts=”10″ blurb_length=”0″ show_thumb=”left”]
- ICE lifespan extended beyond 2035 in Europe following win on e-fuel legislationon March 28, 2023 at 3:21 pm
Manufacturers of internal combustion engines are popping the champagne after regulators in Europe have effectively extended the lifespan of ICE units to beyond 2035, with the help of an E-fuel caveat.
- Nacero is Developing a World Scale Methanol to Jet Fuel Complex with TOPSOE's Supporton March 28, 2023 at 11:30 am
Nacero will transition its current pre-construction, multi-billion facility in Texas, designed to produce low carbon gasoline to the production of sustainable aviation fuel (SAF) and lower carbon ...
- PureWest Energy and Proman Sign Agreement to Reduce Scope 3 Methanol Footprint Through Digital Tokenson March 28, 2023 at 6:13 am
PureWest Energy, LLC ("PureWest"), an independent natural gas producer in Wyoming's Green River Basin, and Proman, a global leader in methanol production, today announced their closure on a blockchain ...
- Ferrari’s Combustion Supercars To Live Beyond 2036 After EU’s E-Fuel Dealon March 27, 2023 at 7:02 pm
The European Union is moving ahead with a plan to phase out new vehicles with internal combustion engines by 2035 but a new deal gives life to supercar makers like Ferrari. Its CEO spoke on the deal ...
- Methane & Methanol Cell Market 2023 Research Analysis, Applications, Demands and Growth Forecast Reporton March 26, 2023 at 11:39 pm
Global Methane and Methanol Cell Market research report offers a detailed analysis of valuable insight into the ...
- What are e-fuels and how are they made?on March 23, 2023 at 10:00 pm
That made us want to know more about these e-fuels and the discussion around their use, to better understand the for and against argument. E-fuel is a synthetic version of fossil fuel. Brilliant ...
- Can e-fuels help make cars CO2-neutral?on March 23, 2023 at 9:49 am
STORY: The European Union has plans to create a new vehicle category – cars that run on carbon neutral e-fuels.The proposal is part of the EU's effort to resolve a spat with Germany over moves to ...
- As European Union looks to phase out CO2-emitting cars, e-fuels may be the solutionon March 18, 2023 at 8:00 am
The European Union is looking to phase out CO-2 emitting cars by 2035, and some believe e-fuels may be a good alternative. Here is what e-fuels are and what they can do.
- All about the bio: SEA-LNG urges use of liquefied bio-methane to speed up decarbonisationon March 15, 2023 at 3:12 am
Ask SEA-LNG chairman Peter Keller about where the focus lies for this pro-LNG industry coalition in 2022 and he has a three-word answer — “bio, bio, bio”. While working towards long-term ...
- Methane & Methanol Cell Market Size, Global Insights and Trends, Forecasts to 2028on February 27, 2023 at 12:57 pm
Feb 27, 2023 (The Expresswire) -- Methane and Methanol Cell Market" is expected to grow at a steady growth during the forecast period 2023-2028, Methane and Methanol Cell Market report offers ...
via Google News and Bing News