Featured Research

from universities, journals, and other organizations

Chemists simplify biodiesel conversion

Date:
October 8, 2010
Source:
Brown University
Summary:
Chemists have streamlined the conversion of waste vegetable oil into biodiesel, eliminating the need for corrosive chemicals to perform the reactions. The researchers were able to pull off the waste vegetable oil-to-biodiesel conversion in a single reaction vessel using environmentally friendly catalysts and making the conversion six times faster than current methods.

Waste not, want not: Aaron Socha, left, and Jason Sello devised a way to convert waste vegetable oil to biodiesel in a single reaction vessel, using environmentally friendly catalysts.
Credit: Mike Cohea/Brown University

As the United States seeks to lessen its reliance on foreign oil, biodiesel is expected to play a role. According to the National Renewable Energy Laboratory, a branch of the Department of Energy, biodiesel "represents a significant energy resource and could someday supply 3 percent to 5 percent of the distillate fuel market."

One major obstacle to achieving that goal is figuring how to efficiently convert the abundant stocks of waste vegetable oil (oil used after cooking French fries, for example) into biodiesel fuel. Current techniques take time, are costly and are inefficient. Worse, the conversion requires the toxic chemicals sulfuric acid and either potassium hydroxide or sodium hydroxide.

That's where Brown University chemist Jason Sello and postdoctoral researcher Aaron Socha come in. They write in the journal Organic & Biomolecular Chemistry that they were able to convert waste vegetable oil to biodiesel in a single reaction vessel using environmentally friendly catalysts. Their process is also six times faster than current methods for converting waste vegetable oil to biodiesel, so it consumes less energy.

"We wanted to develop an environmentally benign and technically simple way to convert waste vegetable oil into biodiesel," said Sello, assistant professor of chemistry. "The production of energy at the expense of the environment is untenable and should be avoided at all costs."

Waste vegetable oil is made up of triacylglycerols, free fatty acids, and water. The conventional way to convert waste vegetable oil into biodiesel requires two separate reactions. The first reaction turns the free fatty acids into biodiesel, but that conversion requires sulfuric acid. The second reaction converts the triacylglycerols into biodiesel, but that conversion requires sodium hydroxide or potassium hydroxide. Sodium hydroxide/potassium hydroxide and sulfuric acid are not compatible with each other, so the reactions must be carried out in separate vessels. That makes the process less efficient.

To find a better way, Sello and Socha went looking for catalysts that would be cheap, chemically stable and of limited toxicity. They settled on the metals bismuth triflate and scandium triflate, commonly used as catalysts in preparative organic chemistry. In addition, they performed the reactions using a microwave reactor instead of a conventional thermal heater. What they found was the new catalysts converted waste vegetable oil into biodiesel in about 20 minutes in the microwave reactor, whereas current reactions without catalysts using a conventional heater take two hours. While their microwave method needs a higher temperature to pull off the biodiesel conversion -- 150 degrees Celsius versus 60 degrees Celsius under current methods -- it uses less energy overall because the reaction time is much shorter.

The chemists also were able to perform the conversion in one reaction vessel, since the catalysts can promote both the reaction that converts free fatty acids into biodiesel and the reaction in which triacylgycerols are converted to biodiesel.

The team also reports that the catalysts in the free fatty acid conversion, which is the more challenging of the two reactions, could be recycled up to five times, while maintaining the capacity to promote a 97 percent reaction yield. The fact the catalysts can be recycled lowers their cost and environmental impact, the researchers said.

"While we have not yet proven the viability of our approach on an industrial scale," Sello said, "we have identified very promising catalysts and reaction conditions that could, in principle, be used for large-scale conversion of waste vegetable oil into biodiesel in an enviornmentally sensitive manner."

The research was funded by the National Science Foundation through a grant to Sello and an American Competitiveness in Chemistry award to Socha. Brown also supported the work through a R.B. Salomon award to Sello.

In a separate yet related paper, a team led by Brown chemistry professor Paul Williard has created a new technique to chart the progress of a reaction in which virgin oils are converted into biodiesel fuel.

The technique, called DOSY (for diffusion-ordered nuclear magnetic resonance spectroscopy), observes virgin oil molecules as they shrink in size and move faster in solution during the reaction. The reaction is complete when all of the molecules have been converted into smaller components known as fatty acid esters. These fatty acid esters are used as biodiesel fuel.

The results are published in the journal Energy & Fuels. The research was funded by the National Science Foundation. Contributing authors include Sello, Socha, Brown graduate students Gerald Kagan and Weibin Li, and lab technician Russell Hopson.


Story Source:

The above story is based on materials provided by Brown University. Note: Materials may be edited for content and length.


Journal References:

  1. Aaron M. Socha, Jason K. Sello. Efficient conversion of triacylglycerols and fatty acids to biodiesel in a microwave reactor using metal triflate catalysts. Organic & Biomolecular Chemistry, 2010; 8 (20): 4753 DOI: 10.1039/C0OB00014K
  2. Aaron M. Socha, Gerald Kagan, Weibin Li, Russell Hopson, Jason K. Sello, Paul G. Williard. Diffusion Coefficient−Formula Weight Correlation Analysis via Diffusion-Ordered Nuclear Magnetic Resonance Spectroscopy (DOSY NMR) To Examine Acylglycerol Mixtures and Biodiesel Production. Energy & Fuels, 2010; 24 (8): 4518 DOI: 10.1021/ef100545a

Cite This Page:

Brown University. "Chemists simplify biodiesel conversion." ScienceDaily. ScienceDaily, 8 October 2010. <www.sciencedaily.com/releases/2010/10/101007145459.htm>.
Brown University. (2010, October 8). Chemists simplify biodiesel conversion. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2010/10/101007145459.htm
Brown University. "Chemists simplify biodiesel conversion." ScienceDaily. www.sciencedaily.com/releases/2010/10/101007145459.htm (accessed July 28, 2014).

Share This




More Matter & Energy News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Lithium Battery 'Holy Grail' Could Provide 4 Times The Power

Lithium Battery 'Holy Grail' Could Provide 4 Times The Power

Newsy (July 28, 2014) Stanford University published its findings for a "pure" lithium ion battery that could have our everyday devices and electric cars running longer. Video provided by Newsy
Powered by NewsLook.com
The Carbon Trap: US Exports Global Warming

The Carbon Trap: US Exports Global Warming

AP (July 28, 2014) AP Investigation: As the Obama administration weans the country off dirty fuels, energy companies are ramping-up overseas coal exports at a heavy price. (July 28) Video provided by AP
Powered by NewsLook.com
Shipping Crates Get New 'lease' On Life

Shipping Crates Get New 'lease' On Life

Reuters - Business Video Online (July 25, 2014) Shipping containers have been piling up as America imports more than it exports. Some university students in Washington D.C. are set to get a first-hand lesson in recycling. Their housing is being built using refashioned shipping containers. Lily Jamali reports. Video provided by Reuters
Powered by NewsLook.com
Europe's Highest Train Turns 80 in French Pyrenees

Europe's Highest Train Turns 80 in French Pyrenees

AFP (July 25, 2014) Europe's highest train, the little train of Artouste in the French Pyrenees, celebrates its 80th birthday. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins