Biodiesel Synthesis

By: Scott Mithoefer, Tim Labonville


A current and significant environmental issue is the dependence on fossil fuels (petroleum) as a readily available energy source. Fossil fuels are used in everything from planes, trains and automobiles, to the way we make heat to warm our home, down to how we create the power being fed to the outlets around our homes and businesses and schools. Petroleum based liquid fuel oils dominate the energy markets in there ease of availability and ease of use.

It is possible to develop fuel sources that do not rely of fossil fuel. A significant hurdle is equivalency, in order to replace fossil fuel sources with a more environmentally friendly one, the new source would have to be able to power existing technology. Solar power, as an example, is not an equivalent fuel source to petroleum, as it can not power existing automobiles without a major technology upgrade. Oils not derived from fossil fuels, such as vegetable oil, are a potential fuel source that has a similar structure fossil fuels, they are both made up of long hydrocarbon chains. There are alternative methods of synthesizing a non-petroleum based, or less petroleum based fuel oil, one method is the synthesis of biodiesel. Biodiesel uses vegetable or animal oils combined with an alcohol and a strong base to synthesize a fuel source that is nearly equivalent to commercial petroleum diesel.

What is petroleum diesel, biodiesel, and vegetable oil?

Petroleum based diesel, biodiesel, and vegetable oil are hydrocarbon chain molecules, What makes them different is subtle but makes a big impact on where we get them and how we make them. Petroleum diesel is a product that is derived through fractional distillation of fossil fuel sources found in deposits around the world. It has taken many millions of years for these fossil fuel oils to settle in the state that they are found. Fossil fuel oils are long hydrocarbon chains that lack oxygen.
Biodiesel Oil Molecule.jpg
Triglyceride (oil) Molecule

Oils, such as vegetable oil, are long hydrocarbon chains connected by three esters. These are also known as triglycerides.
biodiesel petroleum diesel structure.jpg
Petroleum Diesel Structure

Biodiesel results when the triglyceride is broken into three ester molecules, a process known as transesterification. Specifically it is the process of
turning one type of ester into another type of ester (Thompson, 2006).

Transesterification uses a strong base, such as sodium methoxide (the product of sodium hydroxide (NaOH) and methanol), the nucleophile then attacks the carbonyl carbon of the oil to separate the methyl esters from the glycerol backbone. The resulting products are three methyl esters
Biodiesel molecule.jpg
Methyl Ester (biodiesel) Molecule

(biodiesel), glycerol, NaOH, and unreacted methanol. In this example the glycerol, NaOH, and methanol can be use as components of other products (Thompson, 2006). Other alcohols and catalysts can be used, such as ethanol and potassium hydroxide (KOH). Byproducts containing KOH could be used as fertilizer.

Green Chemistry

The Environment Protection Agency (EPA) defines Green Chemistry as "Green chemistry is the design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances. Green chemistry applies across the life cycle of a chemical product, including its design, manufacture, use, and ultimate disposal. Green chemistry is also known as sustainable chemistry." Environmental Protection Agency (EPA, 2014)

The development of biodiesel follows a number of the green chemistry principles, most notably biodiesel is generated from a renewable feedstock. The oil can come from plant or animal sources such as corn, soybean, or algae, just to name a few. Used oil from the cooking industry can be recycled to make biodiesel (though it must be filtered and have the acidity neutralized first). The synthesis of biodiesel uses catalysts for it's reactions, eliminating the need for toxic or environmentally harmful chemicals. The byproducts of the reactants can be recycled in other products, such as soap from glycerol and NaOH (Thompson, 2006) or fertilizer from glycerol and KOH.

Biodiesel Synthesis Experiment

We synthesized eight samples of biodiesel from the following reactants: canola oil, vegetable oil, methanol, ethanol, sodium hydroxide, potassium hydroxide. The samples were tested against commercial petroleum based diesel for compatibility and fuel efficiency.

Contact us

Tim Labonville

Scott Mithoefer


Environmental Protection Agency, (2014), Basics of Green Chemistry, Retrieved from

Thompson, J., (2006), Biodiesel Synthesis. Lane Community College Science Division, Retrieved from