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Cooking oil as methyl esters

While at a farmer’s market I saw a person selling hemp products, both hemp flour and hemp oil. I found the hemp products interesting, I wondered what the chemical profile of the oil was. A term which you might see when biodiesel is mentioned is FAME, this means Fatty Acid Methyl Ester. A more advanced type of biodiesel exists but I will get onto that later. 

I tend to use alkaline methanol to convert the glycerol esters of oils into methyl esters, this is because the glycerol (propane-1,2,3-triol) esters which are too nonvolatile into more volatile methyl esters. This also makes the mixture slightly more simple. if two carboxylic acid residues are present in an oil as glycerol esters then AAA, AAB, ABB and BBB can be present. If this mixture is converted into the ester of a simple monoalcohol then only A and B will be present. So the formation of fatty acid methyl esters makes it more easy to test and examine oils, fats and other lipids. 

Here are the GC traces of five plant oils. 

Gas chromatography traces of plant oils as methyl esters

 

Last summer I purchased a working model of a miners safety lamp, I filled it up with sunflower oil and no matter what I tried I could not get the lamp to light. Recently one of my students was working on a project on oils, as part of his work this student made a moderate sized batch of FAME biodiesel from sunflower oil. I tipped out the sunflower oil and I then refilled my lamp with FAME biodiesel, a match soon rewarded me with a lamp which worked.

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One Response

  1. […] https://markforeman.wordpress.com/2010/06/30/cooking-oil-as-methyl-esters/ […]

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