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United States Department of Agriculture

Agricultural Research Service

Title: Rapid Monitoring of Transesterification and Assessing Biodiesel Fuel Quality by Nir Spectroscopy Using a Fiber-Optic Probe

item Knothe, Gerhard

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 29, 1999
Publication Date: N/A

Interpretive Summary: Biodiesel is an alternative diesel fuel derived from vegetable oils such as soybean oil. It is made from the vegetable oils through a reaction called transesterification. Biodiesel producers carrying out a transesterification reaction need to know if the reaction is successful. Up to the present time, the biodiesel product resulting from the transesterification has been analyzed by an analytical method named gas chromatography (GC). This method is complex to handle and maintain, requires additional chemicals and is relatively time-consuming. The present work shows that a method called near-infrared (NIR) spectroscopy can be an alternative to GC. NIR analyses are faster and easier, do not require additional chemicals, reduce equipment maintenance, and can be accomplished with less investment in training. Such analyses will help reduce cost of biodiesel fuel and, therefore, contribute to successful market penetration. This is in the interest of farmers, biodiesel producers, and the public in general as biodiesel is a renewable domestically produced fuel with reduced emissions.

Technical Abstract: Vegetable oil esters, particularly methyl esters, are being explored and used as alternative diesel fuel (biodiesel). The transesterification reaction which yields the methyl esters can be monitored for completion by near infrared (NIR) spectroscopy using a fiber optic probe. Although the NIR method is less sensitive than gas chromatography (GC) for quantifying minor components, by correlation with existing GC or other analytical data, biodiesel fuel quality can be assessed through the NIR method. The NIR method is easier and faster to use than gas chromatography.

Last Modified: 4/18/2015
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