Fetzthechemist’s Weblog

A lot of the interest in biofuels are in diesel-engine blends of traditional diesel with biodiesel at 4:1, the so-called B20 biodiesel.

The bio part is usually a mix of the methyl esters of fatty acids. The fatty acid are what a lot of companies are trying to make by fermentation by genetically-engineered bacteria or algae.

When you combust this in the diesel engine, the combustion is not very clean – diesels are just that way. Diesels produce a lot of polycyclic aromatic hydrocarbons (PAHs). But as far as I know, no work has been done on the exhaust of biodiesel.

The PAHs might be as important as in regular diesel, but I think there’s a huge probability that biodiesel produces oxygen-containing derivatives of PAHs. The known carcinogenic forms of PAHs are hydroxyl, keto, and other oxygen-containing forms. Could biodiesel create a much worse environmental impact because it spews active carcinogenic forms?