Biodiesel refers to a diesel-equivalent
processed fuel derived from biological sources (such as
vegetable oils) which can be used in unmodified diesel-engine
vehicles. It is thus distinguished from the straight vegetable
oils (SVO) or waste vegetable oils (WVO) used as fuels
in some diesel vehicles.
In this article's context, biodiesel
refers to alkyl esters made from the transesterification
of vegetable oils or animal fats.
On August 31, 1937, G. Chavanne of the
University of Brussels (Belgium) was granted a patent
for a 'Procedure for the transformation of vegetable oils
for their uses as fuels' (fr. 'Procédé de
Transformation d’Huiles Végétales
en Vue de Leur Utilisation comme Carburants') Belgian
Patent 422,877. This patent described the alcoholysis
(often referred to as transesterification) of vegetable
oils using ethanol (and mentions methanol) in order to
separate the fatty acids from the glycerol by replacing
the glycerol with short linear alcohols. This appears
to be the first account of the production of what is known
as 'biodiesel' today.
Biodiesel is biodegradable and non-toxic,
and typically produces about 60% less net carbon dioxide
emissions than petroleum-based diesel, as it is itself
produced from atmospheric carbon dioxide via photosynthesis
in plants. Pure biodiesel is available at many gas stations
in Germany.
