Jatropha oil can be converted to its methyl esters via
transesterification process in the presence of catalyst.
The purpose of the transesterification process is to
lower the viscosity of the oil. Ideally, transesterification
is potentially a less expensive way of transforming the
large, branched molecular structure of the bio-oils into
smaller, straight chain molecules of the type required in
regular diesel combustion engines. Biodiesel from
jatropha oil is free from sulphur and still exhibits
excellent lubricity, which is an indication of the amount
of wear that occurs between two metal parts covered
with the fuel as they come in contact with each other. It
contains very small amount of phosphorus and sulphur
and therefore emission of oxides of sulphur (SO
x) is
almost negligible. In comparison with commercial
petro-diesel, jatropha biodiesel has higher density and
cetane number. In addition, the higher flash point (more
than 100ºC) of jatropha biodiesel makes the storage and
transportation issues less important. It is a much safer
fuel than diesel because of its higher flash and fire point.
The cloud filter pour point is generally higher than that
of diesel and this may involve some complications for
the operation in cold weather. The amount of carbon
residue from the hot decomposition of vegetable
compounds with higher molecular weight is greater
than that of commercial diesel oil. Some of the
important fuel properties of jatropha biodiesel and