Why we suggest chemical compositions and several diesel types?

Petroleum derived diesel is composed of about 75% saturated hydrocarbons (primarily paraffins including n, iso, and cycloparaffins), and 25% aromatic hydrocarbons (including naphthalenes and alkylbenzenes) The average chemical formula for common diesel fuel is C12H26, ranging from approx. C10H22 to C15H32.

Synthetic diesel Wood, straw, corn, garbage, and sewage-sludge may be dried and gasified. After purification the so called Fischer Tropsch process is used to produce synthetic diesel. [2] Other attempts use enzymatic processes and are also economic in case of high oil prices. Synthetic diesel may also be produced out of natural gas in the GTL process. Such synthetic diesel has 30% less particulate emissions than conventional diesel (US- California)

Biodiesel
Biodiesel can be obtained from vegetable oil and animal fats (bio-lipids, using transesterification). Biodiesel is a non-fossil fuel alternative to petrodiesel. It can also be mixed with petrodiesel in any amount in modern engines, though when first using it , the solvent properties of the fuel tend to clear out all the garbage that has built up from the petrodiesel and can clog fuel filters. Biodiesel has a lower gel point than regular diesel, but is comparable to diesel #2. This can be overcome by using a biodiesel/petrodiesel blend, or by installing a small heater in your fuel system, but this is only nessecary during the colder months. There have been reports that a diesel-biodiesel mix results in lower emissions than either can achieve alone. A small percentage of biodiesel can be used as an additive in low-sulfur formulations of diesel to increase the lubricating ability that is lost when the sulfur is removed.

Chemically, biodiesel consists of alkyl (usually methyl) esters instead of the alkanes and aromatic hydrocarbons of petroleum derived diesel. However, biodiesel has combustion properties very similar to regular diesel, including combustion energy and cetane ratings