This is how to make your own biodiesel fuel from used cooking oil. The oil – waste cooking / vegetable oil (WVO) – is often free for the taking. All you need is a few common chemicals and some equipment you can easily buy or make yourself. The result is a cheap, clean-burning, non-toxic, renewable, high-quality
diesel motor fuel you can use in your car without modifications.

Introduction

This is how to make your own biodiesel fuel from used cooking oil. The oil – waste cooking / vegetable oil (WVO) – is often free for the taking. All you need is a few common chemicals and some equipment you can easily buy or make yourself. The result is a cheap, clean-burning, non-toxic, renewable, high-quality
diesel motor fuel you can use in your car without modifications.

CAUTION:
Wear proper protective gloves, apron, and eye protection and do not inhale any
vapors. Methanol can cause blindness and death, and you don’t even have to
drink it, it’s absorbed through the skin. Sodium hydroxide can cause severe burns
and death. Together these two chemicals form sodium methoxide. This is an
extremely caustic chemical. Wear a mask and full body covering for safety, that
means chemical-proof gloves with cuffs that can be pulled up over long sleeves –
– no shorts or sandals. These are dangerous chemicals — treat them as such!
Always have a hose running when working with them. The workspace must be
thoroughly ventilated. No children or pets allowed.

This procedure is called transesterification, similar to saponification. Sound
familiar? Saponification is soap making. To make soap you take a transfatty acid
or triglyceride (oil or kitchen grease) and blend it with a solution of sodium
hydroxide (NaOH, caustic soda or lye) and water. This reaction causes the ester
chains to separate from the glycerine. These ester chains are what becomes the
soap. They’re also called lipids. Their unique characteristic of being attracted to
polar molecules such as water on one end and to non-polar molecules like oil on
the other end is what makes them effective as soap.

In transesterification, lye and methanol are mixed to create sodium methoxide
(Na+ CH3O-). When mixed in with the WVO this strong polar-bonded chemical
breaks the transfatty acid into glycerine and also ester chains (biodiesel), along
with some soap if you’re not careful (more on that later). The esters become
methyl esters. They would be ethyl esters if reacted with booze (ethanol) instead
of methanol.

Figures 1-3 show these two reactions. The zigzag lines in the triglyceride
diagram (Figure 1) are shorthand for carbon chains. At both ends of each line
segment is a carbon atom.

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