Titration and Making a Test Batch
Make solution of
1 gram KOH – Potassium Hydroxide flakes
1 liter of distilled water
Determining Amount of KOH needed
Dissolve 1 gram of KOH in 1 liter of distilled or de-ionized
water (0.1% KOH solution).
In a smaller beaker, dissolve 1 ml of dewatered WVO oil in 10 ml of pure
isopropyl alcohol. Warm the beaker gently by standing it in some hot water
(microwave for 10 seconds), stir until all the oil dissolves in the alcohol and
the mixture turns clear. Add 2 drops of phenolphthalein solution.
Using a graduated syringe, add 0.1% KOH solution drop by drop to the
oil-alcohol-phenolphthalein solution, stirring all the time, until the solution
stays pink (actually magenta) for 10 seconds.
Take the number of milliliters of 0.1% KOH solution you used and add 7.5 for
KOH. This is the number of grams of KOH you'll need per liter of oil.
Number of extra grams of should be between 0 and 3 for most
Preparing the Methoxide
Generally the amount of methanol is 20% of the WVO by
Ex: for 400 milliliters of WVO use 80 milliliters of
everything dry that might touch the KOH
Mix the appropriate number of grams of KOH and 80
ml of methanol in a mason jar until dissolved.
The jar will become slightly hot.
When opening this jar, do not breathe the vapors.
Heat 400 ml of WVO to about 130 degrees.
(Microwave for about 20 seconds)
Add methoxide mixture to jar with WVO. Shake.
Most of the reaction occurs in the first few minutes so
shake vigorously for a few minutes and then gently once a minute for another 10
or 15 minutes. Leave the jar and let the
reactants settle. You should end up with
a layer of glycerin on the bottom and biodiesel on top. Stand away from the top of the jar when you
open it as there will be methanol vapor trying to escape. Even though you might see good separation,
the reaction may continue to occur. This
is just a test batch!
information states that you can use a blender with a glass container. This is not recommended as methanol is highly
flammable and using anything that might create a spark is dangerous. If you choose to make test batches in a
blender, BE CAREFUL!