**2.3 Catalyst**

The catalyst if added in the good proportion will neutralize the free fatty acids (FFA) from the waste vegetable oil and also accelerates the reaction. For this type of transesterification two different catalysts are usually used: Sodium Hydroxide NaOH or Potassium Hydroxide KOH. The catalyst is used to accelerate the chemical reaction. The quantity of catalyst needed depend on the amount of free fatty acids in the waste oil and will be determine by the titration of the oil (process used for the determination of the right amount of catalyst that will be use for the chemical process).
