Biodiesel Production from Vegetable Oil

Converting cooking oil to biodiesel via transesterification

Organic Synthesis Intermediate (High School) 60 min ~$12.00

Objective

Convert vegetable oil to biodiesel (fatty acid methyl esters) by base-catalyzed transesterification with methanol.

Background

Biodiesel is produced by reacting triglycerides (vegetable oil) with methanol in the presence of a base catalyst (NaOH or KOH). The process replaces the glycerol backbone with methanol, producing fatty acid methyl esters (FAME) that can fuel diesel engines. Glycerol is the byproduct.

Safety Warnings

  • Methanol is toxic and flammable — work in fume hood
  • NaOH is corrosive
  • Do not heat methanol with open flames
  • Adequate ventilation is essential

Required PPE

goggles gloves lab_coat

Materials

  • Vegetable oil (100 mL)
    Clean cooking oil
  • Methanol (20 mL)
    Anhydrous
  • Sodium hydroxide (NaOH) (1 g)
    Catalyst
  • Distilled water (100 mL)
    For washing

Equipment

500 mL Erlenmeyer flask Hot plate with stirrer Separating funnel Thermometer Magnetic stir bar

Procedure

1

Dissolve 1 g NaOH in 20 mL methanol to create sodium methoxide. Stir until fully dissolved.

5 min Exothermic — methanol is flammable
2

Heat 100 mL of vegetable oil to 55°C in the Erlenmeyer flask on the hot plate.

5 min
3

Add the sodium methoxide/methanol solution to the warm oil. Stir vigorously.

2 min
4

Maintain temperature at 55-60°C and stir continuously for 30 minutes.

30 min Keep in fume hood
5

Transfer the mixture to a separating funnel and allow to settle for 15 minutes. Two layers should form.

15 min
6

Drain the lower glycerol layer (dark, viscous). The upper layer is crude biodiesel.

3 min
7

Wash the biodiesel layer gently with 50 mL warm distilled water. Allow to separate and drain the water.

5 min
8

Record the volume of biodiesel produced and calculate the conversion rate.

3 min

Expected Results

Two distinct layers: biodiesel (clear, amber upper layer) and glycerol (dark, viscous lower layer). The biodiesel should be less viscous than the original oil. Typical yield is 85-95% by volume.

Cleanup

Glycerol can be disposed of down the drain (biodegradable). Dispose of methanol waste properly. Rinse glassware. The biodiesel should not be used as fuel without further purification.

Details

Category
Organic Synthesis
Difficulty
Intermediate (High School)
Duration
60 min
Est. Cost
$12.00
Steps
8
Materials
4

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Frequently Asked Questions

What is the objective of Biodiesel Production from Vegetable Oil?
Convert vegetable oil to biodiesel (fatty acid methyl esters) by base-catalyzed transesterification with methanol.
How difficult is Biodiesel Production from Vegetable Oil?
This experiment is rated as Intermediate (High School). It takes approximately 60 minutes to complete.
What safety precautions are needed for Biodiesel Production from Vegetable Oil?
Key safety precautions include: Methanol is toxic and flammable — work in fume hood; NaOH is corrosive; Do not heat methanol with open flames.
What materials are needed for Biodiesel Production from Vegetable Oil?
The main materials required are: Vegetable oil, Methanol, Sodium hydroxide (NaOH), Distilled water.
What results should I expect from Biodiesel Production from Vegetable Oil?
Two distinct layers: biodiesel (clear, amber upper layer) and glycerol (dark, viscous lower layer). The biodiesel should be less viscous than the original oil. Typical yield is 85-95% by volume.