How to Make Liquid Glycerin

Glycerin is an organic chemical that is commonly used as a lubricant and surfactant. It can be extracted from fats and is a common by-product during the soap making process. Old fashion soap makers intentionally add glycerin back into the raw soap before it is solidified to help moisturize the user's skin. After the glycerin is separated from the soap, it needs to be purified by distillation to eliminate impurities that occur during the soap-making process.

Things You'll Need

• Animal fat or vegetable oil
• Pot
• Water
• Stove
• Lye (sodium hydroxide or potassium hydroxide)
• Glass stirring rod
• Salt
• Vacuum distillation apparatus

Instructions

1. Fill the pot half full with the animal fat or vegetable oil.

2. Add a small amount of water to the pot.

3. Heat the half-full pot on the stove until the fat is all liquid and the water has started to boil.

4. Turn down the heat and slowly add a small amount (2 to 5 grams) of lye to the pot.

5. Continue adding small amounts of lye while stirring with the glass rod until the lye will no longer dissolve.

6. Heat the mixture for one hour.

7. Remove the pot from the stove and allow to cool.

8. Add about 1/4 of the volume of the pot in water and 10 to 20 grams of table salt. The salt should cause two layers to form. The top layer is crude soap, while the bottom layer is a water-glycerin-salt mixture.

9. Pour off the soap and then pour the water-glycerin-salt mixture into the distillation apparatus.

10. Distill off the water and then purify the glycerin by distilling at 315 degrees Fahrenheit under a pressure of 6 to 12 mm of mercury. The glycerin will condense as the second distillate. At about 300 degrees, change collection flask so that the purified glycerin will condense into a clean, empty flask. Once the rate of the glycerin dropping/pouring into the flask slows drastically or stops, remove the flask and stop the distillation.

References

• Pioneerthinking.com:What is Glycerin
• Springerlink.com: Glycerine Distillation