Extracting limonene using dry ice

Some oil is extracted from orange peel by dry ice.

Scientific name: Supercritical extraction with CO2 is applied to plant material.

YouTube

Extracting limonene using liquid carbon dioxide

by David Read

Dry ice extraction experiment and a possessed test tube

by wazscience

Extraction of D-Limonene/Dry Ice

by jennifer schriver

Safety

Wear eye protection goggles. Due to the high pressure generated during the course of this experiment, there is some risk of vessel rupture. The recommended vessels should be used.

Always follow general safety recommendations. Please note that conducting chemistry experiments you must comply with the relevant legal procedures in your country.

Reagents

  1. Dry ice

Step-by-step instruction

  1. Prepare a 50 ml centrifuge test tube.
  2. Take a piece of wire and make a coil on its end.
  3. Insert a piece of filter paper on the coil end of wire. Its function is to separate plant material from the limonene as it is extracted.
  4. Grate some orange peel (the orange part only).
  5. Put about 2 grams of plant material into the test tube. There should be enough free space to help the extraction.
  6. Fill the test tube with dry ice.
  7. Close the test tube with the cap.
  8. Place the test tube into the beaker.
  9. Add some warm water (40-60 °C) into the beaker to cover most of the test tube.
  10. After a few seconds liquid CO2 appears. The extraction of limonene begins. When all liquid CO2 is evaporated put the test tube out of the beaker using tweezers and carefully open it.
  11. The extraction procedure could be repeated for a better yield.

Scientific background

Limonene is a component of orange essential oil. The experiment under consideration shows a way to extract it from orange peel using dry ice. Liquid CO2 plays the role of a “green” solvent. As a rule organic solvents or high temperatures are used to separate natural compounds from the plant material. From this point of view liquid CO2 has a great advantage since it is not flammable, nontoxic and has low environment impact.

What properties of CO2 make it applicable for the extraction? The answer to this question will become clear if we look at the CO2 phase diagram. Unlike other gases relatively low temperatures and pressures can be used to achieve liquid and supercritical state of CO2. The triple point of CO2 where solid, liquid and gas phases coexist in equilibrium is achieved at 5.2 atm. and 56.6 °C. In this region of temperatures and pressures liquid CO2 is formed. With the increase of pressure and temperature we move toward the critical point of CO2 (73.8 atm. and 31°C). At this point CO2 adopts properties of both gas and liquid. When we place the test tube with orange peel and dry ice into warm water we move through the triple and critical points of CO2. CO2 behave itself like a gas and readily expands filling all the test-tube volume. The following expansion creates very high pressure. But at the same time the fluid phase in the test tube is dense like a liquid.

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Published on 08 October 2015

  • Fire
  • Heating with fire
  • Explosion
  • Poisoned gas
  • Organic
  • Electricity
  • Solution
  • Oxidation reduction
  • Color change
  • Precipitate
  • Gassing
  • Catalyst