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What are Supercritical fluids ?

In physics, common states of matter are solid, liquid and gas. Some other states can exist at extreme conditions, such as "supercritical state" when a fluid is placed at a temperature and pressure above its critical point.

Under this state, the supercritical fluid exhibit interesting properties coupling some properties of a liquid (high density) and some of a gas (high diffusivity, low viscosity).

phases diagram supercritical

The two most widely used supercritical fluids are carbon dioxide (CO2) and water (H2O). Both fluids are readily available and can be used in a pressurized form to replace organic solvents or serve as alternative environment-friendly processes.

Carbon dioxide (CO2)

CO2 is the most commonly used supercritical solvent. Produced in excess by industry at high purity, it is inexpensive, non-toxic, non-flammable and has a near ambient critical temperature (31°C). Critical pressure is reached at 74 bar.

High density coupled with diffusivity gives to the supercritical CO2 a very good and interesting solvent property.

supercritical co2 advantage


Supercritical fluid and high pressure systems enable the development of sustainable and environment-friendly processes and products.

Supercritical processing is widespread across industies including natural products, bio- and advanced-materials, textile manufacturing and others.

The most well-known example is the extraction of caffeine from coffee beans using supercritical CO2, which has been used commercially for many years at a large scale. Today supercritical fluids are efficiently used and developed by Extratex for many applications:

  • Food and Nutraceuticals
  • Perfumes and Cosmetics
  • Pharmaceuticals
  • Textiles
  • Electronics
  • Aerogels, Ceramic and innovative Materials
  • Waste treatment and Waste valorisation
  • Oil and Gas industries
supercritical applications

Supercritical fluid technology is applicable anywhere when the objectives are :

  • to produce higher performant and economical products
  • to use more environment-friendly and sustainable processes
  • to reduce solvent consumption and VOC emissions