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Supercritical Fluid

Tc > Tc(critical), Pc > Pc(critical); CO₂: Tc=31°C, Pc=73.8 bar
Quick Reference
Formula / NotationTc > Tc(critical), Pc > Pc(critical); CO₂: Tc=31°C, Pc=73.8 bar
Also Known AsSCF, supercritical solvent, near-critical fluid

What is Supercritical Fluid?

A substance at a temperature and pressure above its critical point, where it has properties intermediate between a liquid and a gas. Supercritical CO₂ is used as a green solvent for extraction of caffeine and fragrances. It diffuses like a gas but dissolves compounds like a liquid.

Formula & Notation

Tc > Tc(critical), Pc > Pc(critical); CO₂: Tc=31°C, Pc=73.8 bar

Other Names / Synonyms: SCF, supercritical solvent, near-critical fluid

Properties & Characteristics

A supercritical fluid is a substance at a temperature and pressure above its critical point, where it exhibits properties of both a liquid (dissolving ability) and a gas (low viscosity, high diffusivity). It does not have a distinct liquid-gas phase boundary. The density and solvent properties of a supercritical fluid can be tuned by adjusting temperature and pressure. CO₂ is the most widely used supercritical fluid.

Uses & Applications

Supercritical CO₂ is used for extraction of caffeine from coffee, essential oils from plants, and as a dry cleaning solvent. Supercritical fluids are used in chromatography (SFC) for separating chiral compounds. They are used in producing pharmaceutical materials with controlled particle sizes.

Safety Information

Supercritical processes involve high pressures requiring pressure-rated equipment and strict safety protocols. Sudden pressure release can cause rapid phase transition and equipment damage. CO₂ in high concentrations is an asphyxiant.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Supercritical Fluid
Formula Tc > Tc(critical), Pc > Pc(critical); CO₂: Tc=31°C, Pc=73.8 bar
Synonyms SCF, supercritical solvent, near-critical fluid

Frequently Asked Questions

A substance at a temperature and pressure above its critical point, where it has properties intermediate between a liquid and a gas. Supercritical CO₂ is used as a green solvent for extraction of caffeine and fragrances. It diffuses like a gas but dissolves compounds like a liquid.

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