Supercritical Fluid Processes

Chemical processes could be hazardous, expensive and contribute to pollution. Supercritical fluids are an alternative investigated to reduce and eliminate industrial pollution and manufacturing costs. The two examples are supercritical water in biomass refinery and supercritical carbon dioxide to replace organic solvents.
The water processes in the figure below are divided into:

1. Incineration
2. Gasification,
3. Separation,
4. Solubilization,
5. Hydrolysis, and
6. Conversion Reactions.

The carbon dioxide processes are:

• Extraction,
• Organic Synthetic Reactions,
• Catalysis,
• Biotechnology,
• Polymerization,
• Particle Engineering,
• Textile Dyeing, and
• Advanced Material Manufacture.

Supercritical Fluid Carbon Dioxide

Category	Examples
Extraction	Coffee decaffeination Fatty acid refinery Flavour isolation from hops Herbal products
Organic Synthetic Reactions	Friedel Crafts Diels-Alder Aldol Claisen rearrangement Michael addition Kolbe-Schmitt reaction
Catalysis	Fisher-Tropsh Hydroformylation Hydrogenation Heck reactions Suzuki reactions Oxidations Alkylation reactions
Biotechnology	Enantioselective chemical transformations Lipase catalyzed esterifacation Enzyme in Packed column continuous flow with toluene
Polymerization	Amorphous fluoropolymers Polysiloxanes Some hydrocarbon polymers Polybutylacrylate Polystyrene
Particle Engineering	Drug delivery system Rapid expansion of supercritical fluid solutions (RESS) Supercritical fluid anti-solvents (GAS) Polymer supercritical fluid extraction of emulsions (PSFEE)
Textile Dyeing	Dye solvent for polyesters, nylon, silk, cotton and wool
Advanced Material	Ionic liquid as electrolytes in batteries, lubricants, plasticizers, extraction, inorganic and biochemical catalysis Speed up, dry or replace aerogel fabrication Polyimides infusion

References

Ramsey, E., Sun, Q.B., Zhang, Z.Q., Zhang, C.M. & Gou, W. (2009). Mini-review: Green sustainable processes using supercritical fluid carbon dioxide. Journal of Environmental Sciences-China. 21(6), 720-726. DOI:10.1016/S1001-0742(08)62330-X

Arai, K., Smith, R.L. & Aida, T.M. (2009). Decentralized chemical processes with supercritical fluid technology for sustainable society. Journal of Supercritical Fluids. 47(3), 628-636. DOI:10.1016/j.supflu.2008.11.008