Supercritical Fluid Extraction Technology

Supercritical fluid extraction is the world's most advanced physical extraction technology, referred to as SFE (supercritical fluid extraction). At lower temperatures, when the gas pressure is continuously increased, the gas is converted into a liquid. When the pressure increases, the volume of the liquid increases. There is always a critical temperature (Tc) and critical pressure (for a particular substance). Pc), above the critical temperature and critical pressure, the material does not become liquid or gas, which is the critical point. In the range above the critical point, the matter state is between the gas and the liquid, and the fluid within this range becomes a supercritical fluid (SF). Supercritical fluids have strong penetrability similar to gases and large density and solubility similar to liquids, have good solvent properties, and can be used as solvents for extraction and separation of monomers.

Supercritical fluid extraction (SFE) is a high-tech technology emerging from modern chemical separation. SFE combines traditional distillation with organic solvent extraction, and utilizes the excellent solvent power of supercritical CO2 to effectively separate, extract, and purify the substrate and the extract. SFE uses supercritical CO2 to extract the material. CO2 is a safe, non-toxic and inexpensive liquid. Supercritical CO2 has a similar gas diffusion coefficient, liquid solvency, zero surface tension, can quickly penetrate into solid materials, extract its essence, has high efficiency, is not easy to oxidize, Pure natural, no chemical pollution and other characteristics.

Supercritical fluid extraction separation technology is the use of supercritical fluid solvency is closely related to its density, by changing the pressure or temperature of the supercritical fluid density changes. In the supercritical state, the supercritical fluid is brought into contact with the material to be separated, so that it selectively extracts components having different polarity sizes, boiling points, and relative molecular masses in order.

When supercritical extraction is used to extract natural products, CO2 is generally used as an extractant. This is because:

a) Low critical temperature and critical pressure (Tc=31.1°C, Pc=7.38MPa), mild operating conditions, less damage to active ingredients, and therefore particularly suitable for handling high-boiling heat-sensitive substances such as flavors, fragrances, oils, vitamins, etc. ;

b) CO2 can be seen as a non-toxic, cheap organic solvent similar to water;

c) CO2 is stable, non-toxic, non-flammable, safe and environmentally friendly during use, and oxidation of the product can be avoided;

d) The CO2 extract contains no nitrates and harmful heavy metals, and there is no residue of harmful solvents;

e) In supercritical CO2 extraction, the extracted material is reduced in pressure, or

Precipitation at high temperatures eliminates the need for repeated extractions, so the supercritical CO2 extraction process is simple.
Therefore, supercritical CO2 extraction is particularly suitable for the extraction and purification of biological, food, cosmetics and drugs.

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