Supercritical fluid extraction uses supercritical fluids like carbon dioxide above their critical temperature and pressure to extract compounds. This allows extraction to occur quickly in 10-60 minutes without solvent residues. Carbon dioxide is commonly used as it is non-toxic, inexpensive, and allows extraction of thermally sensitive compounds at low temperatures. The supercritical fluid is pumped to the extraction vessel containing the sample, where compounds dissolve and are then collected by reducing the pressure and separating the compounds. This technique is used to extract compounds for food, cosmetics, and pharmaceuticals and to remove alcohol from beverages.

1. BY-
PRINCE MISHRA
B.Voc. FT5

2. abstract
Supercritical fluid extraction is the most effective and efficient way to
extract valuable constituent botanicals. Supercritical Fluid Extraction
(SFE) is the process of separating one component (the extractant)
from another (the matrix) using supercritical fluids that is CO2 as the
extracting solvent. CO2 is the king of extraction solvents for
botanicals. Extraction conditions for supercritical CO2 are above the
critical temperature of 31°C and critical pressure of 74 bar.
Supercritical fluids are highly compressed gases, which have
combined properties of gases and liquids in an intriguing manner.
Supercritical fluids can lead to reactions, which are difficult or even
impossible to achieve in conventional solvents. It is a fast process
completed in 10 to 60 minutes. A supercritical fluid can be separated
from analyte by simply releasing pressure, leaving almost no trace
and yields a pure residue.
Key words: Supercritical fluid extraction, Applications.

3. INTRODUCTION
extraction process?
 Extraction can be defined as the removal of soluble
material from an insoluble residue, either liquid or solid,
by treatment with a liquid solvent. It is therefore, a
solution process and depends on the mass transfer
phenomena. The controlling factor in the rate of extraction
is normally the rate of diffusion of the solute by the liquid
boundary layer at the interface.

4. OBJECTIVES
• Introduction to SCFE
• Common SCF and their common properties
• Instrumentation of SCF extraction
• Advantages and application of SCFE

5. Super Critical Fluid Extraction
 Extraction of compounds of interest using super critical fluid as
an extracting solvent/mobile phase.
 Resembles soxhlet extraction except the fact that the solvent
used here is SCF.
 The SCF state occur when a fluid is above its critical
temperature and critical pressure i.e. between the typical gas
and liquid state. During which the solvating power of mobile
phase will be at its peak.
 The first reported observation was made by Baron in 1822.
 In 1970 significant development in the field off SCFE occurred
by decaffeination of green coffee with CO2 as SCF.

6. Supercritical fluid
 A supercritical fluid is any substance at a temperature and
pressure above its critical point. It can diffuse through
solids like a gas, and dissolve materials like a liquid.
 It exhibit physicochemical properties intermediate
between those of liquid and gases.
 Small changes in pressure and temperature results in
greater changes in density allowing many properties of
SCF to be fine tuned thus SCF can preferably substitute
organic solvents for many of the industrial and laboratory
processes.

7. Phase diagram of SCF
 Critical temperature(TC):
highest temp at which a gas can
be converted to a liquid by
increase in pressure.
 Critical pressure (PC): highest
pressure at which a liquid can
be converted to a gas by
increase in temperature.
 Triple point (TP): a point at
which gas liquid and solid
phases exist in equilibrium.

8. Common SCF
Among the range of super critical fluids used water is used
for power generation and CO2 for decaffeination.
 Carbon dioxide is
Environmentally friendly and generally recognized as safe
by the food and drug administration (FDA)
Odorless, non-toxic, non-flammable, inexpensive, easy to
remove from the product and its TC and PC are relatively
low.
Using CO2 as mobile phase even allow the extraction of
thermally labile/easily oxidisable compounds even at low
temperatures and non oxidant medium.

9. Properties of supercritical fluid
 combine properties of gases and liquids in an intriguing
manner.
 solvent power similar to light hydrocarbons for most of the
solutes.
 Solubility increases with increasing density (that is with
increasing pressure).
 The fluids are commonly miscible with permanent gases (e.g.
N2 or H2) and this leads to much higher concentrations of
dissolved gases than can be achieved in conventional solvents.
In general terms, supercritical fluids have properties between
those of a gas and a liquid.

10. Critical properties for some components
commonly used as supercritical fluids

11. Extraction process by SCF
 The system must contain a pump for the CO2, a pressure cell to
contain the sample,
 The liquid is pumped to a heating zone, where it is heated to
supercritical conditions.
 It then passes into the extraction vessel, where it rapidly
diffuses into the solid matrix and dissolves the material to be
extracted.
 The dissolved material is swept from the extraction cell into a
separator at lower pressure, and the extracted material settles
out.
 The CO2 can then be cooled, recompressed and recycled, or
discharged to atmosphere.

12. Flow diagram of working.

13. Two mode to run the instrument
Static extraction
 The mobile phase fills the
extraction cell and
interacts with the sample.
 The second pump is
opened and the extracted
surface are taken out at
once.
Dynamic extraction
 The second pump sending
the material out to the
collection chamber is
always open during the
extraction process thus
 the mobile phase reaches
the extraction cell and
extracts components in
order to take them out
consistently.

14. Pump
 Carbon dioxide is usually
pumped as a liquid, usually
below 5°C and a pressure of
about 50 bars.
 The solvent is pumped as a
liquid as it is then almost
incompressible.
 For small-scale extractions (up
to a few grams/minute),
reciprocating CO2 pumps or
syringe pumps are often used.
 For larger scale extractions,
diaphragm pumps are most
common.

15. Pressure vessels
 Pressure vessels can range from
simple tubing to more
sophisticated purpose built
vessels with quick release
fittings.
 The pressure requirement is at
least 74 bars,
 The vessel must be equipped
with a means of heating.
 Care must be taken if rubber
seals are used on the vessel, as
the CO2 may dissolve in the
rubber, causing swelling, and
the rubber will rupture on
depressurization.

16. Collection
 The supercritical solvent is passed
into a vessel at lower pressure than
the extraction vessel.
 The density, and thus, dissolving
power, of supercritical fluids
varies sharply with pressure, and
hence, the solubility in the lower
density CO2 is much lower, and the
material precipitates for collection.
 It is possible to fractionate the
dissolved material using a series of
vessels at reducing pressure.

17. Heating and cooling
 The fluid is cooled before
pumping to maintain
liquid conditions, and then
heated after pressurization.
 As the fluid is expanded
into the separator, heat
must be provided to
prevent excessive cooling

18. Application of SCF extraction-
 Separation of essential and its derivative for use in food,
cosmetics and pharmaceutical industry.
 Extraction of oil is used to produce fat free potato chips and
snack food to satisfy the consumer need for lighter food.
 Separation of tocopherol and other anti oxidant because they
have greater solubility in CO2
 Removal of alcohol from wine, beer and similar products.
 Supercritical CO2 coupled with HPLC to extract and
characterize antimicrobial compounds and food preservatives.
 Used to determine the fat content of numerous food products
ranging from beef to oil seeds and vegetables.
 Application in food safety: used in food pollutants analysis,
mainly pesticide residue and environmental pollutants. Etc.