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Prof Hassan Ghaziaskar Isfahan University of

VIEWS: 11 PAGES: 51

									 In the name of God

Particle design using
 supercritical fluids

Supervisor : Dr. Ghaziaskar
        By: M. Amirabadi
                              1
content

• Presentation of Supercritical Fluids
• Reasons of using Supercritical
  Fluids
• Processes of Supercritical Fluid
  producing micro and nano-particles
• Applications of these processes
• Conclusion
• References
                                         2
Supercritical fluid

 A substance At
 temperatures and
 pressures above
 its critical
 temperature and
 pressure ( its
 critical point ) is
 called a
 supercritical fluid.

                        3
Why are we using
supercritical fluids ?




                         4
Properties of some
supercritical fluids
Compound         Tc(oC)   Pc(atm)
CO2               31.7      72.9
H2O              374.1     218.3
NH3              132.5     112.5
Butane(C4H10)     152       37.5
Freon13(CCLF3)    28.8      38.2
Acetone(C3H6O)   235.5       47
Hexan(C6H14)     234.2      29.9
                                    5
Why is CO2 the most
commonly used solvent ?
• It is easy to attain critical
  conditions of CO2
• Inexpensive
• Nontoxic
• Non-flamable
• Providing CO2 in high purity is
  easy
                                    6
Particle design in
supercritical media



                      7
advantages of particle design using
supercritical technology to
conventional methods


Supercritical technology
• Produces very small particles (micro
  & nano)
• Produces narrow particle size
  distribution (PSD)
• Separation of fluid from particles is
  done easily
• Reduces wastes
                                          8
Supercritical fluid methods
for particle design
• RESS (Rapid Expansion of
  Supercritical Solutions)
• SAS/GAS (Supercritical fluid
  Anti-Solvent
• PGSS (Particles from Gas-
  Saturated Solutions (or
  Suspensions)
• DELOS (Depressurization of an
  Expanded Liquid Solution)       9
RESS (Rapid expansion of
Supercritical Solutions)




                           10
Morphology of particles
• Material structure
        Crystalline or amorphose
        Composite or pure
• RESS parameters
         Temperature
         Pressure drop
         Distance of impact of the jet
         against the surface
         Dimensions of the
  atomization
         vessel
         Nozzle geometry                 11
Advantages of RESS
• Producing solvent free products
• With no residual trace of solvent ,
  particles are suitable for therapeutic
  scopes
• It can be used for heat labile drugs
  because of low critical temperature
• It needs simple equipment and it is
  cheap
• Produced particles requires no post
  processing
                                           12
 Key limitations of RESS

• substrate should be soluble in
  CO2
• Co-solvent can be used for
  insoluble substrates but
  elimination of co-solvent is not
  easy and cheap

                                     13
Liquid anti-solvent
process
• There are two liquid solvents
  (A&B)
• Solvents are miscible
• Solute is soluble in A &not
  soluble in B
• Addition of B to the solution of
  solute in A causes precipitation
  of solute in microparticle
                                     14
Supercritical fluid anti-
solvent
• Solute is dissolved in a solvent
• Solute is not soluble in
  supercritical fluid
• Supercritical fluid (anti-solvent)
  is introduced in solvent
• Supercritical fluid expands the
  solution and decreases solvent
  power
• Solute precipitates in the form
  of micro or nano particle
                                       15
Advantages of supercritical fluid
antisolvent to liquid antisolvent
• Separation of antisolvent is
  easy
• SAS is faster because of high
  diffusion rate of supercritical
  fluid
• SAS can produce smaller
  particles
• In SAS particle size distribution
  is possible                         16
The solute is recrystallized
in 3 ways
• SAS/GAS (supercritical anti-
  solvent or gas anti-solvent)
• ASES (aerosol solvent
  extraction system)
• SEDS (solution enhanced
  dispersion by supercritical fluid)


                                       17
SAS/GAS (Supercritical
Anti-Solvent)




                         18
ASES (Aerosol Solvent
Extraction System )




                        19
SEDS (Solution Enhanced
Dispersion by Supercritical
Fluids )




                              20
Experiments are carried
out in three scales

• Laboratorial scale
• Pilot scale
• Plant scale




                          21
Supercritical antisolvent
fractionation of Propolis in
pilot scale

• Propolis has applications in
  medicine ,hygiene and
  beauty



                                 22
Components of propolis

• Flavonoids       Separation with
• Essential oil     extraction


 •High molecular       Separation with
 mass components        SAS



                                     23
Schematic of pilot scale propolis extraction/fractionation plant 24
Crystal formation of BaCl2
and NH4Cl using a
supercritical fluid antisolvent

• SAS process has been used
  to produce crystals of BaCl2
  and NH4Cl from solutions of
  dimethyl sulfoxide (DMSO)


                                 25
26
Parameters that affect
on crystallization of
BaCl2 & NH4Cl


• Injection rate of CO2
• Initial chloride
  concentration in DMSO
• Temperature

                          27
 Instruments used for
 determining particle
 properties
• Morphology
       Scanning electron microscope (SEM)
• Composition
      Energy dispersive X-Ray spectrometer (EDS)
• Internal structure
       X-Ray diffractometer (XRD)
• Particle size
       Image size of SEM photomicrographs

                                            28
   Crystal habit of BaCl2

• Slow injection rate of CO2
     Cubic shaped crystals (Equant habit)
• Rapid injection rate of CO2
     Needle-like crystals (Acicular habit)

The variation in crystal habit result from the
 alteration of the relative growth rate of
 crystal faces
                                             29
30
31
Crystal habit of NH4CL

• Slow injection rate of CO2
  Equant
• Rapid injection rate of CO2
 tabular




                                32
33
34
Internal structure of
BaCl2
• Unprocessed particles
    (Orthorhombic space lattice)


• Processed particles
    (Hexagonal space lattice)



                                   35
Internal structure of
NH4Cl
• Unprocessed particles
  (Cubic)
• Processed particles (Cubic)
• Cubic space lattic is the
  only possible crystal system
  for NH4Cl

                                 36
Crystal size &
composition
• Crystal size
• The slower injection rate of CO2 ,the
  larger crystal size
• Crystal composition
• Composition of crystals did not
  changed after processing by CO2



                                          37
Separation of BaCl2 &
NH4Cl mixtures in DMSO
• The SAS process enables
  the separation of
  multicomponent mixtures if
  the nucleation of each
  component occurs at
  different pressures

                               38
SAS has used in
following applications
•   Explosives and propellants
•   Polymers and biopolymers
•   Pharmaceutical principles
•   Coloring matter, catalysts,
    superconductors and inorganic
    compounds


                                    39
Explosives and
propellants
• Small particles of these
  compound improves the
  combustion process
• Attainment of the highest
  energy from the detonation
  depends on particle size

                               40
Polymers and
biopolymers
 Polymer microspheres can be
  used as:
   • Stationary phases in
     chromatography
   • Adsorbents
   • Catalyst supports
   • Drug delivery system

                               41
Pharmaceutical
principles
• Increasing bio-availability of
  poorly-soluble molecules
• Designing formulations for
  sustained-release
• Substitution of injection
  delivery by less invasive
  methods, like pulmonary
  delivery

                                   42
Coloring matter, catalysts,
superconductors and
inorganic compounds

• Color strength is enhanced if dying
  matter is in the form of micro
  particles
• Catalysts in the form of
  nanoparticles have excellent activity
  because of large surface areas

                                      43
RESS & SAS

• Regarding the materials RESS &
  SAS are complementary
• RESS      Compound is soluble
            in CO2
• SAS       Compound is
            insoluble in CO2

                                   44
Conclusion




             45
Rapid expansion of
supercritical fluid (RESS)
• CO2 is reached to the desired
  pressure and temperature
• In extraction unit solute(s) is
  dissolved in CO2
• In precipitation unit solution is
  depressurized
• Solubility of CO2 is decreased and
  solute(s) precipitates in the form of
  very small particle or fibers and
  films

                                          46
SAS/GAS(supercritical
anti-solvent)
• In this method a batch of
  solution is expanded by mixing
  with supercritical fluid




                                   47
ASES (aerosol solvent
extraction system)
• This method involves spraying
  the solution through an
  atomization nozzle as fine
  droplets into compressed
  carbon dioxide




                                  48
SEDS (solution enhanced
dispersion by supercritical
fluids)
• In this method a nozzle with tow
  coaxial passages allows to
  introduce the supercritical fluid
  and a solution of active
  substance(s) into the vessel




                                  49
Steps of fractionation
of Propolis
• CO2 is supplied from cylinders.
• Solution of Propolis in Ethanol is in storage
  tank1.
• Propolis solution and CO2 are mixed
  before precipitation chamber EX1.
• In EX1 the Propolis solution becomes
  supersaturate and high molecular mass
  components precipitate .
• CO2 and Propolis solution will furture face
  two pressure drop.
• In SV1 flavonoids precipitate.
• In SV3 essential oil and ethanol
  precipitate.
                                                  50
Morphology of particles
• Material structure
        Crystalline or amorphose
        Composite or pure
• RESS parameters
         Temperature
         Pressure drop
         Distance of impact of the jet
         against the surface
         Dimensions of the atomization
         vessel
         Nozzle geometry
                                         51

								
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