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Properties and
Applications ofSupercritical uids
Presented by: Guided by:
Jadhav Manasvi Prof .S.P. Dabke
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When a gas or liquid is compressed(underpressure) and heated past its criticalpoint, it enters a phase called“supercritical phase” and is referred as“supercritical fluid”
The density of both liquid and gas areidentical in this phase.
The critical pressure and criticaltemperature at which this happens are
unique to each substance.
What is a supercritical uid?
PHASE DAIGRAM
Tehno!o"y #ath$%o!&'$issue ($)u!y '**+
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Comparison of Gases, Supercritical Fluids and Liquids
,ro,erties of -iuid
Density !"#m$% &iscosity 'Pa(s% Di)usi*itymm+#s%
Gases ( (* (&(*
SupercriticalFluids
(**&(*** +*&(** *.*(&*.(
Liquids (*** +**&(*** *.**(
Su,erritia! /uids have ,ro,erties bet#een those of "as and !iuid.
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Supercritical fluids have no surface tension because they are not subject to the vapor-liquid boundary so no molecules have the attraction to the interior of the liquid.
The density of supercritical fluid approches density of liquid phase,which helps toimprove its solvating properties.
The other properties like diffusivity and viscosity approches to that of gas,whichenhances the transport properties of supercritical fluid and helps it to penetrate intoporous solid material more liquid solvent resulting in rapid masstransfer and extraction.
or supercritical fluids the heat of vapouri!ation is !ero at and beyond the critical point ,so for this there is no distinction between the phases.
"ts isothermal compressibility tends to infinity ,thus its density changes dramatically.
The dependency of solubility to the specific density is give by empirical correlationproposed by #hrastil as follows
# $ %density&k . exp 'a(T ) b*
where # is the solute concentration, a, b and k empirical constants
Properties of supercritical uids
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Graphs sho-in" chan"e in solu.ility of /aphthalene -ith respect to density
Sol*ent po-er of a SCF increases -ith density at "i*en temperature
Sol*ent po-er of a SCF increases -ith temperature at a "i*en density
Su,erritia! 0!uid E1tration by Mark MHu"h 2%a!3rukonis
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There are 4any other advanta"es of su,erritia! /uid as so!vent instead of usin"
or"ani so!vent
5o residua! so!vent
Su,erritia!/uid as so!vent
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APPL0CA102/S 2F S3P45C5010CAL FL30DS
Due to the s,eia! so!vent ,ro,erties of su,erritia! /uid it has no# beo4e a,art of 4any industria! ,ratie.
(6 Reation7ata!ysis:
) +se of S# # to replace traditional solvents has the benefit of increasing and controlling the
reaction kinetics by altering the pressure.
) asy separation of reaction product and removal of solvent from the system by simpledepressuri!ation.
) /pplication0biochemistry,polymerchemistry and environmental science.
'6 Parti!e 0or4ation:) +se in the production of powders or microparticles with possible use in pharmaceutical industry.
) "t increases the bio availability of poorly soluble molecules.
) 1y rapid depressuri!ing materials dissolves in #,microparticals are thus produced with drugs
embedded in substrate.
86 9!eanin":) ffective solvent for cleaning many kinds of delicate parts,electronics,plastics,parts having small
opening or porous material.
) "t enhances the wetting and diffusion properties of solvent also removes oils,fats,waxes withoutcausing any damage to matrix.
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6 E!etroni hi, 4anufaturin":) lectronic chip manufacturing creats a large amount of environmental burden by
consuming large amount of chemicals,energy and water for cleaning.
) #- with appropriate detergents eliminates need for water
) 2educes energy consumption.) 3ue to low surface tension of S# the cleaning of finer surface features can be done
without any damage.
+6 9hro4ato"ra,hy:)
"t is the technique use to separate the chemical mixures into separate componenets.) #- replaces the mobile phase in 456#.
) "t helps to improve the performance of the separation column by giving higherresolution and faster separation.
;6 In)etion 4o!din" and e1trusion:) # melt in plastic melt lowers its viscosity thereby decreasing the injection pressure
required or decreasing ingection time.
) Thus it increases life of moulding equipmennt and production rate.
) 3ecrease in melt temperature can be used for moulding the thermally labile compound.
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<6 0rationation:) S# are used to fractionate low vapor pressure oils and polymers.
) "t takes the advantage of very high selectivity of S#.
) This fractionation is difficult to achieve in simple distillation as the impurities have thesame volatility as the primary compound reducing selectivity.
) +se to fractionate the synthetic or natural oils such as siliconses,flouroethers,copolymersetc.
=6 Po!!ution abate4ent:) Substitution of organic solvent by S# in painting industry, polymer foaming, cleaning and
degreasing, dry cleaning, recycling processes.) Substitution to water and air polluting processes.
) 7ater stream polluted with water can be treated with # in order to recover the pollutants
prior to water disposal.
>6 E1tration:)
S is an alternative to liquid extraction using solvents such as hexane or dichloromethane.) #arbon dioxide %#& is the most used supercritical fluid, sometimes modified by co-
solvents such as ethanol or methanol.
) # is easy to remove simply by reducing the pressure, leaving almost no trace.
) 5roperties of a supercritical fluid can be altered by varying the pressure and temperature,allowing selective extraction.
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Apllication of supercritical uid C26% in e7traction
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P52C4D354 F25 S3P45C5010CAL FL30D4815AC102/
The !iuid ?S906 is ,u4,ed to a heatin" @one$ #here it is heated to su,erritia! onditions. It then ,asses into the e1tration vesse!$ #here it ra,id!y diuses into the so!id
4atri1 2 disso!ves the 4ateria! to be e1trated. The disso!ved 4ateria! is s#e,t fro4 the e1tration e!! into a se,arator at !o#er
,ressure$ and the e1trated 4ateria! sett!es out. The 9B' an then be oo!ed$ re&o4,ressed and rey!ed$ or dishar"ed to
at4os,here.
( 9ondensation' Pu4,in"8 Heatin" E1tration+ Deso4,ression; Se,aration
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3ue to many special solvent properties of supercritical fluid, it has now become a part
of many industrial processes. "t has replace many organic solvents like hexane due to the increasing pressure of
global warming and o!one depletion. Thus S# have a great future ahead .
1ut the supercritical fluid processes are not always the best answers, but should beconsidered as alternatives among others, with their own advantages an limitations.
19A/: ;23
Conclusion
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