ACADEMIC ESSAY EXTRACTION TECHNIQUES

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HA NOI UNIVERSITY OF SCIENCE AND TECHNOLOGY

SCHOOL OF CHEMICAL ENGINEERING
DEPARTMENT OF PHARMACEUTICAL CHEMISTRY AND
PESTICIDES TECHNOLOGY

ACADEMIC ESSAY

EXTRACTION TECHNIQUES
Instructor: Dr. Dinh Thi Phuong Anh
Student: Ngo Thi Thuy
Student ID: 20175228

HÀ NỘI.1/2022


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Contents
1. Solid-liquid extraction ( ionic liquid) .................................................................5
1.1

Denifintion .....................................................................................................5

1.1.1 Ionic liquids (ILs) .......................................................................................5
1.2

Solid- liquid Extraction Process ....................................................................8

1.2.1Principle of Solid – Liquid Extraction.........................................................8
1.2.2 Solid- liquid Extraction Process .................................................................8
1.3. Solid-Liquid Extraction Equipment...............................................................9
1.4.Applications of Solid-Liquid Extraction(Ionic-liquid) .....................................17
1.5.Example .............................................................................................................18
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. Microwave-assisted extraction .......................................................................23
2.1. Introduction ...................................................................................................23
2.2

Principles of Microwave-Assisted Extraction.............................................24

2.3 Microwave extraction process ........................................................................27
2.4

Microwave Assisted Extraction equipment ................................................29

2.3.1 Soxhlet Extractor ......................................................................................29
2.3.2 Dynamic extractor ....................................................................................31
2.5.Application of MAE .......................................................................................35
2.6.Example ..........................................................................................................36
3. Perstraction...........................................................................................................40
3.1. Introduction ....................................................................................................40
3.1.2. Denifintion : .............................................................................................41
3.2. Principles of Pertraction ..............................................................................42
3.3. Process of perstraction.................................................................................43

3.4.Specific advantages and disadvantages ..........................................................44
3.4.1 Advantages ...............................................................................................44
3.4.2. Disadvantages ..........................................................................................44
3.5.Perstraction equipment ...................................................................................44
3.6. Applications of Perstraction ..........................................................................46


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3.7.Example ..........................................................................................................46


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1. Solid-liquid extraction
1.1 Denifintion
➢ Solid-Liquid Extraction is a solid-liquid contact mass transfer operation in
which solute particles are transferred from solid to liquid.
➢ Solid-liquid extraction is also called Leaching.
➢ Solid-liquid extraction works on the principle of difference in solubility of
specified solids in liquids.
➢ The liquid used for solid-liquid extraction is called the solvent. The Solid
which carries solute particles is called an insoluble solid. (Inc, 2009)
1.1.1 Ionic liquids (ILs)
Ionic liquids (ILs) are widely recognized solvents due to their extended list of
excellent properties, and their success comesmainly fromtheir unique and
fascinating characteristics as non-molecular solvents, a negligible vapor pressure
associated to a high thermal stability, tunable viscosity and miscibility with water
and organic solvents. These properties are the result of being molten salts that are
liquid below 100 ◦C which generally consist of organic cation (e.g. imidazolium,

pyrrolidinium, pyridinium, tetraalkyl ammonium or tetraalkyl phosphonium) and
inorganic or organic anion (e.g. tetrafluoroborate, hexafluorophosphate, bromide).
In addition, the high number of possible combination provides a long list of ILs
with different polarity, hydrophobicity and viscosity, among others. For this reason
ILs are known as “designer solvents”


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Table 1. The structures of the ILs applied in extraction and separation:


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1.2 Solid- liquid Extraction Process
1.2.1 Principle of Solid – Liquid Extraction
Solid-Liquid Extraction occurs in two steps:
• Contacting solvent and solid to effect a transfer of a solute (leaching)
• The separation of the solution from the remaining solid (washing)
❖ Factors Affect Solid-Liquid Extraction Operation
1. Solid: Solid used for solid-liquid extraction can be porous or nonporous. The
solute may be distributed on a solid surface or inside pores of solid.
Recovery of solute from the solid surface is easier than from pores of solid.
Pores of solid create another mass transfer resistance for the solvent to go in
and for the solute to come out. Solid particle's size also plays an important
role in the operation. Recovery of solute from small size solid particles are
easier and more effective than bigger particle sizes.

2. Solvent: The solvent used for operation is also an important parameter to
take into consideration in operation. The solvent which contains desirable
properties which are listed below is more preferred.
3. Temperature: Temperature is also an important parameter in solid-liquid
extraction because the solubility of solid particles is also dependent on
temperature.
4. Mixing: Mixing of solid particles and liquid solvent decides the
effectiveness of contact which is also important for parameter solid-liquid
extraction. More thorough mixing confirms more contact between solid and
liquid and this results in higher mass transfer.
1.2.2 Solid- liquid Extraction Process
➢ Solid-liquid extraction there are steps
1.
2.
3.
4.

Size reduction of solids
Mixing of solids with solvent Liquid
Overflow and underflow separation
Solvent recovery from overflow and underflow


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➢ Solid-liquid phase extraction is achieved through the interaction of three
components:
• the sorbent
• the analyte
• the solvent.

➢ Type of ionlic liquid extraction
This section is thus divided into three parts based on the most frequently
employed extraction processes:
➢ simple IL-based SLE;
➢ IL-based MAE;
➢ IL-based UAE.

1.3.Solid-Liquid Extraction Equipment
1.3.1 Soxhlet Extractor
The Soxhlet extractor is used for liquid-solid extractions when the compound to
be extracted has limited solubility in the chosen solvent and the impurities are
insoluble. During the extraction, solvent vapour will flow up the distillation path,
into the main chamber and up into the condenser where it will condense and drip
down. The solvent will fill the main chamber, dissolving some of the desired
compound from the solid sample. Once the chamber is almost full, it is emptied by
the siphon, returning the solvent to the round bottom flask to begin the process
again. Each time the extraction is repeated, more of the desired compound is
dissolved, leaving the insoluble impurities in the thimble. This is how a compound
is removed from the sample.


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The Soxhlet extractor will run continuously once set up correctly:
Load the sample material containing the desired compound into the thimble
Place the thimble into the main chamber of the Soxhlet extractor
Add the chosen solvent to a round bottom flask and place onto a heating
mantle
➢ Attach the Soxhlet extractor above the round bottom flask
➢ Attach a reflux condenser above the extractor, with cold water entering at

the bottom and exiting above
➢ Now the apparatus is set up, heat the solvent to reflux and leave to extract
for the required amount of time
➢
➢
➢
➢


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1.3.2 Bollman extractor

This type of extractor, widely used for the extraction of vegetable oils from seeds,
consists of a number of baskets fixed to an endless chain having a descending and
an ascending leg, enclosed in a vapour tight chamber. Each basket has a perforated
bottom (wire-mesh). There are two sumps hold the extract streams. Liquids
percolating through the baskets along the two legs flow down to these sumps. The
solid is fed through a hopper into the basket at the top of the descending leg and
partially enriched extract (50% extract) is sprayed on the solid. The liquid
percolates through the slowly moving basket and collects at one of the bottom
sumps of the unit. Fresh extractant is sprayed on the top basket in the ascending leg
and percolates through the rising basket and collects in the other sump at the
bottom in the form of 50% extract, which is sprayed on the top basket of the


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ascending leg. Percolation of the liquid occurs counter-current in the descending
leg and co-current in the ascending leg. An extractor of this type may be 15 – 20

meters high. At the top of the tower, the baskets are tipped into a hopper, which is
provided with a screw conveyor at its bottom to discharge the spent solids.
This process has the following advantages and disadvantages :
Advantage:
1. Can be integrated into continuous process
2. Extraction efficiency is high
3. Final extract is fairly concentrated
Disadvantages:
1. Cost of equipment is high
2. Large equipment, so maintaining stable optimal thermal profile is difficult
3. Hydraulic conductivity of soaked leaves is low and it impairs percolation.
Sometimes chanelling through leaf matrix also occurs which also have
adverse effect on extraction efficiency.


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1.3.3 Hildebrandt Extractor

This type of extractor is being used nowadays in a wide scale for extraction of
different natural products. In this system the solid is immersed in the extractant.
The system comprises of two long sections of tubes fitted with screw conveyors
inside. A feed hopper is provided in one end of the horizontal section and the solid
is loaded into the tube through this hopper. Then the solid is transported to the
other end be the slow moving screw conveyor. At the other end of the tube there is
another section of tube which forms an angle with the first tube. There is a solvent
entry port at around middle of the second tube, through which the extractant is
pumped in. The solid meets the extractant in countercurrent manner when it is
transported through the horizontal tube and in first part of the upward angled tube.
The solid is then carried upward in the second half of the upward angle tube, where

it is drained and the drained solid is ultimately discharged from the extreme end of
the upward angled tube. The extract flows out through an outlet port at the extreme
end of the horizontal section. The entire unit can be steam jackated for precision
temperature control.
➢ Advantages
1. Precision process control


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2. Extraction is through immersion method, so hydraulic conductivity is not an
issue in extraction stage
3. High thermal efficiency
4. High concentration of the product in the extract due to countercurrent
extraction
➢ Disadvantages
1. Hydraulic conductivity may be an issue in the draining stage
2. Precision mechanical parts need high maintenance


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1.3.4.Bonotto Extractor

the solids during their passage through the unit. The design offers the obvious
advantages of countercurrent action and continuous solids compaction, but there
are possibilities of some solvent loss and feed overflow, and successful operation is
limited to light, permeable solids.

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A somewhat similar but simpler design uses a horizontal screw section for leaching
and a second screw in an inclined section for washing, draining, and discharging
the extracted solids.
In the De Danske Sukkerfabriker, the axis of the extractor is tilted to about 10°
from the horizontal, eliminating the necessity of two screws at different angles of
inclination.
Sugar-beet cossettes are successfully extracted while being transported upward in a
vertical tower by an arrangement of inclined plates or wings attached to an axial
shaft. The action is assisted by staggered guide plates on the tower wall. The shell
is filled with water that passes downward as the beets travel upward. This
configuration is employed in the BMA diffusion tower (Wakeman, loc. cit.).
Schwartzberg (loc. cit.) reports that screw-conveyor extractors, once widely
employed to extract flaked oil seeds, have fallen into disuse for this application
because of their destructive action on the fragile seed flakes.
Tray Classifier A hybrid like the screw-conveyor classifier, the tray classifier rakes
pulp up the sloping bottom of a tank while solvent flows in the opposite direction.
The solvent is forced by a baffle to the bottom of the tank at the lower end before it
overflows. The solids must be rugged enough to stand the stress of raking.

1.3.5.Kennedy extraction


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interial into or from the interior of the solid particles rather than the rate of transfer
to or from the surface of particles, the main function of the agitator is to supply
unexhausted solvent to the particles while they reside in the tank long enough for
the diffusive process to be completed. The agitator does this most efficiently if it

just gently circulates the solids across the tank bottom or barely suspends them
above the bottom.
The leached solids must be separated from the extract by settling and decantation
or by external filters, centrifuges, or thickeners, all of which are treated elsewhere
in Sec. 18. The difficulty of solids-extract separation and the fact that a batch
stirred tank provides only a single equilibrium stage are its major disadvantages.
Pachuca Tanks Ores of gold, uranium, and other metals are commonly batchleached in large air-agitated vessels known as Pachuca tanks. A typical tank is a
vertical cylinder with a conical bottom section usually with a 60° included angle, 7
m (23 ft) in diameter and 14 m (46 ft) in overall height. In some designs air is
admitted from an open pipe in the bottom of the cone and rises freely through the
tank; more commonly, however, it enters through a central vertical tube,
characteristically about 46 cm (18 in) in diameter, that extends from the bottom of
the tank to a level above the conical section—in some cases, almost to the liquid
surface. Before it disengages at the liquid surface, the air induces in and above the
axial tube substantial flow of pulp, which then finds its way down the outer part of
the tank, eventually reentering the riser.
1.4.Applications of Solid-Liquid Extraction(Ionic-liquid)
The use of IL-based SLE techniques with pure ILs, as well as with their
aqueous solutions and IL-methanol/ethanol mixtures, for the extraction and
separation of natural compounds, namely alkaloids, terpenoids, flavonoids,
phenolics, saponins, lignans, among others:
➢ The use of IL aqueous solutions on the SLE of
• alkaloids (e.g., glaucine from Glausium flavum).
• caffeine from Paullinia cupana
• galantamine, narwedine, N-desmethylgalantamine, and ungiminorine from
the aerial parts of Leucojum aestivum
• piperine from Piper nigrum.


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1.5.Specific advantages and disadvantages
1.6.Example

Ionic liquid-supported solid-liquid extraction of bioactive alkaloids. II. Kinetics,
modeling and mechanism of glaucine extraction from Glaucium flavum Cr.
(Papaveraceae)
(Ivan Svinyarov, Rozalina Keremedchieva, Milen G. Bogdanov, 2016)

• Materials and methods
Chemicals All chemicals used in this study were purchased from Sigma–
Aldrich (FOT, Bulgaria). The organic solvents were of analytical grade and
acetonitrile used for HPLC analysis was of chromatographic grade. The IL
used for extraction experiments was 1- butyl-3-methylimidazolium


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acesulfamate {[C4C1im][Ace], Fig. 1} and was synthesized, purified and
characterized by the authors according to a recently published procedures for
the synthesis of hydrophilic ILs . Its structure and purity was unequivocally
proven by means of 1 H and 13C NMR spectral analysis . Silver nitrate test
showed no residual chloride anions. Aerial parts of plant material of Glaucium
flavum Cr. and standard sample of glaucine were obtained from the relevant
Laboratory of Natural Products at the Bulgarian Academy of Science. The
plant material was further grinded, and in order to reduce the moisture content,
it was dried under vacuum prior to extraction. The particle size extracted was
0.25–0.40 mm. The same batch of sample was used through this study.

• Equipment, analysis and calculations

Glaucine quantification was carried out by means of reverse phase high
performance liquid chromatographic analyses (RPHPLC), performed on a
GBC liquid chromatography system, equipped with a LC 1100 HPLC pump,
a variable LC 1200 UV/Vis detector, a LC 1431 system organizer, an
injector with a 20 lL loop and N2000 software for data treatment. A
ZORBAX Extend-C18 (150 4.6 mm i.d., 5 lm) was used as an analytical
column. The mobile phase was a mixture of 0.1% triethylamine aqueous
solution and acetonitrile (50:50) delivered at a flow rate of 1 mL/min . The
UV detection wavelength was set up at 280 nm, where aporphine alkaloids
have an optimum absorption. Each injection volume was 20 lL and the
column temperature was ambient. Under these conditions the target alkaloid
glaucine was baseline separated and its peak was symmetrical. The peak
identification was achieved by a comparison of its retention time with the
corresponding peak in a standard solution, and glaucine concentration was
calculated according to a previously developed relationship. For all analysis,
aliquots were taken and were diluted with a certain volume of
acetonitrile/water mixture, in order to fit into the linear range of the standard
curve, then were filtered through a 0.45 lm microporous membrane prior to


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analysis and were directly injected into the HPLC apparatus. All HPLC
analyses were performed in a triplicate and the mean value was adopted.

Pig2. Block diagram for the recovery/production of glaucine from plant
material by means of ionic liquids
• Extraction experiments
Soxhlet extraction procedure The objective of the Soxhlet experiment was, on the
one hand, to determine the total amount of glaucine, on the other, to establish the

presence of other alkaloids in the batch sample. A known mass of about 5 g of
dried and milled plant material of G. flavum was introduced into the Soxhlet and
was extracted with 200 mL of methanol for 24 h at normal pressure. The
experiment was performed in duplicate, with a variation in results of less than 2%.
The HPLC analysis of the Soxhlet extract showed the absence of significant
amount of other aporphine alkaloids in the batch sample. The glaucine content was
found to be 1.8 wt%, which was considered as 100% for the next studies.
• Batch extraction of plant material
The IL-supported solid–liquid extraction experiments were carried out in an open
to the atmosphere 100 mL round-bottomed flask, equipped with a condenser and


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an internal thermal probe. The temperature of the medium was maintained at a
constant level by heating with magnetic stirrer, equipped with PEG-400 bath. A
mass of 100 mL of 1 M [C4C1im][Ace]-aqueous solution was introduced into the
flask under stirring and heated to 80 C. Then, a precisely measured amount of 2.5 g
of milled and dried plant material of G. flavum was introduced into the flask and
was extracted at the above temperature under stirring speed of 200 rpm. At the end
of the extraction (ca. 30 min) [17], the hot extract was filtered through cotton into a
graduated cylinder. To recover the initial volume of the IL-based extractant (100
mL), the residual biomass was washed in triplicate with fresh 1 M [C4C1im][Ace]aqueous solution (8 mL in sum), and the resulted filtrate was analyzed for glaucine
content as described in Section 2.2. In order to check the performance of the
extractive system under study in consecutive extractions without interim
purification, and to achieve a higher glaucine concentration, the above procedure
was repeated nine more times with same IL-aqueous solution, finally resulting in a
100 mL of crude IL-based extract (glaucine concentration = 3.98 mg/mL), the
latter being a stock solution for the following recovery studies. The residual
biomass from the above experiments was collected for recovery and regeneration

of the lost IL. For a comparison purpose, the same procedure was performed with
methanol as extractant, but in this case, the extractions were carried out for 1 h
under reflux.
• Back-extraction with organic solvents
The preliminary screening of the back-extraction ability of a range of molecular
liquids was performed in 15 mL centrifuge tubes by shaking the crude extract with
water immiscible organic solvents, such as toluene, ethyl acetate, tert-butylmethyl
ether, n-butanol, dichloromethane, and chloroform, in a volume ratio 2:1. After
phase separation, the phase volumes were detected, the glaucine content into the
IL-aqueous phase was determined as described in Section 2.2, and EE% was


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assessed by means of Eq. (3).

• Glaucine isolation and IL recycling
A 100 mL of freshly prepared crude glaucine extract (see Section 2.3.2.) was
extracted once with 50 mL chloroform in a separating funnel. After phase
separation, the upper IL-aqueous phase was set aside for subsequent ILregeneration, the chloroform phase was washed twice with deionized water (2 25
mL), and twice with 10 mL of hydrobromic acid aqueous solution (pH = 2). The
organic layer was then dried over sodium sulfate, the solvent was evaporated under
reduced pressure, and the residue was dissolved in 5 mL ethanol. After addition of
several drops of HBr-ethanolic solution, precipitates of glaucine as hydrobromide
salt appear with the time. The target alkaloid was then filtered, washed with cold
ethanol, and dried at 100 C under reduced pressure. The crystals obtained were
pink in color (0.29 g, 60% yield) and possessed mp 233–235 C, the latter being an
indication for purity level higher than 95% (Lit. mp of glaucineHBr 235 C, Ref.
[41]). The purity of glaucine was further proved by means of HPLC and its
structure by means of NMR analyses. The recycling of [C4C1im][Ace] from the

residual IL-aqueous phase was achieved according to the following procedure.
After water removal under reduced pressure, the residue was dissolved in dry
dichloromethane, the solution was filtered, and the organic solvent was evaporated
giving residue consisting entirely of [C4C1im][Ace], the latter being proven by
means of NMR and IR analyses.


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Pig3 Schematic diagrams of integrated processes based on ILs
comprising the extraction and separation of small organic extractable compounds
from biomass and further IL recovery and reuse.

2. Microwave-assisted extraction
2.1. Introduction
Denifine :
• Microwave -assisted extraction is an efficient method which involves
deriving natural compounds from raw plants, using microwave energy to


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heat solvents containing samples, thereby partitioning analytes from a
sample matrix into the solvent.
• Microwave extraction allows organic compounds to be extracted more
rapidly, with similar or better yield as compared to conventional
extraction methods.
• Microwave theory: Microwaves are made up of two oscillating
perpendicular field’s i.e. electric field and magnetic field .

Types of microwave extraction method:
➢ Nature MAE ( solvent):
• This method has been validated using a 1:1 mixture of hexane and
acetone from matrices such as soil, glass-fibers, and sand. Other solvent
systems may have applicability in microwave extraction, provided that
at least one component absorbs microwave energy.

➢ Extractant-Free MAE:
• Extractant-Free MAE Solvent-free microwave extraction (SFME) is a
combination of microwave heating and dry distillation, performed at
atmospheric pressure without adding any organic solvent or water..
2.2 Principles of Microwave-Assisted Extraction
- Microwave-assisted extraction (MAE) is based on the disruption or changes in
the structure of cells when applying nonionizing electromagnetic waves with
frequencies ranging from 300 MHz to 300 GHz to a sample matrix.Microwaves
heat up the molecules by the dual mechanism of ionic conduction and dipole
rotation. Ionic conduction and dipole rotation usually take place simultaneously


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both in the solvent and in the sample, which effectively converts microwave
energy to thermal energy. The ionic conduction generates heat due to the resistance
of the medium to ion flow. The migration of dissolved ions causes collisions
between molecules because the direction of ions changes as many times as the field
changes sign.
The dipolerotation is related to the alternative movement of polar molecules, which
try to line up with the electric field (Fig.1).
Dipolar polarization (also refereed as orientation polarization) is the most
significant heating mechanism in microwave extraction.

Fig. 1 Polarization and relaxation of dipoles according to the field

Extraction principle:
➢ Plant cells contain tiny microscopic traces of moisture that serve as the
target for microwave heating.
➢ The evaporation of moisture present inside the plant cell on heating due to
microwave energy generates a great pressure on the cell wall due to swelling
of the plant cell