Presentation on vacuum distillation

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MAHARSHI DAYANAND UNIVERSITY

• DEPARTMENT OF PHARMACEUTICAL
  SCIENCES
• PHARMACEUTICAL ENGINEERING
• ASSIGNMENT ON
• DISTILLATION UNDER REDUCED PRESSURE/VACUUM
  DISTILLATION
• ROTARY EVAPORATOR
• STEAM DISTILLATION
• SUBMITTED TO DR. HARISH DUREJA
  
• 
  

SUBMITTED BY DEEPIKA ROLL NO 1455 BATCH -A
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VACUUM DISTILLATION/DISTILLATION UNDER REDUCED
PRESSURE

• Vacuum distillation is used for compounds that
  have high boiling points(above 200 C).
• Such compounds often undergoes thermal
  decomposition at temperatures required for their
  distillation at atmospheric pressure.
• The boiling point of compound is lowered
  substantially by reducing the applied temperature
  .
• Liquid boils when vapour pressure is equal to
  atmospheric pressure i.e pressure on its surface.

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FOR EXAMPLE

• Water boils at 100 C atmosphere pressure
  101.31 kPa (760mmHg)
• At 40C vapour pressure equal to 9.83 kPa
  (70mmHg)
• So if external pressure reduced to 9.83 kPa ...
  Then water boils at 40C .
• The important factor in evaporation is
• Mass of vapour formed ? vapour pressure of
  evaporating liquid
• 
  External pressure

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CONSTRUCTION

• It consist of a double neck distillation flask
  called claisen flask . At one neck thermometer is
  attached and the second neck prevent the
  splashing of liquid .
• Thick wall glass apparatus used for vacuum
  distillation .
• Water bath or oil bath is used for heating .
• Claisen flask connected with condenser ? Vaccum
  pump attached to adapter ? It connected to
  receiver? Small vacuum gauge (monometer) inserted
  between pump and receiver .

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DIAGRAM OF VACUUM DISTILLATION SET-UP

• Liquid to be distilled filled ½ to ? volume of
  flask.
• Small pieces of porcelain are added.
• Capillary tube and thermometer placed in flask .
• Required vacuum is applied .
• The contents are heated
• Temp. rises liquid get vapourised rapidly due to
  vacuum
• Vapour pass through condenser
• Condensate is collected in reciever

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VACUUM DISTILLATION IS USED FOR

• To remove solvents from the mixture without
  damaging the product.
• Liquid that chemically change at temperatures
  near their atmospheric boiling points.
• Liquids to be distilled that have high
  atmospheric boiling points.

ADVANTAGES OF VACUUM DISTILLATION

• Faster processing time
• Effective distillation while keeping the process
  under the maximum temperature of distillation
  units heater .

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ROTARY EVAPORATOR

• -
• used to evaporate solvents under vacuum with the
  use of rotation and heat.
• Used by environmental regulatory agencies for
  determining the amount of solvents in paints,
  coating and inks.
• The rotary evaporator rotates the distillation
  flask to enhance the distillation.
• Rotating the flask throws up liquid on walls of
  flask and thus increase the surface area for
  evaporation.
• Heat is often applied to rotating distillation
  flask by partially immersing it in a heated bath
  of water or oil. 

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SETUP WORKING

• Run cold water to the dimorth condenser and add
  ice to the collection flask bath (if needed)
• Clip boiling falsk with sample in place .
• Commence rotation boiling flask .
• Slowly evacuate system.
• Apply heat via the warm water.
• Thus volatile solvents are separated in solvent
  traper from non volatile solutes in the boiling
  flask.

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STEAM DISTILLATION

• Special type of distillation used for material
  that are sensitive to high temperatures
• Many organic compounds (like natural aromatic
  compounds) Decompose at high sustained
  temperature so cannot be separated by simple
  distillation
• ADDITION OF WATER VAPOUR INTO APPARATUS CAN ALLOW
  FOR LOWER TEMPERATURES
• Limonene bp is 175 C but It will boil at a
  temperature close to 100 C using a steam
  distillation .

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PRINCIPAL

• A mixture of immiscible liquids boil ? when sum
  of their vapour pressure is equal to atmospheric
  pressure .
• For example Boiling point of terpentine is
  160C ? when mixed with water boil at 95.6C ? at
  this temperature vapour pressure of water is
  86.25 kPa and temperature is 15.02 kPa .
• So sum is ? 86.25 15.02 101.31 kPa (normal
  atmospheric pressure)
• Distillation is continues until all non- aqaous
  liquids has been separated.

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DIAGRAM working
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STEAM DISTILLATION APPLICATIONS

• Steam distillation is employed in the isolation
  of essential oils . Eg Eucalyptus etc .
• It is also widely used in petroleum refineries
  and protochemical plants .
• Steam distillation also is an important means of
  separating fatty acids from the mixture.
• Aromatic water can be prepared .
• Camphor is distilled by this method .

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ADVANTAGES DISADVANTAGES

• ADVANTAGES
• Volatile oils can be separated At low
  temperatures without loss of aromaticity .
• Substances have low votality can be distilled .
• DISADVANTAGE
• Not suitable when immiscible liquids react with
  water .

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REFERENCES

• https//en.m.wikipedia.org/wiki/Vacuum_distillatio
  n
• https//www.h2o-de.com/en/products/vacudest/workin
  g-principle
• http//www.chem.ucla.edu/bacher/Specialtopics/vac
  uum20distillation.html
• https//www.eia.gov/todayinenergy/detail.php?id91
  30
• https//www.sciencedirect.com/topics/chemistry/vac
  uum-distillation

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