Mechanism of Distillation,simple distillation steam &fractional distillation for Bpharm students

mechanism of distillation ,simple distillation, fractional distillation,steam distillation

1. DISTILLATION BY M.SWETHA

2. Distillation = separates/purifies liquids. Heat mixture of two or more liquids in a flask. More volatile liquid vaporizes 1 st , vapor passes into a water-cooled condensing column, it can reverts back into a liquid (condenses) on the cool glass, then trickles into a collection flask. With further heating the less volatile liquids vaporize and distill at higher temperatures. Types of Distillation Simple Distillation Fractional Distillation

3. Involves vaporization, condensation, and collection of the condensate (distillate). The temperature of the distillate is measured by a thermometer placed in the path of the vapor. MECHANISM INVOLVED

4. Distillation—volatile compound _ reject solid trace Evaporation-volatile oil is let off - solid trace is collected Distillation vs Evaporation

5. The apparatus consist of a still ,a condenser &receiver , chips of porcelain Simple Distillation

6. Liquid is taken in still heated till B.P vapour formed condensed-collected in receiver- distillate is formed

7. Simple distillation is most effective when the mixture contains only one volatile component. More than one ….most effective if the boiling points of the components differ by at least 70 ºC . Exemptions of Simple Distillation

8. Separate volatile compound Purification Distilled water preparation Applications

9. Disadvantages Hot water will go out TYPES OF WATER Water for preparation- Purified water For inj Sterile water

10. Vacuum distillation is a method of distillation whereby the pressure above the liquid mixture to be distilled is reduced to less than its vapor pressure (usually less than atmospheric pressure ) causing evaporation of the most volatile liquid(s ) (those with the lowest boiling points ). This distillation method works on the principle that boiling occurs when the vapor pressure of a liquid exceeds the ambient pressure. Vacuum distillation is used with or without heating the mixture. Vacuum distillation

11. For any liquid, the individual molecules within the liquid are continuously in motion This exerts an opposing pressure on the atmosphere above the solution known as the vapor pressure, P Atmosphere pressure is reduced Atmospheric pressure, P atm Vapor Pressure, P DISTILLATION SYSTEM

12. Distill the liquids which will decompose in the atmospheric pressure. For thermo labile liquids Ex: liquid extract of senna , liquid extract liquorice Applications

13. Industrial model for distill water preparation

14. Distillate is collected in fraction not continuous for that only it is called as fractional distillation. It is used to separate the miscible volatile liquid having different boiling points Based on the difference between the B P method is going to change . Fractional Distillation

15. Difference is more than 4 0 oc same equipment for distillation we will use except collection. First we will rise the heat &maintain the same till first distillate is collected which is vaporized at the temperature. For next distillate collection we will change the receiver& temperature is increased &maintained.

16. Difference is less than 4 0 o c fractionating column is used. Utilizes two or more vaporization condensation cycles, in succession, to effect separation The fractionating column causes the vaporization-condensation cycle to repeat by providing multiple surfaces for the cycle to take place TYPES OF DISTILLATION YSTEM

17. Fractional distillation

18. Crude alcohol Coal tar. Volatile oils in one liquid extarct . Applications

19. Many organic compounds tend to decompose at high sustained temperatures. Separation by normal distillation would then not be an option, so water or steam is introduced into the distillation apparatus. The water vapor carries small amounts of the vaporized compounds to the condensation flask, where the condensed liquids phase separate, allowing for easy collection. This process effectively allows for distillation at lower temperatures, reducing the deterioration of the desired products. If the substances to be distilled are very sensitive to heat, steam distillation may be applied under reduced pressure , thereby reducing the operating temperature further. After distillation the vapors are condensed as appropriate. Usually the immediate product is a two- phase system of water and the organic distillate, allowing for separation of the components by decantation , partitioning or other suitable methods. STEAM DISTILLATION

20. Turpentine oil B P is 160 oc mix with water B P is 95oc(it is lower than water & Turpentine oil boiling point Steam distillation

21. Purification of liquids with high boiling point ex: almond oil. Determination of volatile oil in drugs. Extracting clove, aniseed eucalyptus Applications

22. Vapors from the Distilling flask This cycle will continue until the top of the column is reached E ach vapor-condensation (or mini-distillation) cycle is known as one theoretical plate The length of distilation column required to provide one theoretical plate of separation is known as the height equivalent theoretical plate (HETP) TYPES OF DISTILLATION SYSTEM Fractional Distillation