Steam distillation: Difference between revisions
Reverting possible vandalism by Special:Contributions/125.60.165.197 to version by 74.59.165.139. If this is a mistake, report it. Thanks, ClueBot. (103538) (Bot) |
added Principle of steam distilation |
||
| Line 5: | Line 5: | ||
Many [[organic compound]]s 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. By adding water or steam the [[boiling point]]s of the compounds are depressed, allowing them to evaporate at lower temperatures, preferably below the temperatures at which the deterioration of the material becomes appreciable. If the substances to be distilled are very sensitive to heat, steam distillation can also be combined with [[vacuum distillation]]. After distillation the vapors are condensed as usual, usually yielding a two-[[phase (matter)|phase system]] of water and the organic compounds, allowing for simple separation. |
Many [[organic compound]]s 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. By adding water or steam the [[boiling point]]s of the compounds are depressed, allowing them to evaporate at lower temperatures, preferably below the temperatures at which the deterioration of the material becomes appreciable. If the substances to be distilled are very sensitive to heat, steam distillation can also be combined with [[vacuum distillation]]. After distillation the vapors are condensed as usual, usually yielding a two-[[phase (matter)|phase system]] of water and the organic compounds, allowing for simple separation. |
||
==Principle<ref>Martin's Physical Pharmacy & Pharmaceutical sciences, fifth edition, ISBN- 0-7817-6426-2, Lippincott williams & wilkins</ref>== |
|||
When a mixture of two practically Immiscible liquid is heated while being agitated to expose the surfaces of both the liquids to the vapor phase, each constituent independently exerts its own vapor pressure as a function of temperature as if the other constituent is not preent. Consequently the vapor pressure of the whole system increases. Boiling begins when the sum of the partial pressure of the two immiscible liquids just exceeds the atmospheric presure. Thus in this way many organic compounds insoluble in water can be purified at a temperature well below the point at which decomposition occurs. |
|||
Ex- Boiling point of bromobenzene is 156 deg C,Boiling point of Water is 100 deg C,Mixture of the two boils at 95 deg C |
|||
THus bromobenzene can be easily distilled at a temperature 61 deg C below its normal Boiling point |
|||
== Applications == |
== Applications == |
||
Revision as of 11:07, 10 December 2007
 | This article needs additional citations for verification. (August 2007) |
Steam distillation is a special type of distillation (a separation process) for temperature sensitive materials like natural aromatic compounds.
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. By adding water or steam the boiling points of the compounds are depressed, allowing them to evaporate at lower temperatures, preferably below the temperatures at which the deterioration of the material becomes appreciable. If the substances to be distilled are very sensitive to heat, steam distillation can also be combined with vacuum distillation. After distillation the vapors are condensed as usual, usually yielding a two-phase system of water and the organic compounds, allowing for simple separation.
Principle[1]
When a mixture of two practically Immiscible liquid is heated while being agitated to expose the surfaces of both the liquids to the vapor phase, each constituent independently exerts its own vapor pressure as a function of temperature as if the other constituent is not preent. Consequently the vapor pressure of the whole system increases. Boiling begins when the sum of the partial pressure of the two immiscible liquids just exceeds the atmospheric presure. Thus in this way many organic compounds insoluble in water can be purified at a temperature well below the point at which decomposition occurs. Ex- Boiling point of bromobenzene is 156 deg C,Boiling point of Water is 100 deg C,Mixture of the two boils at 95 deg C THus bromobenzene can be easily distilled at a temperature 61 deg C below its normal Boiling point
Applications
Steam distillation is employed in the manufacture of essential oil, for instance, perfumes. In this method, steam is passed through the plant material containing the desired oils. It is also employed in the synthetic procedures of complex organic compounds. Eucalyptus oil and orange oil are obtained by this method in industrial scale.
Steam distillation is also widely used in petroleum refineries and petrochemical plants where it is commonly referred to as "steam stripping".[2][3][4]
See also
- Azeotropic distillation
- Batch distillation
- Distillation
- Extractive distillation
- Fractional distillation
- Herbal distillates
- Theoretical plate
References
- ^ Martin's Physical Pharmacy & Pharmaceutical sciences, fifth edition, ISBN- 0-7817-6426-2, Lippincott williams & wilkins
- ^ Beychok, M.R., The Design of Sour Water Strippers, Individual Paper 61, Proceedings of Seventh World Petroleum Congress, Mexico City, April 1967
- ^ Kister, Henry Z. (1992). Distillation Design (1st Edition ed.). McGraw-Hill. ISBN 0-07-034909-6.
{{cite book}}:|edition=has extra text (help) - ^ Sour Water Steam Stripper Schematic Diagram
| Principles |  | |
|---|---|---|
| Industrial processes | ||
| Laboratory methods | ||
| Techniques | ||