Steam distillation is used in many of the recipes given in the Kitāb al-Taraffuq fī al-ʿiṭr ('Book of Gentleness on Perfume'), also known as the Kitāb Kīmiyāʾ al-ʿiṭr wa-l-taṣʿīdāt ('Book of the Chemistry of Perfume and Distillations'), attributed to the early Arabic philosopher al-Kindi (c. 801–873).5 Steam distillation was also used by the Persian philosopher and physician Avicenna (980–1037) to produce essential oils by adding water to rose petals and distilling the mixture.6 The process was also used by al-Dimashqi (1256–1327) to produce rose water on a large scale.7
Every substance has some vapor pressure even below its boiling point, so in theory it could be distilled at any temperature by collecting and condensing its vapors. However, ordinary distillation below the boiling point is not practical because a layer of vapor-rich air would form over the liquid, and evaporation would stop as soon as the partial pressure of the vapor in that layer reached the vapor pressure. The vapor would then flow to the condenser only by diffusion, which is an extremely slow process.
Simple distillation is generally done by boiling the starting material, because, once its vapor pressure exceeds atmospheric pressure, that still vapor-rich layer of air will be disrupted, and there will be a significant and steady flow of vapor from the boiling flask to the condenser.
In steam distillation, that positive flow is provided by steam from boiling water, rather than by the boiling of the substances of interest. The steam carries with it the vapors of the latter.
The substance of interest does not need to be miscible water or soluble in it. It suffices that it has significant vapor pressure at the steam's temperature.
If the water forms an azeotrope with the substances of interest, the boiling point of the mixture may be lower than the boiling point of water. For example, bromobenzene boils at 156 °C (at normal atmospheric pressure), but a mixture with water boils at 95 °C.8 However, the formation of an azeotrope is not necessary for steam distillation to work.
Steam distillation is often employed in the isolation of essential oils, for use in perfumes, for example. In this method, steam is passed through the plant material containing the desired oils. Eucalyptus oil, camphor oil and orange oil are obtained by this method on an industrial scale.9 Steam distillation is a means of purifying fatty acids, e.g. from tall oils.10
Steam distillation is sometimes used in the chemical laboratory. Illustrative is a classic preparation of bromobiphenyl where steam distillation is used to first remove the excess benzene and subsequently to purifiy the brominated product.11 In one preparation of benzophenone, steam is employed to first recover unreacted carbon tetrachloride and subsequently to hydrolyze the intermediate benzophenone dichloride into benzophenone, which is in fact not steam distilled.12 It one preparation of a purine, steam distillation is used to remove volatile benzaldehyde from nonvolatile product.13
On a lab scale, steam distillations are carried out using steam generated outside the system and piped through the mixture to be purified.1415 Steam can also be generated in-situ using a Clevenger-type apparatus.16
H. T. Clarke, Anne W. Davis (1922). "Quinoline". Organic Syntheses. 2: 79. doi:10.15227/orgsyn.002.0079. /wiki/Doi_(identifier) ↩
Fahlbusch, Karl-Georg; Hammerschmidt, Franz-Josef; Panten, Johannes; Pickenhagen, Wilhelm; Schatkowski, Dietmar; Bauer, Kurt; Garbe, Dorothea; Surburg, Horst (2003). "Flavors and Fragrances". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a11_141. ISBN 3-527-30673-0. 3-527-30673-0 ↩
Zeki Berk (2018): Food Process Engineering and Technology, 3rd edition. 742 pages. ISBN 978-0-12-812018-7 doi:10.1016/C2016-0-03186-8 /wiki/ISBN_(identifier) ↩
Manuel G. Cerpa, Rafael B. Mato, María José Cocero, Roberta Ceriani, Antonio J. A. Meirelle, Juliana M. Prado, Patrícia F. Leal, Thais M. Takeuchi, and M. Angela A. Meireles (2008): "Steam distillation applied to the food industry". Chapter 2 of Extracting Bioactive Compounds for Food Products: Theory and Applications, pages 9–75. ISBN 9781420062397 https://books.google.com/books?id=hbHa32_IYLIC&pg=PA9 ↩
Needham, Joseph (1980). Science and Civilisation in China. Volume 5: Chemistry and Chemical Technology. Part IV: Spagyrical Discovery and Invention: Apparatus, Theories and Gifts. Cambridge: Cambridge University Press. ISBN 9780521085731. p. 128, note h (cf. the reservations on the authenticity of the work in Needham 1980, p. 128, note d). Translation of some of the recipes as quoted in the 14th-century cookbook Kanz al-fawāʾid fī tanwīʿ al-mawāʾid: Nasrallah, Nawal (2017). Treasure Trove of Benefits and Variety at the Table: A Fourteenth-Century Egyptian Cookbook. English Translation, with an Introduction and Glossary. Islamic History and Civilization. Vol. 148. Leiden: Brill. doi:10.1163/9789004349919. ISBN 978-90-04-34729-8. pp. 425–430. 9780521085731978-90-04-34729-8 ↩
Shreve, Randolph Norris; Brink, Joseph Andrew (1977). Chemical Process Industries. McGraw-Hill. ISBN 978-0-07-057145-7.Axe, Dr Josh; Rubin, Jordan; Bollinger, Ty (2020-06-01). The Chemistry of Essential Oils. Destiny Image Publishers. ISBN 978-0-7684-5702-5. 978-0-07-057145-7978-0-7684-5702-5 ↩
Hill, Donald R. (1993). Islamic Science and Engineering. Edinburgh: Edinburgh University Press. ISBN 9781474469135. p. 85–87. 9781474469135 ↩
Martin's Physical Pharmacy & Pharmaceutical sciences, fifth edition, ISBN 0-7817-6426-2, Lippincott williams & wilkins /wiki/ISBN_(identifier) ↩
M.M. Chakrabarty (9 November 2003). Chemistry and Technology of Oils & Fats. Allied Publishers. pp. 12–. ISBN 978-81-7764-495-1. 978-81-7764-495-1 ↩
M. Gomberg and W. E. Bachmann (1928). "p-Bromobiphenyl". Organic Syntheses. 8: 42. doi:10.15227/orgsyn.008.0042. /wiki/Doi_(identifier) ↩
C. S. Marvel, W. M. Sperry (1928). "Benzophenone". Organic Syntheses. 8: 26. doi:10.15227/orgsyn.008.0026. /wiki/Doi_(identifier) ↩
W. Klötzer, J. Stadlwieser, J. Raneburger (1986). "Electrophilic N-Amination of Imide Sodium Salts with O-Diphenylphosphinylhydroxylamine (DPH): 7-Aminotheophylline". Organic Syntheses. 64: 96. doi:10.15227/orgsyn.064.0096.{{cite journal}}: CS1 maint: multiple names: authors list (link) /wiki/Doi_(identifier) ↩
Kenneth B. Wiberg (1960). Laboratory Technique in Organic Chemistry. McGraw-Hill. ISBN 0070700958. 0070700958 ↩
Walton & Brown, Chemicals From Plants, Imperial College Press, 1999. ↩