Heptanal
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| Names | |
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| IUPAC name
Heptanal
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| Other names
Heptanaldehyde
Aldehyde C-7 Enanthal Heptyl aldehyde n-Heptanal | |
| Identifiers | |
3D model (JSmol)
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| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.003.545 |
| KEGG | |
PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| C7H14O | |
| Molar mass | 114.18 |
| Appearance | Clear liquid |
| Density | 0.80902 at 30 °C |
| Melting point | −43.3 °C (−45.9 °F; 229.8 K) |
| Boiling point | 152.8 °C (307.0 °F; 425.9 K) |
| Slightly soluble | |
| -81.02·10−6 cm3/mol | |
| Related compounds | |
Related aldehydes
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Hexanal |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Heptanal or heptanaldehyde is an alkyl aldehyde. It is a colourless liquid with a strong fruity odor, which is used as precursor to components in perfumes and lubricants.[2]
Production
The formation of heptanal in the fractional distillation of castor oil[3] was already described in 1878. The large-scale production is based on the pyrolytic cleavage of ricinoleic acid ester[4] (Arkema method) and on the hydroformylation of 1-hexene with rhodium 2-ethylhexanoate as a catalyst upon addition of some 2-ethylhexanoic acid (Oxea method):[2][5]
Heptanal naturally occurs in the essential oils of ylang-ylang (Cananga odorata), clary sage (Salvia sclarea), lemon (Citrus x limon), bitter orange (Citrus x aurantium), rose (Rosa) and hyacinth (Hyacinthus).[6]
Properties
Heptanal is a flammable, slightly volatile colorless liquid of pervasive fruity to oily-greasy odor,[7] which is miscible with alcohols[6] and practically insoluble in water.[8] Because of its sensitivity to oxidation, heptanal is filled under nitrogen and stabilized with 100 ppm hydroquinone.[9]
Heptanal forms flammable vapor-air mixtures. The compound has a flash point of 39.5 °C.[8] The explosion range is between 1.1% by volume as the lower explosion limit (LEL) and 5.2% by volume as the upper explosion limit.[8] Its ignition temperature is 205 °C.[8]
Uses
Heptanal can be used for the production of 1-heptanol via hydrogenation:
The oxidation of heptanal with oxygen in the presence of a rhodium catalysts leads at 50 °C to heptanoic acid in 95% yield.[10] Heptanal reacts with benzaldehyde in a Knoevenagel reaction under basic catalysis with high yield and selectivity (> 90%) to alpha-pentylcinnamaldehyde (also called jasmine aldehyde because of the typical jasmine odor),[11][2] which is mostly used in many fragrances as a cis/trans isomer mixture.[12]
A by-product of the given reaction is the unpleasant rancid smelling (Z)-2-pentyl-2-nonenal.[13] When good reasons are given[clarification needed], heptanal can be converted into (Z)-2-pentyl-2-nonenal virtually quantitatively in the presence of aqueous boric acid upon azeotropic removal of water.[14]
Full hydrogenation provides the branched primary alcohol 2-pentylnonan-1-ol, also accessible from the Guerbet reaction from heptanol.[15]
References
- ^ Merck Index, 11th Edition, 4578.
- ^ a b c Christian Kohlpaintner, Markus Schulte, Jürgen Falbe, Peter Lappe, Jürgen Weber. "Aldehydes, Aliphatic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a01_321.pub2. ISBN 978-3527306732.
{{cite encyclopedia}}: CS1 maint: multiple names: authors list (link) - ^ F. Krafft, Distillation of castor oil, under educed pressure, Analyst, 3, 329a (1878).
- ^ A. Chauvel, G. Lefebvre, Petrochemical Processes: Technical and Economic Characteristics, Band 2, S. 277, Editions Technip, Paris, 1989, ISBN 2-7108-0563-4.
- ^ Deutsche Patentschrift DE 102007053385, Verfahren zur Herstellung von Aldehyden, Erfinder: A. Fischbach et al., Anmelder: Oxea Deutschland GmbH, veröffentlicht am 20. Mai 2009.
- ^ a b G. A. Burdock, Fenaroli’s Handbook of Flavor Ingredients, Fifth Edition, 2005, CRC Press, Boca Raton, Fl., ISBN 0-8493-3034-3.
- ^ Richtwerte für gesättigte azyklische aliphatische C4- bis C11-Aldehyde in der Innenraumluft, Bundesgesundheitsbl - Gesundheitsforsch –Gesundheitsschutz, 2009, 52:650–659, doi:10.1007/s00103-009-0860-2.
- ^ a b c d Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health
- ^ Acros Organics, Sicherheitsdatenblatt, Heptaldehyde, stabilized, überarb. am 19. November 2012.
- ^ Deutsche Patentschrift DE 10010771, Verfahren zur Herstellung aliphatischer Carbonsäuren aus Aldehyden, Erfinder: H. Springer, P. Lappe, Anmelder: Celanese Chem Europe GmbH, veröffentlicht am 3. Mai 2001.
- ^ M. Perez-Sanchez, P. Dominguez de Maria, Synthesis of natural fragrance jasminaldehyde using silica-immobilized piperazine as organocatalyst, Catal. Sci. Technol., 3, 2732-2736 (2013), doi:10.1039/C3CY00313B
- ^ Riechstofflexikon A, alpha-Amylzimtaldehyd, Letzte Änderung am 4. August 2000.
- ^ J. M. Hornback, Organic Chemistry, 2nd edition, S. 886, Thomson Brooks/Cole, 2006, ISBN 0-534-49317-3.
- ^ R.D. Offenhauer, S.F. Nelsen, Aldehyde and ketone condensation reactions catalyzed by boric acid, J. Org. Chem., 33(2), 775-777 (1968), doi:10.1012/jo01266a059.
- ^ G.H. Knothe: Lipid Chemistry, Guerbet Compounds, AOCS Lipid Library, 22. Dezember 2011.