2-Ethylhexanol
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| Names | |
|---|---|
| IUPAC name
2-Ethylhexan-1-ol[1]
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| Identifiers | |
3D model (JSmol)
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| 1719280 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| ECHA InfoCard | 100.002.941 |
| EC Number |
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| KEGG | |
| MeSH | 2-ethylhexanol |
PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| C8H18O | |
| Molar mass | 130.231 g·mol−1 |
| Appearance | Colourless liquid |
| Density | 833 mg mL−1 |
| Melting point | −76 °C (−105 °F; 197 K) |
| Boiling point | 180 to 186 °C; 356 to 367 °F; 453 to 459 K |
| log P | 2.721 |
| Vapor pressure | 30 Pa (at 20 °C) |
Refractive index (nD)
|
1.431 |
| Thermochemistry | |
Heat capacity (C)
|
317.5J K−1 mol−1 |
Std molar
entropy (S⦵298) |
347.0 J K−1 mol−1 |
Std enthalpy of
formation (ΔfH⦵298) |
−433.67–−432.09 kJ mol−1 |
Std enthalpy of
combustion (ΔcH⦵298) |
−5.28857–−5.28699 MJ mol−1 |
| Hazards | |
| GHS labelling: | |
 
| |
| Danger | |
| H312, H315, H318, H335 | |
| P261, P280, P305+P351+P338 | |
| Flash point | 81 °C (178 °F; 354 K) |
| 290 °C (554 °F; 563 K) | |
| Explosive limits | 0.88–9.7% |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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| NIOSH (US health exposure limits): | |
PEL (Permissible)
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none[2] |
REL (Recommended)
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TWA 50 ppm (270 mg/m3) [skin][2] |
IDLH (Immediate danger)
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N.D.[2] |
| Related compounds | |
Related alkanol
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Propylheptyl alcohol |
Related compounds
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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2-Ethylhexanol (abbreviated 2-EH) is a branched, eight-carbon chiral alcohol. It is a colorless liquid that is poorly soluble in water but soluble in most organic solvents. It is produced on a massive scale for use in numerous applications such as solvents, flavors, and fragrances and especially as a precursor for production of other chemicals such as emollients and plasticizers. It is encountered in natural plant fragrances, and the odor has been reported as "heavy, earthy, and slightly floral" for the R enantiomer and "a light, sweet floral fragrance" for the S enantiomer.[3]
Applications
Almost all 2-ethylhexanol manufactured is used as a precursor for the synthesis of the diester bis(2-ethylhexyl) phthalate (DEHP), a plasticizer. Because it is a fatty alcohol, its esters tend to have emollient properties. For example, the sunscreen octocrylene contains a 2-ethylhexyl ester for this purpose.
It is also commonly used as a low volatility solvent. 2-Ethylhexanol can also be used as an octane booster when reacted with nitric acid.
Industrial production
2-Ethylhexanol is produced industrially by the aldol condensation of n-butyraldehyde, followed by hydrogenation of the resulting hydroxyaldehyde. The overall process is very similar to that of the Guerbet reaction, by which it may also be produced.[4] About 2,500,000 tons are prepared in this way annually.[5][6] The n-butyraldehyde is made by hydroformylation of propylene, either in a self-contained plant or as the first step in a fully integrated facility. Most facilities make n-butanol and isobutanol in addition to 2-ethylhexanol.
Health effects
Air exposure of 2-ethylhexanol to a human in a case study involving concentrations between 80 and 470 μg/m3 included throat irritation, cough, sore eyes, headache and blurred vision. Other volatile organic compounds were detected in the air as well, but 2-ethylhexanol was of the highest concentration.[7] Another study involving several people exposed to 2-ethylhexanol reported headaches, dizziness, fatigue and gastrointestinal disorders, but the concentration of 2-ethylhexanol in this case is not known.[7] According to animal studies, 2-ethylhexanol does not seem to be carcinogenic.[7]
Nomenclature
Although isooctanol (and the derived isooctyl prefix) is commonly used in industry to refer to 2-ethylhexanol and its derivatives, IUPAC naming conventions[8] dictate that this name is properly applied to another isomer of octanol, 6-methylheptan-1-ol. The Chemical Abstracts Service likewise indexes isooctanol (CAS# 26952-21-6) as 6-methylheptan-1-ol.
See also
References
- ^ "2-ethylhexanol - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2005. Identification and Related Records. Retrieved 29 January 2012.
- ^ a b c NIOSH Pocket Guide to Chemical Hazards. "#0354". National Institute for Occupational Safety and Health (NIOSH).
- ^ Klaus Rettinger; Christian Burschka; Peter Scheeben; Heike Fuchs; Armin Mosandl (1991). "Chiral 2-alkylbranched acids, esters and alcohols. Preparation and stereospecific flavour evaluation". Tetrahedron: Asymmetry. 2 (10): 965–968. doi:10.1016/S0957-4166(00)86137-6.
- ^ Miller, Robert; Bennett, George (January 1961). "Producing 2-Ethylhexanol by the Guerbet Reaction". Industrial & Engineering Chemistry. 53 (1): 33–36. doi:10.1021/ie50613a027.
- ^ C. Kohlpaintner, M. Schulte, J. Falbe, P. Lappe, J. Weber, "Aldehydes, Aliphatic" in Ullmann's Encyclopedia of Industrial Chemistry 2008, Wiley-VCH, Weinheim. doi:10.1002/14356007.a01_321.pub2.
- ^ Ashford’s Dictionary of Industrial Chemicals, Third edition, 2011, page 4180-4181.
- ^ a b c Assessment Report On 2-Ethylhexanol For Developing Ambient Air Quality Objectives Prepared for Alberta Environment by Toxico-Logic Consulting Inc. November 2004.
- ^ IUPAC Blue Book, A2.25