| Colourless liquid|
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.
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.
2-Ethylhexanol is produced industrially by the aldol condensation of n-butyraldehyde, followed by hydrogenation of the resulting hydroxyaldehyde. About 2,500,000 tons are prepared in this way annually.
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. The overall process is very similar to that of the Guerbet reaction, by which it may also be produced.
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. 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. According to animal studies, 2-ethylhexanol does not seem to be carcinogenic.
Although isooctanol (and the derived isooctyl prefix) is commonly used in industry to refer to 2-ethylhexanol and its derivatives, IUPAC naming conventions 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.