2-Ethylhexanol (abbreviated 2-EH) is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon- hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

with formula CHO. It is a branched, eight-carbon

chiral Chirality is a property of asymmetry important in several branches of science. The word ''chirality'' is derived from the Greek (''kheir''), "hand", a familiar chiral object. An object or a system is ''chiral'' if it is distinguishable from i ...

alcohol Alcohol most commonly refers to: * Alcohol (chemistry), an organic compound in which a hydroxyl group is bound to a carbon atom * Alcohol (drug), an intoxicant found in alcoholic drinks Alcohol may also refer to: Chemicals * Ethanol, one of sev ...

. It is a colorless liquid that is poorly soluble in water but soluble in most organic solvents. It is

produce Produce is a generalized term for many farm-produced crops, including fruits and vegetables ( grains, oats, etc. are also sometimes considered ''produce''). More specifically, the term ''produce'' often implies that the products are fresh and ...

d on a large scale (>2,000,000,000 kg/y) 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 plants, fruits, and wines. The odor has been reported as "heavy, earthy, and slightly floral" for the R

enantiomer In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical ant ...

and "a light, sweet floral fragrance" for the S enantiomer.

Properties and applications

The branching in 2-ethylhexanol inhibits crystallization. Esters of 2-ethylhexanol are similarly affected, which together with low volatility, is the basis of applications in the production of

plasticizer A plasticizer ( UK: plasticiser) is a substance that is added to a material to make it softer and more flexible, to increase its plasticity, to decrease its viscosity, and/or to decrease friction during its handling in manufacture. Plasticiz ...

s and lubricants, where its presence helps reduce viscosity and lower freezing points. Because 2-ethylhexanol is a

fatty alcohol Fatty alcohols (or long-chain alcohols) are usually high-molecular-weight, straight-chain primary alcohols, but can also range from as few as 4–6 carbons to as many as 22–26, derived from natural fats and oils. The precise chain length varie ...

, its

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ...

s have

emollient A moisturizer, or emollient, is a cosmetic preparation used for protecting, moisturizing, and lubricating the skin. These functions are normally performed by sebum produced by healthy skin. The word "emollient" is derived from the Latin verb ''m ...

properties. Representative is the

diester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...

bis(2-ethylhexyl) phthalate Bis(2-ethylhexyl) phthalate (di-2-ethylhexyl phthalate, diethylhexyl phthalate, diisooctyl phthalate, DEHP; incorrectly — dioctyl phthalate, DIOP) is an organic compound with the formula C6H4(CO2C8H17)2. DEHP is the most common member of the c ...

(DEHP), commonly used in PVC. The triester tris (2-Ethylhexyl) trimellitate (TOTM) is another common plasticizer produced via the

esterification In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glyceride ...

of three 2-ethylhexanol per

trimellitic acid Trimellitic acid (benzene-1,2,4-tricarboxylic acid) is a chemical compound with the molecular formula C6H3(СООН)3. Like the other isomers of benzenetricarboxylic acid, trimellitic acid is a colorless solid. It is prepared by oxidation of 1,2 ...

. It is also commonly used as a low volatility

solvent A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...

. 2-Ethylhexanol can also be used as a cetane improver when reacted with

nitric acid Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available ni ...

. It also used to react with

epichlorohydrin Epichlorohydrin (abbreviated ECH) is an organochlorine compound and an epoxide. Despite its name, it is not a halohydrin. It is a colorless liquid with a pungent, garlic-like odor, moderately soluble in water, but miscible with most polar orga ...

and

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly caustic base and alkal ...

to produce the glycidyl ether of the molecule which is used as an epoxy reactive diluent in various

coating A coating is a covering that is applied to the surface of an object, usually referred to as the substrate. The purpose of applying the coating may be decorative, functional, or both. Coatings may be applied as liquids, gases or solids e.g. Powde ...

s, adhesives and

sealant Sealant is a substance used to block the passage of fluids through openings in materials, a type of mechanical seal. In building construction ''sealant'' is sometimes synonymous with ''caulking'' and also serve the purposes of blocking dust, sou ...

s applications. It can be used in the development of photos, production of rubber and extraction of oil and gas.

Industrial production

2-Ethylhexanol is produced industrially by the

aldol condensation An aldol condensation is a condensation reaction in organic chemistry in which two carbonyl moieties (of aldehydes or ketones) react to form a β-hydroxyaldehyde or β-hydroxyketone (an aldol reaction), and this is then followed by dehydration ...

of ''n''-

butyraldehyde Butyraldehyde, also known as butanal, is an organic compound with the formula CH3(CH2)2CHO. This compound is the aldehyde derivative of butane. It is a colorless flammable liquid with an unpleasant smell. It is miscible with most organic solvents. ...

, followed by hydrogenation of the resulting hydroxyaldehyde. About 2,500,000 tons are prepared in this way annually. 2-Ethylhexanol Synthese

The ''n''-butyraldehyde is made by

hydroformylation Hydroformylation, also known as oxo synthesis or oxo process, is an industrial process for the production of aldehydes from alkenes. This chemical reaction entails the net addition of a formyl group (CHO) and a hydrogen atom to a carbon-carbon d ...

propylene Propylene, also known as propene, is an unsaturated organic compound with the chemical formula CH3CH=CH2. It has one double bond, and is the second simplest member of the alkene class of hydrocarbons. It is a colorless gas with a faint petrole ...

, either in a self-contained plant or as the first step in a fully integrated facility. Most facilities make ''n''-butanol and

isobutanol Isobutanol ( IUPAC nomenclature: 2-methylpropan-1-ol) is an organic compound with the formula (CH3)2CHCH2OH (sometimes represented as ''i''-BuOH). This colorless, flammable liquid with a characteristic smell is mainly used as a solvent either di ...

in addition to 2-ethylhexanol. Alcohols prepared in this way are sometimes referred to as oxo alcohols. The overall process is very similar to that of the

Guerbet reaction The Guerbet reaction, named after Marcel Guerbet (1861–1938), is an organic reaction that converts a primary alcohol into its β-alkylated dimer alcohol with loss of one equivalent of water. The process is of interest because it converts simple ...

, by which it may also be produced.

Health effects

2-Ethylhexanol exhibits low toxicity in animal models, with

LD50 In toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a toxin, radiation, or pathogen. The value of LD50 for a substance is the ...

ranging from 2-3 g/kg (rat). 2-Ethylhexanol has been identified as a cause of

indoor air quality Indoor air quality (IAQ) is the air quality within and around buildings and structures. IAQ is known to affect the health, comfort, and well-being of building occupants. Poor indoor air quality has been linked to sick building syndrome, reduce ...

Nomenclature

Although isooctanol (and the derived isooctyl prefix) is commonly used in industry to refer to 2-ethylhexanol and its derivatives,

IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations working for the advancement of the chemical sciences, especially by developing nomenclature and terminology. It is ...

naming conventions dictate that this name is properly applied to another

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. ...

octanol Octanols are alcohols with the formula C8H17OH. A simple and important member is 1-octanol, with an unbranched chain of carbons. Other commercially important octanols are 2-octanol and 2-ethylhexanol. There are 89 possible isomers In c ...

, 6-methylheptan-1-ol. The

Chemical Abstracts Service CAS (formerly Chemical Abstracts Service) is a division of the American Chemical Society. It is a source of chemical information. CAS is located in Columbus, Ohio, United States. Print periodicals ''Chemical Abstracts'' is a periodical index th ...

likewise indexes isooctanol (CAS# 26952-21-6) as 6-methylheptan-1-ol.

References

External links