2-Butanol, or ''sec''-butanol, 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 C H₃CH( OH)CH₂CH₃. Its

structural isomer In chemistry, a structural isomer (or constitutional isomer in the IUPAC nomenclature) of a compound is another compound whose molecule has the same number of atoms of each element, but with logically distinct bonds between them. The term met ...

s are 1-butanol.

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 ...

, and ''tert''-butanol. 2-Butanol is

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 ...

and thus can be obtained as either of two stereoisomers designated as (''R'')-(−)-2-butanol and (''S'')-(+)-2-butanol. It is normally encountered as a 1:1 mixture of the two stereoisomers — a

racemic In chemistry, a racemic mixture, or racemate (), is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates. ...

mixture. This secondary alcohol is a flammable, colorless liquid that is soluble in three parts water and completely miscible with organic solvents. It is produced on a large scale, primarily as a precursor to the industrial solvent methyl ethyl ketone.

Manufacture and applications

2-Butanol is manufactured industrially by the hydration of

1-butene 1-Butene (or 1-Butylene) is the organic compound with the formula CH3CH2CH=CH2. It is a colorless gas that is easily condensed to give a colorless liquid. It is classified as a linear alpha-olefin. It is one of the isomers of butene (butylene ...

2-butene But-2-ene is an acyclic alkene with four carbon atoms. It is the simplest alkene exhibiting ''cis''/''trans''-isomerism (also known as (''E''/''Z'')-isomerism); that is, it exists as two geometric isomers ''cis''-but-2-ene ((''Z'')-but-2-ene) and ...

: : Sulfuric acid is used as a

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

for this conversion.. In the laboratory it can be prepared via Grignard reaction by reacting ethylmagnesium bromide with

acetaldehyde Acetaldehyde (IUPAC systematic name ethanal) is an organic chemical compound with the formula CH3 CHO, sometimes abbreviated by chemists as MeCHO (Me = methyl). It is a colorless liquid or gas, boiling near room temperature. It is one of the ...

in dried diethyl ether or

tetrahydrofuran Tetrahydrofuran (THF), or oxolane, is an organic compound with the formula (CH2)4O. The compound is classified as heterocyclic compound, specifically a cyclic ether. It is a colorless, water- miscible organic liquid with low viscosity. It is ...

. Although some 2-butanol is used as a solvent, it is mainly converted to butanone (methyl ethyl ketone, MEK), an important industrial solvent and found in many domestic cleaning agents and paint removers. Though most paint removers have ceased using MEK in their products due to health concerns and new laws. Volatile

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 of 2-butanol have pleasant aromas and are used in small amounts as perfumes or in artificial flavors.

Solubility

The listed solubility of 2-butanol is often incorrect, including some of the most well-known references such as the ''

Merck Index ''The Merck Index'' is an encyclopedia of chemicals, drugs and biologicals with over 10,000 monograph on single substances or groups of related compounds published online by the Royal Society of Chemistry. History The first edition of the Mer ...

'', the ''

CRC Handbook of Chemistry and Physics The ''CRC Handbook of Chemistry and Physics'' is a comprehensive one-volume reference resource for science research. First published in 1914, it is currently () in its 103rd edition, published in 2022. It is sometimes nicknamed the "Rubber Bible ...

'', and ''Lange's Handbook of Chemistry''. Even the International Programme on Chemical Safety lists the wrong solubility. This widespread error originated because of Beilstein's ''Handbuch der Organischen Chemie'' (''Handbook of Organic Chemistry''). This work cites a false solubility of 12.5 g/100 g water. Many other sources used this solubility, which has snowballed into a widespread error in the industrial world. The correct data (35.0 g/100 g at 20 °C, 29 g/100 g at 25 °C, and 22 g/100 g at 30 °C) were first published in 1886 by Alexejew and then similar data was reported by other scientists including Dolgolenko and Dryer in 1907 and 1913, respectively.

Precautions

Like other butanols, 2-butanol has low acute toxicity. The is 4400 mg/kg (rat, oral). Several explosions have been reported during the conventional

distillation Distillation, or classical distillation, is the process of separating the components or substances from a liquid mixture by using selective boiling and condensation, usually inside an apparatus known as a still. Dry distillation is the he ...

of 2-butanol, apparently due to the buildup of

peroxides In chemistry, peroxides are a group of compounds with the structure , where R = any element. The group in a peroxide is called the peroxide group or peroxo group. The nomenclature is somewhat variable. The most common peroxide is hydrogen ...

with the boiling point higher than that of pure alcohol (and therefore concentrating in the still pot during distillation). As alcohols, unlike ethers, are not widely known to be capable of forming peroxide impurities, the danger is likely to be overlooked. 2-Butanol is in Class B Peroxide Forming Chemicals

References

External links

* * * * {{DEFAULTSORT:Butanol, 2- Alkanols Alcohol solvents Secondary alcohols