2-Butanol, or
sec-butanol, is an
organic compoundAn organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with
formulaA chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
CCarbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
H3Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
CH(
OOxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
H)CH
2CH
3. This secondary alcohol is a flammable, colorless liquid that is soluble in 12 parts water and completely miscible with polar organic solvents such as
etherEthers are a class of organic compounds that contain an ether group — an oxygen atom connected to two alkyl or aryl groups — of general formula R–O–R'. A typical example is the solvent and anesthetic diethyl ether, commonly referred to simply as "ether"...
s and other
alcoholIn chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....
s. It is produced on a large scale, primarily as a precursor to the industrial solvent methyl ethyl ketone. 2-Butanol is
chiralA chiral molecule is a type of molecule that lacks an internal plane of symmetry and thus has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom....
and thus can be obtained as either of two
stereoisomersStereoisomers are isomeric molecules that have the same molecular formula and sequence of bonded atoms , but that differ only in the three-dimensional orientations of their atoms in space. This contrasts with structural isomers, which share the same molecular formula, but the bond connections...
designated as
(R)-(−)-2-butanol and
(S)-(+)-2-butanol. It is normally found as an equal mixture of the two stereoisomers — a
racemicIn chemistry, a racemic mixture, or racemate , is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule. The first known racemic mixture was "racemic acid", which Louis Pasteur found to be a mixture of the two enantiomeric isomers of tartaric acid.- Nomenclature :A...
mixture.
Manufacture and applications
2-Butanol is manufactured industrially by the
hydrationIn organic chemistry, a hydration reaction is a chemical reaction in which a hydroxyl group and a hydrogen cation are added to the two carbon atoms bonded together in the carbon-carbon double bond which makes up an alkene functional group. The reaction usually runs in a strong acidic, aqueous...
of
1-butene1-Butene is an organic chemical compound, linear alpha-olefin , and one of the isomers of butene. The formula is .-Stability:1-Butene is stable in itself but polymerizes exothermically. It is highly flammable and readily forms explosive mixtures with air...
or
2-butene2-Butene is an acyclic alkene with four carbon atoms. It is the simplest alkene exhibiting cis/trans-isomerism ; that is, it exists as two geometrical isomers cis-2-butene , shown at the right, and trans-2-butene , not shown.It is a petrochemical, produced by the catalytic cracking of crude oil...
:
Sulfuric acidSulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
is used as a catalyst for this conversion.
Although some 2-butanol is used as a solvent, it is mainly converted to
butanoneButanone, also known as methyl ethyl ketone or MEK, is an organic compound with the formula CH3CCH2CH3. This colorless liquid ketone has a sharp, sweet odor reminiscent of butterscotch and acetone. It is produced industrially on a large scale, and also occurs in trace amounts in nature...
("MEK"), which is an important industrial solvent and found in many domestic cleaning agents and paint removers. Volatile
esterEsters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...
s of 2-butanol have pleasant aromas and are used in small amounts as perfumes or in artificial flavors.
Solubility
The solubility of sec-butanol is incorrect in most sources, including some of the most well-known references such as the
Merck IndexThe Merck Index is an encyclopedia of chemicals, drugs and biologicals with over 10,000 monographs on single substances or groups of related compounds. It also includes an appendix with monographs on organic name reactions. It is published by the United States pharmaceutical company Merck & Co...
, the
CRC Handbook of Chemistry and PhysicsThe CRC Handbook of Chemistry and Physics is in its 92nd edition . It is sometimes nicknamed the 'Rubber Bible' or the 'Rubber Book', as CRC originally stood for "Chemical Rubber Company"....
, and Lange's Handbook of Chemistry. Even the
International Programme on Chemical SafetyThe International Programme on Chemical Safety was formed in 1980 and is a collaboration between three United Nations bodies—the World Health Organization, the International Labour Organization and the United Nations Environment Programme to establish the scientific basis for safe use of...
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 ml 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 ml at 20°C, 29 g/100 ml at 25°C, and 22 g/100 ml at 30°C) was first published in 1886 by Alexejew and then similar data was reported by other scientists including Dolgolenko and Dryer in 1907 and 1913, respectively. As petty of an error as this may seem, teachers and students have been frustrated by the error for years.
Safety
Several explosions have been reported during the conventional
distillationDistillation is a method of separating mixtures based on differences in volatilities of components in a boiling liquid mixture. Distillation is a unit operation, or a physical separation process, and not a chemical reaction....
of 2-butanol, apparently due to the buildup of peroxides 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.