Isobutyric acid
Encyclopedia
Isobutyric acid, also known as 2-methylpropanoic acid, is a carboxylic acid
with structural formula (C
H
3)2-CH-COOH. It is found in the free state in carobs (Ceratonia
siliqua) and in the root of Arnica
dulcis, and as an ethyl ester
in croton oil.
Isobutyric acid is an isomer
of n-butyric acid
; they have the same chemical formula C
4H
8 O
2 but a different structure.
of isobutyronitrile with alkali
s, by the oxidation of isobutanol
with potassium dichromate and sulfuric acid
, or by the action of sodium amalgam
on methacrylic acid
. It is a liquid of somewhat unpleasant smell, boiling at 155 °C. Its specific gravity is 0.9697 (0 °C). Heated with chromic acid
solution to 140 °C, it gives carbon dioxide
and acetone
. Alkaline potassium permanganate
oxidizes it to α-hydroxyisobutyric acid, (CH3)2-C(OH)-COOH. Its salt
s are more soluble in water than those of butyric acid
.
Isobutyric acid is a retained trivial name under the IUPAC rules.
Carboxylic acid
Carboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...
with structural formula (C
Carbon
Carbon 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...
H
Hydrogen
Hydrogen 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...
3)2-CH-COOH. It is found in the free state in carobs (Ceratonia
Ceratonia
Ceratonia is genus of flowering trees in the pea family, Fabaceae, that is endemic to the Mediterranean region. It belongs to the subfamily Caesalpinioideae, tribe Caesalpinieae.An obsolete name for Ceratonia was Acalis....
siliqua) and in the root of Arnica
Arnica
Arnica is a genus with about 30 perennial, herbaceous species, belonging to the sunflower family . The genus name Arnica may be derived from the Greek arna, "lamb", in reference to the soft, hairy leaves....
dulcis, and as an ethyl ester
Ester
Esters 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...
in croton oil.
Isobutyric acid is an isomer
Isomer
In chemistry, isomers are compounds with the same molecular formula but different structural formulas. Isomers do not necessarily share similar properties, unless they also have the same functional groups. There are many different classes of isomers, like stereoisomers, enantiomers, geometrical...
of n-butyric acid
Butyric acid
Butyric acid , also known under the systematic name butanoic acid, is a carboxylic acid with the structural formula CH3CH2CH2-COOH. Salts and esters of butyric acid are known as butyrates or butanoates...
; they have the same chemical formula C
Carbon
Carbon 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...
4H
Hydrogen
Hydrogen 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...
8 O
Oxygen
Oxygen 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...
2 but a different structure.
Production
Isobutyric acid may be artificially prepared by the hydrolysisHydrolysis
Hydrolysis is a chemical reaction during which molecules of water are split into hydrogen cations and hydroxide anions in the process of a chemical mechanism. It is the type of reaction that is used to break down certain polymers, especially those made by condensation polymerization...
of isobutyronitrile with alkali
Alkali
In chemistry, an alkali is a basic, ionic salt of an alkali metal or alkaline earth metal element. Some authors also define an alkali as a base that dissolves in water. A solution of a soluble base has a pH greater than 7. The adjective alkaline is commonly used in English as a synonym for base,...
s, by the oxidation of isobutanol
Isobutanol
Isobutanol is an organic compound with the formula 2CHCH2OH. This colorless, flammable liquid with a characteristic smell is mainly used as a solvent. Its isomers include n-butanol, 2-butanol, and tert-butanol, all of which are more important industrially.-Production:Isobutanol is produced by the...
with potassium dichromate and sulfuric acid
Sulfuric acid
Sulfuric 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...
, or by the action of sodium amalgam
Sodium amalgam
Sodium amalgam, commonly denoted Na, is an alloy of mercury and sodium. The term amalgam is used for alloys, intermetallic compounds, and solutions involving mercury as a major component. Sodium amalgam is often used in reactions as strong reducing agents with better handling properties compared...
on methacrylic acid
Methacrylic acid
Methacrylic acid, abbreviated MAA, is an organic compound. This colourless, viscous liquid is a carboxylic acid with an acrid unpleasant odor. It is soluble in warm water and miscible with most organic solvents. Methacrylic acid is produced industrially on a large scale as a precursor to its...
. It is a liquid of somewhat unpleasant smell, boiling at 155 °C. Its specific gravity is 0.9697 (0 °C). Heated with chromic acid
Chromic acid
The term chromic acid is usually used for a mixture made by adding concentrated sulfuric acid to a dichromate, which may contain a variety of compounds, including solid chromium trioxide. This kind of chromic acid may be used as a cleaning mixture for glass. Chromic acid may also refer to the...
solution to 140 °C, it gives carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
and acetone
Acetone
Acetone is the organic compound with the formula 2CO, a colorless, mobile, flammable liquid, the simplest example of the ketones.Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory...
. Alkaline potassium permanganate
Potassium permanganate
Potassium permanganate is an inorganic chemical compound with the formula KMnO4. It is a salt consisting of K+ and MnO4− ions. Formerly known as permanganate of potash or Condy's crystals, it is a strong oxidizing agent. It dissolves in water to give intensely purple solutions, the...
oxidizes it to α-hydroxyisobutyric acid, (CH3)2-C(OH)-COOH. Its salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...
s are more soluble in water than those of butyric acid
Butyric acid
Butyric acid , also known under the systematic name butanoic acid, is a carboxylic acid with the structural formula CH3CH2CH2-COOH. Salts and esters of butyric acid are known as butyrates or butanoates...
.
Biological production
Isobutyric acid can also be manufactured commercially using engineered bacteria using a sugar feedstock.Isobutyric acid is a retained trivial name under the IUPAC rules.