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2-Methyl Butyric Acid, also known as 2-methylbutyric acid is a branched-chain alkyl carboxylic acid with the chemical formula CH3CH2CH(CH3)CO2H, classified as a short-chain fatty acid.
2-Methyl Butyric Acid exists in two enantiomeric forms, (R)- and (S)-2-methylbutanoic acid.
(R)-2-methylbutanoic acid occurs naturally in cocoa beans and (S)-2-methylbutanoic occurs in many fruits such as apples and apricots, as well as in the scent of the orchid Luisia curtisii.
CAS: 116-53-0
MF: C5H10O2
MW: 102.13
EINECS: 204-145-2
Synonyms
METHYLBUTYRIC ACID, DL-2-;METHYLETHYL ACETIC ACID;(+/-)-2-METHYLBUTYRIC ACID;2-METHYLBUTYRIC ACID;2-METHYLBUTANOIC ACID;RARECHEM AL BO 0094;BUTANE-2-CARBOXYLIC ACID;FEMA 2695
2-Methyl Butyric Acid has a pungent, acrid odor which is similar to Roquefort cheese with an acrid taste.
At low dilutions, 2-Methyl Butyric Acid has a pleasant fruity taste.
2-Methyl Butyric Acid can be prepared either by decarboxylation of methyl ethyl malonic acid or by the oxidation of fermentation amyl alcohol (fusel oil).
2-Methyl Butyric Acid is used as a flavor ingredient for butter, cream, cheese flavor deployment.
2-Methyl Butyric Acid also provides acyl moiety for the preparation of the respective flavor esters.
2-Methyl Butyric Acid has a pungent, acrid odor similar to Roquefort cheese with an acrid taste.
At low dilutions, 2-Methyl Butyric Acid has a pleasant fruity taste.
May be prepared by decarboxylation of methyl ethyl malonic acid (with heat); also by oxidation of fermentation amyl alcohol (fusel oil).
2-Methyl Butyric Acid comprising a butyric acid core carrying a 2-methyl substituent.
Produced from amino acid leucine during nutrient starvation in bacteria.
2-Methyl Butyric Acid is a synthetic compound that has the same stereoisomeric configuration as 2-methylbutyric acid.
The difference in the two molecules is that the (R) form has a hydroxyl group on the alpha carbon, while 2-methylbutyric acid does not.
2-Methyl Butyric Acid is stable under acidic conditions, but hydrolyzes to form butyric acid when exposed to basic conditions.
2-Methyl Butyric Acid is used in industrial applications such as food production and as an intermediate in synthesizing other compounds such as tiglic acid or amido groups.
2-Methyl Butyric Acid is notably different in character from the closely related unbranched aliphatic fatty acid valeric acid and also from the even more closely related isovaleric acid.
2-Methyl Butyric Acid has a mild, soft, dried fruit character, whereas the related fatty acids are stronger, but much more one-dimensional and cheesy in character.
2-Methyl Butyric Acid is very widely distributed in nature and has an unusually wide spectrum of use in flavors.
History
2-Methyl Butyric Acid is a minor constituent of Angelica archangelica and the perennial flowering plant valerian (Valeriana officinalis), where 2-Methyl Butyric Acid co-occurs with valeric acid and isovaleric acid.
The dried root of this plant has been used medicinally since antiquity.
The chemical identity of all three compounds was first investigated in the 19th century by oxidation of the components of fusel alcohol, which includes the five-carbon amyl alcohols.
Among the products isolated was a compound which gave a (+) rotation in polarised light, indicating 2-Methyl Butyric Acid to be the (2S) isomer.
2-Methyl Butyric Acid Chemical Properties
Melting point: -70 °C
Boiling point: 176-177 °C (lit.)
Density: 0.936 g/mL at 25 °C (lit.)
Vapor pressure: 0.5 mm Hg ( 20 °C)
Refractive index: n20/D 1.405(lit.)
FEMA: 2695 | 2-METHYLBUTYRIC ACID
Fp: 165 °F
Storage temp.: Sealed in dry,Room Temperature
Solubility: 20g/l
Form: Liquid
pka: 4.8(at 25℃)
Color: Clear colorless to pale yellow
Odor: at 10.00 % in propylene glycol. pungent acid roquefort cheese
Odor Type: acidic
Biological source: synthetic
Explosive limit: 1.6-7.3%(V)
Water Solubility: 45 g/L (20 ºC)
JECFA Number: 255
BRN: 1720486
LogP: 1.8 at 25℃
CAS DataBase Reference: 116-53-0(CAS DataBase Reference)
NIST Chemistry Reference: 2-Methyl Butyric Acid(116-53-0)
EPA Substance Registry System: 2-Methyl Butyric Acid (116-53-0)
2-Methyl Butyric Acid has a pungent, acrid odor similar to Roquefort cheese with an acrid taste.
At low dilutions, 2-Methyl Butyric Acid has a pleasant, fruity taste.
Slightly soluble in water, soluble in alcohol and oils.
Also soluble in Propylene glycol and poorly soluble in Glycerin.
Reactions
2-Methyl Butyric Acid and its enantiomers react as typical carboxylic acids: they can form amide, ester, anhydride, and chloride derivatives.
The acid chloride is commonly used as the intermediate to obtain the others.
Uses
2-Methyl Butyric Acid, can be used as food additive for butter, cream, cheese flavor deployment.
2-Methyl Butyric Acid is an important raw material and intermediate used in Organic Synthesis, Pharmaceuticals, Agrochemicals and Dyestuff.
2-Methyl Butyric Acid is also used in the synthesis of 2-methylbutyric anhydride.
2-Methyl Butyric Acid was used in the synthesis of 2-methylbutyric anhydride, an acylating agent.
2-Methyl Butyric Acid is a slightly volatile, colorless liquid with a pungent cheesy odor.
The smell differs significantly between the two enantiomeric forms.
2-Methyl Butyric Acid has a pleasantly sweet, fruity odor while (R)-2-methylbutanoic acid has a pervasive, cheesy, sweaty odor.
The main use of the materials, and their esters, is therefore as flavours and food additives.
2-Methyl Butyric Acid' safety in this application was reviewed by an FAO and WHO panel, who concluded that there were no concerns at the likely levels of intake.
Preparation
2-Methyl Butyric Acid can readily be prepared by a Grignard reaction using 2-chlorobutane and carbon dioxide.
2-Methyl Butyric Acid was the target of the first enantioselective synthesis in 1904 when the German chemist W. Marckwald heated ethyl(methyl)malonic acid with the chiral base brucine and obtained an optically active product mixture.
Either enantiomer of 2-Methyl Butyric Acid can now be obtained by asymmetric hydrogenation of tiglic acid using a ruthenium-BINAP catalyst.
