Valeric acid

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Valeric acid or pentanoic acid is a straight-chain alkyl carboxylic acid with the chemical formula Template:Chem2. Like other low-molecular-weight carboxylic acids, it has an unpleasant odor. It is found in the perennial flowering plant Valeriana officinalis, from which it gets its name. Its primary use is in the synthesis of its esters. Salts and esters of valeric acid are known as valerates or pentanoates. Volatile esters of valeric acid tend to have pleasant odors and are used in perfumes and cosmetics. Several, including ethyl valerate and pentyl valerate are used as food additives because of their fruity flavors.

HistoryEdit

Valeric acid is a minor constituent of the perennial flowering plant valerian (Valeriana officinalis), from which it gets its name.<ref name=EB1911>Template:Cite EB1911</ref> The dried root of this plant has been used medicinally since antiquity.<ref>Template:Cite journal</ref> The related isovaleric acid shares its unpleasant odor and their chemical identity was investigated by oxidation of the components of fusel alcohol, which includes the five-carbon amyl alcohols.<ref>Template:Cite journal</ref> Valeric acid is one volatile component in swine manure. Other components include other carboxylic acids, skatole, trimethyl amine, and isovaleric acid.<ref>Template:Cite journal</ref> It is also a flavor component in some foods.<ref>Template:Cite journal</ref>

ManufactureEdit

In industry, valeric acid is produced by the oxo process from 1-butene and syngas, forming valeraldehyde, which is oxidised to the final product.<ref name=Ullmann/>

Template:Chem2 valeric acid

It can also be produced from biomass-derived sugars via levulinic acid and this alternative has received considerable attention as a way to produce biofuels.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>

ReactionsEdit

Valeric acid reacts as a typical carboxylic acid: it can form amide, ester, anhydride, and chloride derivatives.<ref>Template:Cite book</ref> The latter, valeryl chloride is commonly used as the intermediate to obtain the others.

UsesEdit

Valeric acid occurs naturally in some foods but is also used as a food additive.<ref>Template:Cite journal</ref> Its safety in this application was reviewed by an FAO and WHO panel, who concluded that there were no safety concerns at the likely levels of intake.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The compound is used for the preparation of derivatives, notably its volatile esters which, unlike the parent acid, have pleasant odors and fruity flavors and hence find applications in perfumes, cosmetics and foodstuffs.<ref name=Ullmann>Template:Ullmann</ref> Typical examples are the methyl valerates,<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> ethyl valerates,<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and pentyl valerates.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

BiologyEdit

In humans, valeric acid is a minor product<ref>Template:Cite journal</ref> of the gut microbiome and can also be produced by metabolism of its esters found in food.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The restoration of levels of this acid in the gut has been suggested as the mechanism that results in control of Clostridioides difficile infection after fecal microbiota transplant.<ref>Template:Cite journal </ref>

Valerate salts and estersEdit

The valerate, or pentanoate, ion is Template:Chem2, the conjugate base of valeric acid. It is the form found in biological systems at physiological pH. A valerate, or pentanoate, compound is a carboxylate salt or ester of valeric acid. Many steroid-based pharmaceuticals, for example ones based on betamethasone or hydrocortisone, include the steroid as the valerate ester.

ExamplesEdit

ReferencesEdit

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