Petroselinic acid
- (Z )-6- octadecenoic acid (IUPAC)
- Cis-6- octadecenoic
- 18:1 ( ω -12)
White powder
Fixed
0.8700 g · cm -3 ( 40 ° C)
29.8 ° C
1.4533 ( 40 ° C)
Attention
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Petroselinic acid, representatives of monounsaturated fatty acids (18:1), is a naturally occurring isomer of oleic acid. Your systematic name is ( Z )-6- octadecenoic acid ( delta-6- cis- octadecenoic acid ); it is an omega - 12 fatty acid due to the location of its double bond.
Occurrence
Petroselinic acid occurs in specific vegetable and animal oils and fats. It was first isolated in 1909 from the seed oil of parsley. Petroselinic acid was currently in particularly high quantities or main fatty acid in the Araliengewächsen in Griselinia ( Griseliniaceae ) and in the Garryaceae exception of umbelliferous plants. In the Picramniaceae she is the companion tariric. In addition, they could sporadically in spurge ( Mallotus ) Pentaphylacaceae ( Ternstroemia ), Candida species, are found in human sebum and skin surface.
The occurrence of petroselinic acid as the main fatty acid is considered in the chemosystematics as a feature of closely related families within the Apiales and within the Garryales. Besides petroselinic acid is oleic acid also always detectable.
Production and representation
Fatty acids can be obtained by alkaline hydrolysis of the corresponding triacylglycerols by the corresponding fats or oils are boiled with bases. The hydrolysis itself initially provides their salts. The free fatty acids are obtained by neutralization with (mineral) acid. As the natural fats and oils contain many different fatty acids always includes in the control separation of the resulting mixture of. Petroselinic acid is commercially available.
Properties
Physical Properties
Pure petroselinic acid is described at room temperature as a powder or as a highly viscous, colorless, oily and almost odorless liquid. The molar mass is 282.46 g · mol. The fatty acid is insoluble in water but soluble in methanol.
Chemical Properties
Petroselinic acid such as oleic acid, as compared to polyunsaturated fatty acids (e.g., linolenic acid ) is only slightly sensitive to oxidation. Major target of oxidation is the CC double bond. She will be promoted particularly by light, heat or dissolved metal ions and proceeds mainly via radical reaction mechanisms. Important intermediate step of oxidation is the formation of hydroperoxides ( -OOH ) in breaking the carbon-carbon double bond. The functional group ( -OOH ) is itself also radicals, thus promoting an oxidative chain reaction. Next can decompose to ketones and, if it comes to cleavage of the CC single bond, even to aldehydes or carboxylic acids hydroperoxides.
Petroselinic acid, and especially their salts are amphiphilic, meaning they contain both a polar, hydrophilic part ( the carboxyl group ) and a non-polar, lipophilic portion ( hydrocarbon chain).
Biological Properties
Petroselinic acid, in comparison with oleic acid stronger inhibitory activity against bacteria, a lower inhibitory action on cell division, as well as the slower biodegradation.
Proof
The detection and assay of petroselinic acid as well as other fatty acids in fats is carried out usually by gas chromatography of the methyl esters; supplement can be a separation of the unsaturated isomers with silver nitrate thin layer chromatography. A second method of detection is the Bromwasserprobe to C = C -C multiple bonds.
Use
Petroselinic acid is used as a component of mixtures for the preparation of cosmetics.