n-nonanoic acid (Pelargonic acid) is a natural, medium-chain, nine-carbon-atom saturated fatty acid found in edible plants, in the exometabolome of the tomato, in some rhododendrons (Rhododendron mucronulatum), in buttercups (Staphisagria macrosperma), in plants of the Malvaceae family, and in animals.

It appears as a colourless oily liquid insoluble in water, soluble in ether, ethanol and chloroform.

What it is used for and where

Cosmetics

Pelargonic acid and its esters act as fairly safe and non-toxic skin-conditioning agents, but skin penetration is possible. They have proven to be non-irritating and non-sensitising to human skin in laboratory tests, but some formulations may improve penetration into the stratum corneum.

Surfactant - Cleansing agent

Cosmetic products used to cleanse the skin utilise the surface-active action that produces a lowering of the surface tension of the stratum corneum, facilitating the removal of dirt and impurities.

Surfactant - Emulsifying agent

Emulsions are thermodynamically unstable. Emulsifiers have the property to reduce the oil/water or water/oil interfacial tension, improve emulsion stability and also directly influence the stability, sensory properties and surface tension of sunscreens by modulating their filmometric performance.

Medical

A commonly recognised safe antifungal agent and disinfectant (GRAS), it also possesses antimicrobial activity (1) and is used as an aqueous antimicrobial treatment to preserve fresh produce including the possible internalisation of pathogens by plant tissue (2). It is registered with the EPA (3).

Food

Fragrance. Used in the preparation of coconut and berry flavours. FDA-approved food additive. Credited with antimicrobial properties

Other uses

Together with other chemicals, such as glyphosate (Roundup) it is an ingredient in herbicide formulations, herbicides.

Synthetic lubricant, plasticiser, paint dryer.

Safety

It has not demonstrated toxicity to humans at low quantities.

The most relevant studies on this acid have been selected with a summary of the contents:

Pelargonic acid studies

Caratteristiche tipiche del prodotto commerciale Pelargonic acid

Appearance	Colorless oily liquid
Boiling Point	269°C    516.20°F  litre
Melting Point	9°C          48.20°F  litre
Flash Point	100°C         212°F
Density	0.906 g/mL at 25°C
Refraction Index	n20/D 1.432(lit.)
Vapor Pressure	<0.1 mm Hg at 20°C
Vapor density	5.5
PSA	37.30000
LogP	2.82160
Purity	≥99%
Water	≤0.5%
Total acid	97.5%-100%
Acid value	345.00-355.00 mg KOH/g
Iodine value	0.00-0.50 gl2/100g
Iron	0-2 ppm
Transmittance	95-100%   440nm
Transmittance	99-100%   5500nm
Storage	2-8°C
Shelf Life	2 years
Chemical Safety

• Molecular Formula    C₉H₁₈O₂
• Linear Formula  CH₃(CH₂)₇COOH
• Molecular Weight      158.24
• Exact Mass    158.13100
• CAS  112-05-0
• UNII    97SEH7577T
• EC Number   203-931-2
• DSSTox Substance ID  DTXSID3021641   DTXSID5028326    DTXSID9028887
• IUPAC  nonanoic acid
• InChl=1S/C9H18O2/c1-2-3-4-5-6-7-8-9(10)11/h2-8H2,1H3,(H,10,11)
• InChl Key      FBUKVWPVBMHYJY-UHFFFAOYSA-N
• SMILES  CCCCCCCCC(=O)O
• MDL number  MFCD00004433
• PubChem Substance ID    24897735
• ChEBI  29019
• JECFA   102
• FEMA   2784
• RTECS  RA6650000
• NCI    C82932
• Beilstein    1752351
• NACRES NA.25

Synonyms

• Pelargonic acid
• Nonanoic acid
• Nonoic acid
• 1-octanecarboxylic acid
• n-Nonanoic acid

References_____________________________________________________________________

(1) Dev Kumar G, Mis Solval K, Mishra A, Macarisin D. Antimicrobial Efficacy of Pelargonic Acid Micelles against Salmonella varies by Surfactant, Serotype and Stress Response. Sci Rep. 2020 Jun 24;10(1):10287. doi: 10.1038/s41598-020-67223-y. 

(2) Herdt J., Feng H. Aqueous antimicrobial treatments to improve fresh and fresh-cut produce safety. In: Fan X., Niemira B.A., Doona C.J., Feeherry F.E., Gravani R.B., editors. Microbial Safety of Fresh Produce. Blackwell Publishing and the Institute of Food Technologists; Ames, IA, USA: 2009. pp. 169–190.

(3) Biopesticides Fact Sheet for Pelargonic acid (epa.gov)