Octyl acetate
Octyl acetate, also known as octyl ethanoate or acetic acid octyl ester, is a colorless liquid organic compound classified as an ester, with the molecular formula C₁₀H₂₀O₂ and the linear structural formula CH₃CO₂(CH₂)₇CH₃.[1][2] It is formed by the esterification of 1-octanol and acetic acid, resulting in a substance with a pleasant, fruity odor reminiscent of orange blossoms or jasmine.[1] Physically, it appears as a clear, water-insoluble liquid with a density of 0.867 g/mL at 25 °C, a boiling point of 211 °C, a melting point below -40 °C, and a flash point of 86 °C, classifying it as a Class IIIA combustible liquid.[3][4] Octyl acetate occurs naturally in citrus fruits such as oranges and grapefruits, contributing to their characteristic aroma. In industry, it serves primarily as a flavoring agent in the food and beverage sector, imparting an orange-like taste and approved under FEMA number 2806 for such uses at levels up to 30 mg/kg in certain foods. It is also widely employed in perfumery and fragrances due to its floral, citrus notes, and occasionally as a solvent or intermediate in chemical synthesis. The compound's CAS number is 112-14-1, and it is commercially available in high purity grades (≥98%) for these applications.[2] Regarding safety, octyl acetate exhibits low acute toxicity, with an LD50 of 3,000 mg/kg in rats via oral administration, and it is not classified as a skin irritant, eye irritant, or sensitizer under standard testing.[3] However, it is flammable and should be handled with precautions to avoid ignition sources, as its vapor can form explosive mixtures with air (flammable limits: 0.76–8.14%).[4] Environmental assessments indicate it is readily biodegradable and has low bioaccumulation potential, making it suitable for controlled industrial use.[3]Chemical identity and properties
Molecular structure and nomenclature
Octyl acetate has the IUPAC name octyl acetate, while its systematic name is octyl ethanoate, reflecting the ester nomenclature where the alkyl group from the alcohol precedes the alkanoate from the acid.[1] Common names for the compound include acetic acid octyl ester and n-octyl acetate, the latter emphasizing the straight-chain nature of the octyl group.[1][5] The molecular formula of octyl acetate is C_{10}H_{20}O_2.[1] Its structural formula is \ce{CH3CO2(CH2)7CH3}, which depicts the characteristic ester functional group (-CO_2-) formed by the condensation of acetic acid and 1-octanol, where the carbonyl carbon of the acid is bonded to the oxygen of the alcohol's hydroxyl group, and the octyl chain (-\ce{(CH2)7CH3}) extends from that oxygen. This structure highlights the compound's classification as a carboxylate ester, specifically an acetate ester of a primary alcohol.[1] Octyl acetate possesses a molar mass of 172.27 g/mol, calculated from its constituent atoms in the ester framework.[6] As an ester, it is derived from the parent carboxylic acid (acetic acid, or ethanoic acid, \ce{CH3CO2H}) and the parent alcohol (1-octanol, or octan-1-ol, \ce{CH3(CH2)7OH}), where the esterification reaction eliminates water to form the \ce{C-O-C} linkage central to its chemical identity.[1] This relation underscores its position within the broader category of fatty alcohol esters, though its relatively short chain length distinguishes it from longer-chain variants.[7]Physical and chemical properties
Octyl acetate is a colorless liquid at room temperature, exhibiting a fruity odor reminiscent of orange blossom or jasmine.[1] The compound has the following key physical properties:| Property | Value | Conditions/Source |
|---|---|---|
| Density | 0.863–0.87 g/cm³ | 20 °C; various suppliers including Sigma-Aldrich |
| Melting point | −38.5 °C | Literature; Flinn Scientific SDS[8] |
| Boiling point | 206–211 °C | 760 mmHg; PubChem/The Good Scents Company[1] |
| Solubility in water | 0.003 g/100 g | 25 °C; HMDB estimate[9] |
| Solubility in ethanol and ether | Fully miscible | Room temperature; PubChem/JECFA[1] |
| Flash point | 86 °C | Closed cup; Flinn Scientific SDS[8] |