11-Heneicosanone
[CAS# 19781-72-7]

Identification

• Classification: Organic raw materials >> Ketone compound
• Name: 11-Heneicosanone
• Synonyms: henicosan-11-one
• Molecular Formula: C₂₁H₄₂O
• Molecular Weight: 310.56
• CAS Registry Number: 19781-72-7
• EC Number: 243-307-7
• SMILES: CCCCCCCCCCC(=O)CCCCCCCCCC

Properties

• Density: 0.8±0.1 g/cm³ Calc.^*
• Melting point: 64 ºC (Expl.)
• Boiling point: 378.5±10.0 ºC 760 mmHg (Calc.)^*
• Flash point: 77.6±14.6 ºC (Calc.)^*
• Index of refraction: 1.446 (Calc.)^*

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H302-H315-H319-H335
• Precautionary Statements: P261-P305+P351+P338

Discovory and Applicatios

11-Heneicosanone is a long-chain aliphatic ketone belonging to the class of saturated fatty ketones. It has the molecular formula C₂₁H₄₂O and consists of a straight twenty-one-carbon chain bearing a carbonyl group at the 11 position, near the center of the molecule. As a consequence of its long hydrocarbon backbone, it is a hydrophobic, low-volatility solid or high-melting waxy material under ambient conditions. Compounds of this type are structurally related to long-chain hydrocarbons, fatty acids, and alcohols that are widespread in biological and environmental systems.

The recognition of 11-heneicosanone in the scientific literature is tied to systematic chemical analyses of natural waxes and surface lipids rather than to a single landmark discovery. During the mid-twentieth century, advances in chromatographic and spectroscopic techniques enabled chemists to identify and characterize long-chain ketones present in plant cuticular waxes, insect secretions, and other natural lipid mixtures. In these studies, 11-heneicosanone was identified as one of several odd-numbered ketones occurring naturally, often alongside corresponding alkanes, secondary alcohols, and fatty acids. Its structural assignment was confirmed through comparison of melting points, infrared spectra, and later mass spectrometric fragmentation patterns.

In plants, long-chain ketones such as 11-heneicosanone are typically components of epicuticular wax layers that coat leaves, stems, and fruits. These waxes play important protective roles, reducing water loss, reflecting ultraviolet radiation, and forming barriers against pathogens and herbivores. The presence of secondary ketones with the carbonyl group near the center of the chain is a characteristic feature of waxes from certain plant families. Studies of plant surface chemistry have shown that the chain length and functional group distribution of wax components can influence surface wettability and interactions with insects and microorganisms.

11-Heneicosanone has also been reported in the context of insect chemistry. Long-chain ketones are known constituents of insect cuticular lipids, where they contribute to desiccation resistance and may function in chemical communication. In some insect species, specific ketones act as pheromones or semiochemicals involved in mating or aggregation behavior. While 11-heneicosanone itself is not universally assigned a pheromonal role, its identification in insect extracts has contributed to broader understanding of the diversity and function of cuticular lipids.

From a synthetic and analytical perspective, 11-heneicosanone is often used as a reference compound in studies of long-chain lipid chemistry. It can be prepared by established organic reactions, such as the oxidation of the corresponding secondary alcohol or through controlled carbon–carbon bond-forming reactions followed by functional group manipulation. In laboratories, it has been employed as a standard for gas chromatography and mass spectrometry when analyzing natural wax mixtures, because its retention behavior and fragmentation pattern are representative of mid-chain aliphatic ketones.

Applications of 11-heneicosanone are largely indirect and research-oriented rather than industrial. Its role as a naturally occurring wax component makes it relevant to agricultural science, ecology, and plant physiology, where wax composition is correlated with stress tolerance, disease resistance, and environmental adaptation. In chemical ecology, the identification of such compounds contributes to understanding how organisms use lipids for protection and communication. Additionally, long-chain ketones have attracted interest as renewable, bio-derived chemicals, since they can be obtained from biomass-derived fatty acids through catalytic processes. In this broader context, compounds like 11-heneicosanone serve as model molecules for studying the properties and potential uses of bio-based hydrophobic chemicals.

Overall, 11-heneicosanone is best understood as a naturally occurring long-chain ketone whose scientific importance lies in its contribution to the chemistry of biological waxes and lipids. Its discovery emerged from detailed analytical studies of natural materials, and its applications center on research into plant and insect surface chemistry, analytical method development, and the exploration of long-chain ketones as representatives of renewable organic compounds.

References

2007. Dialkylation with Alkyl Halides. Science of Synthesis.
URL: SD-030-00348

2006. Synthesis of Ketones via Alkylation of Methyl (Methylsulfanyl)methyl Sulfoxide. Science of Synthesis.
URL: SD-008-01039

2003. (Z,Z)-6,9-Heneicosadien-11-One, Labile Sex Pheromone of the Whitemarked Tussock Moth, Orgyia leucostigma. Journal of Chemical Ecology, 29(3).
DOI: 10.1023/a:1022802821338