Nonanal (124-19-6) Physical and Chemical Properties
Nonanal
Linear C9 fatty aldehyde with a characteristic orange‑rose aroma, used as a fragrance and flavor intermediate and as an analytical/quality‑control standard in formulation and R&D.
| CAS Number | 124-19-6 |
| Family | Medium-chain aldehydes |
| Typical Form | Colorless liquid |
| Common Grades | BP, EP, FCC, JP, USP |
Nonanal is a linear, saturated aliphatic aldehyde of the n-alkanal class with molecular formula \(\ce{C9H18O}\). Structurally it consists of a terminal formyl group attached to an unbranched nine‑carbon alkyl chain (n‑nonanal); this gives a largely nonpolar hydrocarbon character with a single polar carbonyl oxygen. Electronic structure is dominated by the polarized C=O bond (H‑bond acceptor count = 1, donor count = 0) while the long alkyl segment confers low aqueous solubility and moderate lipophilicity.
Physicochemically, nonanal behaves as a volatile, moderately lipophilic solvent-like aldehyde: low water solubility with significant partitioning into organic phases, a moderate vapor pressure at ambient temperature, and an estimated octanol–water partitioning consistent with XLogP3 = 3.3. Chemically it is susceptible to oxidation (to the corresponding acid), autoxidation and polymerization under acidic or radical‑promoting conditions, and typical aldehyde chemistry (e.g., nucleophilic addition, condensation). Biologically, nonanal occurs naturally as a plant and food volatile and is used industrially as a fragrance and flavouring agent; it is also produced endogenously and can be a product of lipid peroxidation and ozone‑mediated chemistry in biological and indoor air environments.
Common commercial grades reported for this substance include: BP, EP, FCC, JP, USP.
Basic Physical Properties
Density
Reported experimental densities include 0.8264 at 72 \(^\circ\mathrm{F}\) (NTP, 1992) and 0.8264 g/cu cm at 22 \(^\circ\mathrm{C}\). A broader range is cited as 0.820–0.830 (unitless range as reported). These values indicate nonanal is less dense than water and will float on aqueous layers under ambient conditions.
Melting Point
Two experimental melting/freezing values are reported: 145 \(^\circ\mathrm{F}\) (NTP, 1992) and −19.3 \(^\circ\mathrm{C}\). If a single numeric value is required for process design, use the reported experimental value appropriate for the temperature scale of the data source.
Boiling Point
Boiling point data are reported as 374 to 378 \(^\circ\mathrm{F}\) at 760 mmHg (NTP, 1992) and an equivalent 195 \(^\circ\mathrm{C}\). These values represent the normal boiling range for a technical material and are relevant for distillation and recovery operations.
Vapor Pressure
Vapor pressure at 25 \(^\circ\mathrm{C}\) is reported as 0.37 \(\mathrm{mmHg}\) (presented also as 3.7X10-1 mm Hg at 25 \(^\circ\mathrm{C}\) /Extrapolated/). This vapor pressure places nonanal in the semi‑volatile organics range; significant volatilization from aqueous and surface reservoirs can occur under ambient conditions.
Flash Point
Flash point entries include 182 \(^\circ\mathrm{F}\) (NTP, 1992) and 64 \(^\circ\mathrm{C}\) (147 \(^\circ\mathrm{F}\)) closed cup. Nonanal is therefore combustible and should be handled away from ignition sources; appropriate flammable‑liquid precautions are required in storage and transfer.
Chemical Properties
Solubility and Phase Behavior
Experimental solubility data indicate limited water solubility: “Insoluble (<1 mg/mL)” (NTP, 1992) and a measured solubility of 96 mg/L at 25 \(^\circ\mathrm{C}\). Nonanal is readily soluble in nonpolar and moderately polar organic solvents (e.g., ethyl ether, chloroform, alcohols, mineral oil, propylene glycol) and is generally insoluble in glycerol. Given its Henry's Law constant (7.34X10-4 atm·m^3·mol−1 at 25 \(^\circ\mathrm{C}\)), volatilization from aqueous phases is an important fate pathway.
Reactivity and Stability
Nonanal is classified as an aldehyde and exhibits the common reactivity profile of aliphatic aldehydes: it is susceptible to oxidation (forming nonanoic acid), self‑condensation and polymerization (acid‑catalysed), and autoxidation in air (forming peroxides and acids). It is sensitive to air and light and may be stabilized by small amounts of antioxidants (e.g., alpha‑tocopherol noted as a stabiliser in formulations). Incompatibilities include strong oxidizing agents, strong reducing agents and strong bases; exothermic polymerization can occur under acid catalysis. On thermal decomposition, combustion products include carbon oxides and irritating fumes.
Thermodynamic Data
Standard Enthalpies and Heat Capacity
No experimentally established value for this property is available in the current data context.
Molecular Parameters
Molecular Weight and Formula
Molecular formula: \(\ce{C9H18O}\).
Molecular weight: 142.24 \(\mathrm{g}\,\mathrm{mol}^{-1}\).
Exact/monoisotopic mass: 142.135765193 (reported as ExactMass/MonoisotopicMass).
LogP and Polarity
Computed XLogP3‑AA: 3.3 (reported). Topological polar surface area (TPSA): 17.1. Hydrogen bond donor count = 0; hydrogen bond acceptor count = 1. These descriptors are consistent with a molecule that is moderately lipophilic and has low aqueous solubility but a single polar site (the aldehyde oxygen) capable of limited polar interactions.
Structural Features
Nonanal is an unbranched (n‑) aldehyde (n‑nonanal). Key structural and spectroscopic features include: - Terminal aldehyde C=O functional group that dominates reactivity (susceptible to oxidation and nucleophilic addition). - Alkyl chain length (C9) provides the hydrophobic character responsible for aroma/flavour properties and partitioning into lipophilic matrices. - Spectral data: 1H NMR and 13C NMR shifts consistent with a terminal aldehyde (1H ~9.76–9.77 ppm; 13C carbonyl ~202.82 ppm) and aliphatic chain resonances; GC‑MS electron‑impact fragmentation shows dominant ions at m/z 57, 41, 43 and 56 typical of aliphatic aldehydes and alkyl fragments.
Identifiers and Synonyms
Registry Numbers and Codes
- CAS: 124-19-6
- EC (European Community) Number: 204-688-5
- UNII: 2L2WBY9K6T
- FEMA Number: 2782
- ChEBI: CHEBI:84268
SMILES, InChI and InChIKey (provided as structural identifiers):
- SMILES: CCCCCCCCC=O
- InChI: InChI=1S/C9H18O/c1-2-3-4-5-6-7-8-9-10/h9H,2-8H2,1H3
- InChIKey: GYHFUZHODSMOHU-UHFFFAOYSA-N
Synonyms and Structural Names
Common synonyms and name variants reported include: nonanal; n‑nonylaldehyde; 1‑nonanal; pelargonaldehyde; nonanaldehyde; nonyl aldehyde; pelargonic aldehyde; nonanoic aldehyde; n‑nonan‑1‑al. (The substance appears under multiple depositor‑supplied and registry synonyms in commercial and analytical contexts.)
Industrial and Commercial Applications
Representative Uses and Industry Sectors
Nonanal is used as a fragrance and flavouring agent (perfumes, floral/rose compositions, citrus notes) and as an additive in consumer products. It is designated for use as a synthetic flavouring substance and adjuvant in food formulations under recognized food‑use categories. Industry sectors include fragrance and flavour manufacturing, basic organic chemical processing and certain specialty applications in formulations (personal care, household, food flavours).
Role in Synthesis or Formulations
Nonanal serves as both an intermediate and an end‑use functional component: it can be manufactured by catalytic dehydrogenation of n‑nonanol, hydroformylation of 1‑octene, catalytic oxidation of the corresponding alcohol, or reduction of the corresponding acid. In formulations it provides characteristic odor and flavour properties and is used in concentrations consistent with good manufacturing practice for flavours and fragrances.
Safety and Handling Overview
Acute and Occupational Toxicity
Nonanal is an irritant: it can cause skin and serious eye irritation and can produce respiratory tract irritation on exposure to significant vapour concentrations. Reported hazard descriptors include H315 (causes skin irritation), H319 (causes serious eye irritation), and H335/H336 (respiratory irritation and narcotic effects) in notified classifications. Acute toxicity values reported in testing summaries are relatively low‑hazard by systemic toxicity metrics (e.g., LD50 oral entries reported as >5,000 mL/kg in some tables), but severe local dermal effects (including burns) have been observed in concentrated dermal exposures in animal studies. Occupational exposure routes are inhalation and dermal contact; appropriate exposure controls and PPE are recommended.
Environmental hazard information indicates aquatic toxicity for fish and invertebrates at mg·L−1 levels (e.g., LC50 for fathead minnow reported as 5.52 mg/L for 96 hr), and aquatic chronic hazards should be considered in effluent handling and spill response.
For first‑aid, spill response, and firefighting measures: remove contaminated clothing, flush exposed skin/eyes with water, ventilate area, and use water spray, alcohol‑resistant foam, dry chemical or CO2 for fire control. Fires may generate carbon oxides and irritating fumes; firefighters should use self‑contained breathing apparatus where required.
Storage and Handling Considerations
Store in a cool, dry, well‑ventilated area away from heat and ignition sources; keep container tightly closed and upright to avoid leakage. Some suppliers recommend refrigerated storage for extended shelf life. Prevent accumulation of vapour in low areas and implement grounding/bonding during transfer to mitigate static accumulation. Use antioxidative stabilizers where recommended to retard autoxidation. Handle using standard industrial hygiene practices: engineering controls (local exhaust), splash goggles, chemical‑resistant gloves, and, where vapour concentrations warrant, respiratory protection with organic vapour cartridges or supplied air devices.
For detailed hazard, transport and regulatory information, users should refer to the product‑specific Safety Data Sheet (SDS) and local legislation.
