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CAS 123-05-7

CAS 123-05-7 matches 0 EU annex records across Annex II–VI of Regulation 1223/2009.

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Chemical identity and properties

PubChem 2D chemical structure for CAS 123-05-7
CAS 123-05-7PubChem CID 31241

2-Ethylhexanal

2-ethylhexanal is a saturated fatty aldehyde that is heptane in which one of the hydrogens at position 3 has been replaced by a formyl group. It is a metabolite of the plasticisers di-2-ethylhexyl phthalate (DEHP) and di-2-ethylhexyl adipate (DEHA). It has a role as a fungal metabolite and a bacterial xenobiotic metabolite. — ChEBI

IUPAC name
2-ethylhexanal
Molecular formula
C8H16O
Molecular weight
128.21 g/mol
Exact mass
128.120115130 Da
XLogP3
2.6
Topological polar surface area
17.1 Ų
Hydrogen-bond donors
0
Hydrogen-bond acceptors
1
Covalent units
1
Defined stereocentres
0

Also known as

2-EthylhexaldehydeHexanal, 2-ethyl-3-Formylheptane2-Ethylcaproaldehyde2-EthylhexylaldehydeButylethylacetaldehydeEthylbutylacetaldehydeETHYLHEXALDEHYDE
16 more reported names
Butyl ethyl acetaldehydealpha-Ethylcaproaldehydebeta-Propyl-alpha-ethylacroleinalpha-EthylhexanalSEN8S34O6UNSC-42871CHEBI:87809EHALDRefChem:86964204-596-5Octyl aldehyde2-Ethylcapronaldehyde.alpha.-Ethylcaproaldehyde2-ethyl-hexanalNSC 42871.alpha.-Ethylhexanal
Open full PubChem recordPubChem annotations3D structure image
External database identifiers

Evidence from additional scientific databases

NIH PubChem PUG-View
Exact identifier match31241

Attributed physical-property, hazard, environmental and use annotations.

  • First Aid: EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.; SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment.; INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) shou Source: CAMEO Chemicals
  • ERG2024, Guide 129 (Ethylhexaldehyde): General First Aid:; · Call 911 or emergency medical service.; · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.; · Move victim to fresh air if it can be done safely.; · Administer oxygen if breathing is difficult.; · If victim is not breathing:; -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance.; -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).; -- If no pulse detected or no respiratory medical device available, provide continuous compressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.; · Remove and isolate contaminated clothing and shoes.; · For minor skin contact, avoid spreading material on unaffected skin.; · In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.; · For severe burns, immediate medical attention is required.; · Effects of exposure (inhalation, ingestion, Source: Emergency Response Guidebook (ERG)
  • Signal: Warning Source: European Chemicals Agency (ECHA)
  • GHS Hazard Statements: H226 (100%): Flammable liquid and vapor [Warning Flammable liquids]; H315 (15.6%): Causes skin irritation [Warning Skin corrosion/irritation]; H317 (84.4%): May cause an allergic skin reaction [Warning Sensitization, Skin]; H319 (15.6%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]; H361 (84.4%): Suspected of damaging fertility or the unborn child [Warning Reproductive toxicity] Source: European Chemicals Agency (ECHA)
  • Precautionary Statement Codes: P203, P210, P233, P240, P241, P242, P243, P261, P264, P264+P265, P272, P280, P302+P352, P303+P361+P353, P305+P351+P338, P318, P321, P332+P317, P333+P317, P337+P317, P362+P364, P370+P378, P403+P235, P405, and P501 (click each P-code to see the statement) Source: European Chemicals Agency (ECHA)
  • ECHA C&L Notifications Summary: Aggregated GHS information provided per 1785 reports by companies from 11 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.; Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website. Source: European Chemicals Agency (ECHA)
  • NFPA Health Rating: 2 - Materials that, under emergency conditions, can cause temporary incapacitation or residual injury. Source: Hazardous Substances Data Bank (HSDB)
  • NFPA Fire Rating: 2 - Materials that must be moderately heated or exposed to relatively high ambient temperatures before ignition can occur. Materials would not under normal conditions form hazardous atmospheres with air, but under high ambient temperatures or under moderate heating could release vapor in sufficient quantities to produce hazardous atmospheres with air. Source: Hazardous Substances Data Bank (HSDB)
  • NFPA Instability Rating: 1 - Materials that in themselves are normally stable but that can become unstable at elevated temperatures and pressures. Source: Hazardous Substances Data Bank (HSDB)
  • Environmental Bioconcentration: An estimated BCF of 49 was calculated in fish for 2-ethylhexaldehyde(SRC), using a log Kow of 3.07(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is moderate(SRC). Source: Hazardous Substances Data Bank (HSDB)
  • Environmental Fate: TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 18(SRC), determined from a structure estimation method(2), indicates that 2-ethylhexaldehyde is expected to have very high mobility in soil(SRC). Volatilization of 2-ethylhexaldehyde from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 8.4X10-4 atm-cu m/mole(SRC), based upon its vapor pressure, 2 mm Hg(3), and water solubility, 400 mg/L(4). 2-Ethylhexaldehyde is expected to volatilize from dry soil surfaces(SRC) based upon the vapor pressure(SRC). Using OECD Method 301F (Ready Biodegradability, Manometric Respirometry Test) with a domestic activated sludge inoculum and a 28-day incubation period, 2-ethylhexaldehyde had a theoretical BOD of 71.8%(5) which classifies it as readily biodegradable(SRC). By analogy, isobutyraldehyde (a structurally similar branched saturated aldehyde to 2-ethylhexaldhyde), present at 30 mg/L, reached 81% of its theoretical BOD in 4 weeks using an activated sludge inoculum at 100 mg/L in the Japanese MITI test(6) which also classifies it as readily biodegradable(SRC). Source: Hazardous Substances Data Bank (HSDB)
  • Environmental Fate: AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 18(SRC), determined from a structure estimation method(2), indicates that 2-ethylhexaldhyde is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 8.4X10-4 atm-cu m/mole(SRC), derived from its vapor pressure, 2 mm Hg(4), and water solubility, 400 mg/L(5). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 4.6 hours and 4.9 days, respectively(SRC). According to a classification scheme(6), an estimated BCF of 49(SRC), from its log Kow of 3.07(7) and a regression-derived equation(2), suggests the potential for bioconcentration in aquatic organisms is moderate(SRC). 2-Ethylhexaldehyde is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(3). Using OECD Method 301F (Ready Biodegradability, Manometric Respirometry Test) with a domestic activated sludge inoculum and a 28-day incubation period, 2-ethylhexaldehyde had a theoretical BOD of 71.8%(7) which Source: Hazardous Substances Data Bank (HSDB)
  • Environmental Fate: ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2-ethylhexaldehyde , which has a vapor pressure of 2 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 2-ethylhexaldehyde is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 11 hours(SRC), calculated from its rate constant of 3.4X10-11 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Source: Hazardous Substances Data Bank (HSDB)

Mapped by: Existing checksum-valid CAS to unique PubChem CID match. Retrieved: 2026-08-31. Open source record

Scientific classifications and hazard annotations provide context and do not replace the market-specific regulatory decision shown above.

Additional source coverage and match status
SourceResultChecked
NIH PubChem PUG-ViewExact match2026-08-31

A recorded no-match is useful evidence that the source was checked; it is not a claim that the substance does not exist elsewhere.

Retrieved from NIH PubChem on 2026-08-31 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

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How CAS 123-05-7 is used on this site

CAS 123-05-7 is the Chemical Abstracts Service identifier used to pin this page to a specific substance. In the current dataset, 0 EU annex records share this identifier, which helps you cross-check whether the same substance appears under one regulatory context or several.

Use this page when a supplier specification, SDS or raw-material dossier gives you CAS 123-05-7 and you need to see every linked Annex II–VI record in one place. The entry cards above are the quickest route to concentration limits, warnings, annex placement and product-type conditions.