Substance profile
5-Methyl-2-hexanone
5-Methyl-2-hexanone is colorless, clear liquid with a pleasant, fruity odor.
01 · Identification
What 5-Methyl-2-hexanone is
5-Methyl-2-hexanone is colorless, clear liquid with a pleasant, fruity odor. It boils at 144 °C, melts at -73.9 °C.
Under the GHS it carries the signal word Warning. It is classed as flammable agents - 3rd degree.
02 · Identifiers
5-Methyl-2-hexanone identifiers and molecular data
5-Methyl-2-hexanone CAS number and EC number
5-Methyl-2-hexanone molecular formula and molecular weight
Other names for 5-Methyl-2-hexanone
- 5-methylhexan-2-one
- isoamyl methyl ketone
03 · GHS classification
5-Methyl-2-hexanone hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
5-Methyl-2-hexanone pictograms and signal word
5-Methyl-2-hexanone hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Flammable liquids GHS chapter 2.6 | Category 3 | H226 | GHS02 |
| Acute toxicity - inhalation GHS chapter 3.1 | Category 4 | H332 | GHS07 |
5-Methyl-2-hexanone hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H226 | Flammable liquid and vapour. |
| H332 | Harmful if inhaled. |
This page lists only the codes assigned to 5-Methyl-2-hexanone. The full reference lives on the hazard statements hub, the precautionary statements hub and the GHS pictograms hub.
Safety Data Sheet
Getting an SDS for 5-Methyl-2-hexanone
A Safety Data Sheet is written for a product, not for a substance: the supplier of the grade you actually buy issues it, so two suppliers of 5-Methyl-2-hexanone issue two different sheets. That is why there is no single authoritative SDS for a substance to download — what there is, is the job of collecting the sheets for the products you hold and keeping them current as suppliers revise them.
04 · Precautionary statements
5-Methyl-2-hexanone precautionary statements
CLP Annex VI assigns 9 precautionary statements to 5-Methyl-2-hexanone. They are grouped the way a label groups them: what to do before handling, what to do when something has already happened, how to store it and how to dispose of it.
Prevention
What to do before and during handling so the hazard never happens.
Response
What to do once exposure, spillage or fire has already happened.
Reading the notation. … is a blank the supplier fills in — not a truncated sentence.· [square brackets] mark a part printed only when it applies.
05 · Names in the regulation
5-Methyl-2-hexanone name in 23 EU languages
CLP Annex VI Part 3 is published in every language edition of the regulation, and the identification column is written out in each of them. Nothing below is translated by us: each line is the name as that edition prints it. Under Art. 18(2) the substance name from Annex VI is a lawful product identifier, so this is the wording to put on a label going to that market — and where the cell lists several designations, any one of them qualifies.
| Language | Name in CLP Annex VI Part 3 |
|---|---|
| Bulgarian български | 5-метилхексан-2-он изоамилметилкетон |
| Spanish español | 5-Metilhexan-2-ona isoamilmetilcetona |
| Czech čeština | 5-methylhexan-2-on isoamylmethylketon |
| Danish dansk | 5-methylhexan-2-on isoamylmethylketon |
| German Deutsch | 5-Methylhexan-2-on Isoamylmethylketon |
| Estonian eesti | 5-metüülheksaan-2-oon isoamüülmetüülketoon |
| Greek ελληνικά | 5-μεθυλεξαν-2-όνη ισοαμυλομεθυλοκετόνη |
| English English | 5-methylhexan-2-one isoamyl methyl ketone |
| French français | 5-méthylhexan-2-one isoamylméthylcétone |
| Croatian hrvatski | 5-metilheksan-2-on izoamil-metil-keton |
| Italian italiano | 5-metilesan-2-one metil isoamil chetone |
| Latvian latviešu | 5-metilheksān-2-ons izoamilmetilketons |
| Lithuanian lietuvių | 5-metil-2-heksanonas izoamilmetilketonas |
| Hungarian magyar | 5-metilhexán-2-on izoamil-metil-keton |
| Maltese Malti | 5-metilessan-2-on keton tal-metil tal-isoamil |
| Dutch Nederlands | 5-methylhexaan-2-on isoamyl(methyl)ketone |
| Polish polski | 5-metyloheksan-2-on keton izopentylowo-metylowyketon metylowo-izoamylowymetyloizoamyloketon |
| Portuguese português | 5-metilhexan-2-ona isoamilmetilcetona |
| Romanian română | 5-metilhexan-2-onă izoamil-metil-cetonă |
| Slovak slovenčina | 5-metylhexán-2-ón izoamyl(metyl)ketón |
| Slovenian slovenščina | 5-metilheksan-2-on izoamil metil keton |
| Finnish suomi | 5-metyyliheksan-2-oni isoamyylimetyyliketoni |
| Swedish svenska | 5-metylhexan-2-on isoamylmetylketon |
All 23 language editions of Annex VI carry this entry. Irish is the twenty-fourth official EU language and has no line here for a different reason: no consolidated CLP text has ever been published in Irish, so there is no Irish edition of Annex VI to quote a name from. Source: consolidated CLP, CELEX 02008R1272, language editions. © European Union, https://eur-lex.europa.eu — only the electronic Official Journal of the European Union is authentic.
06 · Label elements
5-Methyl-2-hexanone GHS label elements
Everything CLP Annex VI fixes for 5-Methyl-2-hexanone, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Warning
5-Methyl-2-hexanone
- Flammable liquid and vapour.
- Harmful if inhaled.
- Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
- Keep container tightly closed.
- Use explosion-proof [electrical/ventilating/lighting/…] equipment.
- Use only non-sparking tools.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Use only outdoors or in a well-ventilated area.
- IF INHALED:
- Call a POISON CENTER/doctor/… if you feel unwell.
- Store in a well-ventilated place.
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open 5-Methyl-2-hexanone in the GHS label constructor →
07 · Health hazards
5-Methyl-2-hexanone health hazards and exposure limits
5-Methyl-2-hexanone hazard summary
A skin and eye irritant; [CAMEO] Inhalation of high concentrations may cause kidney injury and unconsciousness; [ICSC] Causes liver injury after repeated high-dose inhalation exposures of rats; [HSDB]
Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
5-Methyl-2-hexanone occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 100.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| PEL | 100 ppm (475 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| PEL | TWA 100 ppm (475 mg/m3) See Appendix G | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 50 ppm (240 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | TWA 50 ppm (240 mg/m3) | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | N.D. | The National Institute for Occupational Safety and Health (NIOSH) |
These are United States values. The European Union sets its own indicative and binding limits, and the figure that applies at a given workplace is the one in the local regulation — not the one shown here.
08 · Physical and chemical properties
5-Methyl-2-hexanone properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
5-Methyl-2-hexanone boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 144 °C (291.2 °F) | HSDB | |
| 143.89 °C (291 °F) | NIOSH | ||
| 143.89 °C (291 °F) | at 760 mmHg | CAMEO |
5-Methyl-2-hexanone melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -73.9 °C (-101 °F) | HSDB | |
| -73.89 °C (-101 °F) | NIOSH |
5-Methyl-2-hexanone density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 0.81 g/cm³ | NIOSH | |
| 0.888 g/cm³ | at 20 °C | HSDB |
5-Methyl-2-hexanone solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Miscible with ethanol and ether; very soluble in acetone, benzene; soluble in carbon tetrachloride | HSDB | |
| Miscible with most org solvents | HSDB | ||
| In water, 5400 mg/L at 25 °C | at 25 °C | HSDB |
5-Methyl-2-hexanone vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 5 mmHg | NIOSH | |
| 5.77 mmHg | at 25 °C | HSDB |
5-Methyl-2-hexanone flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | 35.56 °C (96 °F) | HSDB | |
| 43.33 °C (110 °F) | HSDB | ||
| 36.11 °C (97 °F) | NIOSH |
5-Methyl-2-hexanone autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | 190.56 °C (375 °F) | HSDB | |
| 191 °C (375.8 °F) | ICSC |
5-Methyl-2-hexanone lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 1 % by volume | DOE PAC | |
| 1 % by volume | at 93.33 °C | HSDB |
5-Methyl-2-hexanone upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 8.2 % by volume | at 93.33 °C | HSDB |
5-Methyl-2-hexanone vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 3.9 (air = 1) | HSDB |
5-Methyl-2-hexanone odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | 0.012 ppm= detection in air, 0.049 ppm= recognition in air; (purity not specified) | HSDB | |
| Odor Threshold Low: 0.01 [ppm] | Haz-Map | ||
| Odor Threshold High: 0.04 [ppm] | Haz-Map |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
5-Methyl-2-hexanone fire and explosion behaviour
These are descriptions rather than measured values, so they are kept out of the table above and quoted here with the source that reported them.
5-Methyl-2-hexanone fire potential
Flammable
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
5-Methyl-2-hexanone storage and handling
5-Methyl-2-hexanone safe storage
Fireproof.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
5-Methyl-2-hexanone storage conditions
... Store in tightly closed containers in a cool, well ventilated area away from sources of oxidizers (such as perchlorates, peroxides, permanganates, chlorates, and nitrates), strong oxidizers (such as chlorine, bromine, and fluorine), reducing agents, and aldehydes. Sources of ignition such as smoking and open flames are prohibited where methyl isoamyl ketone is handled, used or stored. Metal containers involving the transfer of 5 gallons or more of methyl isoamyl ketone should be grounded and bonded. Drums must be equipped with self-closing valves, pressure vacuum bungs, and flame arresters.
Source: Hazardous Substances Data Bank (HSDB)
5-Methyl-2-hexanone incompatible materials
The vapor mixes well with air, explosive mixtures are easily formed.
Source: Hazardous Substances Data Bank (HSDB)
5-Methyl-2-hexanone reactivity
Ketones, such as 5-METHYLHEXAN-2-ONE, are reactive with many acids and bases liberating heat and flammable gases (e.g., H2). The amount of heat may be sufficient to start a fire in the unreacted portion of the ketone. Ketones react with reducing agents such as hydrides, alkali metals, and nitrides to produce flammable gas (H2) and heat. Ketones are incompatible with isocyanates, aldehydes, cyanides, peroxides, and anhydrides. They react violently with aldehydes, HNO3, HNO3 + H2O2, and HClO4.
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check 5-Methyl-2-hexanone in the storage compatibility matrix →
11 · Transport
5-Methyl-2-hexanone UN number and transport classification
Transport classification is a separate system from the GHS classification above. It decides how a package is marked and how a load may be carried; it does not follow from the workplace label, and the workplace label does not follow from it. The entries below are linked by CAS number, never by name.
5-Methyl-2-hexanone under UN 2302 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| 5-METHYLHEXAN-2-ONE | 3 | F1 | III | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 3 is “Flammable liquids” (ADR 2.1.1.1).
United States · 49 CFR 172.101 Hazardous Materials Table
| Proper shipping name (column 2) | Class or division | PG | Labels (column 6) |
|---|---|---|---|
| 5-Methylhexan-2-one | 3 | III | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 3 is “Flammable and combustible liquid” (49 CFR 173.2).
12 · Questions
5-Methyl-2-hexanone — frequently asked questions
What is the CAS number of 5-Methyl-2-hexanone?
The CAS number of 5-Methyl-2-hexanone is 110-12-3. Its EC number is 203-737-8.
What does a 5-Methyl-2-hexanone label have to show?
Under CLP Annex VI the label for 5-Methyl-2-hexanone carries the pictograms Flame and Exclamation mark and the signal word is Warning.
Is 5-Methyl-2-hexanone flammable?
Yes. CLP Annex VI assigns 5-Methyl-2-hexanone H226 — flammable liquid and vapour. The flash point reported for it is 35.56 °C (96 °F) (HSDB).
Is 5-Methyl-2-hexanone a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for 5-Methyl-2-hexanone. Annex VI is a list of agreed classifications, not a list of substances found safe, so this is an absence of a classification rather than a clean bill of health.
What is the exposure limit for 5-Methyl-2-hexanone?
The US occupational exposure limit reported for 5-Methyl-2-hexanone is 100.0 [ppm] (Haz-Map, Information on Hazardous Chemicals and Occupational Diseases). Limits differ by country: the EU sets its own indicative and binding values, and the figure that applies at a given workplace is the one in the local regulation.
What is the boiling point of 5-Methyl-2-hexanone?
The boiling point reported for 5-Methyl-2-hexanone is 144 °C (291.2 °F) (HSDB).
What is the melting point of 5-Methyl-2-hexanone?
The melting point reported for 5-Methyl-2-hexanone is -73.9 °C (-101 °F) (HSDB).
How should 5-Methyl-2-hexanone be stored?
CLP Annex VI assigns 5-Methyl-2-hexanone the storage statement P403. ... Store in tightly closed containers in a cool, well ventilated area away from sources of oxidizers (such as perchlorates, peroxides, permanganates, chlorates, and nitrates), strong oxidizers (such as chlorine, bromine, and fluorine), reducing agents, and aldehydes. Sources of ignition such as smoking and open flames are prohibited where methyl isoamyl ketone is handled, used or stored. Metal containers involving the transfer of 5 gallons or more of methyl isoamyl ketone should be grounded and bonded. Drums must be equipped with self-closing valves, pressure vacuum bungs, and flame arresters. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to 5-Methyl-2-hexanone
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