Substance profile
Acetyl chloride
Acetyl chloride is a liquid with a pungent odor.
01 · Identification
What Acetyl chloride is
Acetyl chloride is a liquid with a pungent odor. Its molecular formula is C2H3ClO and its molecular weight is 78.5 g/mol. It boils at 51 °C, melts at -113 °C.
Under the GHS it carries the signal word Danger. It is classed as corrosives.
02 · Identifiers
Acetyl chloride identifiers and molecular data
Acetyl chloride CAS number and EC number
Acetyl chloride molecular formula and molecular weight
03 · GHS classification
Acetyl chloride hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Acetyl chloride pictograms and signal word
Acetyl chloride hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Flammable liquids GHS chapter 2.6 | Category 2 | H225 | GHS02 |
| Skin corrosion/irritation GHS chapter 3.2 | Category 1A or 1B or 1C | H314 | GHS05 |
Where two values are shown with “or”, the hazard statement is shared by more than one category or by more than one class, and the code alone does not say which. H272, for example, belongs to oxidising liquids and to oxidising solids — the physical state decides. The binding answer for a specific entry is in the CLP Annex VI table itself.
Acetyl chloride hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H225 | Highly flammable liquid and vapour. |
| H314 | Causes severe skin burns and eye damage. |
Acetyl chloride supplemental EU statements (EUH)
| Code | Statement |
|---|---|
| EUH014 | Reacts violently with water. |
This page lists only the codes assigned to Acetyl chloride. 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 Acetyl chloride
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 Acetyl chloride 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
Acetyl chloride precautionary statements
CLP Annex VI assigns 10 precautionary statements to Acetyl chloride. 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
Acetyl chloride 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 | ацетилхлорид |
| Spanish español | Cloruro de acetilo |
| Czech čeština | acetylchlorid |
| Danish dansk | acetylchlorid |
| German Deutsch | Acetylchlorid Essigsäurechlorid |
| Estonian eesti | atsetüülkloriid |
| Greek ελληνικά | ακετυλοχλωρίδιο |
| English English | acetyl chloride |
| French français | chlorure d'acétyle |
| Croatian hrvatski | acetil-klorid |
| Italian italiano | cloruro di acetile acetile cloruro |
| Latvian latviešu | acetilhlorīds |
| Lithuanian lietuvių | acetilchloridas |
| Hungarian magyar | acetil-klorid |
| Maltese Malti | klorur tal-aċetil |
| Dutch Nederlands | acetylchloride |
| Polish polski | chlorek acetylu chlorek kwasu octowego |
| Portuguese português | cloreto de acetilo |
| Romanian română | clorură de acetil |
| Slovak slovenčina | acetylchlorid |
| Slovenian slovenščina | acetil klorid |
| Finnish suomi | asetyylikloridi |
| Swedish svenska | acetylklorid |
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
Acetyl chloride GHS label elements
Everything CLP Annex VI fixes for Acetyl chloride, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Acetyl chloride
- Highly flammable liquid and vapour.
- Causes severe skin burns and eye damage.
- Reacts violently with water.
- 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.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF SWALLOWED:
- Immediately call a POISON CENTER/doctor/…
- Do NOT induce vomiting.
- Store in a well-ventilated place.
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Acetyl chloride in the GHS label constructor →
07 · Health hazards
Acetyl chloride health hazards and exposure limits
Acetyl chloride hazard summary
Corrosive to skin; [Quick CPC] A corrosive substance that can cause pulmonary edema; [ICSC] Reacts violently with water; Can cause severe burns; [Merck Index] Human inhalation of 2 ppm for 1 minute causes other changes in olfaction and lungs, thorax, or respiration; Causes spastic paralysis, excitement, and other changes in lungs, thorax, or respiration in oral lethal-dose studies of rats; [RTECS] See the Process, Toxic Gas from Spilling Chemical in Water.
Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
Acetyl chloride carcinogenicity classification
CLASSIFICATION: D; not classifiable as to human carcinogenicity. BASIS FOR CLASSIFICATION: No human data or animal data. HUMAN CARCINOGENICITY DATA: None. ANIMAL CARCINOGENICITY DATA: None.
Source: Hazardous Substances Data Bank (HSDB)
An IARC group and a CLP classification answer different questions. IARC judges whether the evidence for cancer in humans is strong enough; CLP Annex VI is the legally binding EU classification. A substance can carry one and not the other.
08 · Physical and chemical properties
Acetyl chloride 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.
Acetyl chloride boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 51 °C (123.8 °F) | HSDB | |
| 50.89 °C (123.6 °F) | at 760 mmHg | CAMEO |
Acetyl chloride melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -112.7 °C (-170.9 °F) | HSDB | |
| -112.22 °C (-170 °F) | CAMEO | ||
| -112 °C (-169.6 °F) | ICSC |
Acetyl chloride density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 1.1029 g/cm³ | at 21.11 °C | HSDB |
| 1.1039 g/cm³ | at 21 °C | CAMEO | |
| 1.1051 g/cm³ | at 20 °C | HSDB |
Acetyl chloride solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Miscible with benzene, chloroform, ether, glacial acetic acid, petroleum ether | HSDB | |
| Miscible with ether, acetone, benzene, chloroform; soluble in carbon tetrachloride | HSDB | ||
| Decomposed violently by water or alcohol | decomposes | HSDB |
Acetyl chloride vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 240.02 mmHg | at 20 °C | ICSC |
| 287 mmHg | at 25 °C | HSDB |
Acetyl chloride flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | 5 °C (41 °F) | HSDB | |
| 4 °C (39.2 °F) | HSDB | ||
| 4.44 °C (40 °F) | CAMEO |
Acetyl chloride autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | 390 °C (734 °F) | HSDB |
Acetyl chloride lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 5 % by volume | HSDB | |
| 7.3 % by volume | ICSC |
Acetyl chloride upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 19 % by volume | ICSC |
Acetyl chloride vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 2.7 (air = 1) | HSDB | |
| 2.7 (air = 1) | at 37.78 °C | CAMEO |
Acetyl chloride critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 246.11 °C (475 °F) | HSDB |
Acetyl chloride corrosivity
| Property | Value | Conditions | Source |
|---|---|---|---|
| Corrosivity | Corrosive | HSDB | |
| Corrosive to metals and tissue | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Acetyl chloride 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.
Acetyl chloride fire potential
Dangerous fire hazard when exposed to heat or flame.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Acetyl chloride storage and handling
Acetyl chloride safe storage
Fireproof. Store in an area without drain or sewer access. Separated from incompatible materials. See Chemical Dangers. Dry. Well closed.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Acetyl chloride storage conditions
Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. Keep away from water. Never allow product to get in contact with water during storage. Hydrolyzes readily. Handle and store under inert gas.
Source: Hazardous Substances Data Bank (HSDB)
Acetyl chloride incompatible materials
Incompatible materials: Water, alcohols, oxidizing agents, strong bases.
Source: Hazardous Substances Data Bank (HSDB)
Acetyl chloride reactivity
ACETYL CHLORIDE reacts violently with water, steam, methanol or ethanol to form hydrogen chloride and acetic acid. Reacts vigorously with bases, both organic and inorganic. Incompatible with oxidizing agents and alcohols. Produces highly toxic fumes of phosgene gas and chlorine when heated to decomposition [Sax, 9th ed., 1996, p. 35]. Reaction in a confined space with even a small amount of water may cause a violent eruption of gases [Bretherick, 5th ed., 1995, p. 281]. Vapor forms an explosive mixture with air [Kirk-Othmer, 3rd ed., Vol. 1, 1978, p. 162]. Polymerization reaction with dimethyl sulfoxide is particularly violent [Buckley, A., J. Chem. Ed., 1965, 42, p. 674]. May react vigorously or explosively if mixed with diisopropyl ether or other ethers in the presence of trace amounts of metal salts [J. Haz. Mat., 1981, 4, 291].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Acetyl chloride in the storage compatibility matrix →
11 · Transport
Acetyl chloride 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.
Acetyl chloride under UN 1717 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| ACETYL CHLORIDE | 3 | FC | II | |
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) |
|---|---|---|---|
| Acetyl chloride | 3 | II | |
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
Acetyl chloride — frequently asked questions
What is the CAS number of Acetyl chloride?
The CAS number of Acetyl chloride is 75-36-5. Its EC number is 200-865-6.
What is the chemical formula of Acetyl chloride?
The molecular formula of Acetyl chloride is C2H3ClO and its molecular weight is 78.5 g/mol.
What does a Acetyl chloride label have to show?
Under CLP Annex VI the label for Acetyl chloride carries the pictograms Flame and Corrosion and the signal word is Danger.
Is Acetyl chloride flammable?
Yes. CLP Annex VI assigns Acetyl chloride H225 — highly flammable liquid and vapour. The flash point reported for it is 5 °C (41 °F) (HSDB).
Is Acetyl chloride a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Acetyl chloride. 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 boiling point of Acetyl chloride?
The boiling point reported for Acetyl chloride is 51 °C (123.8 °F) (HSDB).
What is the melting point of Acetyl chloride?
The melting point reported for Acetyl chloride is -112.7 °C (-170.9 °F) (HSDB).
How should Acetyl chloride be stored?
CLP Annex VI assigns Acetyl chloride the storage statement P403. Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. Keep away from water. Never allow product to get in contact with water during storage. Hydrolyzes readily. Handle and store under inert gas. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Acetyl chloride
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