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Aldehydes and ketones

Methacrolein

Also known as Methacrylaldehyde, 2-Methyl-2-propenal, 2-Methylacrolein

CAS 78-85-3Formula C4H6OMolar mass 70.09 g/molEC 201-150-1
GHS signal word: Danger. Pictograms: Flammable, Corrosive, Acute toxicity (severe), Serious health hazard 9 suppliers listed
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Methacrolein chemical structure, C4H6O, CAS 78-85-3
2D chemical structure

Key facts

What buyers check first

All properties
Appearance
Colorless liquid
Melting point
-81 °C
Boiling point
68.4 °C
Density
Relative density (water = 1): 0.8
Flash point
2 °C
HS code
291219
Category
Aldehydes and ketones
UN number
UN 2396
Illustrative photo, clear colourless liquid in a glass reagent bottle on a laboratory bench
Typical packagingIllustrative packaging image, not the actual product

What is Methacrolein?

Plain description, key identifiers and synonyms

Methacrylaldehyde appears as a colorless liquid. Less dense than water. May be toxic by ingestion, inhalation and skin absorption. Severely irritating to skin and eyes. Used to make plastics.

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
2-methylprop-2-enal
CAS number
78-85-3 CAS number cross-checked
EC number
201-150-1
Molecular formula
C4H6O
UNII
9HRB24892H
MDL number
MFCD00006974
InChIKey
STNJBCKSHOAVAJ-UHFFFAOYSA-N
InChI
InChI=1S/C4H6O/c1-4(2)3-5/h3H,1H2,2H3
SMILES (canonical and isomeric)
CC(=C)C=O

Synonyms

  • Methacrylaldehyde
  • 2-Methyl-2-propenal
  • 2-Methylacrolein
  • 2-Methylprop-2-enal
  • Isobutenal
  • 2-Propenal, 2-methyl-
  • 2-Methylpropenal
  • 2-Methylenepropanal
  • Methylacrylaldehyde
  • Acrolein, 2-methyl-
  • Methacrylic aldehyde
  • alpha-Methylacrolein
  • Methakrylaldehyd
  • 2-Formyl-1-propene
  • methylacrolein
  • alpha-Methacrolein
  • alpha-methylacrylaldehyde
  • Methacrolein-13C
  • Methacrolein (stabilized with HQ)
  • Methacrolein (Stabilized with 1% Hydroquinone)
  • 2-methyl-propenal
  • 2-Methylacrylaldehyde
  • methacroleine
  • Methacraldehyde
  • methyl propenal
Show all 33 synonyms
  • Methacrolein, 95%
  • Methacryaldehyde
  • 2-Methylacrylaldehyde #
  • 2-Methyl propenal
  • Methacrylaldehyde, inhibited
  • CH2=C(CH3)CHO
  • 4-01-00-03455 (Beilstein Handbook Reference)
  • UN 2396 (Salt/Mix)

Physical and chemical properties

Measured values and descriptors computed from the structure

Physical and chemical properties

Measured values, check the supplier specification for your grade

Appearance
Colorless liquidexp.
Melting point
-81 °Cexp.
Boiling point
68.4 °Cexp.
Density
Relative density (water = 1): 0.8exp.
Flash point
2 °Cexp.
Autoignition temperature
295 °Cexp.
Solubility
MISCIBLE WITH WATER, ETHANOL, ETHERexp.
Vapour pressure
155 mm Hg @ 25 °Cexp.

Values vary by grade. Ask suppliers for the COA or TDS of the batch you buy.

Computed descriptors

Calculated from the structure, useful for screening and formulation

Molecular weight
70.09 g/molcalc.
Exact mass
70.0419 Dacalc.
LogP (octanol/water)
0.76calc.
Topological polar surface area
17.07 Ųcalc.
Hydrogen bond donors
0calc.
Hydrogen bond acceptors
1calc.
Rotatable bonds
1calc.
Heavy atoms
5calc.
Rings
0calc.
Aromatic rings
0calc.
Fraction sp3 carbons
0.25calc.
Formal charge
0calc.
Stereocentres
0calc.
Lipinski rule of five
Passes (0 violations)calc.

Calculated for screening. Confirm critical figures with the supplier.

Safety and hazards

GHS classification summary, not a safety data sheet

GHS signal word
Danger
GHS02: Flammable
Flammable
GHS05: Corrosive
Corrosive
GHS06: Acute toxicity (severe)
Acute toxicity (severe)
GHS08: Serious health hazard
Serious health hazard
GHS09: Hazardous to the environment
Hazardous to the environment
332WNFPA 704 rating

Hazard statements

  • H225Highly flammable liquid and vapour.
  • H301Toxic if swallowed.
  • H311Toxic in contact with skin.
  • H314Causes severe skin burns and eye damage.
  • H318Causes serious eye damage.
  • H330Fatal if inhaled.
  • H341Suspected of causing genetic defects.
  • H400Very toxic to aquatic life.
  • H410Very toxic to aquatic life with long lasting effects.
Precautionary statements (37)
  • P203Obtain, read and follow all safety instructions before use.
  • P210Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
  • P233Keep container tightly closed.
  • P240Ground and bond container and receiving equipment.
  • P241Use explosion-proof electrical, ventilating and lighting equipment.
  • P242Use non-sparking tools.
  • P243Take action to prevent static discharges.
  • P260Do not breathe dust, fume, gas, mist, vapours or spray.
  • P262Do not get in eyes, on skin, or on clothing.
  • P264Wash skin thoroughly after handling.
  • P264 + P265Wash skin thoroughly after handling. Do not touch eyes.
  • P270Do not eat, drink or smoke when using this product.
  • P271Use only outdoors or in a well-ventilated area.
  • P273Avoid release to the environment.
  • P280Wear protective gloves, protective clothing, eye protection and face protection.
  • P284In case of inadequate ventilation wear respiratory protection.
  • P301 + P316If swallowed: Get emergency medical help immediately.
  • P301 + P330 + P331If swallowed: Rinse mouth. Do not induce vomiting.
  • P302 + P352If on skin: Wash with plenty of water.
  • P302 + P361 + P354If on skin: Take off immediately all contaminated clothing. Immediately rinse with water for several minutes.
  • P303 + P361 + P353If on skin (or hair): Take off immediately all contaminated clothing. Rinse skin with water or shower.
  • P304 + P340If inhaled: Remove person to fresh air and keep comfortable for breathing.
  • P305 + P354 + P338If in eyes: Immediately rinse with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
  • P316Get emergency medical help immediately.
  • P317Get medical help.
  • P318If exposed or concerned, get medical advice.
  • P320Specific treatment is urgent (see supplemental first aid instructions on the label).
  • P321Specific treatment (see supplemental first aid instructions on the label).
  • P330Rinse mouth.
  • P361 + P364Take off immediately all contaminated clothing. And wash it before reuse.
  • P363Wash contaminated clothing before reuse.
  • P370 + P378In case of fire: Use appropriate media to extinguish.
  • P391Collect spillage.
  • P403 + P233Store in a well-ventilated place. Keep container tightly closed.
  • P403 + P235Store in a well-ventilated place. Keep cool.
  • P405Store locked up.
  • P501Dispose of contents and container in accordance with local regulations.
UN number
UN 2396
Transport hazard class
3
Packing group
II

GHS classification summary, not a safety data sheet (SDS). Classifications can differ by supplier, grade and concentration. Always check the supplier's SDS.

Full safety data and first aid

Methacrolein suppliers

Sponsored listings first, then the documented ranking: membership, verification, replies, completeness, freshness and ratings

All 9 suppliers
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Where suppliers are based

9 suppliers in 3 countries

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Methacrolein price

Indicative price range per kg from live supplier offers

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Uses and applications

What the substance is used for, by industry and function

Chemical intermediate, comonomer in resin prodn.

Copolymers, resins.

As an intermediate in the production of methacrylonitrile or methacrylic acid.

How it is made

Catalytic oxidation of isobutylene

Cross-condensation of propionaldehyde and formaldehyde or the dehydrogenation of isobutyraldehyde.

Regulatory status

Inventories, regulations and trade controls that list this substance

United States

  • TSCA inventory (USA)
    Status: Active in US commerce

HS code and trade data

Customs classification and reported world trade statistics

Global trade

World import and export statistics for the HS code Methacrolein is traded under.

HS 2912.19Indicative HS code

Acyclic aldehydes without other oxygen function, other

World exports in 2024
$679M
+4.8% vs 2023, imports $743M
2019 to 2024
Top exporters
  1. Germany22.0%
  2. China21.2%
  3. United States18.5%
Top importers
  1. United States13.1%
  2. Germany9.6%
  3. Belgium8.2%
Reported customs values in USD, not prices.Full trade data

The HS code shown for Methacrolein is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

Quick answers about Methacrolein, based on the data on this page

What is Methacrolein?

Methacrylaldehyde appears as a colorless liquid. Less dense than water. May be toxic by ingestion, inhalation and skin absorption. Severely irritating to skin and eyes. Used to make plastics.

What is the CAS number of Methacrolein?

The CAS registry number of Methacrolein is 78-85-3.

What is the molecular formula and weight of Methacrolein?

The molecular formula of Methacrolein is C4H6O and its molar mass is 70.09 g/mol.

What is Methacrolein used for?

Chemical intermediate, comonomer in resin prodn. Copolymers, resins. As an intermediate in the production of methacrylonitrile or methacrylic acid.

Is Methacrolein hazardous?

Methacrolein carries the GHS signal word "Danger". Main hazards: highly flammable liquid and vapour, toxic if swallowed, toxic in contact with skin. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of Methacrolein?

Methacrolein is usually classified under HS code 291219 (Acyclic aldehydes without other oxygen function, other). This is indicative, confirm it with your customs broker before shipping.

Where can I buy Methacrolein?

CompoundList lists 9 suppliers of Methacrolein in China, United States and Canada. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

What is the price of Methacrolein?

Suppliers quote Methacrolein on request because prices depend on grade, purity, quantity and destination. A free request on CompoundList gets you several quotes to compare.

Guides for buyers

Practical guides that help when you source, ship or handle Methacrolein

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Data last updated 7 Oct 2026. Details may have changed, please confirm them with the supplier. Report an error on this page
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