Methacrolein
Also known as: 2-Methyl-2-propenal, 2-Methylacrolein, Methacrylaldehyde, Isobutenal, Methylacrolein, 2-Methylpropenal, Methacraldehyde, Methacrylic aldehyde, α-Methylacrolein
Methacrolein (CAS 78-85-3) is a compound in the Aliphatic Hydrocarbons category listed in the Jingsj chemical database. It has the molecular formula C4H6O and a molecular weight of 70.090 g/mol. Key properties include a melting point of -81 °C, a boiling point of 68.0±0.0 °C at 760 mmHg, a density of 0.8±0.1 g/cm3 and a flash point of -15.0±0.0 °C. It is classified under GHS with signal word Danger and hazard statements H225 — Highly flammable liquid and vapour, H301 — Toxic if swallowed and H311 — Toxic in contact with skin. No supplier offers are currently listed; request a quote. Record last updated Aug 21, 2026.
- CAS No.
- 78-85-3
- Jingsj CID
- J-1088856-9
- Molecular Formula
- C4H6O
- Molecular Weight
- 70.090 g/mol
- Category
- Aliphatic Hydrocarbons
- Last updated
- 8/21/2026
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Request a quotePhysicochemical Properties
| Melting Point | -81 °C |
|---|---|
| Boiling Point | 68.0±0.0 °C at 760 mmHg |
| Density | 0.8±0.1 g/cm3 |
| Flash Point | -15.0±0.0 °C |
| Exact Mass | 70.041862 |
| PSA | 17.07000 |
| LogP | 0.54 |
| Additional Property | 2.4 (vs air) |
| Vapor Pressure | 142.3±0.1 mmHg at 25°C |
| Refractive Index | 1.385 |
| Additional Property | 6 g/100 mL (20 ºC) |
GHS Safety & Compliance
- H225 — Highly flammable liquid and vapour
- H301 — Toxic if swallowed
- H311 — Toxic in contact with skin
- H314 — Causes severe skin burns and eye damage
Frequently Asked Questions
What is the CAS number of Methacrolein?
The CAS number of Methacrolein is 78-85-3.
What are the molecular formula and molecular weight of Methacrolein?
Methacrolein has molecular formula C4H6O and molecular weight 70.090 g/mol.
Is Methacrolein hazardous?
Methacrolein has GHS signal word Danger and hazard statements H225 — Highly flammable liquid and vapour; H301 — Toxic if swallowed; H311 — Toxic in contact with skin.
What are the upstream and downstream products of Methacrolein?
For Methacrolein, Upstream Products: Isobutylene, Formaldehyde, Propionaldehyde; Downstream Products: 2-Methyl-2-propene-1,1-diol diacetate, 1,3,4-Trimethylcyclohex-3-enecarbaldehyde, Ethyl 2-hydroxy-5-methylbenzoate.
Data compiled from public chemical databases such as PubChem and supplier catalogs; supplier offers are provided by suppliers.
Last updated:
How to cite: Jingsj. "Methacrolein (CAS 78-85-3)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-1088856-9 (accessed 2026-11-09).
Data for reference only; verify product details with suppliers before purchase.