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Synthetic aroma chemicals

Crotonaldehyde

Also known as 2-Butenal, Crotonal, Crotylaldehyde

CAS 4170-30-3Formula C4H6OMolar mass 70.09 g/molEC 204-647-1
GHS signal word: Danger. Pictograms: Flammable, Corrosive, Acute toxicity (severe), Serious health hazard 34 suppliers listed
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Crotonaldehyde chemical structure, C4H6O, CAS 4170-30-3
2D chemical structure

Key facts

What buyers check first

All properties
Appearance
Water-white, mobile liquid
Melting point
-69 °C
Boiling point
102.2 °C
Density
0.8516 g/cm³ at 20 °C
Flash point
13 °C
HS code
291219
Category
Synthetic aroma chemicals
UN number
UN 1143
Illustrative photo, clear liquid in sealed glass ampoules on a laboratory bench
Typical packagingIllustrative packaging image, not the actual product

What is Crotonaldehyde?

Plain description, key identifiers and synonyms

Crotonaldehyde is an enal consisting of propene having a formyl group at the 1-position.

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
(E)-but-2-enal
CAS number
4170-30-3 CAS number cross-checkedOther or deprecated CAS: 123-73-9
EC numbers
204-647-1, 224-030-0
Molecular formula
C4H6O
UNII
6PUW625907, 9G72074TUW
MDL number
MFCD00007003
INCI name
CROTONALDEHYDE
InChIKey
MLUCVPSAIODCQM-NSCUHMNNSA-N
InChI
InChI=1S/C4H6O/c1-2-3-4-5/h2-4H,1H3/b3-2+
Canonical SMILES
CC=CC=O
Isomeric SMILES
C/C=C/C=O

Synonyms

  • 2-Butenal
  • Crotonal
  • Crotylaldehyde
  • (E)-but-2-enal
  • (2E)-but-2-enal
  • Crotonic aldehyde
  • Methylpropenal
  • 1-Formylpropene
  • beta-Methylacrolein
  • Propylene aldehyde
  • 2-Butenaldehyde
  • Krotonaldehyd
  • beta-Methyl acrolein
  • RCRA waste number U053
  • trans-2-butenaldehyde
  • UN 1143
  • 3-Methylacrolein
  • trans-Crotonaldehyde
  • (E)-Crotonaldehyde
  • trans-2-Butenal
  • 2-Butenal, (2E)-
  • Aldehyde crotonique
  • Topanel
  • trans- Crotonal
  • Topanel CA
Show all 37 synonyms
  • 2-Butenal, (E)-
  • trans-but-2-enal
  • E-2-Butenal
  • Crotonaldehyde, (E)-
  • 2-Butenal, inhibited
  • (E)-Crotonaldehyde (IUPAC)
  • Crotonaldehyde, inhibited
  • 3-Methylacrolein, inhibited
  • RCRA waste no. U053
  • Butenal
  • trans-Crotonaldehyde, trans-2-Butenal
  • (E)-2-Butenal (~0.1% MEHQ)

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
Water-white, mobile liquidexp.
Odour
Pungent, suffocating odorexp.
Melting point
-69 °Cexp.
Boiling point
102.2 °Cexp.
Density
0.8516 g/cm³ at 20 °Cexp.
Flash point
13 °Cexp.
Autoignition temperature
232.2 °Cexp.
Solubility
Heat capacity: 0.7 ca/g Dimerizes under strong acid conditions, slowly oxidizes to crotonic acid. Solubility of water in crotonaldehyde (g/100g) at 20 °C: 9.5, at 5 °C: 19.2exp.
Vapour pressure
30 mm Hg at 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
342WNFPA 704 rating

Hazard statements

  • H225Highly flammable liquid and vapour.
  • H301Toxic if swallowed.
  • H311Toxic in contact with skin.
  • H315Causes skin irritation.
  • H318Causes serious eye damage.
  • H330Fatal if inhaled.
  • H335May cause respiratory irritation.
  • H341Suspected of causing genetic defects.
  • H373May cause damage to organs through prolonged or repeated exposure.
  • H400Very toxic to aquatic life.
Precautionary statements (38)
  • 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.
  • P261Avoid breathing 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.
  • P302 + P352If on skin: Wash with plenty of water.
  • 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.
  • P319Get medical help if you feel unwell.
  • P320Specific treatment is urgent (see supplemental first aid instructions on the label).
  • P321Specific treatment (see supplemental first aid instructions on the label).
  • P330Rinse mouth.
  • P332 + P317If skin irritation occurs: Get medical help.
  • P361 + P364Take off immediately all contaminated clothing. And wash it before reuse.
  • P362 + P364Take off contaminated clothing. And wash it 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 1143
Transport hazard class
6.1
Packing group
I

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

Crotonaldehyde suppliers

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All 34 suppliers
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Where suppliers are based

34 suppliers in 9 countries

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Crotonaldehyde price

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Uses and applications

What the substance is used for, by industry and function

Crotonaldehyde was formerly used in the manufacture of n-butanol, but currently, the most extensive use of crotonaldehyde is in the manufacture of sorbic acid. Crotonaldehyde has also been used as a warning agent in fuel gases, in the preparation of rubber accelerators, in leather tanning, as an alcohol denaturant, and as a stabilizer for tetraethyl-lead.

Manufacture of butyl alcohol, butyraldehyde, methoxybutyraldehyde, sorbic acid, maleic acid, crotonic acid, crotyl alcohol. In polymer chemistry: manufacture of resins and polyvinyl acetals, solvent for polyvinyl chloride, rubber antioxidant, increases rubber strength with ketones. In prepatation of insecticides and fertilizers.

Read more

In production of flavors.

Intermediate for n-butyl alcohol and 2-ethylhexyl alcohol, solvent, preparation of rubber accelerators, purification of lubricating oils, insecticides, tear gas, fuel-gas warning agent, organic synthesis, leather tanning, alcohol denaturant.

Chemical intermediate for n-butyl alcohol, quinaldine, crotonic acid, surface-active agents, textile & paper sizes, insecticides & flavoring agents, fuel-gas warning agent, solvent for polyvinyl chloride, alcohol denaturant, leather tanning agent.

Industrial uses: Intermediate.

Cosmetic ingredient, INCI name CROTONALDEHYDE(antioxidant, fragrance, perfuming)

Functional uses

  • Antioxidant
  • Deodorizer
  • Flavouring and nutrient
  • Fragrance
  • Processing aids not otherwise specified

Cosmetic functions

  • Antioxidant
  • Fragrance
  • Perfuming

Pharmacology

Crotonaldehyde is an unsaturated aldehyde with commercial applications, including the manufacture of sorbic acid, that is also found in tobacco smoke, gasoline and diesel engine exhausts, and smoke from wood burning. Airborne exposure to this chemical can cause eyes, nose, throat, and lung irritation.

How it is made

Aldol condensation of two molecules of acetaldehyde.

The usual method to produce crotonaldehyde is the aldol reaction of acetaldehyde followed by dehydration of the acetaldol and distillation. Typically the product is about 99% pure.

The usual method to produce crotonaldehyde is the aldol reaction of acetaldehyde followed by dehydration of the acetaldol and distillation. Typically the product is about 99% pure. (Crotonaldehyde)

Regulatory status

Inventories, regulations and trade controls that list this substance

Europe

  • EU harmonised classification (CLP Annex VI)
    Index no: 605-009-00-9[1]

Health and food

  • EU cosmetic ingredient inventory
  • EU Cosmetics Regulation Annex II, prohibited in cosmetics
    Name: Crotonaldehyde [1], (E)-crotonaldehyde [2], Ref no: 1065, Annex ref: II/1065

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 Crotonaldehyde 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 Crotonaldehyde is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

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

What is Crotonaldehyde?

Crotonaldehyde is an enal consisting of propene having a formyl group at the 1-position.

What is the CAS number of Crotonaldehyde?

The CAS registry number of Crotonaldehyde is 4170-30-3. Other or deprecated CAS numbers: 123-73-9.

What is the molecular formula and weight of Crotonaldehyde?

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

What is Crotonaldehyde used for?

Crotonaldehyde was formerly used in the manufacture of n-butanol, but currently, the most extensive use of crotonaldehyde is in the manufacture of sorbic acid.

Is Crotonaldehyde hazardous?

Crotonaldehyde 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 Crotonaldehyde?

Crotonaldehyde 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 Crotonaldehyde?

CompoundList lists 34 suppliers of Crotonaldehyde in India, China, United States, United Arab Emirates and 5 more. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

Where can I buy Crotonaldehyde in India?

12 suppliers in India list Crotonaldehyde on CompoundList. Filter the suppliers list by country and send a request to compare prices, grades and delivery times.

What is the price of Crotonaldehyde?

Suppliers quote Crotonaldehyde 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 Crotonaldehyde

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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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