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Methacrolein

HCID 6562
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Basic information

CAS
78-85-3
Standard SMILES
C=C(C)C=O
InChIKey
STNJBCKSHOAVAJ-UHFFFAOYSA-N
Molecular formula
C4H6O
Average molar mass
70.09 g/mol
Monoisotopic mass
70.04186481

Overview

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.

Names & identifiers

Preferred name
Methacrolein
IUPAC
2-methylprop-2-enal
English name
2-Methylacrolein
Molecular formula
C4H6O
Molecular weight
70.08984

Names & synonyms

METHACROLEINMethacrylaldehyde78-85-32-Methyl-2-propenal2-Methylacrolein2-Methylprop-2-enalIsobutenal2-Propenal, 2-methyl-2-Methylpropenal2-MethylenepropanalMethylacrylaldehydeAcrolein, 2-methyl-
Show more names
Methacrylic aldehydealpha-MethylacroleinMethakrylaldehydDTXSID00525409HRB24892HNSC-82602-FORMYL-1-PROPENEmethylacrolein

Database identifiers

CAS
78-85-3
PubChem CID
6562
DTXSID
DTXSID0052540
ChEMBL
CHEMBL4063095
ChEBI
CHEBI:88384
UNII
9HRB24892H
EC Number
201-150-1
Nikkaji
J1.484B

Properties

Computed structural properties

XLogP
0.7
Topological polar surface area
17.1 Ų
Hydrogen bond donors
0
Hydrogen bond acceptors
1
Rotatable bonds
1
Heavy atoms
5
Formal charge
0
Complexity
54.7

Experimental & physicochemical properties

Chemical Classes · 2 items

Other Classes -> Aldehydes

Flammable agents - 3rd degree

SpringerMaterials PropertiesCoriolis coupling
Density · 3 items

0.849 @ 25 °C/4 °C

Relative density (water = 1): 0.8

0.830 @ 20°C

Viscosity · 2 items

0.49 mPa.s @ 20 °C

0.59 mm²/s at 20 °C

Color/FormCOLORLESS LIQUID
Solubility · 3 items

MISCIBLE WITH WATER, ETHANOL, ETHER

Water solubility = 5.9% (59,000 mg/L) at 20 °C

Solubility in water, g/100ml at 20 °C: 6 (soluble)

Flash Point · 3 items

35 °F (NFPA, 2010)

35 °F (2 °C) (OPEN CUP)

-15 °C

Boiling Point · 2 items

68.4 °C

68 °C

Safety & regulation

Safety information is for reference only and does not replace the supplier’s Safety Data Sheet (SDS), applicable regulations, or professional assessment.

GHS classification

GHS Classification · 6 items

Danger

H225 (93.5%): Highly Flammable liquid and vapor [Danger Flammable liquids]

P203, P210, P233, P240, P241, P242, P243, P260, P262, P264, P264+P265, P270, P271, P273, P280, P284, P301+P316, P301+P330+P331, P302+P352, P302+P361+P354, P303+P361+P353, P304+P340, P305+P354+P338, P316, P317, P318, P320, P321, P330, P361+P364, P363, P370+P378, P391, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 170 reports by companies from 11 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Danger

H225: Highly Flammable liquid and vapor [Danger Flammable liquids]

Hazard information

Regulatory Information · 3 items

Chemical: 2-Propenal, 2-methyl-

REACH registered substance: Methacrylaldehyde (EC: 201-150-1)

The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)

DOT LabelFlammable Liquid Poison
Fire Hazards · 3 items

Excerpt from ERG Guide 131 [Flammable Liquids - Toxic; polymerization hazard]:

· HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames.

Highly flammable. Vapour/air mixtures are explosive.

Fire PotentialFIRE HAZARD: DANGEROUS, WHEN EXPOSED TO HEAT, FLAME OR OXIDIZERS. ...CAN REACT VIGOROUSLY WITH OXIDIZING MATERIALS.
Health Hazards · 2 items

Excerpt from ERG Guide 131 [Flammable Liquids - Toxic; polymerization hazard]:

Chemistry & industry

Pharmacology

Metabolism/Metabolites · 2 items

Aldehydes are readily oxidized to organic acids, which, in turn, can serve as substrates for fatty acid oxidation pathways and the Krebs cycle. ... Oxidation of aldehydes is catalyzed by aldehyde dehydrogenase, which has been found in the brain, erythrocytes, liver, kidney, heart, and placenta. /Aldehydes/

... The detoxification of aldehydes can be seen to proceed basically via two routes: (1) an oxidation to yield readily metabolized acids; (2) inactivation by reaction with sulfhydryl groups, particularly glutathione. Under conditions that either deplete glutathione levels, or that result in an inhibition of aldehyde dehydrogenase (for example, Antabuse treatment), the acute and chronic effects of aldehyde toxicity might be more fully expressed. /Aldehydes/

Uses & manufacturing

Uses · 4 items

Used as a chemical intermediate and a monomer to produce resins; [HSDB]

CHEMICAL INTERMEDIATE; COMONOMER IN RESIN PRODN

Copolymers, resins.

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

Methods of Manufacturing · 2 items

CATALYTIC OXIDATION OF ISOBUTYLENE

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

Formulations/PreparationsShipped with 0.1% hydroquinone, as polymerization inhibitor
General Manufacturing Information · 2 items

2-Propenal, 2-methyl-: ACTIVE

Development of more productive catalysts for propylene oxidation, which were not advantages for isobutylene oxidation, and failure of growth in the commercial use of methacrolein contributed to the discontinuance of the manufacture of methacrolein.

Related reactions

103 records
New reaction record
HRID 25929 reaction equation
HRID 25929As productuspto-grants-1979_04
HRID 26791 reaction equation
HRID 26791As reactantuspto-grants-1979_04
HRID 226278 reaction equation
HRID 226278As productuspto-grants-2009_07
HRID 351430 reaction equation
HRID 351430As reactantuspto-grants-2007_02
HRID 351435 reaction equation
HRID 351435As reactantuspto-grants-2007_02
HRID 374003 reaction equation
HRID 374003As reactantuspto-grants-1992_11
HRID 378527 reaction equation
HRID 378527As productuspto-grants-2000_02
HRID 396762 reaction equation
HRID 396762As reactantuspto-grants-2003_08
Page 1 of 13

Compound notes

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Decomposition
DANGEROUS; ON DECOMPOSITION, EMITS TOXIC FUMES...
Melting Point · 3 items

-81 °C

-81 °C

-81 °C

Vapor Density · 2 items

2.4 (AIR= 1)

Relative vapor density (air = 1): 2.42

Vapor Pressure · 4 items

155.0 [mmHg]

155 mm Hg @ 25 °C

Vapor pressure, kPa at 20 °C: 16

120 [mm Hg] @20 °C

Physicochemical properties

Melting point
-81 °C · -81 °C
Boiling point
68.4 °C · 68.4 °C
Density
0.849 g/cm3 · 0.849 g/cm3(Temp: 25 °C)
Symbol(GHS)
2 · GHS02,GHS05,GHS06,GHS08,GHS09
Signal word
Danger
Hazard statements
225 · H225-H301+H311-H314-H330-H341-H410
Precautionary statements
210 · P210-P273-P280-P303+P361+P353-P304+P340+P310-P305+P351+P338
RIDADR
2396 · UN 2396
HazardClass
3 · 3
PackingGroup
II

· TOXIC; may be fatal if inhaled, ingested or absorbed through skin.

Hazards Summary · 1 item

Like acrolein (VP= 274; LC50 (mouse) = 66 ppm; LCLo (human) = 5.5 ppm), methacrolein (VP = 154; LCLo (mouse) = 125 ppm) is a skin and respiratory tract irritant with the potential to cause acute lung injury; [HSDB] Methacrylaldehyde, stabilized (UN2396) has warning of explosive polymerization; [ERG 2016]

DOT ID and Guide2396 131P
Reactive GroupAldehydes
UN ClassificationUN Hazard Class: 3; UN Subsidiary Risks: 6.1; UN Pack Group: II
TSCA Requirements · 2 items

Section 8(a) of TSCA requires manufacturers of this chemical substance to report preliminary assessment information concerned with production, use, and exposure to EPA as cited in the preamble in 51 FR 41329.

Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. 2-methyl-2-propenal is included on this list.

FIFRA Requirements//fifr-a//
Reactivity AlertsHighly Flammable

Safety & protection

Fire Fighting · 2 items

Excerpt from ERG Guide 131 [Flammable Liquids - Toxic; polymerization hazard]:

Use water spray, powder, alcohol-resistant foam, carbon dioxide. In case of fire: keep drums, etc., cool by spraying with water.

First Aid Measures · 4 items

Fresh air, rest.

Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer for medical attention .

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Refer for medical attention .

Accidental Release Measures · 2 items

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

First Aid · 2 items

Excerpt from ERG Guide 131 [Flammable Liquids - Toxic; polymerization hazard]:

General First Aid:

Safe StorageFireproof. Separated from strong oxidants, acids, bases and food and feedstuffs. Cooled. Keep in the dark. Well closed. Keep under inert gas. Store only if stabilized. Provision to contain effluent from fire extinguishing.
Exposure Control and Personal Protection· Wear positive pressure self-contained breathing apparatus (SCBA).
Fire Fighting ProceduresCARBON DIOXIDE, ALC FOAM, FOAM, DRY CHEMICAL.
Nonfire Spill ResponseExcerpt from ERG Guide 131 [Flammable Liquids - Toxic; polymerization hazard]:
Disposal Methods · 1 item

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

Spillage Disposal · 1 item

Consult an expert! Remove all ignition sources. Ventilation. Personal protection: complete protective clothing including self-contained breathing apparatus. Do NOT let this chemical enter the environment. Do NOT wash away into sewer. Collect leaking and spilled liquid in sealable containers as far as possible. Absorb remaining liquid in sand or inert absorbent. Wash away remainder with plenty of water. Then store and dispose of according to local regulations.

Preventive MeasuresPRECAUTIONS FOR HANDLING REACTIVE UNSATURATED ALDEHYDES SUCH AS...METHACROLEIN...SHOULD BE SAME AS THOSE FOR OTHER HIGHLY ACTIVE EYE & PULMONARY IRRITANTS...
Isolation and Evacuation · 2 items

Excerpt from ERG Guide 131 [Flammable Liquids - Toxic; polymerization hazard]:

Immediate precautionary measure

Toxicology

Body BurdenMethacrolein has been qualitatively detected in one out of 12 samples of human adipose tissue from a 0-14 age group in the Southern Region(1).
Environmental Fate · 3 items

TERRESTRIAL FATE: Based on a recommended classification scheme(1), an estimated Koc value of 11.3(SRC), determined from an experimental water solubility(2) and a recommended regression-derived equation(3), indicates that methacrolein will have very high mobility in soil(SRC). Volatilization of methacrolein may be important from moist soil surfaces(SRC) given an estimated Henry's Law constant of 2.86X10-4 atm-cu m/mole, calculated from experimental values of vapor pressure(4) and water solubility(2), and from dry soil surfaces(SRC) based on an experimental vapor pressure of 155 mm Hg(4). Insufficient data are available to determine the rate or importance of biodegradation of methacrolein in soil(SRC).

AQUATIC FATE: Based on a recommended classification scheme(1), an estimated Koc value of 11.3(SRC), determined from an experimental water solubility(2) and a recommended regression-derived equation(3), indicates that methacrolein may not adsorb to suspended solids and sediment(SRC) in the water. Methacrolein may volatilize from water surfaces based on an estimated Henry's Law constant of 2.86X10-4 atm-cu m/mole(SRC), calculated from experimental values of vapor pressure(4) and water solubility(2). Estimated half-lives for a model river and model lake are 5 hours and 4 days, respectively(3,SRC). An estimated BCF value of 1.4(3,SRC), from an experimental water solubility(2), suggests that methacrolein will not bioconcentrate in aquatic organisms(SRC) according to a recommended classification scheme(5). Insufficient data are available to determine the rate or importance of biodegradation of methacrolein in water(SRC).

ATMOSPHERIC FATE: According to a suggested classification scheme(1), an experimental vapor pressure of 155 mm Hg at 25 °C(2) indicates that methacrolein will exist in the vapor phase in the ambient atmosphere. Vapor-phase methacrolein is degraded in the atmosphere by reaction with photochemically produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be about 11.5 hours(3,SRC). Vapor-phase methacrolein is also degraded in the atmosphere by reaction with ozone(SRC); the half-life for this reaction in air is estimated to be about 10.5 days(4,SRC). Methacrolein reacts very quickly in air with oxygen forming peroxides and acids(5). Methacrolein is formed from the gas-phase reaction of ozone with isoprene with a formation yield of 0.387(6).

Food Survey ValuesMethacrolein has been qualitatively detected as a volatile component of Chickpea (Cicer arietinum L) seed(1).
Adverse EffectsToxic Pneumonitis - Inflammation of the lungs induced by inhalation of metal fumes or toxic gases and vapors.
Exposure RoutesThe substance can be absorbed into the body by inhalation of its vapour, through the skin and by ingestion.
Plant ConcentrationsMethacrolein is emitted from Bay-leaved Willow, Aspen, Balsam poplar, European oak, Scots pine, and European larch(1).
Signs and Symptoms · 3 items

Cough. Sore throat. Burning sensation.

Redness. Pain.

Redness. Pain. Burns. Watering of the eyes.

Effluent Concentrations · 1 item

Methacrolein has been reported to be released from gasoline exhaust(1). Methacrolein is formed from burning polyethylene which may occur in fire situations(2). Methacrolein emissions from a single-cylinder, production-type engine using isooctane fuel were 21 and less than 1 mole fraction with a 0.9 and 1.15 fuel-air equivalence ratio, respectively(3). Methacrolein has been detected as an emission from liquid floor wax(4). Methacrolein made up 1.6% of the total hydrocarbons released from a pulse flame combustor using methyl-t-butyl ether as fuel(5).

ICSC Environmental DataThe substance is very toxic to aquatic organisms. It is strongly advised not to let the chemical enter into the environment.
Soil Adsorption/Mobility · 1 item

The Koc of methacrolein is estimated as approximately 11.3(SRC), using an experimental water solubility of 50,000 mg/L(1) and a regression-derived equation(2,SRC). According to a recommended classification scheme(3), this estimated Koc value suggests that methacrolein has very high mobility in soil(SRC).

Atmospheric Concentrations · 2 items

URBAN/SUBURBAN: Air samples from four urban sites in Stockholm contained methacrolein at the following average concentrations: 0.71, 0.19, 0.11, and 0.13 ppb(1).

RURAL/REMOTE: In a rural site, 12 km outside of Stockholm, the average methacrolein concentration was 0.06 ppb(1).

Human Toxicity Excerpts · 3 items

METHACROLEIN WAS LESS CILIOSTATIC (IRRITATING TO TRACHEAL MUCOSA) THAN ACROLEIN.

The low molecular weight aldehydes, the halogenated aliphatic aldehydes, and the unsaturated aldehydes are particularly irritating. The mucus membranes of the nasal and oral passages and the upper respiratory tract are affected, producing a burning sensation, an increased ventilation rate, bronchial constriction, choking, and coughing. The eyes tear, and a burning sensation is noted on the skin of the face. During low exposures, the initial discomfort may abate after 5 to 10 minutes but will recur if exposure is resumed after an interruption. /Aldehydes/

...STRONG IRRITANT.

Regulatory information

TSCA Requirements · 2 items

Section 8(a) of TSCA requires manufacturers of this chemical substance to report preliminary assessment information concerned with production, use, and exposure to EPA as cited in the preamble in 51 FR 41329.

Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. 2-methyl-2-propenal is included on this list.

FIFRA Requirements//fifr-a//

Safety data

ridadr
UN 2396
Signal word
Danger
Symbol(GHS)
GHS02,GHS05,GHS06,GHS08,GHS09
hazard_class
3
packing_group
II
Hazard statements
H225-H301+H311-H314-H330-H341-H410
Precautionary statements
P210-P273-P280-P303+P361+P353-P304+P340+P310-P305+P351+P338