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Methacrylic acid

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Methacrylic acid Basic information

Product Name:
Methacrylic acid
CAS:
79-41-4
MF:
C4H6O2
MW:
86.09
EINECS:
201-204-4
Mol File:
79-41-4.mol
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Methacrylic acid Chemical Properties

Melting point:
16 °C
Boiling point:
163 °C(lit.)
Density 
1.015 g/mL at 25 °C(lit.)
vapor density 
>3 (vs air)
vapor pressure 
1 mm Hg ( 20 °C)
refractive index 
n20/D 1.431(lit.)
Flash point:
170 °F
storage temp. 
Indoors
pka
pK1:4.66 (25°C)
form 
Liquid
color 
Clear
Odor
Repulsive
PH
2.0-2.2 (100g/l, H2O, 20℃)
explosive limit
1.6-8.7%(V)
Water Solubility 
9.7 g/100 mL (20 ºC)
Sensitive 
Moisture & Light Sensitive
Merck 
14,5941
BRN 
1719937
Exposure limits
TLV-TWA 20 ppm (~70 mg/m3) (ACGIH).
Stability:
May be stabilized by the addition of MEHQ (Hydroquinone methyl ether, ca. 250 ppm) or hydroquinone. In the absence of a stabilizer this material will readily polymerize. Combustible. Incompatible with strong oxidizing agents, hydrochloric acid.
InChIKey
CERQOIWHTDAKMF-UHFFFAOYSA-N
CAS DataBase Reference
79-41-4(CAS DataBase Reference)
NIST Chemistry Reference
2-Propenoic acid, 2-methyl-(79-41-4)
EPA Substance Registry System
Methacrylic acid (79-41-4)
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Safety Information

Hazard Codes 
C
Risk Statements 
21/22-35-37-20/21/22
Safety Statements 
26-36/37/39-45
RIDADR 
UN 2531 8/PG 2
WGK Germany 
1
RTECS 
OZ2975000
Autoignition Temperature
752 °F
TSCA 
Yes
HS Code 
2916 13 00
HazardClass 
8
PackingGroup 
II
Hazardous Substances Data
79-41-4(Hazardous Substances Data)
Toxicity
LD50 orally in Rabbit: 1320 mg/kg

MSDS

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Methacrylic acid Usage And Synthesis

Description

Methacrylic acid, abbreviated MAA, is an organic compound. This colourless, viscous liquid is a carboxylic acid with an acrid unpleasant odor. It is soluble in warm water and miscible with most organic solvents. Methacrylic acid is produced industrially on a large scale as a precursor to its esters, especially methyl methacrylate (MMA) and poly(methyl methacrylate) (PMMA). The methacrylates have numerous uses, most notably in the manufacture of polymers with trade names such as Lucite and Plexiglas. MAA occurs naturally in small amounts in the oil of Roman chamomile.

Chemical Properties

Methacrylic acid is a colorless liquid.

Chemical Properties

colourless liquid or crystals with an unpleasant odour.

Uses

Monomer for large-volume resins and polymers, organic synthesis. Many of the polymers are based on esters of the acid, as the methyl, butyl, or isobutyl esters.

Uses

Methacrylic acid is used in the manufactureof methacrylate resins and plastics.

Production Methods

More than 3 million tons of methyl methacrylate (MMA) are produced annually. In one route, acetone cyanohydrin is converted to methacrylamide sulfate using sulfuric acid. That compound is hydrolyzed to methacrylic acid, or it can be converted into methyl methacrylate in one step. In the second route, isobutylene or tertbutanol are oxidized to methacrolein, then methacrylic acid.Methacrolein for this purpose can also be obtained from formaldehyde and ethylene. Isobutyric acid can also be dehydrogenated to methacrylic acid.
Methacrylic acid was first obtained in the form of its ethyl ester by treating phosphorus pentachloride with oxyisobutyric ester.[2] It is, however, more readily obtained by boiling citra- or mesobrompyrotartaric acids with alkalis. It crystallizes in prisms. When fused with an alkali, it forms propanoic acid. Sodium amalgam reduces it to isobutyric acid. A polymeric form of methacrylic acid was described in 1880.

Definition

ChEBI: An alpha,beta-unsaturated monocarboxylic acid that is acrylic acid in which the hydrogen at position 2 is substituted by a methyl group.

General Description

A clear colorless liquid (or low-melting solid) with a pungent odor. Corrosive to metals and tissue. Flash point 170°F. Melting point 61°F. May polymerize exothermically if heated or contaminated. If the polymerization takes place inside a container, the container may rupture violently. Less dense than water. Vapors heavier than air. Used to make plastics.

Air & Water Reactions

Soluble in water.

Reactivity Profile

Methacrylic acid reacts with strong oxidizing agents. Presents a storage hazard: violent exothermic polymerizations leading to explosion can occur spontaneously, particularly at low inhibitor or stabilizer concentrations [Anon., CISHC Chem. Safety Summ., 1979, 50, p. 34; Bond, J., Loss Prev. Bull., 1991, 101, p. 1].

Hazard

Toxic material. Strong irritant to eyes and skin. Questionable carcinogen.

Health Hazard

INHALATION: Severe irritation to respiratory tract. EYES: Short contact can cause severe damage. SKIN: Causes severe irritation and burns. Ingestion: High hazard - may cause death or permanent injury on short exposure to small quantities. OTHER: May affect blood pressure temporarily.

Health Hazard

Methacrylic acid is a highly corrosive liquid.Contact with eyes can result in blindness.Skin contact may produce burns. No inhalation toxicity was observed in rats. Exposureto its vapors may produce skin and eye irritation, which can be mild to moderate. Adermal LD50 value in rabbits is 500 mg/kg.

Fire Hazard

Combustible liquid; flash point (open cup) 76°C (170°F); vapor pressure <0.1 torr at 20°C (68°F). Fire-extinguishing agent: water spray, “alcohol” foam, dry chemical, or CO2; use a water spray to dilute and flush the spill and to disperse the vapors.
Methacrylic acid polymerizes readily. The reaction is exothermic. The rate of reaction accelerates on heating, which may result in violent rupture of closed containers. The polymerization may be inhibited with a trace quantity of hydroquinone and hydroquinone monomethyl ether (Aldrich 2006). The acid may be stored safely below its melting point.

Safety Profile

Poison by intraperitoneal route. Moderately toxic by ingestion and skin contact. Corrosive to skin, eyes, and mucous membranes. Mutation data reported. Flammable when exposed to heat, flame, or oxidizers. A storage hazard; exothermic polymerization may occur spontaneously. To fight fire, use alcohol foam, spray, mist, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes.

Potential Exposure

Methacrylic acid is used in preparation of methacrylates and carboxylated polymers; in the production of the material or its alkyl esters, as monomers or comonomers for synthetic resins for the production of plastic sheets, moldings, and fibers.

Carcinogenicity

Methacrylic acid was considered by the IARC Working Groups, but monographs were not prepared because adequate data on its carcinogenicity were not available. The IUCLID database reports a dermal application study (dose unspecified) of mice treated three times per week for 4 months and then observed for their lifetimes. No excess dermal tumors were observed.

Shipping

UN2531 Methacrylic acid, stabilized, Hazard class: 8; Labels: 8-Corrosive material.

Purification Methods

Aqueous methacrylic acid (90%) is saturated with NaCl (to remove the bulk of the water), then the organic phase is dried with CaCl2 and distilled under vacuum. Polymerisation inhibitors should be added to the distillate and include 0.25% p-methoxyphenol, 0.1% hydroquinone, or 0.05% N,N'-diphenyl-p-phenylenediamine. [Beilstein 2 IV 1518.]

Incompatibilities

Vapor may form explosive mixture with air. A reducing agent; incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Aqueous solution is strongly acidic: incompatible with strong acids; caustics, ammonia, amines, isocyanates, alkylene oxides; epichlorohydrin. Will polymerize readily from heating above 59F/15C, or due to the presence of light, oxidizers (e.g., peroxides); or in the presence of traces of hydrochloric acid, with fire or explosion hazard. Attacks metals. Note: Typically contains 100 ppm of monomethyl ether hydroquinone (150-76-5) as an inhibitor to prevent polymerization

Waste Disposal

Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed.

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Methacrylic acidSupplierMore

J & K SCIENTIFIC LTD.
Tel:
010-82848833- ;010-82848833-
Email:
jkinfo@jkchemical.com;market6@jkchemical.com
Meryer (Shanghai) Chemical Technology Co., Ltd.
Tel:
21-61259100-
Email:
sh@meryer.com
Alfa Aesar
Tel:
400-610-6006; 021-67582000
Email:
saleschina@alfa-asia.com
TCI (Shanghai) Development Co., Ltd.
Tel:
021-67121386 / 800-988-0390
Email:
Sales-CN@TCIchemicals.com
Beijing dtftchem Technology Co., Ltd.
Tel:
010-60275820-
Email:
dtftchem@sina.com;
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