ChemicalBook > Product Catalog > Organic Chemistry > Carboxylic acids and derivatives > Acyclic carboxylic acid > Methacrylic acid
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 n
- Flash point:170 °F
- storage temp. Indoors
- pkapK1:4.66 (25°C)
- form Liquid
- color Clear
- PH2.0-2.2 (100g/l, H2O, 20℃)
- explosive limit1.6-8.7%(V)
- Water Solubility 9.7 g/100 mL (20 ºC)
- Sensitive Moisture & Light Sensitive
- Merck 14,5941
- BRN 1719937
- Exposure limitsTLV-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.
- CAS DataBase Reference79-41-4(CAS DataBase Reference)
- NIST Chemistry Reference2-Propenoic acid, 2-methyl-(79-41-4)
- EPA Substance Registry SystemMethacrylic acid (79-41-4)
- 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 Temperature752 °F
- TSCA Yes
- HS Code 2916 13 00
- HazardClass 8
- PackingGroup II
- Hazardous Substances Data79-41-4(Hazardous Substances Data)
- ToxicityLD50 orally in Rabbit: 1320 mg/kg
Methacrylic acid Usage And Synthesis
- DescriptionMethacrylic 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 PropertiesMethacrylic acid is a colorless liquid.
- Chemical Propertiescolourless liquid or crystals with an unpleasant odour.
- UsesMonomer 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.
- UsesMethacrylic acid is used in the manufactureof methacrylate resins and plastics.
- UsesManufacture of methacrylic resins and plastics
- Production MethodsMore 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. 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.
- DefinitionChEBI: An alpha,beta-unsaturated monocarboxylic acid that is acrylic acid in which the hydrogen at position 2 is substituted by a methyl group.
- General DescriptionA 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 ReactionsSoluble in water.
- Reactivity ProfileMethacrylic 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].
- HazardToxic material. Strong irritant to eyes and skin. Questionable carcinogen.
- Health HazardINHALATION: 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 HazardMethacrylic 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 HazardCombustible 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 ProfilePoison 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 ExposureMethacrylic 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.
- CarcinogenicityMethacrylic 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.
- ShippingUN2531 Methacrylic acid, stabilized, Hazard class: 8; Labels: 8-Corrosive material.
- Purification MethodsAqueous 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.]
- IncompatibilitiesVapor 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 DisposalDissolve 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.
Methacrylic acid Preparation Products And Raw materials
- Preparation ProductsCarbomer 940Isobutyric acid2-[3-(2H-Benzotriazol-2-yl)-4-hydroxyphenyl]ethyl methacrylateDOWEX(R) 1X8Isobutyryl chlorideStyrene-acrylic latexEAM resin adhesive modified with diisocyanate for orthodontiasCC-2SH adhesive composite used in anterior teethButyl methacrylatediagnosis latex microsphors combining anti fetoproteinPOLY(METHYL METHACRYLATE)optical plastics based on coplymer of diene macromoleculeMethacrylamideplastic optical fiberamphoteric polyacrylamide2-BROMOPROPENE2-Hydroxyethyl methacrylateimpregnanting agent for leatherGlycidyl methacrylatemodified filling agent SBRcarboxyl type cation exchange resinEthyl methacrylatemethylacrylate polycyclic norbornene and polymethyl methacrylate copolymer (ARTON)thickening agent PASIsobutyl methacrylateTHERMOPLASTIC ACRYLIC RESIN2-Hydroxypropyl methacrylate transparenting agent for paper6731 acrylic vibration damping coating2-(Diethylamino)ethyl methacrylate5,5-dibutyldihydrofuran-2(3H)-one Ethylene dimethacrylate
- Raw materialsSulfuric acid Sodium cyanideISOBUTYLENEHYDROGEN CYANIDEAcetone cyanohydrin ISOBUTANEMethacrylonitrilemethacrylammonium hydrogen sulphate Methyl 2-hydroxyisobutyrate
- Methacrylic acid Methacrolein 2,4,4-TRIMETHYL-1-PENTENE POLYMETHACRYLATE POLYISOBUTYLENE tert-Butyl methacrylate Isobutenyl sulfide Citric acid Methyl propiolate 2-Methyl-2-propenoic acid, 2-hydroxyethyl ester 2-Methyl-2-propenoic acid methyl ester,Methyl ester of 2-methyl-2-propenoic acid,2-Methyl-2-propenoic acid methyl Glycine Ascoric Acid polyisobutylene rubber phosphoric acid Ethyl 2-(Chlorosulfonyl)acetate Ethylene dimethacrylate POLY(ETHYL METHACRYLATE-CO-METHYL METHACRYLATE)
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