Title: Methacrylic Acid
CAS Registry Number: 79-41-4
CAS Name: 2-Methyl-2-propenoic acid
Additional Names: a-methylacrylic acid
Molecular Formula: C4H6O2
Molecular Weight: 86.09
Percent Composition: C 55.81%, H 7.02%, O 37.17%
Literature References: Occurs in oil from Roman chamomile. Prepd by dehydration of a-hydroxyisobutyric acid: Crawford, US 2143941 (1939 to I.C.I.); by hypochlorite oxidation of methyl a-alkylvinyl ketone: Meitzner, US 2192142 (1940 to Rohm & Haas); by hydrolysis of acetone cyanohydrin: Crawford, GB 405699 (1932 to I.C.I.); by oxidation of methacrolein: Bauer, US 2153406 (1939 to Rohm & Haas). Toxicity study: W. Deichmann, J. Ind. Hyg. Toxicol. 23, 343 (1941). Review: J. W. Nemec, L. S. Kirch in Kirk-Othmer Encyclopedia of Chemical Technology vol. 15 (Wiley-Interscience, New York, 3rd ed., 1981) pp 346-376.
Properties: Long prisms, mp 16°, forming a corrosive liquid. Acrid, repulsive odor. d420 1.0153. bp760 163°; bp30 81°; bp12 63°. nD20 1.43143. Flash pt, open cup: 170°F (76°C). Sol in warm water; miscible with alc, ether. Polymerizes easily, especially on heating or in the presence of traces of HCl. The polymer forms a ceramic-looking mass, sol in abs alc, from which it is precipitated by ether.
Melting point: mp 16°
Boiling point: bp760 163°; bp30 81°; bp12 63°
Flash point: Flash pt, open cup: 170°F (76°C)
Index of refraction: nD20 1.43143
Density: d420 1.0153
Derivative Type: Methyl ester
CAS Registry Number: 80-62-6
Additional Names: Methyl methacrylate
Literature References: Review of carcinogenic risk: IARC Monographs 60, 445-474 (1994).
Properties: Polymerizes easily, forming a clear plastic known as Lucite, Plexiglas, Perspex. Sol in methyl ethyl ketone, tetrahydrofuran, esters, aromatic and chlorinated hydrocarbons. LD50 orally in rats: 8.4 g/kg (Deichmann).
Toxicity data: LD50 orally in rats: 8.4 g/kg (Deichmann)
CAUTION: Potential symptoms of overexposure to methacrylic acid or methyl methacrylate are irritation of eyes, skin, nose, throat, mucous membranes; dermatitis; eye and skin burns. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) pp 194, 214.
Use: In the manuf of methacrylate resins and plastics.