Methyl Methacrylate

methyl methacrylate [¦meth·əl mə′thak·rə‚lāt]

(organic chemistry)

CH₂C(CH₃)COOCH₃A flammable, colorless liquid, soluble in most organic solvents but insoluble in water; used as a monomer for polymethacrylate resins.

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methyl methacrylate

A tough, rigid, transparent acrylic plastic having good resistance to common solvents and acids; subject to crazing.

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Methyl Methacrylate 

a methyl ester of methacrylic acid, CH₂ = C(CH₃) — COOCH₃; a colorless liquid. Boiling point, 101°C; density, 0.936 g/cm3 at 20°C; solubility in water at 30°C, 1.5 percent (by weight). Freely soluble in alcohol and ethyl ether.

Methyl methacrylate hydrolyzes to form methacrylic acid, and upon heating with alcohols (with strong acids serving as catalysts), ester interchange takes place. This process is used in industry to manufacture several other methacrylic acid esters— for example, butyl methacrylate. Methyl methacrylate combines with chlorine, hydrogen, hydrogen bromide, amines, ammonia, mercaptans, amides, aliphatic nitro compounds, and hydrocyanic acid along its double bond. It polymerizes readily, yielding polymethyl methacrylate. Stabilizers (0.005–0.5 percent), such as hydroquinone and copper, are added to methyl methacrylate to prevent polymerization during storage.

Methyl methacrylate is usually prepared industrially from acetone and hydrocyanic acid, via acetone cyanohydrin, (CH₃)₂C(OH)—CN. It has a systemic, narcotic effect, and its vapors irritate the mucous membranes; the maximum permissible level in air is 0.05 mg per liter. Methyl methacrylate is mainly used in the manufacture of Plexiglas.

REFERENCES

Vaculik, P. Khimiia monomerov, vol. 1. Moscow, 1960. (Translated from Czech.)
Sorenson, W., and T. Campbell. Preparativnye melody khimiipolimerov. Moscow, 1963. (Translated from English.)