methyl methacrylate

Methyl methacrylate
IUPAC name methyl 2-methylpropenoate
Other names MMA, 2-(methoxycarbonyl)-1-propene
Identifiers
CAS number	80-62-6 Y
ChemSpider	6406 Y
UNII	196OC77688 Y
KEGG	C14527 N
ChEBI	CHEBI:34840 Y
ChEMBL	CHEMBL49996 Y
RTECS number	OZ5075000
Jmol-3D images	Image 1
SMILES O=C(OC)C(=C)C
InChI InChI=1S/C5H8O2/c1-4(2)5(6)7-3/h1H2,2-3H3 Y Key: VVQNEPGJFQJSBK-UHFFFAOYSA-N Y
Properties
Molecular formula	C5H8O2
Molar mass	100.12 g mol−1
Appearance	Colorless liquid
Density	0.94 g/cm³
Melting point	-48 °C, 225 K, -54 °F
Boiling point	101 °C, 374 K, 214 °F
Solubility in water	1.5 g/100 ml
Viscosity	0.6 cP at 20 °C
Structure
Dipole moment	1.6-1.97 D
Hazards
MSDS	External MSDS
Main hazards	Flammable
Flash point	2 °C (36 °F)
Autoignition temperature	435 °C (815 °F)
Supplementary data page
Structure and properties	n, εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
N (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Methyl methacrylate is an organic compound with the formula CH₂=C(CH₃)COOCH₃. This colourless liquid, the methyl ester of methacrylic acid (MAA) is a monomer produced on a large scale for the production of poly(methyl methacrylate) (PMMA).

Production

The compound is manufactured by several methods, the principal one being the acetone cyanohydrin (ACH) route, using acetone and hydrogen cyanide as raw materials. The intermediate cyanohydrin is converted with sulfuric acid to a sulfate ester of the methacrylamide, methanolysis of which gives ammonium bisulfate and MMA. Although widely used, the ACH route coproduces substantial amounts of ammonium sulfate. Some producers start with an isobutylene or, equivalently, tert-butanol, which is sequentially oxidized first to methacrolein and then to methacrylic acid, which is then esterified with methanol. Propene can be carbonylated in the presence of acids to isobutyric acid, which undergoes subsequent dehydrogenation.^[1] The combined technologies afford more than 3 billion kilograms per year. MMA can also be prepared from methyl propionate and formaldehyde.^[2]

Uses

The principal application, consuming approximately 80% of the MMA, is the manufacture of polymethyl methacrylate acrylic plastics (PMMA). Methyl methacrylate is also used for the production of the co-polymer methyl methacrylate-butadiene-styrene (MBS), used as a modifier for PVC. Another application is as cement used in total hip replacements as well as total knee replacements. Used as the "glue" by orthopedic surgeons to make the bone inserts fix into bone, it greatly reduces post-operative pain from the insertions but has a finite lifespan. Typically the lifespan of methylmethacrylate as bone cement is 20 years before revision surgery is required. Cemented implants are usually only done in elderly populations that require more immediate short term replacements. In younger populations, cementless implants are used before their lifespan is considerably longer ^[3] . Also used in fracture repair in small exotic animal species using internal fixation.

Initiators

Initiators for methyl methacrylate include AIBN, LPO, P-16, AND V-61.

Shortage

In 2010 the world experienced an MMA shortage, believed to be due to production facilities shutting down for economic reasons. One of the largest producers, Dow Chemical, surprised many purchasers when they announced a six month shut down of their plant that produced 60% of MMA.^[4]

See also

• Acrylate
• Methacrylates
• (Meth)acrylates
• PMMA

References

External links

• Chemical data on Chemicalland
• US Environmental Protection Agency, 1994 data
• Intox Cheminfo data
• Methacrylate Producers Association (MPA)
• National Pollutant Inventory - Methyl methacrylate fact sheet