Methacrylic acid

Methacrylic acid
Names
	Preferred IUPAC name 2-Methylprop-2-enoic acid
	Other names Methacrylic acid; 2-Methyl-2-propenoic acid; α-Methacrylic acid; 2-Methylacrylic acid; 2-Methylpropenoic acid
Identifiers
CAS Number	79-41-4 ;
3D model (JSmol)	Interactive image;
Abbreviations	MAA
ChEBI	CHEBI:25219 ;
ChemSpider	3951 ;
ECHA InfoCard	100.001.096
EC Number	201-204-4;
MeSH	C008384
PubChem CID	4093;
CompTox Dashboard (EPA)	DTXSID3025542 ;
	InChI InChI=1S/C4H6O2/c1-3(2)4(5)6/h1H2,2H3,(H,5,6) Key: CERQOIWHTDAKMF-UHFFFAOYSA-N;
	SMILES CC(C(O)=O)=C;
Properties
Chemical formula	C4H6O2
Molar mass	86.06 g/mol
Appearance	Colorless liquid or solid
Odor	Acrid, repulsive
Density	1.015 g/cm3
Melting point	14 to 15 °C (57 to 59 °F; 287 to 288 K)
Boiling point	161 °C (322 °F; 434 K)
Solubility in water	9% (25 °C)
Vapor pressure	0.7 mmHg (20 °C)
Hazards
NFPA 704 (fire diamond)	3 2 2
Flash point	77.2 °C (171.0 °F; 350.3 K)
	NIOSH (US health exposure limits):
PEL (Permissible)	none
REL (Recommended)	TWA 20 ppm (70 mg/m3) [skin]
IDLH (Immediate danger)	N.D.
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Methacrylic acid, abbreviated MAA, is an organic compound. This colorless, 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.

Production and properties

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 tert-butanol 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.^[2]

Methacrylic acid was first obtained in the form of its ethyl ester by treating phosphorus pentachloride with oxyisobutyric ester (A synonym for beta-hydroxy-butyric acid or 3-hydroxybutyric acid^[3]) .^[4] It is, however, more readily obtained by boiling citra- or meso-brompyrotartaric 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.^[5]

References

^ ^a ^b ^c ^d ^e ^f NIOSH Pocket Guide to Chemical Hazards. "#0386". National Institute for Occupational Safety and Health (NIOSH).
^ William Bauer, Jr. "Methacrylic Acid and Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a16_441. Article Online Posting Date: June 15, 2000
^ https://www.vocabulary.com/dictionary/oxybutyric%20acid
^ Edward Frankland Annalen, 1865, 136, p. 12
^ F. Engelhorn et al. Ann., 1880, 200, p. 70.

External links

[1] Methacrylic Acid in Europe.

[PGCH-1] ^ ^a ^b ^c ^d ^e ^f NIOSH Pocket Guide to Chemical Hazards. "#0386". National Institute for Occupational Safety and Health (NIOSH).

[2] William Bauer, Jr. "Methacrylic Acid and Derivatives" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a16_441. Article Online Posting Date: June 15, 2000

[3] ttps://www.vocabulary.com/dictionary/oxybutyric%20acid

[4] Edward Frankland Annalen, 1865, 136, p. 12

[5] F. Engelhorn et al. Ann., 1880, 200, p. 70.

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