acrylic acid

Acrylic acid[1]
IUPAC name	propenoic acid
Other names	acroleic acid ethylenecarboxylic acid propene acid propenoic acid vinylformic acid
Identifiers
CAS number	79-10-7 Y
PubChem	6581
RTECS number	AS4375000
SMILES	C=CC(=O)O
Properties
Molecular formula	C3H4O2
Molar mass	72.06 g mol−1
Appearance	clear, colorless liquid
Density	1.051 g/mL
Melting point	14 °C, 287 K, 57 °F
Boiling point	141 °C, 414 K, 286 °F
Solubility in water	Miscible
Acidity (pKa)	4.25
Viscosity	1.3 cP at 20 °C (68 °F)
Hazards
MSDS	MSDS
R-phrases	R10 R20/21/22 R35 R50
S-phrases	S26 S36/37/39 S45 S61
Flash point	68 °C (154 °F)
Related compounds
Other anions	acrylate
Related carboxylic acids	acetic acid propionic acid lactic acid 3-hydroxypropionic acid malonic acid butyric acid crotonic acid
Related compounds	propenol propionaldehyde acrolein methyl acrylate
Y (what is this?)  (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Acrylic acid ({{IUPAC:prop-2-enoic acid) is an organic compound with the formula CH2CHCO2H. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has a characteristic acrid or tart smell. It is miscible with water, alcohols, ethers, and chloroform. More than one billion kilograms are produced annually.^[2]

Production

Acrylic acid is produced from propene (aka propylene) which is a byproduct of ethylene and gasoline production.

CH₂=CHCH₃ + 1.5 O₂ → CH₂=CHCO₂H + H₂O

Because acrylic acid and its esters have long been valued commercially, many other methods have been developed but most have been abandoned for economic or environmental reasons. An early method was the hydrocarboxylation of acetylene ("Reppe chemistry"):

HCCH + CO + H₂O → CH₂=CHCO₂H

This method requires nickel carbonyl and high pressures of carbon monoxide. It was once manufactured by the hydrolysis of acylonitrile which is derived from propene by ammoxidation, was abandoned because the method cogenerates ammonium derivatives. Other now abandoned precursors to acrylic acid include ketene and ethylene cyanohydrin.^[2]

Reactions and uses

Acrylic acid undergoes the typical reactions of a carboxylic acid and, when reacted with an alcohol, it will form the corresponding ester. The esters and salts of acrylic acid are collectively known as acrylates (or propenoates). The most common alkyl esters of acrylic acid are methyl-, butyl-, ethyl-, and 2-ethylhexyl-acrylate.

Acrylic acid and its esters readily combine with themselves or other monomers (e.g. amides, acrylonitrile, vinyl, styrene, and butadiene) by reacting at their double bond, forming homopolymers or copolymers which are used in the manufacture of various plastics, coatings, adhesives, elastomers, as well as floor polishes, and paints.

Safety

Acrylic acid is severely irritating and corrosive to the skin and the respiratory tract. Eye contact can result in severe and irreversible injury. Low exposure will cause minimal or no health effects, while high exposure could result in pulmonary edema. LD50 = 340 mg/kg (rat, oral).

See also

• Methacrylic acid
• Acryloyl chloride
• Acrylamide
• Acrylate polymers
• Sodium polyacrylate
• Acryloyl group

References

External links

• National Pollutant Inventory: Acrylic acid