Acrylic acid
| Acrylic acid[1] | |
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Prop-2-enoic acid |
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Other names
acroleic acid |
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| Identifiers | |
| CAS number | 79-10-7  |
| PubChem | 6581 |
| ChemSpider | 6333 |
| UNII | J94PBK7X8S |
| DrugBank | DB02579 |
| KEGG | D03397 |
| ChEBI | CHEBI:18308 |
| ChEMBL | CHEMBL1213529 |
| RTECS number | AS4375000 |
| Jmol-3D images | Image 1 Image 2 |
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| 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) | 4.35[2] |
| 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 |
| Main hazards | Corrosive (C), Dangerous for the environment (N) |
| 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 | allyl alcohol propionaldehyde acrolein methyl acrylate |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Acrylic acid (IUPAC: prop-2-enoic acid) is an organic compound with the formula CH2=CHCO2H. 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.[3]
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[edit] Production
Acrylic acid is produced from propene 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, but was abandoned because the method cogenerates ammonium derivatives. Other now abandoned precursors to acrylic acid include ethenone and ethylene cyanohydrin.[3]
Dow Chemical Company and a partner, OPX Biotechnologies, are attempting to demonstrate the technical and financial merits of a process that uses fermented sugar to produce 3-hydroxypropionic acid (3HP); 3HP is then converted to acrylic acid. [4][5]The goal is to reduce greenhouse gas emissions, when compared with current production methods.
[edit] 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 (to form polyacrylic acid) or other monomers (e.g. acrylamides, 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.
[edit] Substituents
As a substituent acrylic acid can be found as an acyl group or a carboxyalkyl group depending on the removal of the group from the molecule. More specifically these are:
- The acryloyl group, with the removal of the -OH from carbon-1.
- The 2-carboxyethenyl group, with the removal of a -H from carbon-3. This substituent group is found in chlorophyll.
[edit] 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. The LD50 is 340 mg/kg (rat, oral).
[edit] See also
[edit] References
- ^ Merck Index, 11th Edition, 124.
- ^ Dippy, J.F.J., Hughes, S.R.C., Rozanski, A., J. Chem Soc., 1959, 2492.
- ^ a b Takashi Ohara, Takahisa Sato, Noboru Shimizu, Günter Prescher Helmut Schwind, Otto Weiberg, Klaus Marten, Helmut Greim “Acrylic Acid and Derivatives” in Ullmann's Encyclopedia of Industrial Chemistry 2003, Wiley-VCH, Weinheim. doi: 10.1002/14356007.a01_161.pub2
- ^ Sweet Deal: Dow and Partner Cook up Sugar-to-Acrylic Plan
- ^ Better Bugs to Make Plastics, Technology Review, September 20, 2010, retrieved January 9, 2012
