Acrylic acid

Acrylic acid[1]
Names
IUPAC name
Prop-2-enoic acid
Other names
acroleic acid
ethylenecarboxylic acid
propene acid
propenoic acid
vinylformic acid
Identifiers
79-10-7 YesY
ChEBI CHEBI:18308 YesY
ChEMBL ChEMBL1213529 YesY
ChemSpider 6333 YesY
DrugBank DB02579 YesY
EC Number 201-177-9
Jmol interactive 3D Image
Image
KEGG D03397 YesY
PubChem 6581
RTECS number AS4375000
UNII J94PBK7X8S YesY
Properties
C3H4O2
Molar mass 72.06 g·mol−1
Appearance clear, colorless liquid
Odor acrid[2]
Density 1.051 g/mL
Melting point 14 °C (57 °F; 287 K)
Boiling point 141 °C (286 °F; 414 K)
Miscible
Vapor pressure 3 mmHg[2]
Acidity (pKa) 4.25[3]
Viscosity 1.3 cP at 20 °C (68 °F)
Hazards
Main hazards Corrosive (C),
Dangerous for the
environment (N)
Safety data sheet MSDS
R-phrases R10 R20/21/22 R35 R50
S-phrases S26 S36/37/39 S45 S61
NFPA 704
Flammability code 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g., diesel fuel Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g., phosphorus Special hazards (white): no codeNFPA 704 four-colored diamond
2
3
2
Flash point 68 °C (154 °F; 341 K)
429 °C (804 °F; 702 K)
Explosive limits 2.4%-8.02%[2]
US health exposure limits (NIOSH):
none[2]
TWA 2 ppm (6 mg/m3) [skin][2]
N.D.[2]
Related compounds
Other anions
 acrylate
acetic acid
propionic acid
lactic acid
3-hydroxypropionic acid
malonic acid
butyric acid
crotonic acid
Related compounds
 allyl alcohol
propionaldehyde
acrolein
methyl acrylate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 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 a thousand kilotons are produced annually.[4]

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 acrylonitrile 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.[4]

Dow Chemical Company and a partner, OPX Biotechnologies, are investigating using fermented sugar to produce 3-hydroxypropionic acid (3HP), an acrylic acid precursor. [5] The goal is to reduce greenhouse gas emissions. [6]

Reactions and uses

Acrylic acid undergoes the typical reactions of a carboxylic acid. When reacted with an alcohol, it forms 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.

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:

  1. The acryloyl group, with the removal of the -OH from carbon-1.
  2. The 2-carboxyethenyl group, with the removal of a -H from carbon-3. This substituent group is found in chlorophyll.

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).

See also

References

  1. ↑ Merck Index, 11th Edition, 124.
  2. 1 2 3 4 5 6 "NIOSH Pocket Guide to Chemical Hazards #0013". National Institute for Occupational Safety and Health (NIOSH).
  3. ↑ Dippy, J.F.J.; Hughes, S.R.C.; Rozanski, A. (1959). J. Chem Soc.: 2492.
  4. 1 2 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
  5. ↑ Sweet Deal: Dow and Partner Cook up Sugar-to-Acrylic Plan. Durabilityanddesign.com. Retrieved on 2012-05-24.
  6. ↑ Better Bugs to Make Plastics, Technology Review, September 20, 2010, retrieved January 9, 2012. Technologyreview.com (2010-09-20). Retrieved on 2012-05-24.

External links

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