|Jmol-3D images||Image 1|
|Molar mass||148.16 g mol−1|
|Appearance||White monoclinic crystals|
|Melting point||133 °C (271 °F; 406 K)|
|Boiling point||300 °C (572 °F; 573 K)|
|Solubility in water||500 mg/L|
|EU classification||Irritant (Xi)|
|Flash point||> 100 °C (212 °F; 373 K)|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
Cinnamic acid is an organic compound with the formula C6H5CHCHCO2H. It is a white crystalline compound that is slightly soluble in water. Classified as an unsaturated carboxylic acid, it occurs naturally in a number of plants. It is freely soluble in many organic solvents. It exists as both a cis and a trans isomer, although the latter is more common.
Occurrence and production
It is obtained from oil of cinnamon, or from balsams such as storax. It is also found in shea butter. Cinnamic acid has a honey-like odor; it and its more volatile ethyl ester (ethyl cinnamate) are flavor components in the essential oil of cinnamon, in which related cinnamaldehyde is the major constituent. Cinnamic acid is also part of the biosynthetic shikimate and phenylpropanoid pathways. Its biosynthesis is performed by action of the enzyme phenylalanine ammonia-lyase (PAL) on phenylalanine.
The original synthesis of cinnamic acid involves the Perkin reaction, which entails the base-catalysed condensation of acetic anhydride and benzaldehyde. Rainer Ludwig Claisen (1851–1930) described the synthesis of cinnamate esters by the reaction of benzaldehyde and esters. The reaction is known as the Claisen condensation. It can also be prepared from cinnamaldehyde and benzal chloride.
Cinnamic acid is used in flavors, synthetic indigo, and certain pharmaceuticals. A major use is in the manufacturing of the methyl, ethyl, and benzyl esters for the perfume industry. Cinnamic acid is a precursor to the sweetener aspartame via enzyme-catalysed amination to phenylalanine.
Cinnamic acid is also a kind of self-inhibitor produced by fungal spore to prevent germination.
- Record in the GESTIS Substance Database from the IFA
- [lxsrv7.oru.edu/~alang/onsc/solubility/allsolvents.php?solute=cinnamic+acid ONSC: Solubility of trans-cinnamic acid. ] doi:10.1038/npre.2010.4243.3
- Dorothea Garbe "Cinnamic Acid" in Ullmann's Encyclopedia of Industrial Chemistry, 2000, Wiley-VCH, Weinheim. doi:10.1002/14356007.a07_099
- Budavari, Susan, ed. (1996), The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals (12th ed.), Merck, ISBN 0911910123
- Cinnamic acid, flavornet.org