Cinnamic acid

Cinnamic acid
IUPAC name (E)-3-phenylprop-2-enoic acid
Other names Cinnamic Acid trans-Cinnamic Acid Phenylacrylic acid Cinnamylic acid 3-Phenylacrylic acid (E)-Cinnamic acid Benzenepropenoic acid Isocinnamic acid
Identifiers
CAS number	140-10-3 Y
PubChem	444539
ChemSpider	392447 Y
KEGG	C00423 N
ChEBI	CHEBI:35697 N
ChEMBL	CHEMBL27246 N
Jmol-3D images	Image 1
SMILES O=C(O)\C=C\c1ccccc1
InChI InChI=1S/C9H8O2/c10-9(11)7-6-8-4-2-1-3-5-8/h1-7H,(H,10,11)/b7-6+ Y Key: WBYWAXJHAXSJNI-VOTSOKGWSA-N Y InChI=1/C9H8O2/c10-9(11)7-6-8-4-2-1-3-5-8/h1-7H,(H,10,11)/b7-6+ Key: WBYWAXJHAXSJNI-VOTSOKGWBT
Properties
Molecular formula	C9H8O2
Molar mass	148.16 g mol−1
Exact mass	148.05243
Appearance	White monoclinic crystals
Density	1.2475 g/cm3[1]
Melting point	133 °C, 406 K, 271 °F ([1])
Boiling point	300 °C, 573 K, 572 °F ([1])
Solubility in water	500 mg/L[1]
Acidity (pKa)	4.44
Hazards
EU classification	Irritant (Xi)
R-phrases	R36
S-phrases	S25
Flash point	>100 °C (212 °F)[1]
N (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Cinnamic acid is a white crystalline hydroxycinnamic acid, which is slightly soluble in water.

It is obtained from oil of cinnamon, or from balsams such as storax.^[2] It is also found in shea butter and is the best indication of its environmental history and post-extraction conditions. It can also be made synthetically.

Cinnamic acid is used in flavors, synthetic indigo, and certain pharmaceuticals, though its primary use is in the manufacturing of the methyl, ethyl, and benzyl esters for the perfume industry.^[2] Cinnamic acid has a honey-like odor;^[3] 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.

Cinnamic acid is freely soluble in benzene, diethyl ether, acetone, and acetic acid;^[2] it is insoluble in hexane.

Cinnamic acid is also a kind of self-inhibitor produced by fungal spore to prevent germination.

Chemical synthesis

Rainer Ludwig Claisen (1851–1930), German chemist, described for the first time in 1890 the synthesis of cinnamates by reacting aromatic aldehydes with esters. The reaction is known as the Claisen reaction.

References

1. ^ ^{a b c d e} Record in the GESTIS Substance Database from the IFA
2. ^ ^{a b c} Budavari, Susan, ed. (1996), The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals (12th ed.), Merck, ISBN 0911910123 
3. ^ Cinnamic acid], flavornet.org