Cinnamic acid
[CAS# 621-82-9]

Identification

• Classification: Pharmaceutical intermediate >> Heterocyclic compound intermediate >> Pyrimidine compound >> Carboxylic acid
• Name: Cinnamic acid
• Synonyms: 3-Phenylpropenoic acid; Phenylacrylic acid
• Molecular Formula: C₉H₈O₂
• Molecular Weight: 148.16
• CAS Registry Number: 621-82-9
• EC Number: 210-708-3
• FEMA: 2288
• SMILES: C1=CC=C(C=C1)/C=C/C(=O)O

Properties

• Density: 1.2±0.1 g/mL, Calc.^*, 1.248 g/mL (Expl.)
• Melting point: 133 °C (Expl.)
• Index of Refraction: 1.616, Calc.^*
• Boiling Point: 265.0 °C (760 mmHg), Calc.^*, 300 °C (Expl.)
• Flash Point: 189.5±9.6 °C, Calc.^*, 165.6

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335

Discovery and Applications

Cinnamic acid is an aromatic carboxylic acid with the molecular formula C9H8O2. It is naturally found in the bark of cinnamon trees and is responsible for the characteristic odor of cinnamon. Cinnamic acid is a key intermediate in the biosynthesis of phenylpropanoids, which are a group of important plant-derived compounds that have various biological activities.

The discovery of cinnamic acid dates back to the early 19th century. It was first isolated from cinnamon oil in 1830 by the German chemist Justus von Liebig. Later, its structure was elucidated, and its properties were studied in greater detail.

Cinnamic acid can be synthesized through various methods. One common route involves the dehydrogenation of cinnamaldehyde, the aldehyde derivative of cinnamic acid, in the presence of a suitable catalyst. Additionally, cinnamic acid can be produced by the microbial fermentation of glucose or other carbon sources in industrial settings.

Cinnamic acid and its derivatives have various applications in multiple industries. One of its primary uses is in the fragrance industry, where it is used to create perfumes and other scented products due to its sweet, spicy odor. Cinnamic acid is also employed in the synthesis of cinnamates, which are used as flavoring agents in food products.

In addition to its use in fragrances and food products, cinnamic acid has potential pharmaceutical applications. It has been found to exhibit anti-inflammatory, antioxidant, and antimicrobial properties. These characteristics make cinnamic acid and its derivatives of interest for the development of drugs targeting a variety of conditions, including inflammatory diseases and infections. Furthermore, cinnamic acid is used as a precursor in the synthesis of other bioactive compounds, such as the anticancer agent 4-hydroxycinnamic acid.

Cinnamic acid is also used in the production of polymers, such as polystyrene and polyesters, where it acts as a monomer or a modifying agent. Additionally, it is used as a starting material for the synthesis of various chemical intermediates, such as cinnamic aldehyde and other related compounds.

In terms of safety, cinnamic acid is generally considered safe for use in food and cosmetic products when used in appropriate concentrations. However, it can cause irritation to the skin and eyes in concentrated forms, and proper handling procedures should be followed to minimize exposure.

In summary, cinnamic acid is a versatile and widely used compound with applications in the fragrance, food, pharmaceutical, and chemical industries. Its role as a precursor for various bioactive compounds and its natural occurrence in plants make it a compound of significant interest in both industrial and research contexts.

References

2005. Fragrance material review on cinnamic acid. Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, 43(6).
DOI: 10.1016/j.fct.2004.09.015

2007. From scratch to value: engineering Escherichia coli wild type cells to the production of l-phenylalanine and other fine chemicals derived from chorismate. Applied Microbiology and Biotechnology, 75(4).
DOI: 10.1007/s00253-007-0931-y

2005. Characterization of Sphingomonas aldehyde dehydrogenase catalyzing the conversion of various aromatic aldehydes to their carboxylic acids. Applied Microbiology and Biotechnology, 68(4).
DOI: 10.1007/s00253-005-1962-x