Cinnamic acid correlation analysis
Cinnamic acid, chemical name β-phenylacrylic acid, has unique properties and multiple applications, and its synthesis is also an important field of chemical research.

Properties
Cinnamic acid is white to light yellow powder, with a slight cinnamon aroma. Melting point is about 133 ° C, boiling point is 300 ° C. It is insoluble in cold water, soluble in hot water, ethanol, ether and other organic solvents. Its molecules contain carbon-carbon double bonds and carboxyl groups, and have both olefin and carboxylic acid chemical properties. Carbon-carbon double bonds enable it to undergo addition and oxidation reactions; carboxyl groups allow it to have the general properties of acids and can react with bases, alcohols, etc.

Application
1. ** Pharmaceutical field **: Cinnamic acid is a key intermediate for the synthesis of many drugs. For example, it can be used as a raw material to synthesize drugs for the treatment of cardiovascular diseases, and its structural properties can be used to regulate blood lipids and improve blood circulation. It also has potential in antibacterial and antiviral aspects. It has inhibitory effects on some bacteria and viruses, and is expected to be developed into new anti-infective drugs.
2. ** Fragrance industry **: Due to its unique aroma, cinnamic acid is used to prepare fragrances. It is often added to food fragrances, such as bread and pastries, to add unique flavor; in cosmetic fragrance formulations, it gives products a pleasant fragrance, and its stability is good, which can make the aroma last.
3. ** Agricultural uses **: Cinnamic acid can be used as a plant growth regulator. Appropriate use can promote plant growth and development, improve crop stress resistance, enhance its resistance to drought, diseases and insect pests, and then improve crop yield and quality.

Synthesis
1. ** Perkin reaction **: This is a classic synthesis method. Benzaldehyde and acetic anhydride are used as raw materials and heated under the catalysis of sodium acetate. The reaction conditions are mild and the yield is high. During the reaction, acetic anhydride forms carbon negative ions under the action of basic catalysts, attacks benzaldehyde carbonyl, and generates cinnamic acid through a series of reactions.
2. ** Knoevenagel reaction **: Benzaldehyde reacts with malonic acid under the catalysis of weak bases such as pyridine to generate cinnamic acid. This method is easy to operate, the product is easy to separate, the atom economy is good, environmentally friendly, and in line with the concept of green chemistry.

Cinnamic acid plays an important role in medicine, fragrance, agriculture and other fields due to its special properties. Its synthesis methods continue to develop and improve, laying the foundation for its wider application.