Cinnamic acid is found both in free form, and especially in the form of esters (ethyl, Cinnamyl, benzyl), in various essential oils, resins and balsams,oil of cinnamon, balsam of Peru, of Tolu, vanilla extract etc..
It was observed Trommsdorf first time in 1780,in oil of cinnamon, but it was confused with benzoic acid. Its structure was established by Dumas and Peligot in 1835, and the first synthesis from benzaldehyde and acetyl chloride was made by Bertagnini in 1856. The process became a classic, the synthesis from benzaldehyde and it was prepared by Perkin in 1877.
The most used method of preparation of cinnamic acid on an industrial scale, is the synthesis Perkin. It also is used on an industrial scale the Knoevenagel method from benzaldehyde and Malonic acid in the presence of amines (pyridine or benzyl amine), or process from benzylidene chloride and excess of sodium acetate at 180 ... 200C.
William Henry Perkin discovered Cinnamic acid as an adolescent. He attended the Royal College of Chemistry where he immediately set to work performing independent chemical experiments. The reaction that is used to make the acid is called the Perkin Reaction. His discovery was developed in relation to use of cinnamic acid in the dying and perfume industry.
Cinnamic acid is an odorless white crystallized acid. It has slight water solubility. The chemicals are obtained from cinnamon. It is also made as a synthetic. Some common uses for the acid include in medicines, perfumes, and as a flavor agent.
Cinnamic acid is used in flavours, synthetic indigo, and certain pharmaceuticals, though its primary use is in the manufacturing of the methyl, ethyl, and benzyl esters for the perfume industry. 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, floral odor" (Merck Index); it and its more volatile ethyl ester (ethyl cinnamate) are flavour components in the essential oil of cinnamon, in which related cinnamaldehyde is the major constituent. It was first discovered by William Henry Perkin and it was prepared by Perkin in 1877.
In biological chemistry, cinnamic acid is a key intermediate in shikimate and phenylpropanoid pathways. Shikimic acid is a precursor of many alkaloids, aromatic amino acids, and indole derivatives. Phenylpropanoid are a class of plant metabolites based on phenylalanine.