kinnaminsyre

Kinnaminsyre, known in English as cinnamic acid, is an organic aromatic carboxylic acid with the formula C9H8O2. Its IUPAC name is (E)-3-phenylprop-2-enoic acid, and it consists of a phenyl ring attached to a trans-CH=CH-CO2H side chain. It exists predominantly as the trans isomer, with the cis form possible but less stable.

Natural occurrence and biosynthesis: Cinnamic acid is found in a variety of plants and is especially associated with cinnamon bark. It is a metabolic intermediate in the phenylpropanoid pathway, formed from the amino acid L-phenylalanine by the enzyme phenylalanine ammonia-lyase. Through this pathway, cinnamic acid serves as a precursor to a wide range of plant secondary metabolites, including coumarins, lignin precursors, and flavonoids.

Properties: Cinnamic acid forms white crystalline solids with a melting point around 133–134 °C. It is sparingly soluble in water but more soluble in organic solvents such as alcohol and ether. It absorbs ultraviolet light, with a maximum in the near-UV region around 270 nm, reflecting its conjugated aromatic structure.

Uses: It is employed as a chemical intermediate in organic synthesis and serves as a starting material for the production of various esters, including cinnamates used as flavors, fragrances, and UV-filtering agents in cosmetics. It also appears as a building block in the synthesis of pharmaceuticals and polymer-related applications.

Safety and handling: Cinnamic acid is a mildly irritant and should be handled with appropriate protective equipment. It should be stored away from strong oxidizers and moisture, and used only in well-ventilated areas.