Acetic acid acid solutions: Concentrated acetic acid can be ignited only with difficulty at standard temperature and pressure, but becomes a flammable risk in temperatures greater than , and can form explosive mixtures with air at higher temperatures (explosive limits: 5.4–16%). Acetic acid Acetic acid , systematically named ethanoic acid , is a colourless liquid organic compound with the chemical formula CHCOOH (also written as CHCOH or CHO). When undiluted, it is sometimes called "glacial acetic acid". Vinegar is no less than 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water. Acetic acid has a
Syringic acid in vinegar. Syringic acid can be enzymatically polymerised. Laccase and peroxidase induced the polymerization of syringic acid to give a poly(1,4-phenylene oxide) bearing a carboxylic acid at one end and a phenolic hydroxyl group at the other. Syringic acid Syringic acid is a naturally occurring "O"-methylated trihydroxybenzoic acid, a type of chemical compound. Syringic acid can be found in "Ardisia elliptica". Syringic acid can be prepared by selectively hydrolyzing (demethylating) eudesmic acid with 20% sulfuric acid. Syringic acid can be found in the açaí palm ("Euterpe oleracea") and its oil (1,073 ± 62 mg/kg). It is also present in wine.