Formic acid

Formic acid, systematically named methanoic acid, is the simplest carboxylic acid. The chemical formula is CH 2 O 2 {displaystyle {{ce {CH2O2}}}} . The chemical composition is HCOOH. It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. The word 'formic' comes from the Latin word for ant, formica, referring to its early isolation by the distillation of ant bodies. Esters, salts, and the anion derived from formic acid are called formates. Industrially, formic acid is produced from methanol. Formic acid is a colorless liquid having a pungent, penetrating odor at room temperature, not unlike the related acetic acid. It is miscible with water and most polar organic solvents, and is somewhat soluble in hydrocarbons. In hydrocarbons and in the vapor phase, it consists of hydrogen-bonded dimers rather than individual molecules. Owing to its tendency to hydrogen-bond, gaseous formic acid does not obey the ideal gas law. Solid formic acid, which can exist in either of two polymorphs, consists of an effectively endless network of hydrogen-bonded formic acid molecules. Formic acid also forms a low-boiling azeotrope with water (22.4%) and liquid formic acid also tends to supercool. In nature, formic acid is found in most ants and in stingless bees of the genus Oxytrigona. The wood ants from the genus Formica can spray formic acid on their prey or to defend the nest. It is also found in the trichomes of stinging nettle (Urtica dioica). Formic acid is a naturally occurring component of the atmosphere primarily due to forest emissions. In 2009, the worldwide capacity for producing formic acid was 720,000 tonnes per year, roughly equally divided between Europe (350,000, mainly in Germany) and Asia (370,000, mainly in China) while production was below 1000 tonnes per year in all other continents. It is commercially available in solutions of various concentrations between 85 and 99 w/w %. As of 2009, the largest producers are BASF, Eastman Chemical Company, LC Industrial, and Feicheng Acid Chemicals, with the largest production facilities in Ludwigshafen (200,000 tonnes per year, BASF, Germany), Oulu (105,000, Eastman, Finland), Nakhon Pathom (n/a, LC Industrial), and Feicheng (100,000, Feicheng, China). 2010 prices ranged from around €650/tonne (equivalent to around $800/tonne) in Western Europe to $1250/tonne in the United States. When methanol and carbon monoxide are combined in the presence of a strong base, the result is methyl formate, according to the chemical equation: In industry, this reaction is performed in the liquid phase at elevated pressure. Typical reaction conditions are 80 °C and 40 atm. The most widely used base is sodium methoxide. Hydrolysis of the methyl formate produces formic acid: Efficient hydrolysis of methyl formate requires a large excess of water. Some routes proceed indirectly by first treating the methyl formate with ammonia to give formamide, which is then hydrolyzed with sulfuric acid: A disadvantage of this approach is the need to dispose of the ammonium sulfate byproduct. This problem has led some manufacturers to develop energy-efficient methods of separating formic acid from the excess water used in direct hydrolysis. In one of these processes, used by BASF, the formic acid is removed from the water by liquid-liquid extraction with an organic base.