What is Formic Acid


Formic acid is miscible with water and most polar organic solvents, and somewhat soluble in hydrocarbons. In hydrocarbons and in the vapor phase, it actually consists of hydrogen-bonded dimers rather than individual molecules. In the gas phase, this hydrogen-bonding results in severe deviations from the ideal gas law. Liquid and solid formic acid consists of an effectively infinite network of hydrogen-bonded formic acid molecules.

Formic acid shares most of the chemical properties of other carboxylic acids, although under normal conditions it will not form either an acyl chloride or an acid anhydride. Until very recently, all attempts to form either of these derivatives have resulted in carbon monoxide instead. It has now been shown that the anhydride may be produced by reaction of formyl fluoride with sodium formate at −78°C, and the chloride by passing HCl into a solution of 1-formimidazole in monochloromethane at −60°C. Heat can also cause formic acid to decompose to carbon monoxide and water. Formic acid shares some of the reducing properties of aldehydes.

Formic acid is unique among the carboxylic acids in its ability to participate in addition reactions with alkenes. Formic acids and alkenes readily react to form formate esters. In the presence of certain acids, including sulfuric and hydrofluoric acids, however, a variant of the Koch reaction takes place instead, and formic acid adds to the alkene to produce a larger carboxylic acid.



Formic acid is the simplest member of the carboxylic acid family. It’s also known as methanoic acid. The chemical’s molecular formula is HCOOH. The molecule is composed of a carboxyl group (COOH) with a hydrogen atom attached. In the carboxyl group, the carbon atom has a double bond joining it to the oxygen atom and a single bond joining it to the hydroxyl (OH) group.

Formic acid can be made synthetically in laboratories. In nature it usually exists in the form of a colorless liquid. This liquid freezes at 8.3 degrees Celsius (46.9 degrees Fahrenheit) and boils at 100.7 degrees Celsius. (213.3 degrees Fahrenheit). It has a strong odor and is often described as having a “pungent” smell.

The Uses of Formic Acid

Industrial Uses

One of the most common industrial uses of formic acid is in the production of leather. Because it is so acidic, formic acid has proven itself to be perfect for use in this fashion. Although formic acid is most frequently used in leather production, other industries currently use formic acid in the process of dyeing and finishing textiles. It is also commonly used as a coagulant in many rubber manufacturing processes. Not only are these formates more effective than traditional salt treatments, they are also more environmentally friendly. When used properly, formates can greatly increase the gripping ability of otherwise slick surfaces, as well as promote the removal of these surfaces with machines and other technologies.

Agricultural Uses

Agriculture accounts for a very high percentage of formic acid use worldwide. Because of its natural antibacterial properties, formic acid has achieved very high use as both an antibacterial preservative and pesticide. In this industry, it is most commonly used as a food additive, and is frequently added to animal feed and silage. When it is used in silage, it serves a dual function. In addition to providing a certain level of antibacterial support, formic acid actually allows silage to begin fermentation at a lower temperature, greatly reducing the overall time that it takes to produce while increasing the nutritional value of the finished product.


Depending on how concentrated it is, formic acid can either be unnoticeable or very dangerous. Through the course of our typical interaction with this chemical, we are exposed only to very low concentrations. Because of this, there is very little to fear. If exposed at high concentrations, however, there are many dangerous side effects that can occur. The most dangerous aspect of the formic acid is its highly corrosive nature when in a concentrated form. Because it is so corrosive, highly concentrated amounts of formic acid can lead to serious injury if it is inhaled, swallowed or touched directly. This includes ulcers, nausea, burns, blisters and extreme discomfort around the affected area. Although it is not likely except under special situations, high concentrations of formic acid should be avoided altogether.



CAS NO : 64-18-6
H.S CODE : 29151100
MOL WT : 46.025 g mol-1
SYNONYMS : Methanoic acid, Formylic acid, Hydrogen carboxylic acid



PHYSICAL STATE : Clear liquid
BOILING POINT : 101oC @ 760 mmHg
PH : 3.47 (1mM)
NFPA RATINGS : Health: 3; Flammability: 2; Instability: 1
STABILITY : Hygroscopic: absorbs moisture or water from the air. Keep Refrigerated. Formic acid may decompose to carbon Monoxide and water or carbon dioxide and hydrogen gas. These decomposition products develop pressure. Heat Sensitive.