Nature
Colorless, transparent, fuming liquid with a strong pungent odor, belonging to the category of strong acids. It can be miscible with water in any proportion and form an azeotropic mixture higher than their boiling points. Flammable, when stored for a long time at temperatures above 30℃, formic acid will slowly decompose and release carbon monoxide. It has strong corrosiveness and can corrode aluminum, cast iron, steel, certain plastics, rubbers and coatings. It can react with strong oxidants and is miscible with many organic solvents, but insoluble in hydrocarbons. Its vapor forms explosive mixtures with air and can cause combustion and explosion when exposed to open flames or high heat.

Preparation method
Desulfurized and compressed carbon monoxide is introduced into a reactor containing 20% to 30% sodium hydroxide solution, where the reaction takes place at 160 to 200 ° C and 1.4 to 1.6MPa to generate sodium formate. Then, it is treated with dilute sulfuric acid to obtain 76% formic acid, a monohydrate azeotrope, which can be further concentrated and refined.

Purpose
Formic acid and its aqueous solutions can be used to clean various metals, metal oxides, hydroxides and salts. The formates generated are all soluble in water. This property makes it a chemical cleaning agent. Due to its strong affinity for chloride ions, formic acid is suitable for cleaning equipment containing stainless steel materials. Due to its high volatility and the ease of thoroughly removing residues, it is widely used in special cleaning projects. Even at low concentrations, formic acid has relatively weak toxicity and corrosiveness to the human body. Therefore, as a cleaning agent, formic acid has multiple advantages, making it a safe and reliable choice.

Safety
The LD50 for oral and intravenous injection in mice is 1100 mg/kg and 145mg/kg respectively. Inhaling formic acid vapor can severely irritate the mucous membranes of the nose and mouth and cause inflammation. It is highly corrosive and irritating, and can cause burns to the human body. The allowable concentration of formic acid in the workplace is 5 g/m ³. When handling concentrated formic acid, proper protection must be taken. If the eyes or skin come into contact with formic acid, rinse immediately with water. Store in a cool, dry and well-ventilated place. Keep away from fire and heat sources. Keep the container sealed. It should be stored separately from oxidants and alkalis.