Solubility : Immiscible with ethers and chlorinated solvents, slightly soluble in benzene, and miscible with water, methanol, ethanol, acetic acid, acetone, dioxane, ethylene glycol, phenol, and lower - esters. It can dissolve casein, but not albumin, as well as some inorganic salts.
Chemical Properties
The hydrolysis rate of formamide at room temperature is very slow, and heating or adding acids and bases can accelerate the hydrolysis.
It can decompose hydrogen cyanide when heated below 35℃ in the presence of a catalyst.
With two active functional groups, the carbonyl and amide groups, it is easy to undergo chemical reactions to generate many nitrogen - containing heterocyclic compounds.
Purity
Generally, the purity of industrial - grade formamide is ≥99.0%, and that of reagent - grade can reach ≥99.5%.
Toxicity
It belongs to toxic substances. The acute toxicity shows that the LD50 of rats by gavage is 6.1g/kg, and that of mice is 3.15g/kg. The acute symptoms are characterized by damage to the nervous system. The threshold concentration for chronic inhalation is 6±4mg/m³. The maximum allowable concentration in the working environment air is 30mg/m³ in the United States and 3mg/m³ in the Soviet Union.
Production Methods
Carbon Monoxide Method : Carbon monoxide and methanol react under the action of sodium methoxide to generate methyl formate, and then methyl formate is ammoniated to generate formamide. The reaction conditions are 80 - 100℃ and 0.2 - 0.6MPa.
Esterification - Ammoniation Method : Formic acid and methanol are first esterified to generate methyl formate, which is then ammoniated to form formamide, and finally, methanol and impurities are separated by distillation to obtain the finished product.
Uses
It is a raw material for pharmaceuticals (such as sulfonamides, vitamins, etc.), spices, and dyes.
It can be used as a paper treatment agent, a softener in the fiber industry, a softener for animal glue, and a polar solvent for organic synthesis.
Reagent - grade formamide can be used as a chromatographic analysis reagent.
Packaging and Storage
Usually packed in 200L plastic drums or steel - plastic composite drums.
It should be stored in a cool, ventilated and dry place, away from fire and heat sources, and the drum cover should be tightly closed to prevent leakage and avoid contact with water.
