How does imidazole react with ammonia

Imidazole is a five-membered heterocyclic aromatic organic compound having two nitrogen atoms. It has a basic reaction.


The synthesis of imidazole can be carried out by the Radziszewski method from the condensation of a 1,2-diketone, ammonia and an aldehyde.


Imidazole is mainly used as a starting product in the manufacture of various drugs, especially fungicides. Another application is the hardening of certain plastics.

Imidazole is also used as a buffer substance in the Karl Fischer method for water determination. In 1984 Eugen Scholz developed the pyridine-free Karl Fischer reagent with imidazole as the base. This reagent not only replaces the poisonous and malodorous pyridine, but also enables faster and more accurate titration, since imidazole buffers in a more favorable pH range than pyridine. Scholz's studies on stoichiometry also showed that methanol (solvent and at the same time involved in the reaction) can be replaced by other alcohols, e.g. B. ethanol, 2-propanol or methoxyethanol, which improved the titer stability of the reagent. Based on these findings, the following reaction equation for the Karl Fischer reaction resulted:

RAW + SO2 + RN → (RNH) • (SO3R)
(RNH) • (SO3R) + I2 + H2O + 2 RN → (RNH) • (SO4R) + 2 (RNH) • I.

Derived connections

Imidazole derivatives occur in many ways in nature. The amino acid histidine and the histamine derived from it contain an imidazole ring, as do the purines, xanthines and their derivatives. Imidazole alkaloids are found in the rhombus family.

The imidazolium cation is easily formed from imidazole. Derivatives of this cation can be found in numerous ionic liquids, the corresponding imidazolium compounds were also the first known.

See also

Categories: Corrosive Substance | Imidazole | Heteroaromatic | Substance group