Bookmark added to your notes.
View Notes

What is Hexamine?

Hexamine can be described as a heterocyclic organic compound having the chemical formula C6H12N4. It is also referred to as Hexamethylenetetramine, Methenamine, or Urotropin.

This compound acts as an anti-infective agent, which is the most commonly used element to treat urinary tract infections. The anti-infective action of hexamine is derived from the slow release of formaldehyde (CH2O) by the process of hydrolysis at an acidic pH of 0.2 molars. Also, methenamine is a colorless, odorless, and lustrous crystal or white hygroscopic crystalline powder.

Synthesis, Structure, Reactivity of Hexamine

Hexamine powder was discovered in 1859 by Aleksandr Butlerov. Industrially, it is prepared by combining ammonia and formaldehyde. This reaction can be conducted in a gas phase and solution.

(Image to be added soon)

(Image to be added soon)

The molecule contains a symmetric tetrahedral cage-like structure, which is similar to adamantane, whose "edges" are methylene bridges, and the four "corners" are nitrogen atoms. Although their molecular shape defines a cage, none of the void space is available at the interior for binding other molecules or atoms, unlike larger cryptand or crown ether structures.

The molecule behaves the same as amine base, by undergoing N-alkylation (For example, Quaternium-15) and protonation.

Properties of Hexamine - C6H12N4

Let us look at some important properties of the hexamine compound.

  • The chemical formula for hexamine can be given as C6H12N4,

  • The density of Hexamine is 1.33 g/cm3,

  • The molecular weight of C6H12N4 is 140.186 g/mol,

  • The Boiling point of Hexamine can be given as "Sublimes,"

  • The Melting point of Hexamine can be given as 280°C,

  • The odor of this compound is Fishy (Ammonia like).

Applications of Hexamine

The dominant use of hexamine can be in the production of liquid or powdery preparations of phenolic resins. The moulding compounds of phenolic resin are added as a hardening component. Where, we can use these products like binders, for example, in clutch and brake linings, non-woven textiles, abrasive products, formed parts produced by the moulding processes, and fireproof materials.

It has been proposed that the hexamine powder could work as a molecular building block for the self-assembled molecular crystals.

Medical Uses of Hexamine

Since the mandelic acid salt (which is a generic methenamine mandelate, USP) is used for urinary tract infection treatments, it decomposes at an acidic pH to produce ammonia, and formaldehyde is bactericidal; which the mandelic acid adds to this effect. Typically, urinary acidity is ensured by co-administering ammonium chloride or vitamin C (otherwise an ascorbic acid).

This compound's usage had temporarily been reduced in the late 1990s because of the adverse effects, specifically chemically-induced hemorrhagic cystitis in the case of overdose. However, currently, its use has been re-approved due to the prevalence of antibiotic resistance to drugs, which are more commonly used. This drug is especially suitable for long-term prophylactic urinary tract infection treatments because the bacteria do not develop resistance to formaldehyde. Also, it should not be used in chronic kidney disease presence.

In the form of spray and creams, hexamine is successfully used for the treatment of concomitant odor and excessive sweating with the medical citation.

Solid Fuel

Together with 1,3,5-trioxane, the hexamine fuel tablets component is used by hobbyists, campers, the relief, and military organizations to heat camp food or military rations. It also burns smokelessly, and it holds a high energy density of 30.0 megajoules per kilogram (MJ/kg), which does not liquify while burning, and does not leave ashes, although it has toxic fumes.

Fire-protection laboratories use the standardized hexamine tablets of 0.149 g as a clean and reproducible fire source to test the flammability of rugs and carpets.

Food Additive

Hexamine can also be used as a food additive as a preservative (with the INS number 239). In the EU, it is approved for usage for this purpose, listed under E number E239. However, it is not approved in other countries such as the USA, Australia, Russia, New Zealand.

Reagent in Organic Chemistry

Hexamine compound is a versatile reagent in organic synthesis. It can be used in the Duff reaction (which is the formylation of arenes), in the Delepine reaction (amine synthesis from alkyl halides), and in the Sommelet reaction (by converting benzyl halides to aldehydes).


Hexamine is a base component for making RDX and, consequently, C-4 and Octogen, hexamine the piper chlorate, hexamine dinitrate, and HMTD.

Health Hazards Associated with Hexamine

A few symptoms include mucous membranes, irritation in the eyes, upper respiratory skin, and tract. This compound can also cause skin rash and kidney irritation. Inhaling this compound can cause breath shortness and coughing. When it contacts the skin, it causes rashes, redness, pain, and burns. Whereas, when it contacts with eyes, it causes blurred vision, pain, and redness. Swallowing this compound results in digestive disturbances and urinary tract irritation.

Hexamethylenetetramine compound can be harmful by skin absorption, ingestion, and inhalation. It is also irritation in the eyes, skin, mucous membranes, and upper respiratory tract.

FAQ (Frequently Asked Questions)

1. What are the Uses of Hexamine?

Let us known the use of hexamine briefly.

  • Hexamine can be used in the production of powdery or liquid preparations of phenolic resins.

  • It is used in the form of cream and sprays to treat excessive sweating and concomitant odor.

  • This compound can be used as binders in brake and clutch linings.

  • It is used in the methenamine silver stain of Grocott.

  • It is used as a food preservative.

  • It is also used as a solid fuel.

  • It is used to prevent vulcanized rubber.

  • It can be used as a primary ingredient in RDX making.

  • We can use it as a corrosion inhibitor for steel.

2. List any 3 named reactions that can be used hexamine as a chemical reagent?

The Delepine reaction, the Sommelet reaction, and the Duff reaction involve the hexamine use as a chemical reagent (hexamine chemical).

3. Comment on the odor and appearance of hexamine compounds?

Hexamine acts as a white crystalline solid under certain ambient conditions, which emanates a fishy and ammonia-like smell.

4. Discuss the historical uses of Hexamine?

Being introduced in 1899 into the medical setting as a urinary antiseptic, it was only used in acidic urine cases. However, boric acid was used to treat urinary tract infections, including alkaline urine. One of the Scientists, named "De Eds," found a direct correlation between the acidity of hexamine's environment and its decomposition rate.

Thus, its effectiveness as a drug depended hugely on the urine acidity rather than the drug amount administered. Hexamine was also observed to be almost completely inactive in an alkaline environment.