[Chemistry Class Notes] Hexamine Pdf for Exam

Hexamine is a heterocyclic organic compound that has the chemical formula C6H12N4. It is also known as Hexamethylenetetramine, Methenamine, or Urotropin. Hexamine acts as an anti-infective agent, the most commonly used element to treat urinary tract infections. 

Aleksandr Butlerov discovered the Hexamine powder in 1859.

Industrially, it is prepared by the combination of ammonia and formaldehyde and the reaction can be conducted in a gas phase and solution.

The molecule contains a symmetric tetrahedral cage-like structure, similar to adamantane, whose “edges” are methylene bridges, and the four “corners” are nitrogen atoms.

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.

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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 an 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 molding 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 molding 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

The mandelic acid salt is used for urinary tract infection treatments, and it decomposes at an acidic pH to produce ammonia, and formaldehyde, which is bactericidal, which the mandelic acid adds to this effect. The use of this compound was temporarily reduced in the late 1990s, because of the adverse effects, specifically because of the chemically-induced hemorrhagic cystitis in the case of overdose. 

Hexamine is considered to be suitable for the long-term prophylactic urinary tract infection treatments. Hexamine should not be used in chronic kidney disease presence. Hexamine is used in the treatment of concomitant odor and excessive sweating.

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 smokeless, 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).

Explosives

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

Some symptoms include mucous membranes, irritation in the eyes, upper respiratory skin, and tract. Inhaling this compound can cause shortness of breath and coughing. When it comes into contact with the skin, it causes rashes, redness, pain, and burns. Whereas, when it comes into contact with the eyes, it causes blurred vision, pain, and redness. Swallowing Hexamine disturbs the digestive and the urinary tract  and causes irritation. Hexamethylenetetramine compounds can be harmful by skin absorption, ingestion, and inhalation. It is also irritation in the eyes, skin, mucous membranes, and upper respiratory tract.