|Preferred IUPAC name
Urotropine; Formin, Aminoform
3D model (JSmol)
|E number||E239 (preservatives)|
CompTox Dashboard (EPA)
|Molar mass||140.186 g/mol|
|Appearance||White crystalline solid|
|Odor||Fishy, ammonia like|
|Density||1.33 g/cm3 (at 20 °C)|
|Melting point||280 °C (536 °F; 553 K) (sublimes)|
|85.3 g/100 mL|
|Solubility||Soluble in chloroform, methanol, ethanol, acetone, benzene, xylene, ether|
|Solubility in chloroform||13.4 g/100 g (20 °C)|
|Solubility in methanol||7.25 g/100 g (20 °C)|
|Solubility in ethanol||2.89 g/100 g (20 °C)|
|Solubility in acetone||0.65 g/100 g (20 °C)|
|Solubility in benzene||0.23 g/100 g (20 °C)|
|Main hazards||Highly combustible, harmful|
|GHS Signal word||Warning|
|P210, P240, P241, P261, P272, P280, P302+352, P321, P333+313, P363, P370+378, P501|
|NFPA 704 (fire diamond)|
|Flash point||250 °C (482 °F; 523 K)|
|410 °C (770 °F; 683 K)|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
Hexamethylenetetramine, also known as methenamine, hexamine, or urotropin, is a heterocyclic organic compound with the formula (CH2)6N4. This white crystalline compound is highly soluble in water and polar organic solvents. It has a cage-like structure similar to adamantane. It is useful in the synthesis of other organic compounds, including plastics, pharmaceuticals, and rubber additives. It sublimes in vacuum at 280 °C.
Hexamethylenetetramine was discovered by Aleksandr Butlerov in 1859. It is prepared industrially by combining formaldehyde and ammonia. The reaction can be conducted in gas phase and in solution.
The molecule has a tetrahedral cage-like structure, similar to adamantane. Four vertices are occupied by nitrogen atoms, which are linked by methylene groups. Although the molecular shape defines a cage, no void space is available at the interior for binding other atoms or molecules, unlike crown ethers or larger cryptand structures.
The dominant use of hexamethylenetetramine is in the production of powdery or liquid preparations of phenolic resins and phenolic resin moulding compounds, where it is added as a hardening component. These products are used as binders, e.g. in brake and clutch linings, abrasive products, non-woven textiles, formed parts produced by moulding processes, and fireproof materials.
As the mandelic acid salt (generic methenamine mandelate, USP) it is used for the treatment of urinary tract infection. In an acidic environment, methenamine is believed to act as an antimicrobial by converting to formaldehyde. A systematic review of its use for this purpose in adult women found there was no good evidence of benefit.
Together with 1,3,5-trioxane, hexamethylenetetramine is a component of hexamine fuel tablets used by campers, hobbyists, the military and relief organizations for heating camping food or military rations. It burns smokelessly, has a high energy density of 30.0 megajoules per kilogram (MJ/kg), does not liquify while burning, and leaves no ashes, although its fumes are toxic.
Hexamethylene tetramine or hexamine is also used as a food additive as a preservative (INS number 239). It is approved for usage for this purpose in the EU, where it is listed under E number E239, however it is not approved in the USA, Russia, Australia, or New Zealand.
Hexamethylenetetramine is a versatile reagent in organic synthesis. It is used in the Duff reaction (formylation of arenes), the Sommelet reaction (converting benzyl halides to aldehydes), and in the Delepine reaction (synthesis of amines from alkyl halides).
Hexamethylenetetramine was first introduced into the medical setting in 1899 as a urinary antiseptic. However, it was only used in cases of acidic urine, whereas boric acid was used to treat urinary tract infections with alkaline urine. Scientist De Eds found that there was a direct correlation between the acidity of hexamethylenetetramine's environment and the rate of its decomposition. Therefore, its effectiveness as a drug depended greatly on the acidity of the urine rather than the amount of the drug administered. In an alkaline environment, hexamethylenetetramine was found to be almost completely inactive.
Hexamethylenetetramine was also used as a method of treatment for soldiers exposed to phosgene in World War I. Subsequent studies have shown that large doses of hexamethylenetetramine provide some protection if taken before phosgene exposure but none if taken afterwards.
Since 1990 the number of European producers has been declining. The French SNPE factory closed in 1990; in 1993, the production of hexamethylenetetramine in Leuna, Germany ceased; in 1996, the Italian facility of Agrolinz closed down; in 2001, the UK producer Borden closed; in 2006, production at Chemko, Slovak Republic, was closed. Remaining producers include INEOS in Germany, Caldic in the Netherlands, and Hexion in Italy. In the US, Eli Lilly and Company stopped producing methenamine tablets in 2002. In Australia, Hexamine Tablets for fuel are made by Thales Australia Ltd. In México, Hexamine is produced by Abiya.