{{#if:140.186 g/molC6H12N41.33 g/cm³ (at 20 °C)280 °C (sublimes)85.3 g/100 mL|! style="background: #F8EABA; text-align: center;" colspan="2" | Properties
Hexamethylenetetramine
Identifiers
CAS number 100-97-0 YesY
PubChem 4101
ChemSpider 3959 YesY
UNII J50OIX95QV YesY
EC number 202-905-8
KEGG D00393 N
MeSH Methenamine
ChEMBL CHEMBL1201270 N
Jmol-3D images Image 1
Molecular formula C6H12N4
Molar mass 140.186 g/mol
Density 1.33 g/cm³ (at 20 °C)
Boiling point

280 °C (sublimes)

Solubility in water 85.3 g/100 mL
Hazards
Main hazards Highly flammable, harmful
Autoignition
temperature
410 °C (770 °F)
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Hexamethylenetetramine 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 chemical compounds, e.g. plastics, pharmaceuticals, rubber additives. It sublimes in a vacuum at 280 °C.

The compound was discovered by Aleksandr Butlerov in 1859.[1]

Synthesis, structure, reactivity

Hexamethylenetetramine is prepared by the reaction of formaldehyde and ammonia.[2] The reaction can be conducted in gas-phase and in solution.

The molecule has a symmetric tetrahedral cage-like structure, similar to adamantane, whose four "corners" are nitrogen atoms and "edges" are 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 molecule behaves like an amine base, undergoing protonation and N-alkylation.

Applications

The main 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.[2]


Outdated Medical Uses

Urotropine in combination with other antibiotics were widespreadedly used back in 1965's to 1990 to deal in combating Urinary Infections until proved for its harmful side effects

Histological stains

Methenamine silver stains are used for staining in histology, including the following types:

Combustion

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 (30.0 MJ/kg), does not liquify while burning, and leaves no ashes.

Standardized 0.149 g tablets of methenamine (hexamine) are used by fire-protection laboratories as a clean and reproducible fire source to test the flammability of carpets and rugs.[3]

The explosives RDX, HMX, and HMTD can be derived from hexamethylenetetramine.

Reagent in organic chemistry

Hexamethylenetetramine is a versatile reagent in organic synthesis. It is used in the Duff reaction (formylation of arenes),[4] the Sommelet reaction (converting benzyl halides to aldehydes),[5] and in the Delepine reaction (synthesis of amines from alkyl halides).[6]

Producers

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.[3]

References

  1. http://library.istu.edu/hoe/books/ruschem.pdf
  2. 2.0 2.1 Karsten Eller, Erhard Henkes, Roland Rossbacher, Hartmut Höke "Amines, Aliphatic" in Ullmann's Encyclopedia of Industrial Chemistry, 2005 Wiley-VCH Verlag, Weinheim. doi:10.1002/14356007.a02_001
  3. 3.0 3.1 Alan H. Schoen (2004), Re: Equialence of methenamine Tablets Standard for Flammability of Carpets and Rugs. U.S. Consumer product Safety Commission, Washington, DC, July 29, 2004.
  4. A. T. Bottini, Vasu Dev, and Jane Klinck (1963), "Syringic Aldehyde", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV4P0866; Coll. Vol. 4: 866
  5. Kenneth B. Wiberg (1963), "2-Thiophenaldehyde", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV3P0811; Coll. Vol. 3: 811
  6. A. T. Bottini, Vasu Dev, and Jane Klinck (1963), "2-Bromoallylamine", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=CV5P0121; Coll. Vol. 5: 121