Hexamin

C with partial decomposition. Synthesized from methanal and ammonia. Hexamine is used as starter fuel for camping stoves, as an... 

Upon heating the polymers, anhydrous gaseous formaldehyde is produced (compare Section 111,17). By allowing a mixture of concentrated ammonia solution and formalin to evaporate, hexamethylenetetramine (also called hexamine, vrotropine) CjHjjNj is formed ... 

Mix 50 ml. of formalin, containing about 37 per cent, of formaldehyde, with 40 ml. of concentrated ammonia solution (sp. gr. 0- 88) in a 200 ml. round-bottomed flask. Insert a two-holed cork or rubber stopper carrying a capillary tube drawn out at the lower end (as for vacuum distillation) and reaching almost to the bottom of the flask, and also a short outlet tube connected through a filter flask to a water pump. Evaporate the contents of the flask as far as possible on a water bath under reduced pressure. Add a further 40 ml. of concentrated ammonia solution and repeat the evaporation. Attach a reflux condenser to the flask, add sufficient absolute ethyl alcohol (about 100 ml.) in small portions to dissolve most of the residue, heat under reflux for a few minutes and filter the hot alcoholic extract, preferably through a hot water fuimel (all flames in the vicinity must be extinguished). When cold, filter the hexamine, wash it with a little absolute alcohol, and dry in the air. The yield is 10 g. Treat the filtrate with an equal volume of dry ether and cool in ice. A fiulher 2 g. of hexamine is obtained. 

From ehloromethyl or bromomethyl aromatic compounds by heating with hexamethylenetetramine (hexamine) in aqueous alcohol or aqueous acetic acid. A quaternary ammonium compound is formed, which yields the aldehyde upon treatment with water in the presence of hexamine for example... 

The process whereby aldehydes are produced from arylmethyl (also alkyl and other) halides by the action of hexamine is known as the Sommelet reaction. The reaction is essentially the conversion of an amine into an aldehyde the hexamine serves the dual role of converting the halide into the amine and the amine into the aldehyde, but its function is different in the two steps. When starting from a halide, the reaction proceeds in three stages —... 

A pH of 6-0-6-5 is generally ensured by the buffering action of the ammonia produced by hydrolysis upon the hexamine salt.)... 

The methylation of benzylamine (1) and of ammonia (2) are competitive processes by increasing the proportion of hexamine, the source of ammonia, the yield of benzaldehyde is increased and that of metliylbenzylamine is decreased. 

Urea - formaldehyde polymers. Formalin and urea (usually in the molecular proportions of 3 2) condense in the presence of ammonia, pyridine or hexamine to give urea - formaldehyde polymers, known commercially as Bedle or Plaskon, and are widely used as moulding powdens. It is believed that the intermediate products in the condensation are methylol-urea and dimethylol-urea ... 

The benzylchloride compound made in the previous recipe can be converted to piperonal or benzaldehyde using a chemical called hexamine [137 p817, 37 p700, 136]. Hexamine, also known as methenamine or hexamethylenetetramine, is a weird looking chemical that is easily made from formaldehyde but is better off being purchased. 

Hexamine, more formally known as Hexamethylenetetramine, is easily and conveniently produced from Formaldehyde and Ammonia solutions. Formaldehyde may be easily produced by depolym-erizing, with heat, Paraformaldehyde (the only ingredient in OTC MildewCide). Hexamine is then reacted with Hydrochloric Acid and heated to yield Methylamine HCI in near quantitative yield. 

The yield of Hexamine should be 140g, white crystals. 

If the crystals are opaque white and do not deliquesce quickly in air of average humidity (65% rh), they may be contaminated with some Hex amine. Washing 100g of the crude product with lOOmL of Chloroform by stirring in a beaker then filtering, repeated as many times as necessary, will remove Hex amine. Methylamine HCI is insoluble in Chloroform whereas Hexamine Is at the rate of 1g to 10mL. 

Ma.nufa.cture. The two most common processes for making RDX and HMX use hexamethylenetetramine (hexamine) as starting material. The Woolwich or direct nitrolysis process used ia the United Kingdom proceeds according to ... 

The Bachmann process, used in the United States and in some European countries, is a simplification of a series of complex reactions. In this process, a solution of one part hexamine in 1.65 parts acetic acid, and a solution of 1.50 parts ammonium nitrate dissolved in 2.0 parts nitric acid and 5.20 parts acetic anhydride are used. The reaction may be summarized as ... 

J. Solomon, Pi Study of the Nitrolysis of Hexamine to Increase HMX Yields, Illinois Institute of Technology, Chicago, 1973. 

Primary and secondary amines readily give alkylaminomethanols the latter condense upon heating or under alkaline conditions to give substituted methyleneamines (59). With ammonia, the important industrial chemical, hexamine, is produced. Tertiary amines do not react. 

Hexamethylenetetramine. Pure hexamethylenetetramine [100-97-0] (also called hexamine and HMTA) is a colorless, odorless, crystalline sohd of adamantane-like stmcture (141). It sublimes with decomposition at >200° C but does not melt. Its solubiUty in water varies Htde with temperature, and at 25°C it is 46.5% in the saturated solution. It is a weak monobase aqueous solutions are in the pH 8—8.5 range (142). Hexamethylenetetramine is readily prepared by treating aqueous formaldehyde with ammonia followed by evaporation and crystallisation of the soHd product. The reaction is fast and essentially quantitative (142). 

A number of disinfectants apparentiy owe their activity to formaldehyde, although there is argument on whether some of them function by other mechanisms. In this category, the dmg with the longest history is hexamethylenetetramine (hexamine, urotropin) [100-97-0] which is a condensation product of formaldehyde and ammonia that breaks down by acid hydrolysis to produce formaldehyde. Hexamine was first used for urinary tract antisepsis. Other antimicrobials that are adducts of formaldehyde and amines have been made others are based on methylolate derivations of nitroalkanes. The apphcations of these compounds are widespread, including inactivation of bacterial endotoxin preservation of cosmetics, metal working fluids, and latex paint and use in spin finishes, textile impregnation, and secondary oil recovery (117). 

Hexamine — see Hexamethylenetetramine 1,4,7,10,13,16-Hexaoxacyclooctadecane — see [18]Crown-6 Hexazinone as herbicide, 1, 187 Hex-2-enopyranoside, 2,3-dideoxy-synthesis, 1, 464 Hexobarbital, 3, 150 Hexogen, 3, 530 a-D-galacto- Hexopyranose nomenclature, 1, 31 Qf-D-ido-Hexopyranose nomenclature, 1, 31... 

During the past four decades phenolic resins have become of increased significance in rubber compounding. For example, the resin based on cashew nut shell liquid, which contains phenolic bodies such as anacardic acid (Figure 23.23), may, when blended with hexamine, be incorporated into nitrile rubber (butadiene-acrylonitrile rubber). 

Similar products from natural rubber may be made by fluxing a cresol novolak containing hexamine with the rubber at 150°C. 

Urea-formaldehyde powders have a limited shelf-life but some improvement is made by incorporating a stabiliser such as hexamine into the moulding power. In some formulations the cure rate and the related time for flow are controlled by keeping the latent acid catalyst fixed and adjusting the stabiliser. 

The resins are hardened by acidic conditions. Phosphoric acid, or more commonly ammonium chloride, an acid donor, is employed. The ammonium chloride functions by reaction with formaldehyde to give hydrochloric acid. Hexamine is also formed during this reaction. 

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