What Do Heat Tablets and Food Additives Have in Common?

October 29, 2015 , Anton Kozyrev

Hexamethylenetetramine, also known as hexamine or methenamine, is the main component of heat tablets, which are often used as a heat source by campers and soldiers. However, it has also found an application in polymer synthesis, medicine, and even in food production. Let’s have a closer look at the compound that plays such an important role in our lives.

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{EverExplore: The camp/ CC BY-NC-ND 2.0}

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{Yikrazuul : Synthesis of hexamine / CC0}

Hexamine and Campers

Back in the days of our childhood, most of us enjoyed spending time in summer camps and doing some hiking there. During our hiking trips, we occasionally cooked meals over a campfire. As romantic as it sounds, making a campfire actually took lots of time and effort: it was especially hard to find appropriate wood.

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{Jelle: Campfire in Belarus/CC BY-SA 2.0}

To overcome this obstacle modern campers use heat tablets, more often called Esbit. These tablets are ultra-lightweight, portable, burn without smoke, and have a very high energy density. There are some drawbacks though, such as possible allergic reactions and toxic fumes (formaldehyde, ammonia, nitrogen oxide, hydrogen cyanide). These toxic fumes (red colored) come mainly from the oxidation and decomposition of hexamine. Below you can see some possible hexamine oxidation and decomposition reactions:

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{Anton K @ MEL Science: Reactions of hexamine/CC0}

Hexamine as a Food Additive

Hexamine is useful not only for campers, but also for food manufacturers. This substance is a common food additive (E239). It is used in cheese, canned fish, and caviar production as a preservative with antifungal and antibacterial effects. Being approved for usage in EU food industry, methenamine is prohibited in the USA, New Zealand, Australia, and Russia, mainly because it can cause long-term stomach indigestion, make asthma worse, and irritate skin. Think of it next time you buy some cheese or fish in the supermarket!

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{Arz: Maasdam cheese /CC BY-SA 3.0}

Other Applications of Hexamethylenetetramine

Besides heat tablets and food additives, hexamine is also used as a vulcanizing and rubber blowing agent, as a stabilizer for oil and synthetic resin, as an anti-corrosive agent in steel, as an additive in deodorizing powder, as a dye fixative, and in explosives production. However, one of its most important applications is as a medicine for urinary tract infections. The mechanism of drug action is based on the fact that in acidic pH hexamethylenetetramine breaks down to its original substances. Formaldehyde, which is one of the decomposition products, has a bactericidal effect. So, summarizing all the information stated in this article, we can easily draw a conclusion that hexamine is an essential compound in industry, medicine, and our everyday life.

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