HMX is a very powerful military explosive with similar properties to RDX, the other great military explosive with which it is often mixed. HMX is technically called octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine, other names include 1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane; cyclotetramethylene tetranitramine; and octogen. HMX is itself an acronym for either High velocity Military eXplosive, or Her Majesties eXplosive depending on what country you are in. HMX is very stable, it requires a powerful detonator or booster charge to detonate. It was first developed during WWII in the never ending search for more powerful bombs.
|acetic acid||500/1000-mL beaker|
|acetic anhydride||500-mL Florence flask|
|ammonium nitrate||graduated cylinder|
Prepare a solution of 748 mL of glacial acetic acid, 12 mL of acetic anhydride, and 17 g of paraformaldehyde, keep this solution at 44 °C while mixing. Prepare a second solution of 217.6 g of ammonium nitrate and 154.6 mL of 99% nitric acid in a 500-mL beaker. Prepare a third solution of 101 g of methenamine, 157 mL of glacial acetic acid, and 296 mL of acetic anhydride in a 1000-mL beaker. Combine the third solution with 112.5 mL of the second solution. Add this combined solution to the first solution over a 15 minute period while stirring rapidly. After the addition, continue stirring for an additional 15 minutes. Next, carefully add 296 mL of acetic anhydride, then carefully add the remainder of the second solution, then add another 148 mL of acetic anhydride, all while stirring. Continue the stirring for 1 hour more. After stirring, add 350 mL of hot water and reflux the whole works for 30 minutes. After this time, cool the liquid down to 20 °C by adding ice. Decant off as much of the liquid from the precipitate as possible and drown the remaining crystals with cold water. Filter to collect the crystals of HMX and wash them with three portions of cold water, allow to dry. The yield is about 95%. You will need a graduated cylinder for measuring liquids, a stirring rod or magnetic stirrer for mixing, and a thermometer to monitor the temperature.
Owing to the large volume of reactants in this lab, in excess of 2.5 L, it is necessary to use a 5-L flask, unfortunately this is beyond most laboratories, and especially the home chemist. This reaction can be carried out in a glass gallon jug or similar large capacity glass container. The refluxing step can be done in portions using a round-bottomed 500-mL Florence flask.
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