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iaminoglyoxime is shown in the foreground, following filtration and drying from the reaction mixture. In the background, DAG is being synthesized in a pair of 500 gram scales. Photo: Eric C. Johnson

Diaminoglyoxime, or DAG, is an extremely powerful high-energy explosive. But one significant drawback is the waste involved, since 60 percent of the possible product is lost in the traditional method. It can also be dangerous, because of the heat released in the process, which brings with it the possibility of accidental combustion.

A new recipe developed by scientists from the U.S. Army Research Laboratory and the Lawrence Livermore National Laboratory instead lowers that loss to just 20 percent, according to a new paper in the American Chemical Society’s journal Organic Process Research and Development.

“The new DAG synthesis is much cheaper and safer to produce, thus paving the way for this material to be made in larger scale quantities,” said Jesse Sabatini, an Army Lab chemist and one of the authors.

In the old method, glyoxal was treated with hydroxylammonium chloride and sodium hydroxide to form glyoxime. That compound was then treated again with both hydroxylammonium chloride and sodium hydroxide – except this time at 95 degrees Celsius. The two recrystallizations were necessary to get the pure form of the product, the scientists report. A second process could take just one combination of four parts each of hydroxylammonium chloride and sodium hydroxide and was completed in just a few hours – but led to a loss of the majority of the material.

Throughout the two processes, the possibility of the high heat released in the reaction causing ignition needs to be closely monitored, the scientists say.

“This can lead to an unintentional combustion event or an unintended explosion,” said Sabatini. “Due in part to these cost and safety issues, explosive derived from DAG have seen limited potential application.”

The new procedure involves three full days of stirring – but works much more efficiently, they report.

“By simply adding an aqueous solution of glyoxal to an aqueous solution of hydroxylamine heated to 95 degrees Celsius, followed by stirring for three days, DAG is produced in a much improved 80 percent yield,” said Sabatini.

Additionally, not much heat is released, the scientists conclude.

“The exothermic nature of the reaction is also minimized by this updated process,” they write.

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