Cryogenic vacuum trapping, isolation

The PAN was isolated from the numerous side products by gas chromatography on preparatorysized columns and collected by cryogenic trapping. The PAN was then placed in large air canisters, diluted with zero air, and stored in a cold room for future use. Safety precautions are required with this method, because explosive accidents have been reported. The cause of the explosions is believed to be condensation of PANs in vacuum or pressure gauge systems. Like all nitrates, the peroxy nitrate PAN has explosive potential, and care must be taken when handling PAN on metal surfaces. The Stephens synthetic approach illustrated by Reaction 19.7 to Reaction 19.11 was quite successful, and a number of publications on the toxicity of PAN and its chemical and physical properties resulted from the use of the scheme. ... 

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