Distillation kinetics of solid mixtures of hydrogen peroxide and water and the isolation of pure hydrogen peroxide in ultrahigh vacuum

We present results of the growth of thin films of crystalline H ₂O₂ and H₂O₂·2H ₂O₂ (dihydrate) in ultrahigh vacuum by distilling an aqueous solution of hydrogen peroxide. We traced the process using infrared reflectance spectroscopy, mass loss on a quartz crystal microbalance, and in a few cases ultraviolet-visible reflectance. We find that the different crystalline phases-water, dihydrate, and hydrogen peroxide-have very different sublimation rates, making distillation efficient to isolate the less volatile component, crystalline H₂O₂.