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Post by crpearson on Jan 15, 2020 18:02:18 GMT
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Post by rayrocketman on Jan 25, 2020 19:33:41 GMT
A few thoughts on hydrogen peroxide purification and concentration. I have never attempted this, but have queried those that have at length.
First, start with the purest and most concentrated feed stock practical. Semiconductor grade seems ideal.
Second, be aware that hydrogen peroxide is always decomposing and heat accelerates that process. Typically, hydrogen peroxide is distilled under vacuum to lower the boiling temperature.
Third, be especially aware that while hydrogen peroxide is detonable in the liquid form, it is significantly more sensitive in the vapor form.
Water desensitizes hydrogen peroxide by providing a "cushion" between molecules, dampening any shock waves that may be initiated.
There are other ways to separate the two: sparging is the process of bubbling clean, dry air though the solution, which carries water off easier than hydrogen peroxide due to its lower boiling point.
In addition to different boiling points, water and hydrogen peroxide have different freezing points and may be separated in this manner. Be aware that there is a eutectic at around 65% H2O2. Some other form of separation must be employed to get past this region. Above this point, freeze separation may once again be employed to obtain a very pure product.
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Post by crpearson on Feb 4, 2020 19:10:33 GMT
It seems like the standard process is to (as you said) begin with the best feed stock you can with a few stabilizers as possible. Using vacuum distillation with tall condensers to pull off the water leaving something above 65% which can then be purified with fractional crystallization.. This can then be diluted back down to 90% with distilled water. Like you, I have note done this yet, but have had a number of conversations with folks who are familiar with it. The idea of having H2O2 in vapor form is very scary to me, and it seems avoiding that is a very good idea. Fractional crystallization also has the advantage of dramatically reducing any stabilizers or impurities that have been added.
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