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I'm planning to get hold of some 99% isopropyl alcohol (aka rubbing alcohol) for the purpose of cleaning electronics, and am going to transfer it from the plastic bottle it comes in to a smaller, clear dropper bottle or similar. However, I vaguely remember being told that isopropyl alcohol shouldn't be stored in a clear container - possibly something to do with speedier evaporation, but I'm really not sure.

Is this true? Are there any downsides to storing 99% isopropanol in a clear container? Will storing the solution in direct sunlight change this at all?

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    $\begingroup$ Generally more transfer means purity goes down. However this can be negligible. No a clean container does nothing bad. Shadow and caps are generally better. Storing a solvent with no cap is not safe or likely no storing at all :) $\endgroup$ – Alchimista Mar 27 '18 at 9:36
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    $\begingroup$ Ps isopropyl alcohol for cleaning is justified in industrial environments. For most cases ethanol etc work as well $\endgroup$ – Alchimista Mar 27 '18 at 9:37
  • $\begingroup$ @Alchimista What do you mean by shadow? $\endgroup$ – Hashim Mar 27 '18 at 9:38
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    $\begingroup$ I mean common sense. Do not store anything on a beach $\endgroup$ – Alchimista Mar 27 '18 at 9:39
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    $\begingroup$ @Alchimista Definitely don't. Pirates are everywhere! $\endgroup$ – Karl Jan 31 at 9:43
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I would not expect that isopropanol would evaporate appreciably from a properly sealed container. Rather the main purpose of storing isopropanol out of light is to prevent peroxide formation. Isopropanol can form peroxides and when distilled they can concentrate and explode. A clear container allows more light to pass and thus more peroxides to form.

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I am no expert, but I have some experience dealing with solvents such as isoproponal in a research setting. Normally in a lab solvents are not stored in the open, exposed to light, for the exact reason that you mentioned- speedier evaporation. Hence, even if you were to store it in a clear container, I would make sure to cap it and stow it away in a dark place as soon as you are finished with it.

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    $\begingroup$ Alcohols exposed to light form peroxides. The guy responsible for lab safety in your place should get a hard kick in the back if he didn't explain why exactly you have to keep most solvents not only cool but also in the dark. $\endgroup$ – Karl Jan 31 at 9:41

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