Sciencemadness Discussion Board

Decomposing methyl iodide

Dihydrogenmonoxide - 12-6-2023 at 13:47

I have a quantity of a couple grams of methyl iodide to get rid off. The wiki and other soures recommend the reaction with hydroxide solution to decompose to methanol + iodide, but while this has reacted with all the free iodine that was dissolved it has over multiple days not lead to a visible decrease in the amount of MeI, the reaction rate appears to be very low.

Is there any practical way to convert methyl iodide to something safe?

[Edited on 12-6-2023 by Dihydrogenmonoxide]

unionised - 12-6-2023 at 14:07

Are you stirring it?

Anyway, I suspect the reaction with ammonia would be quicker.

Dr.Bob - 13-6-2023 at 09:13

any amine will be much faster.

Metacelsus - 14-6-2023 at 06:23

Yes, add it to ammonia. This is also how I got rid of dimethyl sulfate back when I was using it in my chemistry research.

woelen - 14-6-2023 at 23:27

Is it only a few grams? I would suggest going outside in the wind, pouring all of your liquid on a piece of paper tissue. Any CH3I quickly evaporates (I think it only takes minutes) and is blown away, the wet piece of tissue can be thrown in the waste bin. In nature, the CH3I will have a very short half life. I expect it to be gone within a day, especially if it is sunny and warm. The amount is so small that you could even do this on a balcony, when your neighbours are not sitting outside (also take into account the people above and below your apartment!).

chloric1 - 15-6-2023 at 16:57

Quote: Originally posted by woelen  
Is it only a few grams? I would suggest going outside in the wind, pouring all of your liquid on a piece of paper tissue. Any CH3I quickly evaporates (I think it only takes minutes) and is blown away, the wet piece of tissue can be thrown in the waste bin. In nature, the CH3I will have a very short half life. I expect it to be gone within a day, especially if it is sunny and warm. The amount is so small that you could even do this on a balcony, when your neighbours are not sitting outside (also take into account the people above and below your apartment!).

Well that’s the simplest approach but if it was a larger portion I’d personally want to reclaim the elemental iodine. If sodium hydroxide is not attacking the MeI, add methanol,acetone or ethanol. All of those dissolve the resulting sodium iodide quite nicely.