Sciencemadness Discussion Board

Manganese dioxide effectiveness issues

German - 2-4-2019 at 14:10

Has anyone had any issues or know of any issues of varying effectiveness of manganese dioxide? The reason I ask is because I tried a very simple, well known, historically reproducible MnO2 oxidation on a very expensive sample and there was no reaction as per TLC. It should have moved completely from 0.22 to 0.77. However, a related very similar sample with the same MW is known not to react at all... and that substance is substantially cheaper. So I do not know if I should be calling out my supplier (which unfortunately I already jumped the gun at doing) or if I can blame the MnO2 which would be the only other possibility. The MnO2 was purchased on Ebay but it was reagent grade and from a seller I have been satisfied with by other items. I am wondering if there is some reason why I need to purchase the Mn02 from a reputable chemical supply house like I do for most chems.

So does MnO2 have known varied activity levels depending on preparation? Or maybe the target sample is not what I paid for.

German - 2-4-2019 at 15:32

I think I found my answer. MnO2 seems to need to be activated since water seems to make in unactive. Activated MnO2 is usually either made fresh from a variety of ways so there are no hydrates to begin with, or apparently just some oven drying can activate deactivated MnO2.

Feel free to either remove post or leave it up in case someone else runs into the same issue.

S.C. Wack - 2-4-2019 at 16:20

http://reag.paperplane.io/00001793.htm