Sciencemadness Discussion Board


Chem Science - 4-8-2018 at 18:50

Hello everyone !!
So Dioxane is a nice solvent for chemistry, particularly amateru chemistry. It's an ether and can sustain Grignard ( although it has its problems like complex formations so reserch is good in these case ) it is miscible with water and easily made in amateur lab, There are alternatives to the Sulfuric Acid dehydrating agent ( My post using phosphoric acid )But like all ethers Dioxane forms Peroxide on storage, and removing theme is important. There are methods that use solutions of Iron (ll) salts, but my problem was that adding water is detrimental, because i then had to remove it, and dont have acces to sodium metal that will dry it nicely. so i tried a method that uses very little to no water, and works well for peroxide removal


I used 400ml of Dioxane ( Bottle was closed from 1998 so i bet my ass it has a lot of peroxides ) that was positive for peroxides with iodine test. to these i add 5g of anhydrous ferrous chloride and 5g of Sodium bisulfate monohydrate and a stirr bar, i close the aparatus and let it stirr for 30hs the solution turns light red from Iron (III) formation . I tested for peroxides in between time to se the progres ( See Peroxide Test ) After no peroxide wass detected, the dioxane was filtered and 25g of Sodium Hydroxide was added and let sit for 24hs. I didint have sodium or sodium-Magnesium oxide agreggate to dry but here is a good place to use it!!. Distillation of these dioxane to ALMOST DRYNESS gets you Dry peroxide free dioxane boiling at 101 degrees.

Take 5 ml or less of Dioxane and add an equal volume of distilled water, To these add 0,5g of NaOH and agitate for 5 min. Filter these by gravity ( Do not assist filtration ) Then pipete out the dioxane layer and test the presence of peroxide using a solution of 5% KI acidified with 10% HCl and Starch suspension. A blue color indicates presence of peroxides.

These method is good if you don't want to deal with the removal of water from the peroxide removal step, and it works well. Yeah the super old Dioxane is now back on service for me... See you Nex Time !!

elementcollector1 - 4-8-2018 at 18:53

Nice! Can you post some pics of your process?

Chem Science - 4-8-2018 at 19:42

Sorry :( but i Didn't take pictures .. i didn't thought about that.