Wikibooks : Chemical synthesis/Methyl ethyl ketone peroxide

Chemical synthesis/Methyl ethyl ketone peroxide

From Wikibooks, the open-content textbooks collection, as of september 6, 2007

Read Wikibooks:Risk disclaimer before attempting anything on this page. Some of the information here may be incorrect, unverified, and dangerous.

Required chemicals / apparatus

* 40mL 27.5% H2O2 solution (hydrogen peroxide)
* 25mL CH3COCH2CH3 (methyl ethyl ketone, butanone) [beware - this will dissolve most plastics. Use a glass syringe!]
* 5mL 98% H2SO4 (w:sulphuric acid)
* 200mL NaHCO3 solution
* 2x 100mL beaker
* 300mL beaker
* Glass syringe
* Glass rod
* Standard laboratory equipment
* Safety equipment, minimally including heavy leather gloves, impact-resistant goggles, hearing protection, and face shield.

Synthesis
(anhydrous dimeric form - appears as an oily liquid, more stable but more powerful)

As with other reactions that pose the risk of explosion, synthesis should not be performed in an enclosed area.

Place 25mL of methyl ethyl ketone in a 100mL beaker. Place this beaker in an ice bath at temperatures ranging preferrably from -10 to 5°C; the lower end of the described recommended temperature range is preferable. (To achieve this, you can use w:dry ice) Then, place 40mL of 27.5% H2O2 solution in a 100mL beaker. Place this beaker in an ice bath at temperatures ranging preferably from -10 to 5°C; the lower end of the described recommended temperature range is preferable. Wait for the temperature of both the methyl ethyl ketone and the temperature of the 27.5% H2O2 solution to fall into the recommended temperature range. Then, pour the beaker of methyl ethyl ketone into the beaker of hydrogen peroxide solution. Stir this solution for thirty seconds.

Add 5mL of 98% sulphuric acid slowly, drop by drop, taking care to keep temperatures within the recommended temperature range, into the beaker containing the monomeric methyl ethyl ketone peroxide. If the temperature rises above 5°C, stop adding the sulphuric acid immediately.

After all of the sulphuric acid is added, wait 24 hours. It is highly recommended to attempt to keep the temperatures within the recommended temperature range during the entirety of every step (this is a very common mistake made when attempting to make trimeric acetone peroxide; most will not bother to keep the temperatures around zero degrees Celcius while waiting 24 hours or so for the reaction to complete; the result of that is far less stable acetone peroxide due to lower yields of the trimeric form and higher yields of the dimeric form).

The beaker should by now have two layers; a thick oily layer on the top, and a translucent white, relatively thin liquid on the bottom. The thick oily layer on top is the anhydrous dimeric methyl ethyl ketone peroxide. All traces of acid must now be removed. Pour this beaker into a 300mL beaker. Then slowly add 200mL of NaHCO3 solution. Stir vigorously for five minutes; try to keep the size of the pockets of the oily liquid (the anhydrous dimeric methyl ethyl ketone peroxide) as small as possible when stirring. Most of the anhydrous dimeric methyl ethyl ketone peroxide will now begin to sink to the bottom of the beaker. Extract it with a syringe. Some will also remain on the surface; extract this also with a syringe (it is possible to isolate the anhydrous dimeric methyl ethyl ketone peroxide by decantation, but this process can be very time consuming, frustrating, and you will not be able to harvest nearly as much of the anhydrous dimeric methyl ethyl ketone peroxide as by the syringe extraction method).

If you wish to further deacidify the anhydrous dimeric methyl ethyl ketone peroxide, place it in an airtight aluminum container, in an ice bath (extremely important!). Leave the methyl ethyl ketone peroxide in the airtight aluminum container until bubbles no longer form. A safer alternative to this process is to add non-crumpled pieces of aluminum foil to the anhdrous dimeric methyl ethyl ketone peroxide (also in an ice bath); however this will often make it difficult to recollect all of the anhdrous dimeric methyl ethyl ketone peroxide, due to it sticking to the pieces of aluminum foil; it can be very difficult to remove from that surface.

Now pour the deacidified anhydrous dimeric methyl ethyl ketone peroxide into an open glass, or plastic (not made of a polyhydrocarbon plastic!). Let it stay in the open at temperatures around 15°C to allow most of the water to evaporate off. Now that the anhydrous dimeric methyl ethyl ketone peroxide is dehydrated, it is ready for use.

Even though it is not recommended to store MEKP for a long time, if need be you can pour the anhydrous dimeric methyl ethyl ketone peroxide into a sealed plastic container (not made of a polyhydrocarbon plastic!) for storage. The reason for sealing it is to prevent loss of anhydrous dimeric methyl ethyl ketone peroxide due to evaporation. The lower the temperatures are during storage, the better, with the exception of temperatures so low that it freezes the anhydrous dimeric MEKP.