Sciencemadness Discussion Board

OTC benzoyl peroxide...

evil_lurker - 24-5-2005 at 16:43

I am working on a way to isolate the benzoyl peroxide out of some fiberglass resin hardener.

The product is approx 50% by weight, however it has some type of damn plasticizer in it called isodecyl benzoate compromising most of the other weight along with 1-5% of some surfactant called Ucon lubricant 50-HB-260 (CAS#9038-95-3) .

Anyways, how would be the best way to get to the good stuff out?

Neither the benzoyl peroxide or the isodecyl benzoate is soluable in water, however the surfactant is. The benzoyl peroxide has a specific gravity that is greater than water (1.33) and is a solid, and the isodecyl benzoate is oily and has a specific gravity of less than water (.95). Both are soluble in methanol.

Would it be a proper extraction to first take a small amount of methanol and dissolve the hardener cream into it, then simply add water until the benzoyl peroxide precipitates out of the solution, decant, and wash again?



[Edited on 25-5-2005 by evil_lurker]

chemoleo - 24-5-2005 at 16:50

I remember having done precisely this a long time ago, use trichloroethylene to dissolve the hardener in, and heat gently. Iirc the crystals of benzoyl chloride form shortly after, and after a couple of repeats one gets a fairly pure sample.
It burns well with a smokey flame.

evil_lurker - 24-5-2005 at 17:14

I was hoping to skip the benzoyl chloride and go straight for the peroxide.

Is this going to be possible with cool methanol or will the benzoyl peroxide attack it and I end up with benzoyl chloride?

chemoleo - 24-5-2005 at 17:22

Eh?

It's just a recrystallisation of the b.p., no benzoyl chloride or anything.
Most chlorinated solvents should work (for their inertness), but methanol may be not ideal.
Try chloroform for starters.

evil_lurker - 24-5-2005 at 17:38

I'm trying to keep the whole deal as OTC as possible.

It doesn't help much that I'm new to the whole chemistry thing either.

Guess I'll try to get my hands on some and see what happens... I just won't dehydrate the final product until right before I am ready to use it.

Nicodem - 25-5-2005 at 01:20

Pure benzoylperoxide is quite instable. And the additive is not only a plasticizer but it is also there to dillute and stabilize the benzoyl peroxide.
What do you need it for? If you need it as a radical iniciator, I think you can use the 50% one without problems as this same preparation is used exactly as a radical iniciator itself (for styrene polymerizations). There is no need to purify it and you don't need much of it neither.

[Edited on 25-5-2005 by Nicodem]

evil_lurker - 25-5-2005 at 04:57

I was toying with the idea of chlorinating toluene according to vogel's using surfuryl chloride and the benzoyl peroxide as a radical initiator.

According to Vogel's "with an excess of sulphuryl chloride, benzal chloride is formed, but chlorination does not proceed beyond this stage.

Purifying benzoyl peroxide medication?

rsgpit - 31-5-2006 at 13:53

I just though of an easy source of primary explosive. Acne medication is 10% benzoyl peroxide and comes in 56g tubes. Thats 5.6g of the organic peroxide similar to AP and MEKP. I tried to dissolve it, because it is only slightly soluable in water, but the rest of the ingredients that are unlisted are insoluable in water. Does anyone know a way to purify the medication in to 90-100% purity range?

guy - 31-5-2006 at 14:10

What are the other ingredients?

rsgpit - 31-5-2006 at 14:20

Carbomer, Disodium EDTA, Hydroxypropyl Methylcellulose, Laureth-4, Sodium Hydroxide, Water.


Just found it.

guy - 31-5-2006 at 14:34

Soluble in water: carbomer(acrylic acid), disodium EDTA, sodium hydroxide
Soluble in alcohol: Laureth-4 (dodecanol)

Hydroxypropyl Methylcellulose is insoluble in hot water and soluble in cold water. I don't know if the benzoyl peroxide will decompose in hot water.

rsgpit - 31-5-2006 at 14:46

I bet that if i dissovle the water soluable ingredients and leave the laureth 4, it will act as somewhat of a stabilizer, or just completely ruin the properties we want. Ill try it tomorrow in cold water.

chemoleo - 31-5-2006 at 16:03

I just merged this thread as it is on the same topic of purification, albeit a different source.

Quote:
Thats 5.6g of the organic peroxide similar to AP and MEKP


Hardly, nowhere near as similar. Try buring it. It burns, with lots of soot, but nowhere near the flashlike effect you get with other peroxides. The oxygen balance is WAY too bad to make it useful as a primary...

For purification, try using a chloro alkane, such as chloroform or trichloroethylene, as described above.