Sciencemadness Discussion Board

Successfully purified Benzoyl peroxide.

rsgpit - 2-6-2006 at 08:10

I succesfully made around 1.5g of benzoyl peroxide from the 1 oz 10% acne medication. All i did was dissolve it in water and let the peroxide precipitate out, then decanted the liquid. It is not enough to detonate, but it does make a characteristic AP like fireball.

garage chemist - 3-6-2006 at 05:19

I made some benzoyl peroxide (ca. 7g) yesterday from my newly acquired benzoyl chloride.

It is synthesized by stirring hydrogen peroxide solution in an ice bath and slowly dropping in NaOH solution and benzoyl chloride simultaneously, while paying attention than the liquid should always be slightly basic and temperature does not exceed 8°C.
After all reactants were added, stirring is continued for at least 30 minutes (Liquid must still be basic, an excess of NaOH is used, this is to avoid benzoic acid contamination of the product), then the precipitate of benzoyl peroxide is filtered, washed and dried.

I met problems as the benzoyl peroxide was generated in the form of several hard pellets which enclosed unreacted benzoyl chloride. I had to crush all of them manually with a spatula before continuing the stirring. But after that, the synthesis went fine. The yield was just somewhat on the low side.

The product isn't really that explosive, only when heated from below does it deflagrate with a sooty fireball.

It is useful as a radical initiator for the polymerization of unsaturated compounds (styrene, acrylates etc...) and for radical reactions like the chlorination of toluene with sulfuryl chloride, which does not proceed past the benzal chloride stage.


Benzoyl chloride is the least reactive acyl chloride I've ever seen. If dropped into water, it forms oily drops which sink to the bottom and do nothing. They very slowly coat themselves with a sparingly soluble slime of benzoic acid and withdraw themselves from hydrolysis this way.

rsgpit - 3-6-2006 at 14:00

Well I tried it again, and got a better yeild this time, around 2g, 2.8g being full yeild. I loaded it in a film canister and let it completely dry. All I got when I iginited it was a fireball again. I'm starting to wonder if the purification is flawed. Shouldn't 2 grams detonate like AP.

garage chemist - 3-6-2006 at 14:25

No, they shouldn't. BPO isn't very energetic. I have some pure product, and it doesn't detonate.

Zinc - 4-6-2006 at 01:28

Is benzoyl peroxide more or less stable than AP?

rsgpit - 4-6-2006 at 08:45

I smacked the dry powder with a hammer and it didnt do anything. It has to be held in flame for a couple seconds to fireball. So it is less sensitive than AP how I made it.

AreteVeteran - 4-6-2006 at 21:01

ive done this before
the first time you put in soultion, use very cold water
filter out the BzP then use very hot water
this BzP should be much more pure because the 10% aqueous gel has another majopr ingredient that is completely insoluable in water, while BzP itself is only insoluable in cold water
use <5oC water first followed by >60oC water the second time

you should get lots more

~Arete

Canuck - 12-6-2006 at 23:38

Does BP detonate? or is it a rapidly buring peroxide?

DrP - 13-6-2006 at 00:35

I saw a post grad hit some of the dry powder with a spoon and it caused a fire in his fume cupboard. (stupid to be pratting about with it next to some acetone soaked tissues really) - small amounts seemed to 'crackle' under the impact.

I'm sure there was a case from history of a uni professor or a student taking some dry stuff on a train and getting blown up when the train bumped arround - possible that it is just a ghost story to get students to respect the stuff though(?).

Zinc - 25-4-2008 at 12:20

Sorry to bring up an old thread but this was the closest fitting topic for this post.

How could benzoyl peroxide be made from benzaldehyde?

Formatik - 26-4-2008 at 19:28

Quote:
Originally posted by Zinc
Sorry to bring up an old thread but this was the closest fitting topic for this post.

How could benzoyl peroxide be made from benzaldehyde?


There is a method for benzoyl peroxide from H2O2 solution, benzaldehyde and H2SO4 with the addition of alcohol in B. 33, 2484.

From benzaldehyde can also acetylbenzoyl peroxide (C6H5.C:O.O.O.C:O.CH3 = C9H8O4) be made which is more powerful and has a better oxygen balance than benzoyl peroxide (C14H10O4), but is also chemically less stable and significantly more sensitive.

S.C. Wack - 26-4-2008 at 20:16

Quote:
Originally posted by Schockwave
Quote:
Originally posted by Zinc
Sorry to bring up an old thread but this was the closest fitting topic for this post.

How could benzoyl peroxide be made from benzaldehyde?


There is a method for benzoyl peroxide from H2O2 solution, benzaldehyde and H2SO4 with the addition of alcohol in B. 33, 2484.


No. That gives 3,6-diphenyl-1,2,4,5-tetroxane aka dibenzal diperoxide, benzaldehyde peroxide, etc.

Convert benzaldehyde to benzoyl chloride to the peroxide.

Formatik - 26-4-2008 at 20:54

Quote:
Originally posted by S.C. Wack
Quote:
Originally posted by Schockwave
Quote:
Originally posted by Zinc
Sorry to bring up an old thread but this was the closest fitting topic for this post.

How could benzoyl peroxide be made from benzaldehyde?


There is a method for benzoyl peroxide from H2O2 solution, benzaldehyde and H2SO4 with the addition of alcohol in B. 33, 2484.


No. That gives 3,6-diphenyl-1,2,4,5-tetroxane aka dibenzal diperoxide, benzaldehyde peroxide, etc.

Convert benzaldehyde to benzoyl chloride to the peroxide.


Whoops, that's right. Was switching back and forth between benzaldehyde and benzoyl peroxide.

Zinc - 27-4-2008 at 11:00

Quote:
Originally posted by S.C. Wack
No. That gives 3,6-diphenyl-1,2,4,5-tetroxane aka dibenzal diperoxide, benzaldehyde peroxide, etc.


Very interesting. Were could I find more information about benzaldehyde peroxide?
Quote:
Originally posted by S.C. Wack
Convert benzaldehyde to benzoyl chloride to the peroxide.


Is there no easier way?


And what is B. 33, 2484.?

[Edited on 27-4-2008 by Zinc]

crazyboy - 27-4-2008 at 14:14

I just purified some benzoyl peroxide from zit cream. its pretty weak and burns with a very sooty flame.

heres a video: http://www.youtube.com/watch?v=J2hK53W2Z1M

Formatik - 27-4-2008 at 15:50

Quote:
Originally posted by Zinc And what is B. 33, 2484.?


It's one of the most cited chemistry references.

Zinc - 27-4-2008 at 23:52

Quote:
Originally posted by Schockwave
It's one of the most cited chemistry references.


Where could I find it?
Quote:
Originally posted by crazyboy
I just purified some benzoyl peroxide from zit cream.


How did you purify it? And how much benzoyl peroxide did you get from how much cream?

crazyboy - 28-4-2008 at 15:00

Quote:

How did you purify it? And how much benzoyl peroxide did you get from how much cream?



The cream I used was 10% benzoyl peroxide I used almost a ml of zit cream mixed into 10 ml water this I put in a filter set up to which I added 30 more ml cold water. A vacuum filter would be ideal because the matrix is a thick go but because I didn't have one I let most of the water drain then I manually squeezed the goop out. I was left with maybe .1-.2g benzoyl peroxide.

Formatik - 28-4-2008 at 17:07

Quote:
Originally posted by Zinc
Quote:
Originally posted by Schockwave
It's one of the most cited chemistry references.


Where could I find it?


Any good library will carry it. The aldehyde (-CHO) group is quite reactive, so it can be less stable. Though it has a poorer oxygen balance (C14H12O4) than benzoyl peroxide and is described as a solid that melts around 202 deg. evolving gas.

Zelot - 29-4-2008 at 15:26

I purified some (less than 1mg) by dissolving in water and filtering. There were some tiny crystals on the coffee filter. I let it dry out and then lit the filter. When it got to the crystals it made a sooty fireball. Interesting stuff