Sciencemadness Discussion Board

Benzoyl Peroxide > Benzyl Alcohol

Siddy - 16-1-2008 at 20:06

Is there a high yielding method to make Benzoyl Peroxide (Dibenzoyldioxidane) to Benzyl Alcohol, or Benzyl Chloride?

Also, what does it decompose into?

[Edited on 16-1-2008 by Siddy]

len1 - 17-1-2008 at 00:05

The major product of the decomposition of benzoyl peroxide in water is benzoic acid. I dont know whether acidic media, or non-aqueous solvents might give a different equilibrium. The peroxide is much more expensive than the alcohol though. The best way to the alcohol is toluene oxidation. But benzyl chloride is one of the most horrible chemicals Ive encountered.

Klute - 17-1-2008 at 00:06

There was a discussion on this some time ago, search the site. IIRC, the bottom line was that only benzoic acid was obtainable. But have a look on Org.Syn or similar, you will surely find more reliable info (than my memory, not than this site :) ).

Nicodem - 17-1-2008 at 12:17

Quote:
Originally posted by Siddy
Also, what does it decompose into?

The main product from dibenzoyl peroxide thermal decomposition is biphenyl and CO2, but other products can also form (for example, by the reaction of the intermediate radicals with the solvent, etc.)

Siddy - 17-1-2008 at 12:58

Thanks,
As you have said, benzoic acid seems to be the main product (90%+, with solvents changing the remaining 10%).

I can get Benzoyl peroxide for $8 a litre or $140 20L, i though that was really cheap so i was wondering if i could get a bargain by using it - probably not though.

Swany - 17-1-2008 at 18:35

Benzoyl peroxide is a solid; liters?

Nicodem - 18-1-2008 at 14:42

I think Siddy is talking about the dibenzoyl peroxide solution as usually available in hardware stores for styrene based resins polymerization.

Benzoic acid only forms from dibenzoyl peroxide if reduced or hydrolyzed. Otherwise heating it makes it decompose (potentially dangerously!) to biphenyl and CO2 as already mentioned. If you want to use it to prepare benzyl alcohol you can use it as a radical initiator for the chlorination of toluene to benzyl chloride with trichloroisocyanuric acid or chlorine. Benzyl chloride can be hydrolyzed to benzyl alcohol, oxidized to benzaldehyde...

[Edited on 18/1/2008 by Nicodem]

len1 - 18-1-2008 at 22:07

Quote:
Originally posted by Siddy
Is there a high yielding method to make Benzoyl Peroxide (Dibenzoyldioxidane) to Benzyl Alcohol, or Benzyl Chloride?

Also, what does it decompose into?

[Edited on 16-1-2008 by Siddy]


Valid question, I dont think this has been discussed seriously here.

As I said in water you get benzoic acid,
thermal decomposition gives biphenyl etc
some of the more interesting ones:

in chlorofom -> COCl2 (phosgene) Cl3CC6H4COCl benzene
in alcohols -> benzene (20%), aldehyde, benzoic acid etc..
in acetic acid -> benzene(30%)
in alkenes -> cleavage of double bond + ester

all reactions also yield about a mole CO2 per mole peroxide

[Edited on 19-1-2008 by len1]