Sciencemadness Discussion Board

diacetyl peroxide formation

symboom - 29-1-2012 at 02:46

ive used a mix of 5% vinegar and 3% peroxide to a piece of zinc to see if i could form zinc peroxide or is this diacetyl peroxide forming and i have a precipitate of some white powder

Adas - 29-1-2012 at 11:21

This must be zinc peroxide. Diacetyl peroxide does not form so easily and it would react with organics in vinegar.

symboom - 29-1-2012 at 12:03

though organic what do you mean
white vinegar is made chemically. what i used
brown vinegar made from bacteria is what you must mean

kavu - 29-1-2012 at 12:29

Zinc dissolves in acetic acid to give ZnĀ²⁺ ions. A commonly known procedure for synthesis of zinc peroxide is to react a zinc salt with an aqueous solution of hydrogen peroxide. You have not given any information on the quantities used, so I'd say that the ppt contains mostly ZnO2 and ZnO alongside with a cocktail of other zinc compounds.

A procedure for zinc peroxide is described for example in the recent article N. Singh, S. Mittala, K. Sood, P. Gupta CONTROLLING THE FLOW OF NASCENT OXYGEN USING HYDROGEN PEROXIDE RESULTS IN CONTROLLING THE SYNTHESIS OF ZnO/ZnO2, Chalcogenide Letters, Vol. 7, No. 4, April 2010, p. 275-281

Synthesis of diacetyl peroxide, an extremely dangerous thing to do, calls for more concentrated acetic acid or acetic acid derivatives.

[Edited on 29-1-2012 by kavu]

Adas - 29-1-2012 at 13:30

Quote: Originally posted by kavu  
Synthesis of diacetyl peroxide, an extremely dangerous thing to do, calls for more concentrated acetic acid or acetic acid derivatives.


Yes, it can be made of acetyl chloride and BaO2, for example. If information given about DAP by Wiki is not exaggerated, it is really extremely dangerous stuff.

symboom - 31-1-2012 at 09:35

yeah i guess i could have used my glacial acidic acid (from distilling it from sodium acetate with sulfuric acid.) but i was afraid of actyl peroxide forming so i just used sore bought stuff.

zinc peroxide white to yellow powder seems right what i have.
any experiments to prove zinc peroxide formation

burning the filter paper it is on with it.
any suggestions?

kotze - 31-1-2012 at 10:16

Zinc peroxide vigorously reacts with sulfur when heated and forms shock-sensitive mixtures with it. I doubt you have much ZnO2 in your precipate because of low H2O2 concentration. ZnO2 is best made by boiling ZnO with >30% H2O2 until dry. A dark yellow to orange powder is thus obtained which is somewhat delicate to store - the slightest presence of moisture will cause the container to blast open.

kavu - 31-1-2012 at 10:19

You can determine the approximate composition by thermal decomposition of zinc peroxide to form zinc oxide. Weight a known amount of the product and heat it. Cool it in a dessicator, weigh and repeat untill you get a constant weight. From the weight difference you can calculate the approximate amount of zinc peroxide in your sample.

MrHomeScientist - 31-1-2012 at 11:02

Quote: Originally posted by symboom  
though organic what do you mean
white vinegar is made chemically. what i used
brown vinegar made from bacteria is what you must mean

Organic chemistry is anything dealing with carbon-based molecules, regardless of how they were made. Acetic acid is classified as an organic acid, whether it came from a flask or from living things.

Adas - 31-1-2012 at 13:05

Quote: Originally posted by kotze  
ZnO2 is best made by boiling ZnO with >30% H2O2 until dry.


Boiling H2O2? Really?

Quote: Originally posted by kotze  
ZnO2 is somewhat delicate to store - the slightest presence of moisture will cause the container to blast open.


Isn't moisture everywhere? Can you post any refference?

kotze - 2-2-2012 at 10:18

Yes you need to boil it down. ZnO2 is relatively temperature-stable and fixes most of the O-O before it decomposes. I made some myself years ago, from ZnO, H2O2 and a little NH3. After filling it into a tight glass bottle it shattered the bottle, scattering glass and ZnO2 everywhere. The bottle was washed shortly before and I probably didn't get it fully dry. ZnO2 is somewhat of a suspicious substance, I remember it crackled and flashed with a blue flame when thrown onto a red-hot heating plate.

Adas - 2-2-2012 at 12:30

That seems very dangerous. But there is no such info on Wikipedia..

entropy51 - 2-2-2012 at 17:22

Quote: Originally posted by Adas  
But there is no such info on Wikipedia..
Well that clinches it, doesn't it?

Vikascoder - 2-2-2012 at 21:54

But if you will heat the hydrogen peroxide there is a risk of detonation if some impurities are present