[GinaTageldin]

I bought m-phenylene diamine and it was black and melted like a wax.
Does anyone work with it before as i am worry since its physical properties showed it is a white solid.
Does anyone has a method for purification?

[rolnor]

Often the color comes from small amounts of impurities and purification is not nescesary.
One procedure is to use activated carbon to get rid of the brown.

[GinaTageldin]

Often the color comes from small amounts of impurities and purification is not nescesary.
One procedure is to use activated carbon to get rid of the brown.

what is the suitable solvent that i use while boiling with charcoal? and left to precipitate while cooling

[rolnor]

Methanol maby?

[GinaTageldin]

Methanol maby?

Thank you Sir

[wildfyr]

I remember buying the p phenylene diamine and it being a brownish color. Come to think of it, I had issues getting that chemistry to work. It was my first year, probably should have tried troubleshooting rule #1: purify your reagents.

[clarkstill]

Anilines always darken over time (aerobic oxidation I guess?). Can't you NMR it to check purity? It might not be too bad, my supervisor used to say 'a little colour goes a long way'.

[wildfyr]

Maybe some N-oxide gives color?

[kriggy]

I suppose if was brownish its more likely some residual nitro-aniline.

[GinaTageldin]

Anilines always darken over time (aerobic oxidation I guess?). Can't you NMR it to check purity? It might not be too bad, my supervisor used to say 'a little colour goes a long way'.

It is not a little color, it is waxy and very dark black  color and i think it is difficult to run NMR on it

[rolnor]

If it is really bad many you need to cromatograph or buy a new bottle.