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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: GinaTageldin on June 07, 2017, 09:59:22 AM

Title: m-phenylene diamine color???
Post by: GinaTageldin on June 07, 2017, 09:59:22 AM
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?
Title: Re: m-phenylene diamine color???
Post by: rolnor on June 07, 2017, 11:52:56 AM
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.
Title: Re: m-phenylene diamine color???
Post by: GinaTageldin on June 07, 2017, 12:29:45 PM
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
Title: Re: m-phenylene diamine color???
Post by: rolnor on June 07, 2017, 12:39:53 PM
Methanol maby?
Title: Re: m-phenylene diamine color???
Post by: GinaTageldin on June 07, 2017, 12:54:16 PM
Methanol maby?
Thank you Sir
Title: Re: m-phenylene diamine color???
Post by: wildfyr on June 08, 2017, 03:14:03 AM
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.
Title: Re: m-phenylene diamine color???
Post by: clarkstill on June 08, 2017, 06:33:02 AM
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'.
Title: Re: m-phenylene diamine color???
Post by: wildfyr on June 08, 2017, 07:37:46 AM
Maybe some N-oxide gives color?
Title: Re: m-phenylene diamine color???
Post by: kriggy on June 09, 2017, 05:56:57 AM
I suppose if was brownish its more likely some residual nitro-aniline.
Title: Re: m-phenylene diamine color???
Post by: GinaTageldin on June 11, 2017, 05:36:13 PM
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
Title: Re: m-phenylene diamine color???
Post by: rolnor on June 12, 2017, 05:58:56 AM
If it is really bad many you need to cromatograph or buy a new bottle.