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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: prncess23 on November 02, 2008, 03:28:31 AM

Title: Flow chart: separate p-nitroaniline and p-dichlorobenzene mixture
Post by: prncess23 on November 02, 2008, 03:28:31 AM
I have to draw a flow chart to show how to separate a p-nitroaniline and p-dichlorobenzene mixture...i dont know even where to start.

please help.
Title: Re: Flow chart: separate p-nitroaniline and p-dichlorobenzene mixture
Post by: prncess23 on November 02, 2008, 05:17:56 AM
i got this....i dunno if it is right or not.

1. p-nitroaniline + p-dichlorophenol mixture dissolve in diethyl ether
2. add 1N aqueous NaOH
3. separate layers
4. remove the solvent from the organic layer to give p-dichlorophenol
5. acidify the aqueous layer with HCl
6. extract this with diethyl ether
7. remove the solvent from the organic layer to give p-nitroaniline.
Title: Re: Flow chart: separate p-nitroaniline and p-dichlorobenzene mixture
Post by: sjb on November 02, 2008, 05:49:42 AM
Right sort of idea, but check your compounds, you seem to have changed from p-dichlorobenzene to p-dichlorophenol from the first post to the next.

You also seem to have mixed up the two compounds in the second post. How would the aniline react with base, and the phenol? So where would they both prefer to be... ?
Title: Re: Flow chart: separate p-nitroaniline and p-dichlorobenzene mixture
Post by: prncess23 on November 02, 2008, 03:45:04 PM
i got this....i dunno if it is right or not.

1. p-nitroaniline + p-dichlorobenzene mixture dissolve in diethyl ether
2. add 1N aqueous NaOH
3. separate layers
4. remove the solvent from the organic layer to give p-p-dichlorobenzenol
5. acidify the aqueous layer with HCl
6. extract this with diethyl ether
7. remove the solvent from the organic layer to give p-nitroaniline.

is that better???
Title: Re: Flow chart: separate p-nitroaniline and p-dichlorobenzene mixture
Post by: sjb on November 03, 2008, 02:10:22 PM
You've still changed from a chlorine to a hydroxyl from stage 1 to 4.

Assuming the chlorine is right, the functional groups you have are a nitro group and an amine on one molecule, and a chlorine on the other (actually twice, but it makes no difference here).

What happens to each of these groups when you treat them with base? What happens when you treat them with acid?