Sciencemadness Discussion Board

Nitration Toluene - Colorless crystals

Wolf-Aalude - 11-2-2014 at 18:31

Procedure;

To 100 mL of toluene was added 250 mL of (1:1 Sulfuric/Nitric acid) in 5 mL portions. The temperature was maintained below 40°C with ice bath, with one 5-minute interval of 45°C.

The majority of the reaction was carried out between 15-25°C.

The layers were separated and the organic layer was stripped of remaining toluene under vacuum. The organic solution was then cooled to -20° C and centrifuged. The solid was separated from the liquid.

The solid appeared as large crystalline spikes (>1cm in length) while the liquid was pale yellow.

Assumedly the solid is p-nitrotoluene, however all references say it is pale yellow.

The di-nitro products are also pale yellow as well as the tri-nitro compounds.

What is this?

Magpie - 12-2-2014 at 13:19

Hi Wolf-Aalude,

I have an interest in making o, p-nitrotoluenes also so have been searching for a good procedure. On versuchschemie.de, the German hobby chemist forum, Stefan posted a picture of purified p-nitrotlouene that he made. I repost it below:

Attachment: p-nitrotoluene (Stefan).doc (81kB)
This file has been downloaded 610 times


Does this look like your product?


Magpie - 19-2-2014 at 21:27

Shown below is a picture of 6.7g of p-nitrotoluene that I synthesized yesterday. Its mp is 51-52°C in agreement with Wiki's 51.7°C. It is white with a very pale yellow cast. I separated it from the mixed isomers by freezing to -16 °C. I caught the needle shaped crystals on a Buchner funnel, washing them with a little heptane.

I will detail my preparation later after I finish my separation work on the mother liquor. This contains the o-nitrotoluene and the remaining p-nitrotoluene.



p-nitrotoluene crystals.jpg - 69kB

Magpie - 20-2-2014 at 09:20

Here's another picture of p-nitrotoluene from versuchschemie.de by Ameisensulfat. Unfortunately it is unwashed. But his crystals do indeed appear to be white without the yellow cast.



p-nitrotoluene unwashed (Ameisensulfat).jpg - 76kB