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Topic: Workup of Sandmeyer reaction?  (Read 330 times)

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Offline levis123

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Workup of Sandmeyer reaction?
« on: February 18, 2020, 02:23:45 PM »
I am trying out a Sandmeyer reaction to replace two -NH2 groups with two -Br on an aromatic ring. The compound also has en ester group on. The only solvent I am using is water.

The paper I am following does not say anything about the workup. Does this mean it should crystallize in solution? However this does not make sense to me, because the reaction is carried on at 0 C and then at room temperature.

Should I do an extraction? Diazonium compounds are dangerous to handle and I dont want to make a mistake.
« Last Edit: February 18, 2020, 03:39:52 PM by levis123 »

Offline pgk

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Re: Workup of Sandmeyer reaction?
« Reply #1 on: February 18, 2020, 02:52:57 PM »
1). Before working in the lab, read carefully the Vogel’s Textbook of Practical Chemistry (e.g. 5th Edition)-Chapter: Reactions involving replacement of the diazo group (bromo-, dibromo-, tribromobenzene).
2). Work in the lab hood and shut the protective screen.
3). Wear protective eye-glasses.
4). The temperature must not exceed 0-5oC during nitrite addition and 10oC during the reaction, except if otherwise written in the Vogel's Textbook.
5). Keep a spare amount of ice for cooling until the end of the reaction; you may need it if the reaction gets vigorous.

Offline levis123

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Re: Workup of Sandmeyer reaction?
« Reply #2 on: February 18, 2020, 03:06:25 PM »
1). Before working in the lab, read carefully the Vogel’s Textbook of Practical Chemistry (e.g. 5th Edition)-Chapter: Reactions involving replacement of the diazo group (bromo-, dibromo-, tribromobenzene).
2). Work in the lab hood and shut the protective screen.
3). Wear protective eye-glasses.
4). The temperature must not exceed 0-5oC during nitrite addition and 10oC during the reaction, except if otherwise written in the Vogel's Textbook.
5). Keep a spare amount of ice for cooling until the end of the reaction; you may need it if the reaction gets vigorous.

Thank you for your response, but what I am asking is what happens after the reaction is complete - is my product supposed to precipitate in the solution?

I have read about the safety issues of diazo compounds, but I will continue to do so until I know everything about the reaction.

Offline pgk

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Re: Workup of Sandmeyer reaction?
« Reply #3 on: February 18, 2020, 03:15:39 PM »
Whether crystallizing or not, it depends on your molecule.
Anyway, if not crystallizing and being an oil, it can be separated by extractions with an organic solvent.

Offline levis123

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Re: Workup of Sandmeyer reaction?
« Reply #4 on: February 18, 2020, 03:37:25 PM »
Whether crystallizing or not, it depends on your molecule.
Anyway, if not crystallizing and being an oil, it can be separated by extractions with an organic solvent.

Ok, thank you! :)

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