Meltonium
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The Most Useful Bromo
I am in a bit of a pickle, here. I have some bromine and need to use it for something. The problem is, I can't really think of something to use it
for. Well, I can think of things, but I'm not sure if it is worth.
I want to know the most useful organic building block to use bromine for.
If you had the last available bromine left on Earth and had to use it, what would you use it for?
"If at first you don't succeed, fail, fail again."
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Metacelsus
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If you want to convert your bromine into something more easily storable, you could make N-bromosuccinimide (of course, this requires succinimide as a
starting material). N-bromoacetamide would be easier to make but generally not as useful.
[Edited on 2-17-2017 by Metacelsus]
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Magpie
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You could make acetic anhydride or a Grignard reagent..
The single most important condition for a successful synthesis is good mixing - Nicodem
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Amos
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Buy some MSG at an Asian market, health store, or grocery. Convert to succinic acid (https://www.youtube.com/watch?v=kDLSRk068SU&t=20s).
Dehydrate with heat to succinic anhydride, add your bromine. Now you can store it indefinitely!
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Texium
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If you have benzene, you could make bromobenzene, using just a bit of aluminum foil to generate the necessary catalyst. Easier to store it, and it can
be used for phenyl Grignards. I wouldn't say it's the most useful thing, but it is a useful thing.
The NBS idea is good too. I haven't made it before, but I've used it at work and it is a pleasure to work with.
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Boffis
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@Amos, if you are trying to produce N-bromosuccinimide you have missed out an important step. The introduction of the vital nitrogen of the "imide"
group. At a guess I think you would need to heat the ammonium succinate salt.
It also depend on where your interests lie. I would use the bromine to add across the double bond of fumaric or acrylic acid. The resulting dibromo
compounds can be dehalogenated to acetylene carboxylic acids with alcoholic KOH. Very useful intermediates... for me at least. 
[Edited on 17-2-2017 by Boffis]
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JJay
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I'm planning on making some aluminum bromide once the weather warms up and I can do it outside. It's a strong Lewis acid that can be used for
Friedel-Crafts alkylations and acylations. The most useful building block you can make with bromine... hmm... good question....
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Assured Fish
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You could possibly try converting it back to its sodium or potassium salt, i had this idea a while back.
3Br2 + 2Al -----> Al2Br6 + 6H2O -----> 2Al(OH)3 + 6HBr
6HBr + 6NaOH -----> 6NaBr
This may seem a little boring but it would mean you could save the bromine for a better project and still do something experimental at the same time.
Id start by putting some aluminium foil in a RB flask with water and stirring and a reflux condenser and then slowly adding the bromine and letting it
react until most of the color dissapears, this will take a while because of the aluminium oxide layer but then you could simply add your desired KOH
or NaOH solution and filter to remove the Aluminium hydroxide. The bromide salt will remain dissolve in the filtrate and you can evaporate that away
to get a dry salt.
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PHILOU Zrealone
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NaOH + Br2 -heat-> NaBr + NaBrO3
I should also work on that because I own two 2L liquid Bromine Glass bottles...and I don't like the idea of it escaping or breaking...
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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Chlorine
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Your best option would to convert it to a metal salt, NaBrO3, KBrO3.
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Amos
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Quote: Originally posted by Boffis  | @Amos, if you are trying to produce N-bromosuccinimide you have missed out an important step. The introduction of the vital nitrogen of the "imide"
group. At a guess I think you would need to heat the ammonium succinate salt.
[Edited on 17-2-2017 by Boffis] |
Ah, woops! It was late at night and I forgot that step. It's actually even easier than that; it can be prepared simply by heating together succinic
anhydride and urea, analogous to the preparation of phthalimide.
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PHILOU Zrealone
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| Quote: Originally posted by Amos | | Quote: Originally posted by Boffis | @Amos, if you are trying to produce N-bromosuccinimide you have missed out an important step. The introduction of the vital nitrogen of the "imide"
group. At a guess I think you would need to heat the ammonium succinate salt.
[Edited on 17-2-2017 by Boffis] |
Ah, woops! It was late at night and I forgot that step. It's actually even easier than that; it can be prepared simply by heating together succinic
anhydride and urea, analogous to the preparation of phthalimide. |
Should work also via diammonium succinate heating (intermediary formation of amide or diamide) and via heating of a mix of urea succinate
(transamidation).
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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Magpie
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| Quote: Originally posted by Boffis |
It also depend on where your interests lie. I would use the bromine to add across the double bond of fumaric or acrylic acid. The resulting dibromo
compounds can be dehalogenated to acetylene carboxylic acids with alcoholic KOH. Very useful intermediates... for me at least.
[Edited on 17-2-2017 by Boffis] |
Isn't NaNH2 required to get the acetylene bond?
The single most important condition for a successful synthesis is good mixing - Nicodem
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tsathoggua1
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I'd go for methyl bromide and a grignard with benzyl cyanide. Ideally creating amphetamine on the hydrolysis of the grignard complex
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Boffis
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| Quote: Originally posted by Magpie | | Quote: Originally posted by Boffis |
It also depend on where your interests lie. I would use the bromine to add across the double bond of fumaric or acrylic acid. The resulting dibromo
compounds can be dehalogenated to acetylene carboxylic acids with alcoholic KOH. Very useful intermediates... for me at least.
[Edited on 17-2-2017 by Boffis] |
Isn't NaNH2 required to get the acetylene bond? |
No. See Org. Synth., Coll Vol 2, p10
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PHILOU Zrealone
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Normally a first halide is substracted at ambiant T° (KOH/Ethanol) and the second needs more forcing conditions (thus slight heating).
PH Z (PHILOU Zrealone)
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Metacelsus
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| Quote: Originally posted by tsathoggua1 | | I'd go for methyl bromide and a grignard with benzyl cyanide. Ideally creating amphetamine on the hydrolysis of the grignard complex |
Depending on your workup, you'd get either the imine or the ketone. Of course, making the amine from either of these would be straightforward.
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