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Author: Subject: Spa Brominator as a possible NBS Substitute
benzylchloride1
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cool.gif posted on 30-11-2007 at 20:02
Spa Brominator as a possible NBS Substitute


An attempt at the bromination of toluene to benzyl bromide was made in a test tube. Approximently 5 mL of toluene was added to a large test tube. The powdered spa brominator was added and a small amount of 3% hydrogen peroxide was added. This was added because it catalyzes the release of bromine from the brominator, but the water probably will reduce the yield of the bromide due to the Sn1 reaction. The reaction mixture turned red. While stirring with a thermometer the test tube broke and the benzyl bromide instantly reacted with the water. I could tell that benzyl bromide was produced because I recognized the lachramatory odor from a organic chemistry lab I did at the university several weeks ago. I plan to scale this synthesis up to around 50 mL of product with my organic lab kit when I get a blower for my fume hood. I wonder of benzoyl peroxide could be used as the catalyst. I plan on testing this reagent on some alkenes when I get a chance.
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Sauron
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[*] posted on 30-11-2007 at 21:31


What is the chemical identity of the spa brominator?

One of the hydantoins, most likely.




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chemrox
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[*] posted on 30-11-2007 at 21:49


I thought they used mixtures of hypohalites and the equilibrium prevented Cl from being released. I seem to recall a thread here on this. I'm confused by this because I've seen a hydantoin bromide as well. So, by all means please tell us. What's your plan for dealing with the water? Could the brominator be adsorped onto a polymer substrate? or clay? Use excess toluene as the solvent for a solid state reax? MW the mixture?



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[*] posted on 1-12-2007 at 03:02


Benzyl bromide hydrolyses only very slowly in water. At room temperature it takes several days and a cosolvent (acetone, etc.) is required.
Hydrogen peroxide is pretty useless as a radical initiator. You need benzoyl peroxide (which is available OTC).

PS: What the hell is "spa brominator" anyway? Use chemical names! Commercial names differ widely by country and language.




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Sauron
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[*] posted on 1-12-2007 at 05:03


"Spa brominator" is sold to treat outdoor hot tubs often in a floating dispenser. A googling will reveal the usual suppliers and manufacturers but so far none has disclosed chemical composition or a MSDS.

I agree with Nicodem, that the chemical name needs to be known, and I said so upthread.




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[*] posted on 1-12-2007 at 05:11


Not that this is what is referred to, if you go here http://www.lesliesmsds.com/MSDSSearchPage.aspx and put in "brominating tables" as the product name, there are a couple of MSDS records, both dimethylhydantoin
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[*] posted on 1-12-2007 at 06:46


That was my best guess, upthread. It's pretty much the state of the art in water treatment bromination. What the thread author has done, in all likelihood, is to find an OTC source.

Halogenated dimethylhydantoins are well known halogenating agents in organic synthesis.

Dollars to donuts, that's what he is talking about.




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[*] posted on 1-12-2007 at 07:23


BromoChlorohydantoine is very often sold as a spa brominator, I guess that's the product he's talking about. Much more common than dibromohydantoine where I live. But some product contains bromates. I've also seen KBr in pools shops, sold as brominating agent, to strenghen the bromohydantoines. It's usually written that it needs to be combined with oxidizers (H2O2, hydantoines, TCCA) to be usefull.
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[*] posted on 1-12-2007 at 07:38


1-bromo-3-chloro-5,5-dimethylhydantoin is the most common of all "Spa Brominator's" although the dibromo version is a useful reagent (as too is the diiodo variant from early reports), little is said about the use of this variant for the bromination (or chlorination for that matter) of organics in the literature to date (or that I've found).

http://www.bromine-tablet.co.uk/ (MSDS is here too)

If chlorinated as discussed by Nicodem elsewhere would give off bromine (and a mixture of chlorine, etc.) althoughI suspect that could be resolved by passing the vapours through another solution of BCDMH (maybe even two or three times) until the only gaseous product remaining was bromine.




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[*] posted on 2-12-2007 at 14:04


Okay, I have spa brominator that's a mix of bromochloro dimethylhydantoin and dichloro dimethylhydantoin. I tried mixing it with 3% H2O2 as well as 5% household ammonia. Both clearly produced bromine. However, the ammonia/brominator mix produced a lot of bubbles, which had a slight green tint. The smell of chlorine/bromine was very distinct.
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[*] posted on 2-12-2007 at 21:54


There really is nothing novel about halohydantoins as haloamine halogenating reagents. They ar in same general class as TCCA and NCS/NBS and their chemical behavior is well understood.

I will have a look in Paquette's book and see if their is anything unique or advantageous about them.




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[*] posted on 3-12-2007 at 02:02


Quote:
Originally posted by bilcksneatff
However, the ammonia/brominator mix produced a lot of bubbles, which had a slight green tint. The smell of chlorine/bromine was very distinct.

These bubbles are nitrogen gas. The ammonia is oxidized mainly to nitrogen gas. At the same time, the pH goes down considerably, and this causes formation of Cl2 (in the case of TCCA) or Br2 (in the case of bromine-releasing tablets).




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[*] posted on 5-12-2007 at 20:04


Yes it is one of the hydatonin brominators. It was given to me by a friend several years ago and I forgot to write down the chemical formula. Another attempt was made a making benzyl bromide, but I had to stop all experiments of this sort because of the lachramatory nature of this chemical.
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[*] posted on 5-12-2007 at 20:15


No fume hood, huh?

It is very well known that benzyl bromide was tried as a military grade lachrymator in WWI and subsequently may have been used as a police tear gas, but discarded as too toxic.

See Sartpri "The War Gases" in forum library.

Fume hood and scrubber are musts; personal protective gear advised in addition.

At least you weren't trying to make xylidene dibromide.




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[*] posted on 5-12-2007 at 21:57


I agree with my friend Sauron about personal protective gear and if you want specifics I can post some info on respirators and cartridges. I consider these and gloves a must when working with volatiles and toxics whether one has a hood or not. Remember, "shit happens."



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[*] posted on 10-12-2007 at 09:05


I bought a Kewaunee Scientific fume hood. It is nice, but the $1000 that it cost including shipping burndt a major hole in my wallet. My parents banned me from using H2S and sulfer until the fume hood is operational. The experiments I do are mainly classic experiments of organic and inorganic chemisty.
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[*] posted on 10-12-2007 at 12:09


Quote:

I bought a Kewaunee Scientific fume hood. It is nice, but the $1000 that it cost including shipping


I remember looking at the specs for Kewaunee hoods prior to building my hood. They did look nice. You got one hell of a deal for <$1000. Did it come with a fan and ducting or will you have to provide those yourself?
Quote:

I do are mainly classic experiments of organic and inorganic chemisty.


This is my favorite chemistry too. But it is hard or politicaly incorrect to get many of the chemicals you need so you have to end up making many yourself. But that in itself is often challenging and fun.

I 2nd Sauron's comment in another thread. Congratulations for taking such bold steps at such a young age!




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benzylchloride1
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[*] posted on 12-12-2007 at 10:54


The hood does not have a blower, that is why i am not using it yet. What is the best type of blower for this type of hood? I want to get one as soon as possible.
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[*] posted on 12-12-2007 at 12:54


Benzyl bromide is mainly an incapacitating agent. Long term effects are probably not good either, but a sane person only has ONE run in with benzyl bromide in his life.

It just feels like your eyes are crawling out through your spastically shut eyelids.




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[*] posted on 12-12-2007 at 15:48


For relative visciousness, how would benzylchloride and benzalchloride compare with benzylbromide?



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