05-11-04 05:53
No 506354
i would like to synth benzyl cl with this proceedure:
from Rhodium
../rhodium /benzylc
Ca(OCl)2 Chlorination of Toluene [2]
Toluene and dry Calcium Hypochlorite (bleaching powder) are heated together to 105°C in the abscence of other reagents. This avoids by-product formation. If equal amtounts are used, volume-wise, there is a high conversion. If more bleaching powder is used, the conversion is more robust, but contaminants such as benzal chloride and benzotrichloride are formed [...]
my question is what does "in the abscence of other reagents" exactly mean. does this mean it must be performed in an inert atmosphere?
also... can the product just be distilled?
thanks for all input.
(Stranger)
05-11-04 05:54
No 506355
oops
(Hive Bee)
05-11-04 08:39
No 506376
absence of other reagents means nothing else there, not necessarily an inert atmosphere. Just dont add anything else apart from toluene and Ca(OCl)2.
Just mind the point
If more bleaching powder is used, the conversion is more robust, but contaminants such as benzyl chloride and benzotrichloride are formed
So your reaction is:
2(Toluene) + Ca(OCl)2 --> 2(benzyl chloride) + Ca(OH)2
Note: is this synth supposed to say chlorotoluene instead of
contaminants such as benzyl chloride
???
Its just my opinion, but no-one listens to me anyway, and rightly so...
(Stranger)
05-11-04 16:14
No 506430
thanks App
so after the conversion how best should separarion be done? I assume Ca(OH)2 will be a solid(lime?) but what about any side products and unreacted toluene?
(Chief Bee)
05-11-04 17:43
No 506449
If you read closely, the text doesn't say "contaminants such as benzyl chloride", it says "contaminants such as benzal chloride". Spelling is everything in chemistry.
Benzal Chloride Info (http://www.chemicalland21.com/arokorhi/
The Hive - Clandestine Chemists Without Borders
(Stranger)
05-12-04 05:46
No 506577
a couple more i am sure annoying questions. I just bought a ton of calcium hypo for cheap from pool store. However it is only 67% hypo and 33% inert ingredients. Is there any way to know if the "inert ingredients" will interfere with the desired product or yeilds?
also is this an "in situ" clorination? or will there be cl2 gas evolved that will kill me if not done in a fume hood?
sorry for the lame posts ... but i assume that this is what the newbie forum is for. i did utfse alot on this btw
(acetaminophanatic)
05-12-04 06:29
No 506581
My merck index says it's very rare for calcium hypochlorite to be pure. Probably they did some funny electrolysis of calcium chloride and that was it. No other purification.
Very likely those inert ingredients will not interfere.
also is this an "in situ" clorination? or will there be cl2 gas evolved that will kill me if not done in a fume hood?
I would say both. It's in situ because you're not generating the chlorine externally. However, I bet it will evolve decent amounts of gas. Not so much, but some.
What you really have to watch out for is the benzyl chloride. It's supposed to be really nasty.
Furthermore, I think gunning for lower yields but purer product is a good idea, because if it isn't pure, you have to distill it, and that is a VERY nasty thing to do. So I hear.
Benzyl chloride and chloroacetone. Handy, but hard to deal with.
Take care.
...it's an AOL chatroom for dyslexic spider monkies...
(Stranger)
05-12-04 06:36
No 506586
thanks ning. when i ustfe last time i must have fucked up. i just did it now and got more info than i really cared for. essentially this synth seems to suck... most cuz bzcl is very ugly. i was planning on going from bzcl to b-dehyde... but now i don't know. i really don't have much in the way of a fume hood yet. and i am rather attached to my lungs atm. i guess its back to tfse to find a more lung friendly way to b-dehyde
(Stranger)
05-12-04 06:55
No 506593
ok so i synth bzcl this way, adding extra hypo to make sure i get a mix of benzyl and benzal, then in the same flask i add hexamine and boil (reference Organikum: http://www.sciencemadness.org/talk/viewt
aromatic sidechainchlorinations - Toluene - Benzylchloride, Benzaldehyde, Benzotrichloride and followup reactions yielding Benzaldehyde and Benzoic Acid. Polverone bonus: Chlorination of Acetic Acid) can anyone tell me if the lime water (Ca(OH)2) and the unreacted toluene cause very much trouble? and if not will the b-dehyde be easy to separate from the mess?
(Wonderful Personality)
05-12-04 11:50
No 506624
First add hexamine, then water and HCl and boil the shit.
look here for the procedure:
Patent US4321412
[/quote]
EXAMPLE
1,050.1 g of chlorinated p-xylene, consisting of 47.61% of p-xylyl chloride, 43.76% of p-xylene, 3.6% of nuclear-chlorinated p-xylene and 5.03% of polychlorinated p-xylenes, the mixture containing exactly 500 g (3.55 moles) of p-xylyl chloride, are stirred with 546.7 g (3.9 moles) of urotropin for 15 minutes, under nitrogen, in a 4 liter three-necked flask equipped with a reflux condenser and stirrer.
1,000 g of water are then added and the mixture is refluxed for 3 hours. It is then allowed to cool, brought to a pH of 3-4 at room temperature with 170 ml of concentrated HCl, and then refluxed for a further 15 minutes.
Thereafter, the mixture is allowed to cool again and the aqueous phase is separated off. The organic phase is distilled after addition of 0.01 g of hydroquinone.
[quote]
You can steamdistill the benzaldehyde out of the reaction flask first, separate water and organic layer consisting of benzaldehyde and toluene and separate those by usual separation preferable under reduced pressure.
The nitrogen atmosphere is not necessary but unavoidably some benzylalcohol will be formed when oxygen is present.