Author Topic: hey! Bandil, there is for sure great interest...  (Read 3775 times)

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armageddon

  • Guest
stinky stuff
« Reply #20 on: August 30, 2004, 01:02:00 AM »
BTW - SWIAs biggest problem smellwise is this strange high-boiling "side-product" from this grignard rxn.

BzCl is nasty, but ceases to smell after a few days - but this stuff has a really disgusting smell of rotten eggs, citric acid and who knows what else... (not describeable)  :(

And even the glassware used still smells from that stuff, although several cleaning attempts with acids, lyes and even DCM, ether, toluene and ethyl formate were done! DON'T ATTEMPT TO DISTILL THAT STUFF EVEN WITH THE BEST VACUUM YOU CAN IMAGINE! At least I seriously wouldn't recommend it if you want to reuse your glassware...

Greetz A


Bandil

  • Guest
Brown color
« Reply #21 on: September 02, 2004, 01:33:00 PM »
I'd bet that the brown color originates from the sieves used. If they are stirred at more than 60 RPM (1 rotation per second), which is agonizingly slow, they will give of brown color, which can be removed by water wash. So I seriously doubt that you get peroxides in you ether that fast. Try stirring the sieves really slow in the ether and see if that clears up things!

Regards
Bandil


armageddon

  • Guest
weelll...
« Reply #22 on: September 02, 2004, 05:05:00 PM »
Um, it seems you two (Moo and Bandil) were both right: SWIAs ether contained impurities as well as grinded sieves (washing with brine and redist. over NaOH did the trick), AND contained a little peroxide (potassium iodide/wheat starch) - but these were still present after dist....  ::)

Nevertheless SWIA wasn't able to reproduce Bandil's results and will probably stick with tin(2)chloride reduction of nitropropenes to prepare his perfumery ketones - less hassle with this oldschool route...  ;)

Greetz A


Bandil

  • Guest
Other high boiling imputities!
« Reply #23 on: September 03, 2004, 09:42:00 AM »
If you add the benzylchloride too fast, to the magnesium covered in ether, you will get quite an amount of 1,2-diphenylethane. This boils at 284°C, corresponding nicely with your findings. Read the first five lines from

this

(https://www.thevespiary.org/rhodium/Rhodium/chemistry/phenylacetic.html) document. It describes the problem and solution quite nicely  ;)

Regards
Bandil


armageddon

  • Guest
thank you for clarifying on that!
« Reply #24 on: September 03, 2004, 02:08:00 PM »
You're the best! SWIA is currently recrystallizing a large amount of rather useless bibenzyl from chloroform - nice colorless needles... ;D

once more: Thanks a lot! I already was beginning to think that the reused solvent was really the big problem - now I know at least what SWIAs mistake was, and maybe he'll try the rxn once more if I tell him about that.

Greetz