Author Topic: Bisulfite adduct OK ?  (Read 702 times)

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wolfx

  • Guest
Bisulfite adduct OK ?
« on: December 30, 2003, 02:29:00 AM »
Two different ketone samples have been tested for bisulfite adduct formation. Both formed the bisulfite, but :

1) Sample A initially did not formed anything, even after shaking a lot and letting inside freezer for a while. Let it sit for a few days, nothing, then added a bit more ketone, it then formed the xtals in I guess less than half an hour.

2) Sample B did not form the xtals initially, then let it sit for a while, next day here they are.

In both cases, xtals forming both at the top and bottom, everything frozen inside the test tube, then loose again after shaking. Xtals look clean, just a bit like chicken fat on the top. In both cases, ketone not 100 % pure, but not quite impure either. Planning to make more, combine and re-distill before amination.

Does this looks like good adduct ? Ketone OK ?

abolt

  • Guest
I would think that your lower crystals are...
« Reply #1 on: December 31, 2003, 03:39:00 AM »
I would think that your lower crystals are precipitated metabisulphate caused by the lowering of your aqueous solubility by freezing.

"Chicken fat" is not what you want to see. Look for a mat of fine shards floating on top of your saturated bisulfite solution.

You can always try a polymerisation test by heating a small sample in atest tube to 220 C or so and see if tar forms.


wolfx

  • Guest
Xtals
« Reply #2 on: January 01, 2004, 12:26:00 AM »
I would like to add a bit more information :

In sample A, after adding the extra ketone, all of the xtals were initially at the top. After shaking, most of it sunk, still a little bit remained atop the liquid. This sample only put in freezer for a while.

In sample B, xtals formed both on top and bottom, all look the same. This one has not been put in freezer.

Thanks for the help.