10-19-03 15:00
No 465597
4g of 2,5-DMPEA was added to 4g or GAA, then set to the side. In another beaker, 4g of GAA was added, then set to the side. In the 3rd beaker 4g of bromine was to be added, but to find out after the fact, 12g was added. all were combined.
Long night..
Is there anything anybee can suggest to possibly salvage this dream? Bromine is pretty heavy, too heavy if you ask me!
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(Newbee)
10-19-03 16:59
No 465609
Ahhhhh, the old forgetting the density of bromine problem. Yup - you learned the hard way that 4ml of Bromine is ~12g. I think you could probably salvage this by removing all the volatiles under vaccum (this includes the excess bromine)....but do so very carefully, you dont want to be breathing bromine fumes. When you remove all the volatiles, you will most probably be left with a mass of tan solid that is crude monobrominated product. I dont think you have too much to worry about, your product is still in there.
Peace, love and empathy
(Chief Bee)
10-19-03 17:31
No 465614
With that huge excess, you might have gotten some dibrominated product, so be sure to recrystallize the HBr salt to remove it.
(Hive Bee)
10-19-03 18:30
No 465621
If this mixture (which hasn't solidified any) was left sitting for a while, would the excess bromine evaporate away, crystalizing the product?
After all washes and an a/b, the 2c-h freebase was still on the dark side, but clear. It's very abundant and overwhelmingly bloody looking.
Of course that would be excess bromine too. When a certain procedure calls for the removal of solvents under vacuum, is it really necessary? In this scenario, many writeups have removed solvents such as DCM under vacuum. The available pump was too strong, so the dcm was stripped at atm. I didn't see how this could be bad as I assumed the feebase wouldn't be harmed by temps that low. Is this not the case? I read:
the solvent removed under vacuum and the residue was distilled at 6 mmHg to give 16.8 grams of 2C-H as a yellowish oil (65%).
Have you ever had really pure mdp2p, almost colorless, the faintest hint of greenish clear, and heated it up to distill it again for extreme purity, and notice upon heating the ketone in the boiler flask, the color went from near clear, to very distinct yellow/gold??? Maybe thats why my 2c-h came out darker than the person who vacuum distilled his solvents off?? Heat discoloursation?
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(Chief Bee)
10-19-03 19:48
No 465641
You didn't distill the 2C-H freebase? Then you might have a *lot* of byproducts in there preventing crystallization. After an LAH reduction and A/B purification, only about 2/3 of the remaining oil will distill in the 2C-H range.
I'd suggest that you use an aspirator to remove excess bromine and part of the GAA, it'll take too long if you simply wait it out.
When a certain procedure calls for the removal of solvents under vacuum, is it really necessary?
If you use diethyl ether or dichloromethane, and heat using a ~60°C water bath (so that you are sure that you won't overheat it after the solvent is mostly gone), then it usually makes no difference, other than that it takes a lot longer time. If you distill off higher-boiling stuff like toluene, xylene or somesuch, then it can be bad to skip the vacuum.
The available pump was too strong
Then arrange a suitable leak so that the vacuum becomes just right.