04-16-03 20:07
No 427325
Bp = 139°c
Why is it so hard to distill at atmospheric pressure?? The most violent boiling I have ever scene occured when the oil bath hit 160°c
I can not tell a lie. I almost shit my pants when I saw the 600ml's of Xylene begin to boil. Not 1 drop ever made it way to the recieving flask. After much external cooling, it calmed down and my boxers remained clean. Ie, you could blow your nose with them and not notice anything funny.
So what the fuck? Why all this craziness? I just want to reduce the volume before gassing commences, or even better, reduce the volume completely, to obtain my crude freebase, then distill that, to get pure freebase.
Any ideas?
100% _______
(Hive Bee)
04-16-03 20:47
No 427335
Don't know what the problem is with distilling the xylene. I've never tried distilling a pure xylene/freebase mixture, but a Xylene/methanol[/water] mixture comes over as an azeotrope at reasonable temps. Attempting to distill the Xylene off at atmospheric pressure was probably a bad idea, temps that high will destroy your product.
If you want to reduce the volume of solvent without distilling you can always perform an A/B on the xylene. Wash xylene with acidic h2o, basify h20, extract with DCM (or xylene again if you don't want to distill your freebase, just use less volume than your original 600 ml). That will distill off the freebase easily, allowing you to then distill your freebase.
See Post 286519 (MaDMAx: "LOOK! Recrystallization and A/B general info", Newbee Forum).
(Hive Bee)
04-17-03 01:56
No 427423
I understand an a/b can be done, but I would rather not. Im trying to minimize every solvent/chem used, and recycle everything possible, all the while, conserving energy. (heat)
What about using DCM as a non polar to extract the freebase out of the basified al/hg rxn mix?
Does anyone forsea this causing any problems? Is DCM an acceptable solvent in the scenario?
100% _______
(Hive Bee)
04-17-03 06:00
No 427481
By doing that you are implying you wish to skip the A/B, which only has the potential to cause yourself more problems later on and more impurities in your product. Distilling the freebase is not a replacement for an A/B, one removes stuff the other can't and vise versa.
If you're really interested in saving solvents and energy, create your MeAm seperately (I assume you're reducing nitro simultaneously) and you'll be able to process a lot more with the same amount of solvents.
(Synaptic Self-Mutilator)
04-17-03 21:45
No 427623
I would not recommend DCM for extracting, but it does work. Toluene is more forgiving... it seems to form fewer emulsions.
(Hive Bee)
06-18-03 21:12
No 440862
After weeks and weeks of numerous testing of DCM as a solvent, I have concluded it is the best non polar solvent to use if you like to:
1. recycle your non polar
2. have a roto vap available for quick distillation (800ml = 20 minutes)
3. Use less non polar
4. Prefer inhaling the occasional DCM fume over Toulene.
5 Speed up the whole process
It's easier to distill and faster to distill than any other non polar I have used. You will want ice water circulating in your condensor othewise you may experience escaping DCM. Ice bath!
Having a Buchi 205 roto vap is pimp shit, and makes the process 100x better. The second you use one you want to kick yourself for not using one from the get.
The 205 has an oil bath that reaches 180°c, and with the right pump, you can distil
ketone/freebase at warping speeds with excellent purity.
The freebase sinks to the BOTTOM when you basify the rxn contents right? Where does the DCM go when added?? Well yes, if you didn't allow the rxn contents to cool 100%, the dcm will end up in the air your breathing, BUT if you let everything cool down, once the DCM is added, it will sink to the bottom WITH YOUR GOODIES! Where does Xylene go? Toulene? To the top of course! It just makes much more sense, and because you used DCM, you need less than the amount needed had you used Toulene.
How much less? Well, lets see. MethyMan's ratios scaled up 2.5x would normally call for a total of 2100 ml of non polar. When using DCM, you can, and will, collect 90% of your freebase on the first collection using 600ml's of DCM!!!!! The next collection using another 600ml's will get the next 9%, and the last collection, usually results in a drop or two of freebase, and time after time, it has been proven to be a waste of time top collect the 3rd.. to each his own.
So whats the catch!?
Chromic said it. Emulsion.. BUT!!! Once you pour your rxn contents/non polar into the nearest 4L sep, you then have the oppertunity to clean the lab for 20 minutes, or get head while wait. In 20 minutes, your sep funell will have seperated nicely and your DCM will be ready to be tapped off and evaporated. After a few try's you'll get a system down. and find something very productive to do.. (start another rxn if you haven't already?!)
Once all the dcm has been removed, you are left with your freebase and whatever crap that may have slipped in with the dcm (less than 1% of contents)
Empty this into a beaker and continue with your next batch, adding each collection to the beaker.
When finished you can do an a/b then distill, or, if your really pressed for time, you can do washes on the freebase, sep, then distill. The only downside to this is your eyes will light up when you see so much freebase comming over, thinking you struck it rich, but in all reality it's just the unconverted ketone mixed with your freebase. Either way, at a scale of 2.5, you will expect at least 50g of freebase per rxn, even though your collection weighs 70g.
If you do an a/b, you will leave the ketone behind and collect only the clear freebase.
Either method will produce what your looking for. DCM is the ONLY non polar solvent to use for me!
A tip for those scaling up the MM:
At x2.5 after basification and addition of DCM (600ml) you have utilized 99% of your 4L sep. Your now being productive
Fans are beautiful things, but whats even better?? An Air Conditioner!! Your makin big bucks now, go buy an a/c that rolls around your work area! The floor model kind. They aren't that efficient, but the fact that you can roll it over to the 5L flask your working with is great and every single reduction you do will be done with alot less heart beats. They also remove air from the workspace while pushing fresh air in the lab. The reflux rate went from 5 drops a second, to 1, the whole time!! (2hours per rxn) Turn off the A/C after the addition has finished. Let rxn cool off on it's own (1hr) for optimum yeilds.
Bee safe bees.
100% rich!
(Newbee)
06-19-03 05:18
No 440939
If DCM can be used then could chloroform be used instead of that. Swim has copius amounts of chloroform but DCM supply has dried up.
Everything should be the same except the slightly higher boiling point.
Thanks
Edit LT/: for the answer, see Post 440947 (Mr_Reflux: "Chloroform in mod. performic?", Newbee Forum) .
"Now they call taking drugs an epidemic - that's 'cos white folks are doing it - Richard Pryor.
06-19-03 22:40
(Rated as: crossposted)
06-20-03 04:19
(Rated as: crossposted)
(Hive Bee)
06-20-03 04:26
No 441186
NO SOURCES
and
NO CROSSPOSTING
and that IS one fine piece of equipment
t
06-20-03 05:29
(Rated as: misinforming)
(Hive Bee)
06-20-03 06:28
No 441209
Yea - you're right - thats not really a source... I was just caught up in the moment - like good p0rn.........
T
(Daddy)
06-20-03 13:14
No 441285
This rule is not so explicitely written, but we discourage new members to adopt usernames which have a near resemblance to old, established ones:
Beaker_Is_Alive is much too near to Beaker , so you'll have to make a new username which is unique, and mention in your first new username post that you were Beaker_Is_Alive , so the FSE will find both names in 2 posts (this one also). Your too identical name will be erased now. LT/
WISDOMwillWIN
(Chief Bee)
06-20-03 21:57
No 441377
The rules on our front page states, among other things:
No offending, off-topic, crossposted, misinforming, or insignificant postings.
To post a picture of a standard lab rotavap without any useful comments at all is definitely "insignificant", as is when other users are commenting on such a nonsenical post.