The Vespiary
The Hive => Chemicals & Equipment => Topic started by: grellobanans on March 26, 2003, 10:38:00 AM
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I found one of those vacuum adapters with long drip tip, but the drip tip broke off. I put a short hose over the broken part to act as a drip tip. My question is, is this adapter safe to use under vacuum? Will the broken drip tip mess with the strength of the glass? Implosions are not fun.
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but the drip tip broke off
Wierd,drip tube/tip is pretty inside of the adapter,how did you manage that?Anyways i think you can still use
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the drip tip IS inside the adapter, but this particular one was designed so that the drip tip extends even further past the ends of the adapter a few cm so when connected to a flask, a few cm of the tip is actually inside the flask. I hope that clarifies things.
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Guess you have to just try,if stuff jumps into your vacuum hose,it is not ok,but otherwise,yes.
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swim has a vac adaptor with no drip tip left at all, and a crack running vertically down to the chipped male-connector. ketone still drips from the middle though so it skips past the vacuum nozzle.
swim threw some ptfe paste on the vac-adaptor and pulled some mdp2p at 85-89C. it forms hard chunky oxime crystals from nh2oh so purity is okay. vac adaptor held up fine. swim is just making do until he can have some new glass sent, like a vigreux for 20bux, and much much more...
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This has nothing to do with the original question.Madprosr, what damn vacuum source are you using? Pulling ketone at 85C! Most GOOD vacuums get it at about 100-140C, I thought. Do tell!
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85c is good, but not uinheard of.A common hvac pump will pull ketone over at this temp.
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SWIM distilled MDMA freebase at 79-80 C with a ritchie yellow jacket 2 CFM model. Is this too strong for good seperation?
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Some bee's say it's too strong, but for the life of me, I don't see why.. if safrole comes over at 60c and ketone at 85, then how is the separation going to get any better at 100/125?!
But anyway, the only downside to having a strong pump like that is the fact that you will need another pump thats not nearly as strong to distill water/solvents. If you are getting your ketone at 85c, then I bet your pump will boil water @ atmospheric pressure.
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My 10 mm pump boils water @ 10 degrees.Pump that pulls ketone over @ 80C should pull about 0,05 torr or close to that.Good pump ya got there mon.
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My 10 mm pump boils water @ 10 degrees
Have you actuallty verified this by experiment?
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Yes,a week ago.Filled volumetric flask half full with 10C water and attached to pump.Then at some point water started boiling violently.0 degree water and 5 degree water didn't start to boil even if i waited few minutes.Then grabbed monograph and looked for corresponding pressure.I reached the same conclusion when i pulled MDP-2-P over @ 150C.Nomograph gave me 10 mm which is not very good but enough for me at this point.
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just a Mastercool 250micron rotary vane pump. my point was that swim pulled 100 microns on a cracked vac adaptor without it shattering. ;)
the pump used to pull mdp2p around 100C. then swim feed it some residual dcm and switched to a braided-hose, which somehow boosted it to like 100 microns.
ketone purity is ok at 85-89C, if you remove the forerun repeatedly. swim got 14g mda.hcl from 21.25g ketone via the oxime, which is okay...
swim will never use MeOH in the AcOH/al/hg again btw. post-rxn he added brine/base 3x vol of the MeOH and still got persistent emulsions when extracting with toluene...
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Is there heavy bumping when distilling ketone @ so low temperature?Raf distills his ketone without stirring,there is some bumping but i can live with that.
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With the good quality pump you mentioned, raf, you could get away with using a capillary, in order to avoid bumping. Do you think your Ketone seperation is going to be good at such a low temp? Swim would say that 130 C. would be a good temp to start collecting ketone at.
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150C and low temp?Raf pump is just little better than aspirator.I was referring to somebee who pulls his ketone over @ 80 C.Good pumps are expensive and cool,but raf thinks 150 C will do no harm to MDP-2-P so he doesn't plan buying new one.