Bumping can occur at any pressure, so an aspirator won't prevent the problem

Doesn't the bumping tend to be worse when the vacuum is stronger? It seems to me that it would be, and makes sense because of how bumping occurs. I was thinking this would reduce the likely hood of it being such a problem.

As quoted by MM from someone on SM:

Once something really starts bumping, it can rocket through 600mm vigreux columns instantly. If it's bumping, it's often a sign that you're doing something wrong.

Wrong flask, no stir bar, no boiling chips (only works at atm pressure), too hard a vacuum, heating too rapidly etc... in general, too much aggression.

Plus perhaps the reason boiling chips do not work well under vacuum is because their is no small air bubbles on them to aid in preventing the over heating via the rapid bubble expansion?

jon, all I know about boiling stones I learned from my organic chemistry lab survival guide (who wrote that again?).  Anyway he mentions that the air cavities in the stones were the actual nucleation site and that when you pull a vacuum those holes get filled with liquid meaning bumping will normally.

Yes, bumping is definitely pressure dependent phenomena. Anyway ever used a gast or a welch?  The flask starts bumping when you pull the vacuum too hard

Bumping can occur at STP, it's a phenomenon that develops whenever super heating occurs 

i got a suspicion your working with albidum oil, it contains:
safrole
phelladrene
pinine
eugenol
camphor
and some other shit.
you probably got some phellandrene hanging around

Jon, im 100% positive what im dealing with is Sassafrass oil. I have been steam distilling oils since I was 16 . The process used was simular to steam distilling known as hydrodistillation where the plant material and the water are in the same vessle. Its like a hybrid between distillation and steam distilling and given the volume of water used its more like steam distilling. It was recovered solely from Rootbark and nothing else.

Methyl:

Using a larger flask then normal may save you some headache here but be careful not to destroy product.

[quote ]
Methyl:

Using a larger flask then normal may save you some headache here but be careful not to destroy product.
[/quote]

Like instead of trying to distill a volume of 500 mL in my 1000 mL flask, I should try something like 300 mL? I guess that could help a little, but that would only be like an inch less in height up the flask... man when that stuff superbumps, it can climb out of the whole flask pretty easily. But yes I can see how the less material and the more headroom there is in the flask, the less bumping would be prone to happen... hopefully... but if the capillary tube trick really works well, then I'd rather do big 500 mL distillations, naturally.

lugh: thanks man. I think I will just do it. I'd rather not have to buy a bump flask at the moment. But knowing me, I might just because the apparatus would look really cool and geeky with the double stack flasks. I guess it's okay to pull vac on a 3-neck flask since Zubrick shows it in the illustration, heh heh.

MM, distilling 500mL in a 1000mL is not a problem at all.  Just use a capillary/needle and make sure it goes fairly deep into the solution.  It will boil a bit more violently, but no more bumping.  The problem with every bump flask I've ever used is that the liquid settles in the bump flask and you have to return it back into the flask every so often.  PITA with vacuum.  A 100mL bump flask would be just fine, you could use a 250 if you wanted to be safe.

Maybe you have some low boiling contaminant?  Do you have a bunsen burner?  They're really convenient for regulating vacuum for minimizing bumping.  Even better than a capillary IMHO

You can use a heat source such as an infrared lamp to boil out what remains in the bump flask after most of the distillate is in the receiver 

don't know for sure if its true or not but in my experience acetic acid alone does such a good job the end result is often quite pure.
a real timesaver.

no i can't say i have. perhaps it's because i was'nt pulling hard vacum like youse guys are talking about.
his name is james zubrick
damn good book by the way best 5 dollars i ever spent, and i've had some really good acid so that's saying something.

gast pumps are just nice diaphragm pumps that pull a vacuum around 100torr.  Best part is the output doubles as an air compressor on most of them.  Makes running columns a breeze.  Now if only I could get my ass a rotovap...

chuck it in freezer straight after you distill without agitating it or playing with it.. if you have safrole you will be able to freeze it but, like you say, sometimes with my oil it would just not freeze unless it was freshly distilled (so i thought)

where is the oil origin? you sure you are getting safrole?

ahh ok so ur got some dirty china oil

let me tell you what you need to do, this will save you alot of heartache, chuck it out. haha na jkn

If u got GAA wash with that ala Jonshak then if its visibly dirty set your vac up distill the whole lot over fast as you can efficiently do

then set up for NON vaccum distillation and collect your only trusted safrole when it rolls over at 232.. dont be suprised when your oil is only 40% and dont be suprised when you find out youve been using the wrong fraction in your failed synths


as for the bumping, in my experience if you are taking on a project like vacuum distilling saf then you should have a mag stirrer.. thats like trying to make lsd with pots and pans on the stove

my 1st hotplate was an electric pot, removed thermistat, fitted a stove temp controller dial for a temp control. worked great, boiling stones didnt,

so the electric pot was put on stilts almost a foot high, then i took apart one of those square window fans, got the engine and a few strong coathangers and wired them all around the engine in and out of holes then bent the legs down so the engine sat facing upwards with 3 feet like the moon landing vehicle thing.. took alot of tweaking before the engine sat directly upways. these type fans are straight through drives shaft come out of the bottom and the top. which is handy because these engines have fans not only to cool you but also themself! so you can fit magnets in top and a cooling fan on bottom

so the moon landing fan engine had a mini fan fixed to the bottom and the shaft on top spun 2 magnets which were taken from a speaker... and the moon lader mag stirrer was made stable thankyou to areldite, i glued each leg down tight, i glued an alan key there fixt to the engine and to the bench it was fixed to the bench in general. if i was to thank a company for making this all possible it would be the areldite people lol

this hair brain set up worked, but only after a flat round piece of ally was fitted spinning under the pot to shield heat from the fan engine, 3 or 4 hours of ditilling with those temps shes gotta last!