Boiling flask busted in rotovap, clean contaminated crude?

I ran my roto overnight with a new Chinese flask, well it busted sometime overnight detroying my vapor tube with it and dumping about a liter of crude and about 2liters of solvent into the bath. It was just RO water in the bath I save it all. What steps should i take other than distilling off the water?


Filter the glass out


try picking it up with a nonpolar solvent, then rotovap the solvent off.


Try to save a little time running the roto overnight and this is what I get lol. Cheap Chinese glass is not the way lol

How did it break, Any clue? Was the rotovap being continously fed? I wager that the vapor tube broke first, then the flask dropped and smashed around.

What’s a good cheap nonpolar solvent? Maybe some
dichloromethane used for thinning? I could do a purity distillation on it first to remove any mystery oils

You have axcess to pentane?

Inseenit online for sale but it looks like some high dollar stuff

I shot an email to Northeast butane to see if they have pentane or hexane
@Shadownaught do you have any small quantitys for sale?

1 Like

Is pentane better than hexane?

It usually can be found in much purer grades for cheaper.


Unfortunately we only do pentane in 55 gallon units. I would suggest purchasing smaller volumes from our friends at


Cant blame the glass. I ran my roto for
9.5g w/o issues

1 Like


This is a buchi and I bought a China 3l flask to use. The 5l I was using for vacuum busted earlier that day. I should have known

1 Like

Re-501 china glass

9.5 gallons of ethanol wash ran this run.

I also swap to a 2l flask from the same company so I dont loose too much oil trapped in the 5l flask.

Now the glass may have been compromised from the start. My 5l and 2l flasks both have a slight wobble . My replacement feed tube thing had a hair line crack in it (Dave at usalabs is sending me out a replacement).

These are probably worse than those. My buchi just uses 24/40 flasks so I scored some cheap universal Chinese 24/40 round bottoms. They both wobbled as much as half an inch on their orbit. I just bought a couple used Pyrex flasks for the time being but it also broke my vapor duct and that was a 200 dollar piece of glass to replace

1 Like

What does it mean to bust a boiling flask?

Were you using a vapor pressure controller that could have gotten stuck, allowing the vacuum to break and the flask to slip?

Long story short:

I have multiple design limitations and i pushed them all passed the point of their design parameters. I let my roto run overnight. i throttled my feedstock petcock just slightly too high and the input overcame the output/distillation rate. Then the evaporation/boiling flask over the course of hours filled completely with input material. this chinese flask i used was too off center and with a full flask created too much force/moment on the vapor tube which acts as the axle of rotation. the vapor tube broke then the off balance chinese flask was really flopping around at this point which must have caused it to strike the inside heater bath. i imagine this is what cause the flask to crack and spill its guts into the water bath.


you need a parastaltic pump to meter the imput.
Set the feed pump to about 75% of what your rotovap is capable of, set the out pump wide open.