Last thing I took a photo of, was actually a video, of how to set up a vacuum distillation. Had problems with the actual distillation since the pump was giving me trouble in the intense heat of the weather at the time whilst my current hotplate's replacements (2 hotplate/magnetic stirrers and a brand new heating mantle, with stirring too:D) haven't arrived at my doorstep yet, I did get the distillation done, deciding to accept some loss of material and cautiously employ, after consulting with others experienced with the compound to be distilled, a direct flame, using a gas torch and holding the flame a fair way away from my flask to avoid damage to it, which got the goods distilling over at a good startup speed.
I'll post a video once I've spliced the two sections together and ripped away the metadata, showing how a vacuum distillation is set up (in this case I didn't, due to the relatively small quantity of material that was being distilled, there can be considerable bumping, I.e rapid, roiling boiling thats overvigorous and can send bits of whatever the liquid in the flask is, including fractions of higher boiling material you didn't want in the distillate up into the still head and into your collection flask, boiling chips don't work since in a vacuum air can't nucleate on the rough bits it normally does, since its removed by the vacuum anyway, although a spinning magnetic stirbar can be used in the absence of magnetic material, and as can the approach of introducing a long glass capillary tube, such as can be either bought, pulled from a pasteur pipette under heating to soften the glass or else hacking the other end off a thermometer if one has been broken close to one end, or gutted for caniballizing things like mercury metal or galinstan (a low melting liquid alloy of gallium, indium and tin [the latin for tin, is 'stannum' which is where the last bit of the name is derived from] and gallium, in combination with indium can be used, in the form of galinstan as a potential replacement for mercury-based amalgam reductions involving aluminium as it too shares in the disruptive effect of mercury and its salts on the passivating oxide surface layer of aluminium) the fine internal bore of a thermometer works well if both ends are open. This is passed through a thermometer adapter or holed stopper, preferably wrapped with a few turns of teflon tape, and it permits a tiny stream of air to be sucked through by the vacuum, not much, just enough to allow bubbles to nucleate and agitate the liquid being distilled so it doesn't superheat, flash-boil and 'kick' suddenly. For highly air-sensitive substances and pyrophoric compounds you'd use a better seal than a thermometer adapter of course, and connect the other end of the capillary to a nitrogen tank or argon tank or else a tank of helium and allow a slow bleed of gas to be sucked in to prevent bumping whilst disallowing reaction with air and destruction of one's compounds, catalysts or just plain setting shit on fire. Which is often fun in a lot of circumstances, but would be a total pig if it happened in a flask containing a liter of ether or THF containing a pyrophoric hydride reducing agent, or organometallic compound being reacted with the valuable, difficult to make and excruciating to purify project you might have spent weeks or months on preparing, or something that made use of something literally irreplaceable you bought as a 1-time available thing. I have something of that nature, just 5g of it, earmarked for two unique new compounds afaik that have never been in man before. Or if they have, then surely never more than a handful of them. And the precursor compound cost me nearly £90 for just 5g. And such an accident would be unforgiveable, as it looks like it would be extremely difficult to synthesize, needing the addition of a strongly electron-withdrawing substituent to a benzene ring already bearing two extremely EWGs (fluorinated at that, too) and whilst I managed to get some of what I need to make what I wish to make with it, it is not a commercial item produced in large scale but a specialist acquisition I managed to make by pure luck being in the right place at the right time.
Anybody wish to see the vacuum distillation video? if so I can do the video editing/splicing segments together and pop it up on my lab thread for y'all:)
