Last week I run a reaction in molten imidazole without a solvent, at 240C in a pressure vessel. This reminds me – in Prague we would heat quantities of beta naphtol with neat hydrazine hydrate in a “Bombenrohr” in the electrical oven at 150C, and we were taking that alarming thing periodically out and giving it a hard shake while hot. (Bombenrohr is a fancy German word for a pipe bomb, a steel tube with screws at ends). The resulting ooziness was then poured and spooned out into vats of boiling water, to extract away the unreacted hydrazine, naphtol and the sideproduct – betanaphtylamine (I know how it smells so I am gonna die) – and the leftover slime was then repeatedly precipitated as HCl salt, to get 1,1′-binaphtyl-2,2′-diamine. We were making 50 g batches of the racemic stuff that way and we were then resolving them with CSA.
The meanest reaction I did was melting binaphtol with 3 equivalents of Ph3PBr2 without solvent, to get binaphtyl dibromide. The procedure called to “dilute the melt with equal volume of dry Celite, cool the mixture to solidification, break the flask and peal off the glass, crush the solidified reaction mixture into half-inch sized chunks and extract them in Soxhlet” – which I managed, except that hammering the mean black 250mL tar-ball into chunks produced lots of corrosive bits flying everywhere while I was choking on the HBr fumes.
There is no moral to this sad story.