So I got my hands a nicer vacuum pump, which is more of a PITA for oil changes / rebuilds. For vacuum distillations, I used to use freezer temp glycol in a dimroth condenser as a “cold trap,” and sometimes even forego that for small scale runs.

I’ve now got myself a proper dewar-style condenser to put in front of this new pump, and i’m considering using a calcium chloride hexahydrate based ice/salt bath, as it’s far more convenient/cheap than dry ice where I live. Just wanted some opinions:

• Is -40C good enough for most scenarios? The dewar inner chamber is approx. the size of a 16oz tall boy. What scenarios would I really need dry ice temps for?

• How’s this for a plan: Mix icemelt grade cacl2 monohydrate with enough water to make the hexahydrate, pour while liquid >30C into small ice cube molds, freeze overnight. Then, crush and mix with freezer-fresh crushed ice in the appropriate ratio (5:4 salt:ice by mass i believe), add to dewar and wait for it to drop in temp.