comments:
I got this setup and have done several runs with it so far. Very happy with it, good quality thick glass. The top of the funnel comes apart to reveal a nice puck of product that's super easily removed with the filter paper. I already had a small vacuum pump lying around so the $50 for the glass and $10 for a pack of 100 filters that fit perfectly (they can be reused a few times) is cheap for what it does. Arguably the next best money spend on upgrades after a grain mill. I also use it to filter the EtAc after neutralization, super fast and maximum recovery of the solvent from the mush of sodium carbonate/fumarate with minimal fumes. A quick rinse under warm tap water, air dry (use a little acetone or 99% IPA if you need it quick) and it's ready to go again. Do you use a filter paper (or nylon) in on top of the frit at the bottom of your funnel? If not, you should... it will prevent clogs, greatly facilitate removal of the product and likely maximize recovery.
The differential weighing is an excellent method, probably the best and safest... I'm just too lazy, and I trust my nose 🤣 And I'm never that anxious of getting a final weight... I've already waited days to get nice crystals, a bit of extra drying time is nothing at that point. On a related note, this winter I started using a vacuum filtration apparatus... I already had a small lab vacuum pump lying around, so $50 for the glass on Amazon is not that much a really nice upgrade. Quality filters are not that expensive either and can easily be reused a few times. Filtering a quart of solvent takes maybe a minute I'd guess, there is minimal fumes, and it makes nice little pucks of product... I let it run dry for another minute or two at the end and the product is done air drying really quickly after that. It's also great for filtering the solvent after regeneration with minimal loss in the mass of sodium carbonate.