recrystallization / purification

[tecnikal]

SWIM has obtained about 2.5 g of crude mescaline via acid base extraction. He would like a pure product and is considering one of the two types of crystallization procedures discussed here. One involved M.E.K, another involved iso and acetone. He is curious about the differences between the two methods. He has lab grade filter paper but no access to a vacuum filter. Would pouring the crystals obtained from either of these procedures into a funnel lined with lab grade filter be sufficient enough? Will he lose any pure product? How large are the crystals produced?


Thanks

[tregar]

Congratulations on your a/b product tecnikal.

I'm finally getting around to the MEK crystallization in dreams very soon, it's been a long wait, but the last of the materials acquired. I also don't want anyone else around when I'm boiling solvent under the fume hood, so privacy is something else I been waiting on, it comes in sporadic days, so that explains the additional long wait, But good things come to those who prepare & wait. See post #91 below:

http://forums.mycotopia.net/botanica...-easy-pie.html

The MEK re-crystallization has been developed and used successfully by me! and several others "in the know". The MEK and drops of water added while boiling is a "dual solvent" recrystallization that works very well.

99% isopropyl alcohol and water returns over 75% of the product as "crystalline" and holds about 25% in solution.

MEK/H2O or the MEK/iso/H20 method generally returns high 80 to 95 percent of "crude" as off white Xtals.

I cannot tell you what the percentage for iso and acetone would be, but it's most likely around 80% and higher.

The crystals are large enough to be caught on top the filter paper, no vacuum required, it just makes the filtering go faster, spectacular white to clear needle formations, each roughly .10 mm in length. Going from boiling to room temp, to fridge, then to freezer will give you the biggest crystals.

However, I highly recommend getting a buchner filtering system for around $60 or so, they are worth their weight in gold. It's not fun waiting around for solution to filter thru filters with gravity alone...it seems like it takes ages sometimes.

You will not loose any product so long as you rinse your crystals with "dry" cold acetone. Dry your acetone by adding a couple of small handfulls of dried epsom salts (400 degrees in oven for 2 hours) to your can, shake the can every few minutes for 1/2 hour, then let it sit undisturbed for an hour or two, then decant off the acetone above the rocks into a vacant jar, then pour your acetone through a vacuum buchner setup to get out any traces of epsom salts from the acetone--this will take a long time if you don't have a vacuum buchner system with vacuum (water aspirator, dedicated vacuum motor or deluxe food saver vacuum port). It takes a good 10 minutes or so of filtering using a good buchner system with poweful food saver vacuum pull attached, so imagine how long it would take to filter out the trace epsom salts without a vaccuum pull--a very long time, many many hours is my estimation. NOTE: You do not want to dry acetone with those round calcium chloride d*** r** pellets, even though it is tempting. Magnesium sulphate (epsom salts) is the preferred drying agent. Calcium chloride and ketones can react together to form schiff bases if left to sit for a long time, something you don't want, whether or not this happens within the short time frame you dry your solvent is not known, it may or may not happen, but better safe than sorry.

Dry the MEK before you use it too.

Don't forget that after you rinse the crystals with acetone, and they dry, that you will then need to add them to a minimal amout of boiling hot distilled water, this will cause any residual solvent fumes to be "driven off"....evaporate off the hot water in a pyrex dish under a fan on "high" setting, when all the water has evaporated off, scrape up your clean, dry crystals.

[tecnikal]

wow. thank you for that very informative reply