Can't find it via search or the wiki or google. I realize one can just dump in FA until it doesn't dissolve anymore to obtain FASI, then filter off FA, but I can't find anywhere with a value. 5g/473ml were used in one tek = 1g/94.6ml, does that sound right?

Why do you want a value if the 'dump till doesnt dissolve' works? You can always just evap/dry whatever is undissolved and stay on the bottom and retrieve it back.

In any case for values, check this out

https://www.dmt-nexus.me...ts&m=96059#post96059

Well endlessness, it's not really a life or death situation, I understand. If one is using 99.9% IPA, it would be a good idea to minimize exposure to the atmosphere, which would happen in the filtration process. I realize for all practical purposes, loss would not be too significant. If one has a limited amount of fumaric acid, it would be a good idea to know how much to add to IPA as not to add too much solvent.

I saw that article before I posted, but I wasn't sure of my calculations. Here's what I wrote:




0.0307g/ml

It took me 28.5 grams of Fumaric acid to saturate 1000 ml of IPA @ 21.5 C.

One point where this is important to know is when you use FASI (FASIPA) to precip out D-Fumarate from NPS followed by re-disolution in H2O to separate out the remaining NPS and then dry. The idea is to use as exactly as possible only what you need. Otherwise, you are over-loading your final solution with fumaric acid which, on drying, throws off the final product weight and purrity with excess Fumaric. Of course, after dried you can wash that out with IPA but then you lose some D-Fum also and add another step not otherwise necesssary. (You can also do the precip drip by drip until no more precip forms, but on 500 HRRB batches, this takes a long time. I just dump in the correct amount of FASIPA, let the solution clear (15 mins) and then double check with a single drip.

By the way, I have found the MAX ION tech plus this FASIPA the best overall method with yields approaching 3%.