could someone illustrate the required amount of DCM to use to recover the finished honey from say a 2.5 KG NaBH4 post reduction solution (flooded workup)?
You cannot determine it beforehand without knowing the partition coefficient for MDMA between DCM and aqueous alcohol (and I doubt anyone has tabulated that anywhere). It will also differ if you have more or less salts dissolved in the solution, as well as if you have used methanol, ethanol or isopropanol as the alcohol, and how much water you flooded it with.
But - if you adhere to a standard protocol, and measure how much product you get in the first, second and third extraction, you can calculate the solubility product as in Post 464877 (https://www.thevespiary.org/talk/index.php?topic=6709.msg46487700#msg46487700)
(Chromic: "Okay, more guessing", Chemistry Discourse) and then from that you can work out the optimal number of extractions, and how large each of them should be to retrieve 99.5% of all your product.
Critical compilation of scales of solvent parameters.
Part I. Pure, non-hydrogen bond donor solvents
Pure Appl. Chem., Vol. 71, No. 4, pp. 645-718, 1999
http://www.iupac.org/publications/pac/1999/71_04_pdf/abboud.pdf (http://www.iupac.org/publications/pac/1999/71_04_pdf/abboud.pdf)
Excerp......
It has long been known that solvents often affect chemical reactivity, this involving, e.g., the shift of the position of chemical equilibria (thermodynamic aspect) as well as significant changes in reaction rate constants (kinetic aspect). Physical properties, particularly the frequencies and intensities of transitions in IR, UV-visible, fluorescence, NMR and ESR spectroscopies are also known to be affected by solvents.
These phenomena are consequences of differences in the solvation of reagents and products (thermodynamic effects) or reagents activated complexes (kinetic effects). Differential solvation of species in the ground and excited states accounts for the spectral phenomenology indicated above. Differences in solvation of a given solute in two different solvents determine the size of the corresponding partition coefficient.
What rubber hose, gasket material to choose with different solvents see the chemical resistance chart....
http://www.akrongasket.com/charts.html (http://www.akrongasket.com/charts.html)