hi all, just winding up on an extraction on some acacia but a little concerned with my final extract. d-limonene was used as the np solvent and the alkaloids were then salted out with a mixture of vinegar and water (bout 1/3 vinegar)

after 4 pulls from the limonene with acidic solution i combined them all and there were small traces of limonene on top - normally with other solvents this wouldn't be such an issue as they evap clean but I was aware of the issue of limonene leaving residues.. so I decided to pour a little toluene on top of the acidic solution in hope that that remaining traces of limo would be miscible with the solvent and then removed.. so I removed the toluene and reduced the combined saltings over a low heat, while simultaneously blowing on it with the hair drier to speed up the process

when I was satisfied that all water was removed I added a generous amount of sodium carb to the alkaloids and mashed it into a paste, allowing to sit for 5 minutes or so (in hindsight I would wait a little longer but time was an issue).. i then poured isopropyl over the paste and stired the two together for about 10 minutes. at this point the isopropyl took on a dark orangy colour and the sodium carb was a bright white colour again. the isopropyl was carefully filtered several times to remove any traces of sodium carb and was then poured into a glass dish to evaporate

after about 30 hrs it had evaporated entirely and nice needles were stuck to the side of the dish.. the base however remained very gooey and crystallised over time. it hasn't really solidified yet but I am a little worried as there is an obvious orangy smell to it. I am wondering whether something in the limonene could have migrated over to the acidic fraction during the salting or whether it is just traces that didn't leave with the toluene (after removing the toluene there was no orangy smell to the saltings just very small traces of toluene on top which evaporated as the solution was reduced)?

I would really like to remove any contaminents from the limonene so if anybody has any suggestions or ideas as to how this could occur that would be great. the limonene is pure and from a good source

If you can get fumaric acid its very easy to just wash the fumarates with IPA/acetone to remove any limo traces.

But even if you cant and dont do anything else and had a tiny tiny percentage of limo residue it wouldnt be the end of the world I guess, no?

My guess is the toluene smell is gone, since the toluene evaporated, but left still traces of limo which is what you are smelling.

I'd suggest skipping the limo and just using toluene as a NP solvent, solves that problem.

Otherwise, you can dissolve the stuff in vinegar and repeat the process until the smell is gone, washing with toluene is another good idea too, but hard without a separatory funnel.

third option, give it enough time, few weeks or so, the d-limo will eventually evap, whether it leaves a residue or not I don't know, but i'm fairly certain the orange smell is the limo itself, not the residue.

What the residues actually are is a good question, probably terpene oxidation products, d-limo can be oxidized on its double bonds, its a non-aromatic. Oxidation products are determined to be Carvone, carvol, and limonene oxide, which all have too high b.p. to evap out, (but they don`t smell like oranges)

Everytime I use limonene I have this problem. I wait a couple weeks and then dissolve in water or vinegar and filter through tight cotton. Seems to get rid of limonene residue and any other impurities that managed to solidify over time.

I've found this too, limonene - or something similar such as citral - is somewhat soluble in vinegar. It could be that DMT acetate acts like a cationic surfactant, just looking at the molecule.

This also applies to citrates, so it could be that limonene (or citral) is attracted by the indolethylammonium cations.

Slewb's cotton trick seems like a good answer for those without fumaric acid & IPA/acetone