Ionic strength and crystallisation

[dooby]

Hello,

While experimenting with the water crystallisation process I think I found out that a high ionic strength is detrimental to crystal formation...

I added a bunch of NaCl to an aqueous solution containing dmt-citrate and NaOH in order to increase the solutions density without affecting pH or creating unwanted by-products...

I was trying to make all of the freebase float

My best guess would be that the decrease in crystal formation in a solution with a high ionic strength is caused by inter- or intramolecular forces that are beyond my comprehension

For now, the main question derived from this would be how to lower the ionic strength of a solution without affecting pH too much or without creating unwanted by-products...

Or would pulling with an nps be my best option at this point?

My goal to have a sufficiently dense solution to make dmt-freebase crystals float remains but I will have to look for other ways to accomplish this than by adding NaCl...

 

[Dr_Sister]

Hello,
I added a bunch of NaCl to an aqueous solution containing dmt-citrate and NaOH in order to increase the solutions density without affecting pH or creating unwanted by-products...

More likely you added NaCl to a mixture of dmt freebase/sodium citrate/NaOH especially if the solution is basic.

For now, the main question derived from this would be how to lower the ionic strength of a solution without affecting pH too much or without creating unwanted by-products...

what you are actually doing by adding NaCl to your solution is forcing the dmt freebase out of solution

Or would pulling with an nps be my best option at this point?

It will be, because otherwise your final product will be contaminated with NaOH, if you extract your dmt into a NPS then you can wash it to remove any NaOH that gets carried over. Trying to isolate your freebase directly a basic solution gives no way of removing these impurities, without recrystalizing your product. If you are patient enough, your freebase should eventually form its own layer, and quite possibly crystallize on it own right there. With tryptamine, sometimes the freebase forms a top layer, sometime a bottom layer, but it always forms a layer, and always crystallizes if it is pure.

My goal to have a sufficiently dense solution to make dmt-freebase crystals float remains but I will have to look for other ways to accomplish this than by adding NaCl...

Patience should work as well as NaCl, but you will still need to purify it

 

[dooby]

Thank you for chiming in - your opinion and advice are highly regarded

As for "More likely you added NaCl to a mixture of dmt freebase/sodium citrate/NaOH especially if the solution is basic." yes that would have been a more accurate description of the situation (I foolishly described the left side of the equation)

And yes, forcing the dmt out of solution (I just read it's called "to drown out") is what I was trying to do but obviously it doesn't seem to work as well as I had hoped...

The solution has been sitting in the fridge for a few days now, and compared to a non-NaCl sample there seems to be a limit as to how much dmt will crystallise which made me wonder if this was due to the higher ionic strength of the NaCl sample than of the control sample. Perhaps the process is merely slowed down, but I'll never add NaCl again in a water crystallisation

This situation stems from a back-salting of toluene with citric acid and I was trying the freebase reconversion/water crystallisation route so I might try a water (slightly basic) wash to purify or perhaps I should dry some acetone? (I already have a batch of water crystallised freebase dmt that hasn't been purified yet)

I'll pull from this batch and re-x as you advised...

Thanks again

PLUR