Hey there,

So we were reviewing Vovin's Tek and at the last stage, they instruct that we wash the naphtha pulls with a solution of a little sodium carbonate. Then, the Tek recommends doing a 2nd and 3rd wash, but using only distilled water.

Our question was whether it was counter-productive to do a 2nd and 3rd wash using plain distilled water, as opposed to doing a 2nd and 3rd wash of the same sodium carbonate solution. We were thinking that the distilled water may ionize some of the DMT with it's pH of ~7, and so using the sodium carbonate solution would be better suited, in part from its higher pH, granted we decide to perform a 2nd and 3rd wash.

Distilled water is fine, however distilled water may dissolve carbon dioxide, forming dilute carbonic acid. I don't think a heavy yield loss due to the formation of DMT carbonate should be expected however. I've washed with distilled water every time and never observed a loss.

I would suggest recrystallizing though as carbonate/bicarbonate tend to make their way into the dish.

Is there a chance that this is a negligible amount? I've seen potency loss through recrystallization and have recently stopped. The stuff I pull out of the freezer seems really nice but now I wonder if I have a more-than-negligible lye contamination in my crystals. I had previously thought sodium carb washes to be more of a precaution than a requirement but maybe I should reconsider.

The idea behind washing with water is to remove basic media from the solution. Warm water saturated with bicarbonate tends to leave a residue on your glass and get into your end product, which is likely why the tek calls for 2 more washes with regular distilled water.

I've always washed the organic solution with water, and I've yet to notice a loss of yield from doing do. If you are concerned about it, boil the distilled water and seal the container as it cools to removed dissolved CO2.

^This is actually a good idea for preparing NaOH solutions for basing as the H2CO3 complexes with NaOH to form sodium carbonate/bicarbonate. --weaker-base.

Edit: Sodium carbonate has a melting point pf ~850C, while it certainly won't hurt anything, it will adulturatr your end product and throw off your measurements. Recrystallizing leaves that behind.