Hello,

Vovin's Tek is an A/B tek that tells you to do a sodium carbonate wash, which makes sense, but they also instruct you to do 2 more washes to the solvent layer with plain distilled water.

My question is: Does washing the solvent layer with water reduce yields of DMT by acidifying some of it and letting it dissolve into the water?

My reasoning is as follows: The water has a pH of 7, which leads me to believe that it would convert the DMT (pKa ~8.7?).

Any thoughts?

I would think no...seeing as pKa is really just used to determine ph of a buffer solution. Though it does show you which acid is weaker or stronger. Comparing water with a ph of 7 and dmt with a pKa of 8.7 was kind of confusing for me. The pKa of water is 15 i think(anything above 2 is weak). Though it is neutral it can both donate or recieve a proton making it capable of being both an acid or a base. Either way it shouldnt in theory make your product acidic. Maybe someone a little more certain will respond, but ima go with no.

I've always done a water wash on my solvent pulls. Despite knowing the theory behind it I'm still paranoid of lye. And, no matter how well I let it separate and how festidious I am in pulling off the solvent layer it always seemed that the rinse water took on a pinkish hue indicating it was rinsing something from the solvent. But My yields have always been what I've expected.

Looking at it a bit more washing with water shouldn’t effect yield, and can remove that nasty sodium hydroxide by dissociating it into its ions which are then removed when you siphon off the water from the dmt saturated naptha solution. But by introducing sodium carbonate you are creating carbonic acid. Not exactly harmful and it is soluble in water but I cant find anything about its solubility in naptha or how it reacts. Maybe im way off base but if the carbonate isn’t to remove the NaOH then the only other thing would be for the HCl acid. But that seems unlikely you would have any leftover and even if you did the water wash in theory would strip HCl of its H ion and leave Cl ions floating around in the water solution. I could very well be wrong but it seems like adding the sodium carbonate is just excess material that could result in diluting the final product(someone please correct me if im wrong, cant learn if I don’t know). But going back to the beginning water shouldn’t acidify the solution and if you are that worried then look into making a buffer solution for NaOH. But again, extra steps…

Water washing is really not necessary if instead a recrystallization is performed on the dmt crystals yielded initially. When redissolving the (possibly lye or plants particly tainted) crystals in fresh solvent, any lye or plant particles still present tend to agglomerate or even stick to the glass and are easily separated by decanting the hot dmt laden solvent into a clean precipitation container for recrystallization.

Lye particles will not color impure dmt purple, tiny drops of plant soup will. The way to minimize these tiny droplets of polar solution floating in the nonpolar solution after mixing the layers is quite simple: Collect all the nonpolar layers removed from the baisfied plant soup into a container that is kept in a warm water bath (to prevent premature crystallization around the floating impurities). When not in contact with the basic plant soup, the nonpolar solvent can be kept quite warm without picking up the waxes and other stuff that typically impart a yellow discoloration onto the product when the basic soup and solvent are too hot during extraction. Once the solvent has been separated this is no longer an issue. After standing in the warm water bath for 30 minutes, nearly all floaters will have sunk to the bottom and adhered to the glass. Decant into clean container to cool and freeze. Recrystallize anyway.

You asked very same question 2 years ago.
Distilled vs. Sodium Carbonate Water for Subsequent Final Washes Per Vovin's Tek
1ce said no problemo using plain water, and he could even see (bi)carbonates ending up in the end product skewing one's measurements. Imho that's exaggerated but I have no proof, yet I haven't seen any proof given of measurable (bi)carbonates contamination either. Did I missed it?

Norman and burnt have another idea on the matter and speak of using higher pH as a playing factor, so preferring carbonate over bi-carbonate:
Ammonia wash AND recrystallization?

So we have contradicting intel/opinions.
Those saying 'no yield loss' by using plain water: was that a double test, a comparative test? No details on that. I guess they were just satisfied with the end yield number.

Only double tests can show differences, if there was any reported I'd sure like to know.

I could see it causing a difference if the water had a pH below 7. Distilled water collects carbon dioxide from the air which forms carbonic acid. I would double check the pH of the water beforehand, however I just checked and my distilled water has a pH of 7 and I've had it for a few weeks now.

Comparing pKas to pH is simple. If the pH is below the pKa you will usually find the compound protonated. And if the pH is above the pKa you will usually find it deprotonated(freebase). The higher the pH the more deprotonated it will be relative to the Ka. The Ka is just 10^-pKa. But there's alot of chemistry and calculating that'll go into all of that calculating but it can be done. You will lose a very small fraction to the water, but is incredibly negligible at pH7 especially if you only use a small amount of water. We're talking less than .01%

If you are considering if (bi)carbonate is soluble in naptha you needed worry as it is not considered to be soluble in nonpolar solvents nor alcohols(solubility referenced from Pubchem). If you really are worried then you can rinse your final DMT product with a little water and it will wash away all carbonates.

If you dont use carbonate, but instead use bicarbonate your solution will still be basic. Giving you a pH roughly equal to it's Kb(7.7) Which will decrease your loses even more than the amount mentioned with just plain water.

BASICALLY( ), water is fine. If you use bicarb, youre fine, if you use carb, you're very fine. Carbonic acid will not form in appreciable amounts unless you lower the pH to below 3.5 as noted in this graph. Carbonate Titration Curve