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TEK The benzoic acid tek

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Understood, but your basified polar phase is full of bark solids when you throw and mix non polar in, right? Need a confirmation on this.

Totally understand you can use one volume. But with two it should go a lot faster. Also it should work with FASA MASA CASA equally well, maybe not as fast?
 
Ruffles said:
Understood, but your basified polar phase is full of bark solids when you throw and mix non polar in, right? Need a confirmation on this.

Totally understand you can use one volume. But with two it should go a lot faster. Also it should work with FASA MASA CASA equally well, maybe not as fast?
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@Jan e Kharabat replied and I do the same I leave the bark and lye solution and just add the NP swirl a little even leave overnight some times.

 
I'm a chemistry newb and I'm still trying to wrap my head around the atomic interactions of acids and bases. So far my understanding is that most acids work by donating a proton to water, forming a hydronium ion. What is happening to benzoic acid in NPS that allows it to be an acid? Where is the proton going if there's no water?
 
Icon said:
I'm a chemistry newb and I'm still trying to wrap my head around the atomic interactions of acids and bases. So far my understanding is that most acids work by donating a proton to water, forming a hydronium ion. What is happening to benzoic acid in NPS that allows it to be an acid? Where is the proton going if there's no water?
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Benzoic acid has its benzene ring which pays a large part in its solubility patterns. Another aspect is that carboxylic acids can form hydrogen-bonded dimers in non-polar environments. The acidity (in terms of pKₐ) of carboxylic acids depends on the rest of the molecule, [hence trifluoroactic acid is way more acidic than plain acetic acid on account of the electron-withdrawing properties of fluorine]. In that respect, benzoic acid is rather weak because the electron-rich phenyl substituent discourages ionisation.

So, in the case of benzoic acid in NPS, the greatly preponderating proportion of the protons remain bound to the oxygen atoms in the benzoic acid molecules and their dimers. Since all of this exists as an equilibrium, there are still sufficient 'exposed' protons for a base like DMT to start mopping them up. Electrostatics and lattice energy soon begin to drive precipitation of insoluble DMT benzoate, and since this forms exclusively from dissociated and monomeric benzoic acid, this - in accordance with Le Chatelier's principle - leads to further dissociation of the dimer until either or both of the reagents get used up.
 
I'm doing the benzoic acid tek right now as a purification step. I had a jar of yellow aqueous DMT HCL that I freebased with lye, which precipitated a bunch of DMT that coagulated into a reddish brown syrup at the boundary layer above the water. Pulling with hexane, salting with benzoic acid saturated hexane.

I've yielded some of the DMT benzoate and dried it, it does look pretty pure and very fine, like a pharmaceutical powder.

It's sloooow going with hexane though because solubility of DMT and benzoic acid is very low in it. I kind of regret not using naphtha, but I figured hexane will be most selective and yield more pure results. Spending a lot of time letting the precipitation settle, then checking the DMT content with more drops of acidified hexane. Volumetrically, I'm finding that it takes more than 1:1 ratio of acidified hexane to precipitate spice-saturated hexane. I'm trying to avoid adding benzoic acid directly to the saturated hexane so the BA doesn't get locked up in precipitates.

I noticed the suspended benzoate solution clears up sooner the quicker I mix the reagents, so now I'm adding 1:1 right off the bat and mixing it with a power drill + PTFE stirring paddle. The DMT-Benzoate salts seem to coagulate better with vigorous mixing and settle to the bottom within a couple minutes vs tens of minutes. I even started twist-tying a filter parachute of benzoic acid to the paddle, aiming to get continuous dissolution and centrifugal release of fresh BA while depleting the DMT. Seemed to be working really well.

When I finally stop seeing a reaction from BA, I transfer the depleted hexane back to the alkaline water + freebase syrup vessel and gently stir it until it picks up a faint yellow color, shrinking the syrup layer slightly. Then I pull it and repeat the salting step.

Then I hit a snag. I was starting to get impatient so I used the drill stirrer to really whip up the basic salt water + DMT syrup into the hexane and get a bigger pull. After everything settled into separate layers again, the hexane was twice as yellow compared to gentle stirring. I waited a few more minutes for micro-drops of oversaturated syrup to oil out before pulling it. But when I went to salt it (with BA hexane, not even the BA parachute), zero precipitation was forming... Assuming the syrup is still DMT, why isn't the saturated hexane precipitating salt anymore?

I separated the deep yellow hexane and did a mini-A/B on it with fresh HCL, which pulled all the yellow back into aqueous solution (exactly how the DMT HCL solution looked originally). I based it again with lye solution, and again huge clouds of precipitate coagulated into an oily layer above the pale water. I gently mixed the hexane until it was light yellow before pulling it. I was able to salt out the DMT with fresh BA hexane again, and the hexane turned clear as the DMT was depleted. Everything went back to normal.

Something changed when I was using the drill. Right now my guess is the freebase DMT syrup polymerized over time or specifically during high speed mixing (the syrup physically looked chunkier after), which seemingly increased its solubility in hexane, but totally eliminated its ability to react with BA hexane. Or maybe it was reacting, but the salted polymer was not precipitating out. Does that sound possible?
 
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DMT is weird and likes to misbehave in the lab :ROFLMAO:

Red syrup is typically polymeric as far as we know - but it won't be homogeneous. It dissolves in hot heptane, but precipitates back out on cooling below ~70°C. Maybe the whipping produced some kind of colloid? Or the smaller oligomers get released from the body of the goo, hence the stiffening observed after vigorous stirring. These small-chain oligomers apparently form a benzoate which is soluble in hexane. If the basicity of the material is lowered as a result of oligomerisation, that would go some way toward explaining why the resulting benzoate remains soluble in the hexane, perhaps.
 
@Transform (or anyone) can you help me understand an observation?

I've dissolved pure white, washed DMT benzoate in distilled water. The solution is light yellow. I intend to convert it back to freebase.

Even though I've washed the powder a few times already, I figured why not wash aqueous solution with hexane once more before freebasing. I used a PTFE stirrer in the drill again, for about 30 seconds, until it looked homogeneous. The solvents instantaneously separated, but the hexane adopted the same color as the water (yellow). I wasn't expecting that. I slept on it and slowly over the course of ~15 hours the hexane turned clear again.

I assumed any ionic solutes would want to stay in the aqueous layer, since DMT benzoate is insoluble in hexane. But since both benzoic acid and DMT are soluble in hexane, does their dissociation in water allow the individual ions to get temporarily trapped as solutes in the hexane layer? At rest, the solutes don't seem to want to disperse into the non-polar layer, but with power-stirring there's a clear yellow effect.

The solvent layers appear totally separated, I can't visibly see any emulsion, yet it's similar to an emulsion in that the yellow solutes want to return to water but take a lot longer to exit the NPS than water itself. At first I was thinking oh, with only itself ionizing the solution, it might be a fairly neutral pH that is letting some of the DMT migrate into NPS. But after seeing the yellow hexane eventually clear up, I'm a little confused how to interpret this.

Anyway, assuming there's both DMT and benzoic acid ions getting temporarily suspended in NPS: my plan is to separate the yellow NPS and salt out benzoic acid with NaOH while simultaneously freebasing the DMT. I assume DMT will stay in hexane solution and sodium benzoate will move into the aqueous NaOH solution. I'm looking forward to this; feels like it should be a really straight forward and clean conversion. I'm hoping it yields ultra pure DMT. I'm trying to avoid the scenario where too much freebase crashes out of aqueous for the NPS to pick up and coagulates into an oil layer. If I'm only picking up a handful of ions with the NPS to get freebased in a separate container, that will hopefully ensure all the DMT getting freebased fits into that volume of NPS.

It makes me wonder if there's another way to salt out benzoic acid without introducing OH- ions? Since DMT cations are apparently soluble in NPS temporarily, if you only salt out the benzoic acid without changing the DMT cation, what would that do? Would it settle / precipitate itself out as goo? Polymer goo?
Jan e Kharabat said:
. . . I neutralized the excess BA from the left over extract using some NaCO3 . . .
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Oh, NaCO3. Or wait, wouldn't that form DMT carbonate and sodium benzoate.

What happens if you dry out a solution of NaOH? Does the Na+ always end up precipitating with OH- or is there a way to isolate sodium cations? Electrolysis?
 
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Maybe the yellow in hexane are the multitude of tiniest water droplets holding benzoate and they take longer to drop down? If so, a centrifugation would clear the hexane instantly.
 
Icon said:
@Transform (or anyone) can you help me understand an observation?

I've dissolved pure white, washed DMT benzoate in distilled water. The solution is light yellow. I intend to convert it back to freebase.

Even though I've washed the powder a few times already, I figured why not wash aqueous solution with hexane once more before freebasing. I used a PTFE stirrer in the drill again, for about 30 seconds, until it looked homogeneous. The solvents instantaneously separated, but the hexane adopted the same color as the water (yellow). I wasn't expecting that. I slept on it and slowly over the course of ~15 hours the hexane turned clear again.

I assumed any ionic solutes would want to stay in the aqueous layer, since DMT benzoate is insoluble in hexane. But since both benzoic acid and DMT are soluble in hexane, does their dissociation in water allow the individual ions to get temporarily trapped as solutes in the hexane layer? At rest, the solutes don't seem to want to disperse into the non-polar layer, but with power-stirring there's a clear yellow effect.

The solvent layers appear totally separated, I can't visibly see any emulsion, yet it's similar to an emulsion in that the yellow solutes want to return to water but take a lot longer to exit the NPS than water itself. At first I was thinking oh, with only itself ionizing the solution, it might be a fairly neutral pH that is letting some of the DMT migrate into NPS. But after seeing the yellow hexane eventually clear up, I'm a little confused how to interpret this.

Anyway, assuming there's both DMT and benzoic acid ions getting temporarily suspended in NPS: my plan is to separate the yellow NPS and salt out benzoic acid with NaOH while simultaneously freebasing the DMT. I assume DMT will stay in hexane solution and sodium benzoate will move into the aqueous NaOH solution. I'm looking forward to this; feels like it should be a really straight forward and clean conversion. I'm hoping it yields ultra pure DMT. I'm trying to avoid the scenario where too much freebase crashes out of aqueous for the NPS to pick up and coagulates into an oil layer. If I'm only picking up a handful of ions with the NPS to get freebased in a separate container, that will hopefully ensure all the DMT getting freebased fits into that volume of NPS.

It makes me wonder if there's another way to salt out benzoic acid without introducing OH- ions? Since DMT cations are apparently soluble in NPS temporarily, if you only salt out the benzoic acid without changing the DMT cation, what would that do? Would it settle / precipitate itself out as goo? Polymer goo?

Oh, NaCO3. Or wait, wouldn't that form DMT carbonate and sodium benzoate.

What happens if you dry out a solution of NaOH? Does the Na+ always end up precipitating with OH- or is there a way to isolate sodium cations? Electrolysis?
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That's an interesting proposition. Try shining a narrow-beam torch or laser through the (yellow) hexane and viewing it from the side. If there's an emulsion, the beam will be visible due to scattering. A red light is preferable, as fluorescence might, conceivably, confound the test.

DMT (bi)carbonate is distinctly unstable, but appears to be involved in solubilising DMT freebase into water which often contains dissolved atmospheric CO₂ even if it's not isolable as a solid.

Sodium cations are not isolable. Sodium hydroxide is recovered by evaporation, although you'd have to exclude CO₂ to prevent formation of appreciable quantities of SC.

*Na₂CO₃ ;) You can call it SC if you like 😁
 
Transform said:
That's an interesting proposition. Try shining a narrow-beam torch or laser through the (yellow) hexane and viewing it from the side. If there's an emulsion, the beam will be visible due to scattering. A red light is preferable, as fluorescence might, conceivably, confound the test.

DMT (bi)carbonate is distinctly unstable, but appears to be involved in solubilising DMT freebase into water which often contains dissolved atmospheric CO₂ even if it's not isolable as a solid.

Sodium cations are not isolable. Sodium hydroxide is recovered by evaporation, although you'd have to exclude CO₂ to prevent formation of appreciable quantities of SC.

*Na₂CO₃ ;) You can call it SC if you like 😁
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What does this mean:

I can see the beam in the hexane before stirring it up yellow, maybe there is still an invisible emulsion from yesterday, even though it's nearly back to colorless. I tested the laser through a control jar of hexane and could still see the beam, but it was noticeably less bright.

View attachment IMG_0872.jpeg

After stirring it yellow, the beam looks the same, maybe a little more visible and scattered on the playing card backdrop.

View attachment IMG_0875.jpeg

I forgot to take a measurement before mixing, but the solution's electrical conductivity after mixing is 2200 μS/cm. Yellow hexane's EC was 0 (just checking). I'll take another reading tomorrow after the hexane clears up.

pH is 6.95. Is that just a coincidence or does dissolved DMT benzoate simply not affect water's pH?

DMT Benzoate crystals in the bottom of a flask, indicating the solution is saturated.
IMG_0867.jpeg
 
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Icon said:
pH is 6.95. Is that just a coincidence or does dissolved DMT benzoate simply not affect water's pH?
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It's just coincidence. While the theoretical pH of pure water is near 7.0, you're unlikely to ever directly observe this. Purified water is typically acidic due to carbon dioxide absorbed from the atmosphere, though your meter may fail to reliably measure that due to its low EC. Tap water usually shows pH close to 7, but that's some combination of carbonate buffer from limestone formations and deliberate adjustment by the utility.

Assuming pKa = 4.20 for the benzoic acid and pKaH = 8.68 for DMT, we expect pH for a strong solution in water around the midpoint, 6.44. That's the steep part of the titration curve, so small deviations from a 1:1 molar ratio may cause large changes in pH. So your measurement seems pretty close, though I've never worked with DMT benzoate myself.
 
Does this look like sodium benzoate? At the bottom of a jar, after freebasing a dmt benzoate solution with NaOH.
 

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