The Chemistry of Extraction

[ChemisTryptaMan]

Hello Nexians, I wanted to share some basic knowledge of chemistry that comes in handy when performing an extraction. There are several topics in chemistry that one should have a firm grasp on in order to understand exactly what is happening throughout the extraction process. These include:

1) Solubility

2) Partition Coefficients

3) Ionic Strength

4) Acid/Base Chemistry

Solubility:

Solubility is the extent to which a solute(anything being dissolved) can dissolve in a particular volume of solvent(the liquid holding the solutes). In a chemistry classroom what they will tell you is that "likes dissolve likes". This refers to the polarities of the molecules that one is attempting to dissolve. In general, non-polar molecules will dissolve in non-polar solvents(oils) and polar molecules will dissolve in polar solvents(water). This is why oil and water don't mix. The molecules of each are not soluble in each other, so they wont mix. The term miscibility is usually used for liquid-liquid situations, like ethanol being completely miscible with water means that they can be mixed in any proportion and it will form a homogeneous mixture. The truth of the matter is that oil and water do mix, just in such small amounts that we cant see it. As far as extraction goes, this means that there is some amount of naphtha in the water, and some amount of water in the naphtha. This is because at low ionic strengths(more on this later) most of the water molecules are neutral and do not repel the non-polar molecules as strongly as strongly as a fully charged ion in solution. Spice can exist in different forms that have different solubility in both water and naphtha. Solubility in both will increase at higher temperatures, as this is the case with most solutes and solvents. Higher temperatures mean higher solubility.

Partition Coefficients:

Partition Coefficients are a measure of how a solute will behave in a biphasic(2 layered) liquid system. These have values that are given in terms of the concentration in the non polar layer divided by the concentration in the aqueous layer. The standard solvent system which most literature values is given are for an octanol:water system. The goal when performing these extractions is to get the highest Partition Coefficient for the DMT so that most of it will end up in the non-polar layer(naphtha). This process of finding the optimum PC is different for every solute in every solvent system. We are mostly working with freebase DMT in a Naphtha: water system. We do this by attempting to decrease the solubility in the water layer while increasing the solubility in the naphtha layer. How can we do this? Well heating the entire solution will increase the solubility in both layers, to different extents, but the bottom line here is that you want the bottom layer to be cool when your pulling the spice from it, so if your going to use temperature your best option is to heat the naphtha before adding it to the cool(room temp) water and mixing as much as possible before the temperature equilibrate(which happens within seconds). There is another way to achieve our goal though, and that is by increasing the ionic strength of our aqueous layer in order to decrease the solubility of the spice in the aqueous layer. This also has the added benefit of decreasing the solubility of the water within the naphtha and the naphtha in the water, which is why adding salt results in less emulsions forming at higher ionic strengths, a more complete separation of the two layers is achieved.

Ionic Strength:

Ionic strength is essentially a measure of how much charge is present in a solution. It has a value that is calculated by taking the concentration of every solute in solution, raising that concentration to its charge, and then adding these all together. This means that molecules with more than one unit of charge have a much greater effect on the ionic strength. Calcium and Magnesium both have a charge of +2, While sulfate and phosphate ions have varying charges based on the pH of the solution, but at the high pH's that we run the extractions at they carry a charge of -2 and -3 respectively. pH plays an important role in ionic strength for reasons we will get into momentarily. I don't like to encourage the use of distilled water, I prefer filtered water and for this reason alone, distilled water has had its ionic strength lowered to the lowest possible level intentionally, what you are buying is de-ionized water. With filtered or spring water you have had anything that might be harmful to the process removed and are left with a plethora of ions such as sodium, potassium, chloride, magnesium, calcium, and many, many more. I understand the desire to start with distilled water but from a chemists perspective it is not really necessary and may actually decrease your yield if a high enough ionic strength has not been reached.

Acid/Base Chemistry:

Alright so this is where I want to begin with the two different forms of DMT. These are the Salt and the Freebase forms. The only difference between the two is that in the salt an extra hydrogen nucleus(proton) has been attached to the molecule at the amine(where the nitrogen is located). This makes this form have a charge of +1 at the Nitrogen. The charge is actually spread out over the the atoms surrounding the nitrogen, but most of the charge is located right on the added proton. The rest of the molecule is still very non-polar and hence still quite soluble in the naphtha, but the charge has a powerful effect on the solubility in water because water can easily dissolve charged molecules, even when they have a large non-polar region. Every molecule that can either receive or give up a proton will exist in the two different forms with different pH's determining what state that molecule is in. This switch from one form to another happens around a particular pH for each molecule. For DMT, this pH(known as it's pKa) is around 8.5. When a molecule is dissolved in a solution where the pH is equal to it's pKa, exactly 50% of the molecules exist in each form, so in the case of DMT a pH of 8.5 will cause the DMT molecules to be 50% freebase and 50% salt. Moving one pH unit higher will make the proportion !0:1(around 90%) freebase to salt. Two pH units above the pKa(10.5), and 99% of the molecules will be in freebase form. At !!.5, 3 pH units above, 99.9% will be in freebase form and so on. So a pH of twelve is really a desirable level for the extraction. This topic is also relevant to increasing ionic strength using the protein that is present in the plant material being used. A protein carries a charge of -1 at extraction pH levels, but when a protein is heated for several hours under heat in the presence of either acid or base as a catalyst, it will break apart into it's constituent amino acids, which will each have a charge of -1 at the high pH levels being used. This could potentially have a drastic effect on the final ionic strength of the aqueous layer but I have not yet tried it myself. The pKa where most amino acids gain a charge of -1 is around 10-12, so even higher pH's will ensure that a full charge is gained by every molecule where a charge can be gained. Some molecules with amine groups like DMT itself will actually lose a charge of +1 and become neutral, but since we are already working at high pH's this effect should be be negligible.

There are other topics that need to be covered, like crystallization, but really the most important thing here is that buy reducing the volume of your pulls you are raising the concentration of spice in the NPS used. When you put your pulls in the freezer you are decreasing the solubility of the spice in the NPS and forcing the crystals to crash out.

I hope this info comes in useful for those just learning the process and I am willing to answer any questions that any of you may have. I may make a more comprehensive guide including some chemdraw illustrations when I have some time.

With Love,

CTM

edit: I just want to say that this is a basic understanding of how cybs tek really works so well and so simply. In his tek he uses all this information to fine-tune his process. I highly suggest giving that one a shot if you are new to this process.

 

[cyb]

:thumb_up: Awesomeness :thumb_up:​

 

[ChemisTryptaMan]

I'm actually hoping for some questions that others think might be important so I can make this as comprehensive as possible for those who want to know more. I studied this stuff for way to long to not put as much of it on here as I can.

 

[infinitynlove]

excellent!

thank you very much for posting, so much good information, cleared up some issues I was thinking about!

fantastic!

 

[ChemisTryptaMan]

I'm already beginning to create a more comprehensive post that will cover crystal formation and I will elaborate on solubility by adding a section on polarity. I will have a great deal of chemdraw illustrations to produce, and a lot of extra writing so the format will be more organized and hopefully every aspect of chemistry relevant to extraction would be covered in the guide. Thank you for the kind words, I think a guide of this sort might greatly help beginners in learning how to successfully perform the extractions.

 

[Legit]

I'm probably missing something, but theoretically, for max yield:

-Keep all liquids warm. (What is the ideal temp at each stage?)
-Add salt to the basic water. (How much is best? Have you figured this out yet?)
-The basic water itself should be around 12 pH.

I'm trying to condense essential info to put into my extraction notebook.

 

[ChemisTryptaMan]

You don't want to keep all liquids warm, just the upper layer. Increasing the temp in the aqueous layer will increase solubility of the spice in this layer and lower the partition coefficient. Cooling the aqueous layer, then adding heated naphtha and agitating quickly would probably give a very nice first pull, just so long as the aqueous layer isnt cold enough to cool the NPS enough to decrease solubility in that layer, I just ensure the mix has cooled to room temp before doing any pulls, which I usually heat.

You should also add salt before you add the lye, although as long as they are both in there before the MHRB then everything should work fine. We still have not found the optimum level but there are people working on this now. I found that adding the same amount of salt as you add lye worked great.

The pH of 12 will ensure that all of the spice is in its neutral(non-polar)form, but pH's above this will work fine too. As long as the solution has turned dark brown/black then your pH should be sufficiently high.

 

[ymer]

Great information, I would love to see more details when you update :thumb_up: :thumb_up: :thumb_up:

 

[Shaolin]

While Merck reports the pKa being at 8.68, Chemicalize (manage calculations) calculates a value of 9.55. Something to consider.

Interesting theory about protein breakdown. It would be interesting to see what conditions would invoke the breakdown and how would that effect the process.

 

[ChemisTryptaMan]

While Merck reports the pKa being at 8.68, Chemicalize (manage calculations) calculates a value of 9.55. Something to consider.

Interesting theory about protein breakdown. It would be interesting to see what conditions would invoke the breakdown and how would that effect the process.

There is a wide range of pKa values for just about every molecule, though some more commonly used chems have exact values known(acetic acid =4.76), most molecules have not been calculated to this precision due to lack of their presence in the laboratory. To calculate a pKa you have to titrate very carefully and then calculate the inflection point on the curve. As easy as this might sound, every time a measurement is taken a different value could show up.

The info on protein breakdown is not a theory, except for its effect on the extraction process. It is a fact that proteins heated in both acidic and basic solutions are broken down into their constituent amino acids. Anyone who has taken an intro level biochemistry course is taught this within the first few classes usually. It will certainly effect the ionic strength of the solution, but to what extent we still don't know. It will likely vary with the plant material being used as they will have differing protein content.

 

[Shaolin]

Hm, which data to use then ?

Could it be that the difference is due to that Merck reporting a value obtained experimentally, while Chemicalize calculates it ? In this case, would the latter be more "precise" (lack of space for human error) ? However, practice might differ from theory. Vicious cycle this is

It seems to me that both statements can't be correct at the same time.

a) pH of 8.6 will cause the DMT molecules to be 50% freebase and 50% salt. (Merck)
b) pH of 9.5 will cause the DMT molecules to be 50% freebase and 50% salt. (Chemicalize)

Although with excess basification it wouldn't really matter. Extraction wise.

Can you tell more/link about the conditions (pH, temperature, duration) for protein breakdown ? I'm especially interested in comparisons between different values of different factors (aka do we really need hours ? Why not just up the temp via pressure).

 

[ChemisTryptaMan]

I would trust the merck value as they actually spent time studying a vast number of indoles and are pretty much the standard in modern times, them and aldrich. I have a crc handbook and will try to find a value in there to see how they compare. The pKa is dependent on temp and pressure so the values given are at STP(1 atm, 25 C). But this is mostly irrelevant as the pH values we use are in great excess of the pKa no matter which one you use. the difference would be about 1%.

As far as the acid or base cook for breaking down proteins this is dependent on pH and temperature. I'm sure pressure has a minor effect but for our purposes its negligible. The pH should be lowered to about 3, maybe even 2 if you are going to do this in acid and the temp should be around 70 C. Just above the temp you can hold in your hand comfortably(55-60 C for most people). The hotter the mixture and the more extreme the pH, the faster this will happen, but I have been recommending about 8 hours in an acid bath and even longer for a base bath at 70 degrees. Proteins can be very large and they are almost all folded into intricate shapes that may take time to fully break down. This is why a long cook in acid is going to be necessary to maximize the effect.

 

[Shaolin]

Why only 70 C ?

As for pressure I meant using a pressure cooker to further up the temperature to ~120C.

The logic that I am using here is higher the temp, less overall time needed.

 

[ChemisTryptaMan]

Your logic is sound, and the higher temp will decrease the time needed, I just don't like to work with solvent approaching their boiling points, this can complicate things. Google "Acid catalyzed protein hydrolysis" and "base-catalyzed protein hydrolysis" to see if you can find what the standard is, I had to give up my bio-chem books(which I had plenty of) when I moved back east. Every time I have done this the pH was lowered below 3 and the temp was around 70 C. Though I was only separating a dipeptide, so perhaps larger proteins need higher temps but I doubt it. I think time is the only thing they need more of.

 

[Jees]

Nice initiative, many thanks.

Why is it, that this H-ion, this proton, likes to bind itself so much to the nitrogen side of the amine molecule, to come to the salt form?

 

[Kerberos]

perhaps larger proteins need higher temps but I doubt it. I think time is the only thing they need more of.

I am not a chemist so please forgive me if this is a stupid question. Is there any sort of Protease that could be used to break down the proteins? specifically pineapple bromelain as i can buy that from the health food shop. (Please stop laughing)

 

[ChemisTryptaMan]

any and all proteases will definitely speed up the process

 

[ChemisTryptaMan]

Nice initiative, many thanks.

Why is it, that this H-ion, this proton, likes to bind itself so much to the nitrogen side of the amine molecule, to come to the salt form?

Although water might appear to be shaped like a V, it is actually a tetrahedron. The two corners not occupied by hydrogen atoms(protons) are actually filled with a pair of electrons. These electron pairs are highly negative, and so they attract any proton in solution and for a bond. In an acidic solution there are no free floating protons in the solution. water molecules carry these protons around as hydronium atoms H3o+. The same geometry exists around an amide group that is what the nitrogen containing piece of the spice molecule is. Nitrogen only has a single electron pair exposed as three of the other tetrahedral corners are occupied by actual atoms. It comes down to the charges attracting one another and ultimately bonding. Water is capable of going either way, when protons become scarce in solution as they are in a basic solution, water molecules give up a proton to become hydroxide molecules ( OH-). This is the basis of acid base chemistry. The tendency of an electron pair to pick up a proton in solution is based on the pH, which is just a measure of the concentration of protons in the solution. This is where the pKa comes from, at what pH does there become more molecules holding onto those extra protons than those that dont. The level of 7 is neutral, above this and there is more hydroxide than protons in solution. below this there are more protons than hydroxide. this is due to the pKa values of water, its waters pKa that makes 7 the neutral value.

 

[Kerberos]

any and all proteases will definitely speed up the process

Has any work been done in this regard? specifically how much of what and when is this added, before baseing/acidifing? what happens to the protease and is it pulled into the solvent?

Could this be used in dry teks instead of the salt to help increase yields?

Sorry about all the questions, however with a statement like yours ChemisTryptaMan it certainly gives credence to the "one answer begets 7 more questions":?

 

[ChemisTryptaMan]

D-empty, thats exactly the purpose of the salt.