Mhrb Methanol-DCM-Heptane Extraction - Poor Yield

[Trickster]

The tek:

1. 50 g of powdered mhrb were extracted in Continuous Solid Liquid Extractor with methanol until the solvent became completely clear (3 hrs).
2. Methanol has been distilled and the extract dried. Dark burgundy thick syrup smelling of methanol is all I could reduce it to.
3. The extract was dissolved in 250 ml of acidic water (pH4).
4. The solution was put in a fridge for 12 hrs to settle, then decanted and filtered.
5. The solution was basified to pH 12.3
6. 3 DCM pulls 50 ml each.
7. DCM was distilled and light yellow oily extract has been dried as much as possible.
8. 15 ml of warm Heptane (~50 C) were added to the extract and stirred for some time.
9. Heptane has been decanted and reduced to 7 ml (it's became cloudy). The yellow oil has been discarded.
10. Heptane was put in a fridge and then in a freezer.
11. In 12 hrs there were a few white bumps on the jar bottom. No crystalls but the spice smell was there.

Yield proved to be quite disappointing - only 0.5%. Same powder is known to produce ~1% or more.

What I did not like is the methanol smell most of the time. It was lingering until the product was completely dried.

Just in case, I did 4 Heptane pulls on the basic solution. They produced 2-3 mg of spice.

Earlier similar tek yielded ~1.2%. That time I used ethanol for preliminary CSLE extraction and pulled the basified solution with Heptane.

Can anybody look through the steps and point to a possible error?

 

[Spiceman]

I see no reason for the poor yeilds... I wrote up a nice alcohol tek on this board and I would reccomend starting with basic rather than acidic alcohol, and then re-basifying after the reduction of liquid, directly before your pulls. I know that ph is a related to water and not alcohol.. for all those who want to jump me on that point, however there is enough residual water in the bark and the solvents to give the liquid a basic property.

When using the basic boil rather than acidic.. i noticed a huge increase in yeilds

also i noticed Di-ethyl ether... if available to you.. is a better solvent for this type of extraction ...peace and godspeed!

 

[Shaolin]

Hm, bioassay ?

 

[Trickster]

Hm, bioassay ?

The product is very good, but where is the rest?

I suspect 4 possible reasons of such a poor yield:

1. The spice was not properly extracted by methanol even if the powder looked very pale and methanol was completely clear. I used methanol of unknown quality and did not acidify it.

2. Methanol may have been of poor quality. My previous ethanol extraction produced ~1% of good quality spice.

3. pH range during the A/B stage was too narrow (4 - 12.3). This is not very likely because it has been applied to the extract that did not contain unbroken cells of plant material.

4. DCM pulls should have been applied to acidic solution rather than to basic solution. Also unlikely. To rule out this possibility I pulled the remaining basic solution with heptane and got nothing. If spice was not extracted by DCM it would have been pulled by heptane.

So this poor yield remains a mystery to me.

Anybody did Soxhlet alcohol extractions of mhrb? Any comments on the above?

 

[Shaolin]

3&4 are not it in my opinion, while option 1 or 2 on the other hands... I'm rooting for methanol quality since the DEA also used methanol in their paper and got ~1%.

To solve this, experiment with lab grade methanol might be in order.

 

[Trickster]

3&4 are not it in my opinion, while option 1 or 2 on the other hands... I'm rooting for methanol quality since the DEA also used methanol in their paper and got ~1%.

To solve this, experiment with lab grade methanol might be in order.

Thanks. That is what I think.

Now I am planning to run an experiment that will help me to pinpoint one of two possible culprits:
- Poor quality of methanol, or
- Insufficient extraction.

I may also exclude DCM from the tek and use heptane only.

 

[Shaolin]

I would be careful about changing too many variables at once. If DCM is lab grade I can't think of it as being guilty of getting a lower yield, even more DCM should be the factor for a bigger yield, hehe.

Since the pull with heptane was applied (and came up empty) we can conclude that DCM took it all. I'm wondering, did you maybe do a mass test before re-X ? Or if you have good eyeball skills, was the amount before Re-X "right" or did it "feel" small(er then usual) ?

Actually I would re-do the same experiment again (it's something Ron said about alkaloid extractions being crazy different in yield terms even when being "the same" ) changing nothing and then do another with lab grade methanol so we would be able to conclude things more precisely.

Why methanol anyway ? More available/cheaper/less usage than ethanol ?

Also a person desire oops Comparison of the effiency of the DCM pulls. I'm speculating that one 50ml pull would be plenty - g's terms.

 

[Trickster]

I would be careful about changing too many variables at once.

I know what you mean but I'd like to leave DCM out so I would be back to my previous successful extraction with only one variable changed - methanol instead of ethanol.

If DCM is lab grade I can't think of it as being guilty of getting a lower yield, even more DCM should be the factor for a bigger yield, hehe.

DCM is marked as "Analytical Grade". To be on the safe side I even did 3 30 ml DCM pulls which is an overkill. That's why I am so confused.

Since the pull with heptane was applied (and came up empty) we can conclude that DCM took it all. I'm wondering, did you maybe do a mass test before re-X ? Or if you have good eyeball skills, was the amount before Re-X "right" or did it "feel" small(er then usual) ?

DCM pulls brought ~3-5 ml of light yellow oily extract after distilling and drying off all remaining DCM. I thought that 15 ml of warm heptane will dissolve all spice and will leave only useless oils. 15 - 20 ml is the amound of NPS to which I reduce my combined pulls. I was so damn sure I got all the spice that I discarded the oils which was stupid. . Now, maybe that was even more probable couse of yield loss. I should've done 3 heptane pulls as usual.

Actually I would re-do the same experiment again (it's something Ron said about alkaloid extractions being crazy different in yield terms even when being "the same" ) changing nothing and then do another with lab grade methanol so we would be able to conclude things more precisely.

Great idea! I'll distill methanol and will run the same procedure, but this time I will do 3 heptane pulls on the DCM extract.

Why methanol anyway ? More available/cheaper/less usage than ethanol ?

I am experimenting with different alcohols (IPA, ethanol, methanol). Methanol is the last on the list. I am trying to find out wich of them is better. So far ethanol is the best.

Also a person desire oops Comparison of the effiency of the DCM pulls. I'm speculating that one 50ml pull would be plenty - g's terms.

Will do it sometime later.

 

[Shaolin]

Aha, so basically two (methanol & DCM) variables were new. Well that means you'll have to do two at least One with methanol/heptane and one with methanol/DCM (unless if the methanol/heptane fails).

I'm curious why the pH of 12.3 ? I remember you using 11.5 in previous extractions.

Thanks for the DCM test and be well my friend.

 

[Trickster]

I'm curious why the pH of 12.3 ? I remember you using 11.5 in previous extractions.

Indeed in my last successful extraction I raised pH to 11.5 only. Later, out of curiosity, I raised the pH of the same basic solution to 12.5 and pulled it again. AFAIR, I collected another 0.3%. The second extract was not crystalline, just off-white sticky powder. Maybe it was not pure spice. I did not check its quality separately, but the product combined from both extractions was very good. That's why this time I decided to raise the pH higher than 11.5.

Next time I will use pH 11.5 again and will pull the remaining basic solution at higher pH separately.

Thanks for your input.

 

[Trickster]

The tek has been slightly modified and produced 0.85% of white crystalline powder.

1. 70 g of powdered MHRB were extracted in Continuous Solid Liquid Extractor with methanol until the solvent became completely clear (4 hrs).
2. Methanol has been distilled and the extract dried as much as possible. Smell of methanol was almost completely gone.
3. The extract was dissolved in 300 ml of acidic water (pH4). This time phosphoric acid was used instead of acetic.
4. The solution was put in a fridge for 12 hrs to settle, then decanted and filtered.
5. The solution was basified to pH 11.6 with lye.
6. 3 DCM pulls 50 ml each.
7. DCM was distilled and light yellow oily extract has been dried as much as possible.
8. 3 hot (~70C) Heptane pulls 15 ml each.
9. Heptane has been reduced to 15 ml until it's became cloudy.
10. Heptane was put in a fridge and then in a freezer.
11. In 12 hrs 0,6 g of white crystalline powder were collected.

Thick yellow oil from DCM pulls was stored for possible future bioassay.

The tek proved to be quite efficient. Chemicals losses during the extraction:

100 ml of Methanol.
~1 ml of H3PO4
25 ml of DCM
30 ml of Heptane.

 

[Shaolin]

Same methanol source ?

Do you believe that the yield is higher due to acid change ?

 

[Spiceman]

Same methanol source ?

Do you believe that the yield is higher due to acid change ?

GOOD question.. im curious too...

 

[Trickster]

Same methanol source ?

Yes, but I've found out that it is of lab grade.

Do you believe that the yield is higher due to acid change ?

No. Most probable cause is

8. 3 hot (~70C) Heptane pulls 15 ml each from dried DCM extract instead of 1 pull with warm Heptane.

I plan to do a few more pulls to see of there is anything left in the oil and will smoke it to check if it is active.

 

[Shaolin]

I would add a checkpoint. Total Mass of the DMT freebase (before re-X) if you believe that heptane was the key.

Also if you wish to further minimize the chemical losses, you should consider the optimal number of DCM/Heptane pulls.

That being said, thank you for sharing you results. I love it

 

[Shaolin]

9. Heptane has been reduced to 15 ml until it's became cloudy.

How was the heptane reduction done ?