Amphetamine purification by acid-base extraction

[teodor]

hi.can i use benzene to extract the amphetamine base

 

[G.Patton]

hi.can i use benzene to extract the amphetamine base

teodorHello, yes

 

[TimmyT]

Hey, first of all thanks a lot for the detailed instructions! I only have 2 questions:

1. you always talk about H2SO4 1:1 mixed with acetone, however in my country the acid is a controlled chemical, while H3PO4 is freely available. However, the problem with phosphoric acid is that it is only ever available as an aqueous solution (e.g. 25% water content). Does step 11 still work as described, or would the water content dissolve the amphetamine phosphate? If it doesn't work with this, what do I need to do to make it work with this aqueous acid? Could I dry it with magnesium sulphate?

2. can I also apply these instructions 1:1 like this to MDMA-HCl and Ketamine-HCl and if not (which would be my guess bcs of the -HCl), what would I have to do differently for these substances?

 

[UWe9o12jkied91d]

Hey, first of all thanks a lot for the detailed instructions! I only have 2 questions:

1. you always talk about H2SO4 1:1 mixed with acetone, however in my country the acid is a controlled chemical, while H3PO4 is freely available. However, the problem with phosphoric acid is that it is only ever available as an aqueous solution (e.g. 25% water content). Does step 11 still work as described, or would the water content dissolve the amphetamine phosphate? If it doesn't work with this, what do I need to do to make it work with this aqueous acid? Could I dry it with magnesium sulphate?

2. can I also apply these instructions 1:1 like this to MDMA-HCl and Ketamine-HCl and if not (which would be my guess bcs of the -HCl), what would I have to do differently for these substances?

TimmyT1, IMO H3PO4 is more difficult to work with because of what you said, it is easy to overshoot and dissolve your product in a puddle. you can obtain the oxalate using oxalic acid in alcohol.Oxalate salt is nice and stable, not hygroscopic.If you can't find oxalic, which i doubt, you can obtain fumarate, stearate, glutamate, succinate from the corresponding acids.

2. To mdma yes, ketamin idk

 

[TimmyT]

1, IMO H3PO4 is more difficult to work with because of what you said, it is easy to overshoot and dissolve your product in a puddle. you can obtain the oxalate using oxalic acid in alcohol.Oxalate salt is nice and stable, not hygroscopic.If you can't find oxalic, which i doubt, you can obtain fumarate, stearate, glutamate, succinate from the corresponding acids.

2. To mdma yes, ketamin idk

UWe9o12jkied91d1. so if I understand your answer correctly u suppose I use Oxalate instead of H3PO4. Would the end product then be amphetamine oxalate? And if so, why is this never mentioned anywhere else when reading about acid base purification? And Why did i have to add the phosphoric acid with the acetone, but with Oxalate suddenly the salt and not the acid?

2. When using this technique for MDMA-HCl as the name implies it in it’s hydrochloride salt form. But as neither H2SO4 nor H3PO4 contain hydrochloride how would the HCl be created? Or would I have to use hydrochloric acid instead of H2SO4? And would the NaOH still be able to create the freebase Version of the MDMA in step 2? And another question is, as Ketamine-HCl and MDMA-HCl both contain HCl, doesn’t this imply that the same technique that works for MDMA also ha to work for ketamine?

 

[UWe9o12jkied91d]

1. so if I understand your answer correctly u suppose I use Oxalate instead of H3PO4. Would the end product then be amphetamine oxalate? And if so, why is this never mentioned anywhere else when reading about acid base purification? And Why did i have to add the phosphoric acid with the acetone, but with Oxalate suddenly the salt and not the acid?

2. When using this technique for MDMA-HCl as the name implies it in it’s hydrochloride salt form. But as neither H2SO4 nor H3PO4 contain hydrochloride how would the HCl be created? Or would I have to use hydrochloric acid instead of H2SO4? And would the NaOH still be able to create the freebase Version of the MDMA in step 2? And another question is, as Ketamine-HCl and MDMA-HCl both contain HCl, doesn’t this imply that the same technique that works for MDMA also ha to work for ketamine?

TimmyTGood questions!

1.Yes, you use oxalic acid instead of phosphoric or sulphuric.Yes, correct, amphetamine oxalate.Sulphuric is just the de-facto acid, cant say exactly why, maybe cause it has dehydrating properties and is used widely in industry, but a lot of other acids produce suitable salts.If you don't believe me look at what kind of salts adderall contains
The last question I don't understand, but it dosen't matter how you add it, some things are better in solution of acetone others alcohol because of solubility, however you can just add phosphoric as is, or oxalic in solid form..you will have some stirring to do but eventually salts will precipiate, if added in sol. of alcohol precipitation will be more or less instant, I hope it is clear.

2.Yes.You would use the corresponding acid ofcourse, which as you said is HCl.Yes, naoh will liberate your amine regardless.that would be the logical conclusion, but since I have no idea about ketamine I prefer not to comment, the freebase form might be super volatile and just degrade, or get hydrolised or who knows what else, I prefer not to comment if I don't know.

 

[HerrHaber]

Good questions!

1.Yes, you use oxalic acid instead of phosphoric or sulphuric.Yes, correct, amphetamine oxalate.Sulphuric is just the de-facto acid, cant say exactly why, maybe cause it has dehydrating properties and is used widely in industry, but a lot of other acids produce suitable salts.If you don't believe me look at what kind of salts adderall contains
The last question I don't understand, but it dosen't matter how you add it, some things are better in solution of acetone others alcohol because of solubility, however you can just add phosphoric as is, or oxalic in solid form..you will have some stirring to do but eventually salts will precipiate, if added in sol. of alcohol precipitation will be more or less instant, I hope it is clear.

2.Yes.You would use the corresponding acid ofcourse, which as you said is HCl.Yes, naoh will liberate your amine regardless.that would be the logical conclusion, but since I have no idea about ketamine I prefer not to comment, the freebase form might be super volatile and just degrade, or get hydrolised or who knows what else, I prefer not to comment if I don't know.

UWe9o12jkied91djust remember oxalic acid has a toxicity aspect to some extent (not that the body would be intoxicated with it but for example kidney stones are comprised of aprox. 80% calcium oxalate) the oxalate salt from my perspective shouldn't be abused (this may actually teach some people that there is a secret in using amphetamines, that one must come to realize "less is more")

 

[TimmyT]

just remember oxalic acid has a toxicity aspect to some extent (not that the body would be intoxicated with it but for example kidney stones are comprised of aprox. 80% calcium oxalate) the oxalate salt from my perspective shouldn't be abused (this may actually teach some people that there is a secret in using amphetamines, that one must come to realize "less is more")

HerrHaberThanks for the warning. I have now researched a bit on drying the solution of acetone and phosphoric acid and found out that this is possible with magnesium sulfate as the likelihood of a reaction is pretty low, so I‘m gonna go for that option. But what I also found out is that both H2SO4 and H3PO4 are relatively poorly soluble in acetone. Wouldn't that mean that parts of the acid could precipitate out of the solution and end up in the filter together with the amphetamine salt as the crystalised form of the acid?

 

[HerrHaber]

Thanks for the warning. I have now researched a bit on drying the solution of acetone and phosphoric acid and found out that this is possible with magnesium sulfate as the likelihood of a reaction is pretty low, so I‘m gonna go for that option. But what I also found out is that both H2SO4 and H3PO4 are relatively poorly soluble in acetone. Wouldn't that mean that parts of the acid could precipitate out of the solution and end up in the filter together with the amphetamine salt as the crystalised form of the acid?

TimmyTwhen strong acids are implied it is kindly advised to use at least 1:10 (v/v) ratio acid to acetone

 

[TimmyT]

Alright thanks for the answer. I have just a few last questions to ensure I do nothing wrong. So If I use oxalic acid, could I also just mix it 1:1 with acetone or is ethanol required? Does the oxalate change the physical or chemical properties (especially solubility in different solvents sich as acetone and hexane) compared to amphetamine sulphate? And last but not least does the mixture of acetone/ethanol and acid have to be dry, so do I have to dry it again explicitly with magnesium sulphate or was it enough to just dry the solvent before mixing it with the acid or would a water content not matter at all?

Edit: this message was meant as a response to @UWe9o12jkied91d , but don’t know how to delete it now ^^

 

[UWe9o12jkied91d]

Alright thanks for the answer. I have just a few last questions to ensure I do nothing wrong. So If I use oxalic acid, could I also just mix it 1:1 with acetone or is ethanol required? Does the oxalate change the physical or chemical properties (especially solubility in different solvents sich as acetone and hexane) compared to amphetamine sulphate? And last but not least does the mixture of acetone/ethanol and acid have to be dry, so do I have to dry it again explicitly with magnesium sulphate or was it enough to just dry the solvent before mixing it with the acid or would a water content not matter at all?

Edit: this message was meant as a response to @UWe9o12jkied91d , but don’t know how to delete it now ^^

TimmyTyou want everything as dry a possible, water is the enemy in this case, not a bad idea to dry all solvents.
I think meOH ipOH etOH all will work, acetone might, depends on solubility of the acid, best to look this up and use the biggest one.Off the top of my head I don;t think it's soluble in acetone, but look it up pls.

 

[HerrHaber]

also be minful of the fact that acids and alcohols form esters in an equilibrium reaction kinetics, therefore do not store solutions of especially strong acids in alcohols (primary alcohols especially methanol is a no no; IPA is better but acetone is best)

 

[diogenes]

also be minful of the fact that acids and alcohols form esters in an equilibrium reaction kinetics, therefore do not store solutions of especially strong acids in alcohols (primary alcohols especially methanol is a no no; IPA is better but acetone is best)

HerrHaberI have found IPA:H2SO4 (10:1) very stable, once I left it for weeks room temperature (plugged to keep from oxygen and moisture in the air), then, when I realized it is still there some weeks later, tried it to Precipitate the A-sulphate and it worked perfectly fine.

Acetone, on the other hand never stayed stable for a longer period in the presence of 10% volume H2SO4, it turned a red colour, with an unpleasant smell. I tried several different methods, several H2SO4 (different brands etc.), and distilled&dried Acetone but it always turned red in a few hours. The only way this redness could be delayed was using freezer cold Acetone and H2SO4 with very slow dropwise addition of the acid (this addition creates a lot of heat). This way it remained colourless long enough to make the salt with the colourless mixture.

At some point I made a comparison of neutralizing equal amounts of base (dissolved in IPA) with either IPA:H2SO4 vs Acetone:H2SO4. The resulting weight of the salt was almost equal.

This red colour change with Acetone was so annoying that I started a conversation with to experts but I we couldn`t reach a final conclusion, they said it must have been some impurities, and recommended the cooling, which solved the problem but did not make the solution stable. Perhaps I was not careful enough to keep it from air and some oxidation product is causing this colour which is sped up by heat?

 

[HerrHaber]

I have found IPA:H2SO4 (10:1) very stable, once I left it for weeks room temperature (plugged to keep from oxygen and moisture in the air), then, when I realized it is still there some weeks later, tried it to Precipitate the A-sulphate and it worked perfectly fine.

Acetone, on the other hand never stayed stable for a longer period in the presence of 10% volume H2SO4, it turned a red colour, with an unpleasant smell. I tried several different methods, several H2SO4 (different brands etc.), and distilled&dried Acetone but it always turned red in a few hours. The only way this redness could be delayed was using freezer cold Acetone and H2SO4 with very slow dropwise addition of the acid (this addition creates a lot of heat). This way it remained colourless long enough to make the salt with the colourless mixture.

At some point I made a comparison of neutralizing equal amounts of base (dissolved in IPA) with either IPA:H2SO4 vs Acetone:H2SO4. The resulting weight of the salt was almost equal.

This red colour change with Acetone was so annoying that I started a conversation with to experts but I we couldn`t reach a final conclusion, they said it must have been some impurities, and recommended the cooling, which solved the problem but did not make the solution stable. Perhaps I was not careful enough to keep it from air and some oxidation product is causing this colour which is sped up by heat?

diogenesthis is true, reason for which the acid solution must be prepared on spot

 

[DavidNichols]

also be minful of the fact that acids and alcohols form esters in an equilibrium reaction kinetics, therefore do not store solutions of especially strong acids in alcohols (primary alcohols especially methanol is a no no; IPA is better but acetone is best)

HerrHaberOne correction: any strong acid will start catalytic self-condensation of acetone with results of colorful tars and various unsaturated ketones.

 

[HerrHaber]

One correction: any strong acid will start catalytic self-condensation of acetone with results of colorful tars and various unsaturated ketones.

DavidNicholscan get deep red when forgotten about it but I advise throwing it away as soon as job is done, I am most mindful that vitriol is a strong oxidiser by tradition and I had a solution made of it in a compound that can yield triacetoneper...kaboom if by chance the oxidant was 50%+ a.q. peroxide

 

[sadow]

hello everyone. I did a wash to my 3-fma with alcohol IPA

I did 5 washes and lost more than 50% of the product. I did not have good filters or good material, since I could not do vacuum filtration, I filtered by gravity and used a little pressure to dry as much as possible and now it is drying

I also measure ph and it comes out high, I'm not sure if in 7 or 8 I also attach a photo of the ph

Could someone advise me a bit? Did it really have so many excipients or synthesis remains? or that it was also cut, a small part has remained in the glass and in the filters since I used very fine fabrics but of course, no matter how fine it is, it is not a filter filter and a lot of material has remained in it since I could not remove it without take me fibers Was the work worth something? can anyone help me?

my english is really bad sorry if you don't understand something

This is the final result. I forgot to take a photo before starting the wash.

Next time I will take notes of what I have to do before starting and thus have the steps to follow. in addition to getting coffee filters that were nowhere to be found

any help and advice is welcome

 

[diogenes]

hello everyone. I did a wash to my 3-fma with alcohol IPA

View attachment 11125
I did 5 washes and lost more than 50% of the product. I did not have good filters or good material, since I could not do vacuum filtration, I filtered by gravity and used a little pressure to dry as much as possible and now it is drying

I also measure ph and it comes out high, I'm not sure if in 7 or 8 I also attach a photo of the ph

View attachment 11126

Could someone advise me a bit? Did it really have so many excipients or synthesis remains? or that it was also cut, a small part has remained in the glass and in the filters since I used very fine fabrics but of course, no matter how fine it is, it is not a filter filter and a lot of material has remained in it since I could not remove it without take me fibers Was the work worth something? can anyone help me?

my english is really bad sorry if you don't understand something

This is the final result. I forgot to take a photo before starting the wash. View attachment 11127
Next time I will take notes of what I have to do before starting and thus have the steps to follow. in addition to getting coffee filters that were nowhere to be found

any help and advice is welcome

sadowHave you dried you IPA before using it for washing? Was it ice-cold? These two things are basic, and washing 5X seems excessive, especially with a slightly wet solvent. I think 3 washing sould be enough and at least one of them should be DRY acetone (preferably the last one as then you have easier job evaporating your solvent).

 

[HerrHaber]

I am pretty sure acetone is what I observe you didn't mention so don't throw your IPA just let evaporate part of it then add cold acetone with stirring and it will come out of solution. Yes, acetone ore even MEK are this much better than IPA.

 

[ACAB]

2. Add 50% NaOH solution to pH 12 with small portions. A solution of NaOH in distilled water (room temperature) is poured by drops, depends on the volume. When pH 12 is reached, an oily layer (amphetamine free base) forms on the top surface of Rm. The amount of amphetamine base is equal to the mass of dissolved amphetamine. The color can be from amber to transparent, depending on the purity of the salt.​

​

3. Pour petroleum ether (20% by volume) into Rm and mix thoroughly. Let the layers separate. The ether is insoluble in water, as is the free base, but the base is soluble in ether. In this way, we remove some of the water-soluble impurities from amphetamine.​

​

4. Separate the top layer with the extract into an another container using a plastic / glass syringe or separating funnel. If DCM was used instead of petroleum ether, then we separate the bottom layer. Avoid the ingress of water into the separated extract.

5. Wash the water (the remaining lower layer) with petroleum ether three times (5% of the water volume).

6. Combine the extracts.​

​

7. Dry the extract with anhydrous MgSO4 for 1 hour, placing it in the freezer. The glass should be hermetically sealed.

MgSO4 is added to Rm 3-20% (depends on amount of water there) of the volume of ether. Drying is necessary to remove the remaining water from the ether, which in further stages, by dissolving the amph salt in water, will lead to a lower (by weight) yield of pure product. You can wrap it with cling film for container tightness. It must be closed to avoid saturation of the solution with moisture concentrating in the freezer. If MgSO4 is not available, keep Rm in the freezer for 12 hours. Then, in case of formation of water at the bottom of the container (in a layer or drops), the ether should be carefully decanted (poured out) without touching the water.​

​

8. We filter the extract from MgSO4 that has absorbed water using a vacuum pump connected to a Buchner funnel with a Bunsen flask and a paper filter. You can use a conventional filter without vacuum, which will slightly reduce the yield (you have to wash the filter with an anhydrous solvent). The solution should be decanted onto the filter without lifting the sediment from the bottom. MgSO4 remaining at the bottom of the beaker has to be washed with an anhydrous solvent (pour it onto a filter) and disposed of.​

G.PattonThe following observation, which synthesis route to amphetamine does not matter.
After the A-freebase is released with the addition of NaOH and collects oilily on the surface, I perform an extraction with petroleum ether.
First I transfer the solution to a cylinder and wait for the layers to form. With a syringe I collect the upper layer in an Erlenmeyer flask. Then the solution comes into the separating funnel and is shaken with 10% of the volume of the solution 3 times with petrol ether and also collected in the Erlenmeyer.

Here it is noticed that the amphetamine base does not mix completely with the petroleum ether and two layers are formed here as well.
The Erlenmeyer is dried with 1-2 teaspoons of MgSO₄ and now something strange happens.
The solution becomes thicker and thicker even shaking does not help, it becomes a mush. Two hours in the freezer and then vacuum filtered and I now have much more salt than I added.

What happens here?
Does the A-freebase react with the SO₄ from the MgSO₄ and form amphetamine sulfate?

When I partially dissolve the salt in a beaker with water, an oily layer forms again. After adding NaOH, the upper layer can be extracted and placed together with the petroleum ether on a dish to evaporate the ether.

Who can tell me what happens there with the MgSO₄ during drying, is another desiccant to choose?
Use something else like petroleum ether?
Am grateful for any help. thanks

 

[diogenes]

The following observation, which synthesis route to amphetamine does not matter.
After the A-freebase is released with the addition of NaOH and collects oilily on the surface, I perform an extraction with petroleum ether.
First I transfer the solution to a cylinder and wait for the layers to form. With a syringe I collect the upper layer in an Erlenmeyer flask. Then the solution comes into the separating funnel and is shaken with 10% of the volume of the solution 3 times with petrol ether and also collected in the Erlenmeyer.

Here it is noticed that the amphetamine base does not mix completely with the petroleum ether and two layers are formed here as well.
The Erlenmeyer is dried with 1-2 teaspoons of MgSO₄ and now something strange happens.
The solution becomes thicker and thicker even shaking does not help, it becomes a mush. Two hours in the freezer and then vacuum filtered and I now have much more salt than I added.

What happens here?
Does the A-freebase react with the SO₄ from the MgSO₄ and form amphetamine sulfate?

When I partially dissolve the salt in a beaker with water, an oily layer forms again. After adding NaOH, the upper layer can be extracted and placed together with the petroleum ether on a dish to evaporate the ether.

Who can tell me what happens there with the MgSO₄ during drying, is another desiccant to choose?
Use something else like petroleum ether?
Am grateful for any help. thanks

ACABYou probably make some Na2SO4 because of NaOH remaining in your ether/oily base mixture. Why don`t you just wash it a couple of times with some distilled water before drying it and see what happens.

 

[ACAB]

You probably make some Na2SO4 because of NaOH remaining in your ether/oily base mixture. Why don`t you just wash it a couple of times with some distilled water before drying it and see what happens.

diogenesThat's sounds good...I.will try next time.

But can you also explain where does the A-freebase come from when I dissolve the filtered salt with water? Does it form back again?

 

[G.Patton]

The following observation, which synthesis route to amphetamine does not matter.
After the A-freebase is released with the addition of NaOH and collects oilily on the surface, I perform an extraction with petroleum ether.
First I transfer the solution to a cylinder and wait for the layers to form. With a syringe I collect the upper layer in an Erlenmeyer flask. Then the solution comes into the separating funnel and is shaken with 10% of the volume of the solution 3 times with petrol ether and also collected in the Erlenmeyer.

Here it is noticed that the amphetamine base does not mix completely with the petroleum ether and two layers are formed here as well.
The Erlenmeyer is dried with 1-2 teaspoons of MgSO₄ and now something strange happens.
The solution becomes thicker and thicker even shaking does not help, it becomes a mush. Two hours in the freezer and then vacuum filtered and I now have much more salt than I added.

What happens here?
Does the A-freebase react with the SO₄ from the MgSO₄ and form amphetamine sulfate?

When I partially dissolve the salt in a beaker with water, an oily layer forms again. After adding NaOH, the upper layer can be extracted and placed together with the petroleum ether on a dish to evaporate the ether.

Who can tell me what happens there with the MgSO₄ during drying, is another desiccant to choose?
Use something else like petroleum ether?
Am grateful for any help. thanks

ACABHi, amph base reacts with Mg2+ ions after a long exposition. I think it is a reason of your mash formation. It isn't best desiccant for amines. Na2SO4 is better for this procedure.

 

[G.Patton]

Ok, but what you mean with long exposition? The reaction starts immediately after putting the salt into the solution.
And MgSO4 is also recommended here in the article as a desiccant, I was not familiar with anything else before, but what else do we extract other than amines?
I will try that first, because that also matches with my observation that A-freebase must have reacted with the salt, because the filtered salt released the base again after dissolving in water.

ACABI carried out amphetamine A/B extraction with MgSO4 without problems. Probably, your problem reason is different.

 

[ACAB]

I carried out amphetamine A/B extraction with MgSO4 without problems. Probably, your problem reason is different.

G.PattonYes me too, but sometimes i have this result that something is reacting while drying. I thought that I am not the only one who happens

 

[diogenes]

The following observation, which synthesis route to amphetamine does not matter.
After the A-freebase is released with the addition of NaOH and collects oilily on the surface, I perform an extraction with petroleum ether.
First I transfer the solution to a cylinder and wait for the layers to form. With a syringe I collect the upper layer in an Erlenmeyer flask. Then the solution comes into the separating funnel and is shaken with 10% of the volume of the solution 3 times with petrol ether and also collected in the Erlenmeyer.

Here it is noticed that the amphetamine base does not mix completely with the petroleum ether and two layers are formed here as well.
The Erlenmeyer is dried with 1-2 teaspoons of MgSO₄ and now something strange happens.
The solution becomes thicker and thicker even shaking does not help, it becomes a mush. Two hours in the freezer and then vacuum filtered and I now have much more salt than I added.

What happens here?
Does the A-freebase react with the SO₄ from the MgSO₄ and form amphetamine sulfate?

When I partially dissolve the salt in a beaker with water, an oily layer forms again. After adding NaOH, the upper layer can be extracted and placed together with the petroleum ether on a dish to evaporate the ether.

Who can tell me what happens there with the MgSO₄ during drying, is another desiccant to choose?
Use something else like petroleum ether?
Am grateful for any help. thanks

ACABACAB, I have re-read your post and I think the key to the problem is in this sentence:
`Here it is noticed that the amphetamine base does not mix completely with the petroleum ether and two layers are formed here as well.` This means that the layer what you extract as `oily base` is not pure oily base. Why don`t you use some petroleum ether (or other non-polar solvent) here too? I mean from the point your solutions reaches pH12 and a layer forms, it is ok, to separate the oily layer, but put this in the separating funnel and add equal amount of petroleum ether, then save the petroleum ether layer in the Ehrlenmeyer if two layers are formed. The not petroleum ether layer (if it forms) you can add to the original water and then extract with the rest of the water. Using only 10% of the water volume 3 times is probably too little, use 30% then 20% then 20%.

I know it is quite a lot of ether, you can use the water as indicator: the water becomes almost clear when most of the oil has been extracted.

Combine the petrol ether fractions add them to the separating funnel and wash at least 2-3X with distilled water, then 1X with brine (saturated NaCl solution). Then start drying it, but only add `enough` MgSO4, not `more is better`. When the MgSO4 is showing snowball effect after 15-20 minutes, then you are good. If you have mol sieve then you can use that too instead of MgSO4/Na2SO4. GRAVITY filter the MgSO4. I don`t really like it as it has quite small molecular size and might come through some filters and need filtering more than one time.

When you have your clear and dry petrol ether then distill it, so that using more before won`t matter, you get it back. You should do this anyway with most of your solvents.

Also, as a general rule, when cooling or just leaving outside any dry solutions, never forget to cover it with kitchen kling film and a rubber band so that it is airtight.

Let us know if the problem still persists if you follow this way.

 

[ACAB]

ACAB, I have re-read your post and I think the key to the problem is in this sentence:
`Here it is noticed that the amphetamine base does not mix completely with the petroleum ether and two layers are formed here as well.` This means that the layer what you extract as `oily base` is not pure oily base. Why don`t you use some petroleum ether (or other non-polar solvent) here too? I mean from the point your solutions reaches pH12 and a layer forms, it is ok, to separate the oily layer, but put this in the separating funnel and add equal amount of petroleum ether, then save the petroleum ether layer in the Ehrlenmeyer if two layers are formed. The not petroleum ether layer (if it forms) you can add to the original water and then extract with the rest of the water. Using only 10% of the water volume 3 times is probably too little, use 30% then 20% then 20%.

I know it is quite a lot of ether, you can use the water as indicator: the water becomes almost clear when most of the oil has been extracted.

Combine the petrol ether fractions add them to the separating funnel and wash at least 2-3X with distilled water, then 1X with brine (saturated NaCl solution). Then start drying it, but only add `enough` MgSO4, not `more is better`. When the MgSO4 is showing snowball effect after 15-20 minutes, then you are good. If you have mol sieve then you can use that too instead of MgSO4/Na2SO4. GRAVITY filter the MgSO4. I don`t really like it as it has quite small molecular size and might come through some filters and need filtering more than one time.

When you have your clear and dry petrol ether then distill it, so that using more before won`t matter, you get it back. You should do this anyway with most of your solvents.

Also, as a general rule, when cooling or just leaving outside any dry solutions, never forget to cover it with kitchen kling film and a rubber band so that it is airtight.

Let us know if the problem still persists if you follow this way.

diogenesI assume that the formed layer can be separated (for me this is A-oil, because something else cannot be in there, except impurities, after I have released the freebase) and I only have to extract the rest of the solution with petroleum ether. Is this assumption not correct?
Because if I try to extract the two layers with petroleum ether, I always have 3 layers and I do not get everything extracted, or I would have to make many extractions until the middle layer is completely dissolved. If that is possible at all.