Phenylacetone (P2P) synthesis from benzaldehyde with butanone

[MadHatter]

That's perfectly doable. Of course it's second best, but hydrogen peroxide in concentrations above 3% is a strictly controlled substance nowadays in most of EU.
One thought though: wont the carbonate ion react really vividly with the acetic acid? And maybe neutralize it?

 

[Rabidreject]

That's perfectly doable. Of course it's second best, but hydrogen peroxide in concentrations above 3% is a strictly controlled substance nowadays in most of EU.
One thought though: wont the carbonate ion react really vividly with the acetic acid? And maybe neutralize it?

MadHatterLook at hydroponic ph+ solution - it is 35% I am from the UK. Dunno if that would suffice but those are how I get my hydrogen peroxide and my 35% sulphuric acid also tbf! Very useful for multiple applications in my life!

 

[WillD]

maybe can buy ready peracetic acid, and use it for complete reaction without acetic acid and H2O2

 

[Mo0odi]

maybe can buy ready peracetic acid, and use it for complete reaction without acetic acid and H2O2

WillDHow do we use peracetic acid? Is there an explanation?

 

[Fenster]

Aldol Condensation.

The directions for this are in Organic Reactions

200 gms of Benzaldehyde and 300 gms of Methyl Ethyl Ketone are mixed in a 1 litre beaker and cooled below 5°C. HCl gas is bubbled through until 40gms has been added. The mixture goes from a clear solution to a red colour and becomes turbid so that you can't see through it. The mixture is kept over night and becomes a brown colour. It is washed with water and then 10% NaOH solution, the organic layer seperated and distilled. At 240°C a yellow oil comes accross and the temperature gradually rises to 260°C.

The oil can be crystalized by cooling in the freezer overnight. This in itself does not induce crystalization but if you also put a spoon in the freezer and then dip it in and out of the cool mixture you get some seed crystals that induce crystalization. The mass turns from an orange oil to sulfur coloured crystals, mp 38°C, 180 gms (Methyl Phenyl Butenone.

This write up seems to be more inline with what I am seeing. Has anyone actually tried to extract with solvent from the organic layer. Using chloroform won't work, as it's miscible with the organic layer. Unless I'm missing something the write up needs to be tested and modified.

Anyone tried this synth before.

 

[TheNut22]

Aldol Condensation.

The directions for this are in Organic Reactions





This write up seems to be more inline with what I am seeing. Has anyone actually tried to extract with solvent from the organic layer. Using chloroform won't work, as it's miscible with the organic layer. Unless I'm missing something the write up needs to be tested and modified.

Anyone tried this synth before.

FensterOK. Just heat the benz-hyde and MEK with hydrochloric acid about 3-5 hours. Temp: 90-110 C.
Just thank me.

 

[lalalander]

The best amount I got, was the minimal amount I used the reagents. So, put 10 g of benzaldehyde + 25 g of MEK + 30 g of hydrochloric acid. I got 28 grams of crystals, that were wet, and when I got the dry as I CAN get them, I got 13 grams of Methylphenylbutenone.

TheNut22I assume the concentration of hydrochloric acid is 37%?

 

[TheNut22]

I assume the concentration of hydrochloric acid is 37%?

lalalanderMy hydrochloric acid is ~20% strenght.

 

[lalalander]

My hydrochloric acid is ~20% strenght.

TheNut22Thanks for your answers.

 

[TheNut22]

Thanks for your answers.

lalalanderNo problem. I'm here to learn and also help. Remember, no bullshit from my mouth, because these
syntheses cost money.

 

[lalalander]

No problem. I'm here to learn and also help. Remember, no bullshit from my mouth, because these
syntheses cost money.

TheNut22Did you add the hydrochloric acid all at once? It says elsewhere that the mixture should be kept cold for 6 hours after adding the hydrochloric acid. I thought it should only be kept cold while adding the hydrochloric acid.

My current goal is to synthesize as many methyl phenyl butanone crystals as possible. Dealing with small portions will be very time consuming.

 

[TheNut22]

Did you add the hydrochloric acid all at once? It says elsewhere that the mixture should be kept cold for 6 hours after adding the hydrochloric acid. I thought it should only be kept cold while adding the hydrochloric acid.

My current goal is to synthesize as many methyl phenyl butanone crystals as possible. Dealing with small portions will be very time consuming.

lalalanderJust weight all in and start heating. One pot reaction, and nothing complicated here. I'm so tired for all those chemists (not you) that are just repeating all the very old books and not trying something new, and when asked they repeat blindly those old books and all same tecniques.

 

[TheNut22]

Did you add the hydrochloric acid all at once? It says elsewhere that the mixture should be kept cold for 6 hours after adding the hydrochloric acid. I thought it should only be kept cold while adding the hydrochloric acid.

My current goal is to synthesize as many methyl phenyl butanone crystals as possible. Dealing with small portions will be very time consuming.

lalalanderJust look at for example hydrogenations. You will see that almost 98% they are palladium on carbon.

 

[lalalander]

Just look at for example hydrogenations. You will see that almost 98% they are palladium on carbon.

TheNut22Thank you very much. The information you provide will be very useful to me.

 

[Fenster]

Ok, step 3 - I added NaOH solution heated to 50c and put into mag Stir after 6 hours a thick almost solid creamy mess was in my rbf. I added DCM and two layers appeared. At first, I was very happy!!! As the creamy thick layer sat on the bottom and I thought the clearer layer was the DCM extracted goodies was on top. No no no..... The Milky thick layer was the DCM. I know for a fact that when I remove the DCM I'm not going to have a yellow clear oil aka p2p.


@HEISENBERG

Have you team reviewed this process before publishing. Seems the experts have gone silent on this proceedures. Would be nice to get some support on a method your team published.

Ok, so I'll attempt Distillation on the creamy mess and see what comes over.

 

[TheNut22]

Ok, step 3 - I added NaOH solution heated to 50c and put into mag Stir after 6 hours a thick almost solid creamy mess was in my rbf. I added DCM and two layers appeared. At first, I was very happy!!! As the creamy thick layer sat on the bottom and I thought the clearer layer was the DCM extracted goodies was on top. No no no..... The Milky thick layer was the DCM. I know for a fact that when I remove the DCM I'm not going to have a yellow clear oil aka p2p.


@HEISENBERG

Have you team reviewed this process before publishing. Seems the experts have gone silent on this proceedures. Would be nice to get some support on a method your team published.

Ok, so I'll attempt Distillation on the creamy mess and see what comes over.

FensterJust use my own method, that is: Heat MEK and benz, with hydrochloric acid: 90-110 C, 3-5 hours.
Then put 10% KOH-solution in, and crystals appear immediately. Get rid of the water. Put them in freezer. Get rid of the oil. Pure, white crystals. ...you're wellcome!

 

[Cbison]

I forgot to mention, that before you put the KOH-solution in, wash the organic layer with same amount of acid you used.

TheNut22I already have the MPB solution and would like to get the crystals without distillation. The adol condensation was done through acid gassing. Do you think if acid is introduced in the Benz + MEK solution through gassing and heated up to 90-110°C for 3-5 hrs and washed with hcl before adding 10% KoH, is there a possibility of crystals precipitate immediately? Is it important to freeze solution to get crystals and what are your reagent measurements.

 

[Cbison]

I forgot to mention, that before you put the KOH-solution in, wash the organic layer with same amount of acid you used.

TheNut22I already have the MPB solution and would like to get the crystals without distillation. The adol condensation was done through acid gassing. Do you think if acid is introduced in the Benz + MEK solution through gassing and heated up to 90-110°C for 3-5 hrs and washed with hcl before adding 10% KoH, is there a possibility of crystals precipitate immediately? Is it important to freeze solution to get crystals and what are your reagent measurements.

 

[TheNut22]

10 g benzaldehyde + 24 g MEK + 28 g hydroc.acid (~20%) = 28 g of crystals, dried in pyrex dish = 13 g of crystals.
Just keep it simple. When you are done heating, extract the brown organic layer. Wash with 40 ml of water. Extract again. Put 20 ml:s of 10% KOH-solution in. Get rid of the water. Check pH. If too acidic, or too basic, put it to 7. Get rid of the water again. Put it in freezer, because you can then, when frozen, pour the oily shit away, and get almost white crystals. Put the crystals in pyrex dish, or something and dryi it. It can liquify, but no problem. Just heat, freeze, heat, freeze, you dry those crystals, but they cannot be crispy dry. Don't know why. Maybe they are just like that.

 

[TheNut22]

10 g benzaldehyde + 24 g MEK + 28 g hydroc.acid (~20%) = 28 g of crystals, dried in pyrex dish = 13 g of crystals.
Just keep it simple. When you are done heating, extract the brown organic layer. Wash with 40 ml of water. Extract again. Put 20 ml:s of 10% KOH-solution in. Get rid of the water. Check pH. If too acidic, or too basic, put it to 7. Get rid of the water again. Put it in freezer, because you can then, when frozen, pour the oily shit away, and get almost white crystals. Put the crystals in pyrex dish, or something and dryi it. It can liquify, but no problem. Just heat, freeze, heat, freeze, you dry those crystals, but they cannot be crispy dry. Don't know why. Maybe they are just like that.

TheNut22But there is one odd thing. When I don't measure pH-level at all, and just put those white crystals in my measuring flask in freezer, I get double amount of pure white crystals. Today, I made almost same amount of reagents, and same way, BUT I titrated the pH-level to 7, I got just half of the crystals. I think there is something to this. Now in the evening I just put those lame 20 ml:s of crystals in freezer, and they are orange! half of it looks like might get just oil, but I just checked there is some kind of reaction between the orange solution and upper layer white crystals that have appeared in about 10 minutes. I have come to conclusion that when you do the aldol with acid and you get basic crystals and don't titrate the pH-level at all, you get double or triple amount of Methylphenylbutenone, and when it is overnight in freezer, you dump the oil in the upper layer, and thats it. So, from now on, I don't recommend the pH-level titration.

P.S I'm sorry, I made some Methcathinone today and I'm so tired, so I'm sorry for the unclear text.
Going to sleep now.

 

[lalalander]

But there is one odd thing. When I don't measure pH-level at all, and just put those white crystals in my measuring flask in freezer, I get double amount of pure white crystals. Today, I made almost same amount of reagents, and same way, BUT I titrated the pH-level to 7, I got just half of the crystals. I think there is something to this. Now in the evening I just put those lame 20 ml:s of crystals in freezer, and they are orange! half of it looks like might get just oil, but I just checked there is some kind of reaction between the orange solution and upper layer white crystals that have appeared in about 10 minutes. I have come to conclusion that when you do the aldol with acid and you get basic crystals and don't titrate the pH-level at all, you get double or triple amount of Methylphenylbutenone, and when it is overnight in freezer, you dump the oil in the upper layer, and thats it. So, from now on, I don't recommend the pH-level titration.

P.S I'm sorry, I made some Methcathinone today and I'm so tired, so I'm sorry for the unclear text.
Going to sleep now.

TheNut22I really benefit a lot from your feedback. But are the crystals obtained without titrating the pH of the crystals of sufficient quality to go to the next step? How can we test this?

 

[TheNut22]

I really benefit a lot from your feedback. But are the crystals obtained without titrating the pH of the crystals of sufficient quality to go to the next step? How can we test this?

lalalanderI cannot test anything, but the appearance and smell, and the melting point are correct.

 

[TheNut22]

I cannot test anything, but the appearance and smell, and the melting point are correct.

TheNut22I have also made peracetic acid oxidation with accurate calculations and after more than ten attempts I got it to work, so I believe in this synthesis even though it has cost me a lot of money. It has taken some time, but it doesn't matter because I like syntheses, especially when they are so OTC.

 

[lalalander]

I have also made peracetic acid oxidation with accurate calculations and after more than ten attempts I got it to work, so I believe in this synthesis even though it has cost me a lot of money. It has taken some time, but it doesn't matter because I like syntheses, especially when they are so OTC.

TheNut22Finally, I wonder what your P2P yield is.

 

[TheNut22]

Finally, I wonder what your P2P yield is.

lalalanderFrom 20 g of MPB, with all those steps required, and didn't distill (witch was bad choice), just evaporation, and stupidly boiled those solutes away, had succeeded just two times to P2P, about 3 g of P2P. This is why I surely want to distill from now on

 

[TheNut22]

I don't have the courage to try this reaction yet.

Benzaldehyde is too valuable a reagent to be sacrificed for testing. It frustrates me that the final efficiency does not exceed 35% under the best conditions.

I've read that people who have mastered this reaction talk about methods they keep secret that increase the yield to 90%, but they seem to be silent because they don't want the narcotics to subject the reagents used in this reaction to heavy control.

35% yield is not a good rate for people who are not really chemistry lovers. So they seem to be trying to prevent it from becoming a new favorite method to synthesize P2P.

lalalanderThis recipe needs to be changed a bit. I got an exceptionally good yield. From 17 grams of MPB, 10 grams of acetoxyphenylpropene. I have now hydrogenated it with base for several hours for P2P and it looks good.

 

[TheNut22]

I really benefit a lot from your feedback. But are the crystals obtained without titrating the pH of the crystals of sufficient quality to go to the next step? How can we test this?

lalalanderWell, I've notived, that it's good to make the pH to around seven.

 

[TheNut22]

Today when I made this again, I didn't get any water layer when I put the KOH solution in, and I got straight white precipitate and I put it in a freezer.