Phenylacetone (P2P) synthesis from benzaldehyde with butanone

[MadHatter]

is it possible to replace chloroform?

a_kingWhy would you want to replace chloroform? It's easy to synthesize yourself with acetone and bleach. Check youtube.
But if you really need to for some reason, dichloromethane and chloroform are usually interchangeable.

 

[TheNut22]

Why would you want to replace chloroform? It's easy to synthesize yourself with acetone and bleach. Check youtube.
But if you really need to for some reason, dichloromethane and chloroform are usually interchangeable.

MadHatterI tried DCM for the first time, and it failed totally.
I extracted the product with ethyl acetate (more) and xylene (less)-mix.

 

[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]

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

TheNut22What does it do?

 

[TheNut22]

What does it do?

lalalanderIt does the aldol condensation of MEK and benzaldehyde. The product is: Mehtylphenylbutenone.

 

[lalalander]

It does the aldol condensation of MEK and benzaldehyde. The product is: Mehtylphenylbutenone.

TheNut22You seem very sure of your procedure. Can we conclude that you tried it and succeeded?

 

[TheNut22]

You seem very sure of your procedure. Can we conclude that you tried it and succeeded?

lalalanderOK. I have spend hundreds of euros to make this work, and now you are questioning will it work?!
I'm really pissed right now! I will not publish... spoon feed my info anyone here from now on.
God damn! I suggest you also read chemistry before you start questioning my methods. If chemistry doesn't interest you, but you want the information on this entire synthesis, which I tried 16 times with difficulty, forget it. I'm not going to answer anyone's questions at all, because I got my knowledge from science articles myself, but I applied it to practice with my own knowledge of chemistry. Yes. Aldol condensation at the point of synthesis works with better yields than in gasification. I am not going to answer anyone about any other point regarding the synthesis in question. Thank you and goodbye!

 

[lalalander]

OK. I have spend hundreds of euros to make this work, and now you are questioning will it work?!
I'm really pissed right now! I will not publish... spoon feed my info anyone here from now on.
God damn! I suggest you also read chemistry before you start questioning my methods. If chemistry doesn't interest you, but you want the information on this entire synthesis, which I tried 16 times with difficulty, forget it. I'm not going to answer anyone's questions at all, because I got my knowledge from science articles myself, but I applied it to practice with my own knowledge of chemistry. Yes. Aldol condensation at the point of synthesis works with better yields than in gasification. I am not going to answer anyone about any other point regarding the synthesis in question. Thank you and goodbye!

TheNut22I don't understand why you find it so offensive. I was just trying to communicate using formal language.

 

[TheNut22]

I don't understand why you find it so offensive. I was just trying to communicate using formal language.

lalalanderI'm sorry about my frustration. I was very tired at time. The aldol works.

 

[TheNut22]

I don't understand why you find it so offensive. I was just trying to communicate using formal language.

lalalanderAnd, using "Twodogs" and "Bio"s procedure, the acetoxyphenylpropene aso worked like a charm.

 

[lalalander]

And, using "Twodogs" and "Bio"s procedure, the acetoxyphenylpropene aso worked like a charm.

TheNut22It's okay. We're all human beings at the end of the day. Can you share the amounts of reagent you use?

 

[TheNut22]

It's okay. We're all human beings at the end of the day. Can you share the amounts of reagent you use?

lalalanderThe 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.

 

[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]

Just 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!

TheNut22Do you cool the BENZ & MEK mixture before adding the 10% KoH solution. With this procedure there will be no need for vacuum distillation right.

 

[TheNut22]

Do you cool the BENZ & MEK mixture before adding the 10% KoH solution. With this procedure there will be no need for vacuum distillation right.

CbisonIt's cooled to room temperature. Then collect the brown organic layer. Put 20 ml 10% KOH-solution in it. If the pH is too acidic or too basic, get it to pH: 7. Get rid of the water, when the pH is 7. Put the flask in freezer for at least 4 hours. Discard the upper oily shit when frozen. No need for distillation or even drying the solution, because the crystals appear immediately in the flask, you just have to freeze them, to get the oily layer, witch is just some by-products.

 

[TheNut22]

It's cooled to room temperature. Then collect the brown organic layer. Put 20 ml 10% KOH-solution in it. If the pH is too acidic or too basic, get it to pH: 7. Get rid of the water, when the pH is 7. Put the flask in freezer for at least 4 hours. Discard the upper oily shit when frozen. No need for distillation or even drying the solution, because the crystals appear immediately in the flask, you just have to freeze them, to get the oily layer, witch is just some by-products.

TheNut22I forgot to mention, that before you put the KOH-solution in, wash the organic layer with same amount of acid you used.

 

[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]

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

TheNut22OH my god. DONT wash with acid, OK. Same amount of water that you used acid.

 

[bigbadbear]

​

Step 2. 2-Acetoxy-1-phenyl-1-propene (cas 24175-87-9) synthesis.

1. 3-Methyl-4-phenyl-3-buten-2-one (cas 1901-26-4) 1 kg from Step 1, glacial acetic acid 10 L and hydrogen peroxide (H2O2) 1300 g 50 % are poured into a 25-30 L batch reactor with reflux condenser, stirred and at 55 °C for 23 h.
2. Next, distilled water 10 L is added.
3. The reaction mixture is extracted with chloroform 5 L and dried over magnesium sulphate (Na2SO4).
4. Solvent is evaporated under vacuum. 2-Acetoxy-1-phenyl-1-propene (cas 24175-87-9) yield is 800 g.​

View attachment 1387​

For the second step, can I use a 15-liter flask ? and carry out the extraction process in a 50-liter plastic barrel?

William Dampier

 

[bigbadbear]

For the second step, can I use a 15-liter flask ? and carry out the extraction process in a 50-liter plastic barrel?

 

[Irving Langmuir]

Hi everyone !

I've tried this synthesis twice, and here's my conclusion on this one.

Firstly, I'm far from being a trained chemist, so what I say should be taken with a grain of salt. Feel free to correct what I say.

The reactions and mechanisms are the result of my research and my understanding of synthesis, and are therefore also open to criticism.

I just saw that a lot of people had already discussed the subject, so I hope my post won't be redundant. Also, the link at the end of my post has already been posted on the topic. Sorry if you don't learn anything from my post.


Step 1: crossed aldol condensation :
Normally we use a small excess of MEK in this reaction because ketones can self-condense, but this reaction is thermodynamically devafable, and will be done up to a maximum of 5% in the literature I've been able to find. Nevertheless, according to this paper, benzaldehyde can react with the final product, which would greatly lower the yield, hence the use of excess MEK to make sure that the benzaldehyde reacts with the right molecule. (Moreover, according to the same paper, distillation between crossed aldol condensation and Baeyer-Villiger oxidation is not useful, as the by-products will not react during the Baeyer-Villiger oxidation and can be eliminated with the next distillation). I wondered whether it wouldn't be better to add the benzaldehyde drop by drop, which would make sure there was an excess of MEK, and thus prevent the benzaldehyde from reacting with the newly formed product. And since the aldol self-condensation of ketones is not very favorable, proceeding in this way may be better for yield. But as I said, what I'm saying needs to be verified.

As a catalyst we can normally use either an acid or a base for aldol reactions. I assume, however, that here we're using an acid to avoid a Cannizzaro reaction, because benzaldehyde is non-enolizable. By using an acid catalyst, we go through the formation of an enol instead of the enolate.

As an acid catalyst, I tried a strong addition of concentrated H2SO4 the first time I did this reaction, and the second time I only added a few drops. The difference I noticed between the two was that if too much H2SO4 was added, the product polymerized, making distillation almost impossible due to bumping.

Crossed aldol condensation will lead to 3-methyl-4-phenyl-3-buten-2-one.

For Baeyer-Villiger oxidation, I wanted to try perborate or sodium percarbonate. The only problem I saw with using sodium percarbonate was that it would react with the GAA and gradually neutralize it. And indeed this is a pretty bad idea, having tried it on a small scale. Percarbonate has trouble solubilizing, and needs a medium containing a little more water. Once that's done, you have to be careful not to release too much CO2. Peracetic acid is formed in situ and reacted with 3-methyl-4-phenyl-3-buten-2-one. To make my percarbonate solubilize, I added a little H2O2. But I'd say, if you don't have 50% H2O2, don't waste your time on this synthesis. And that's my conclusion. Although this synthesis may seem attractive, it's tedious and labor-intensive, especially with all those vacuum distillations (I've tried without, it works, but leads to working with high temperatures, and I've even managed to destroy product that way!). So I'd advise anyone to turn to another synthesis method. I managed to get what I think was the desired product in the end, but in my opinion not enough to justify the whole procedure. For those who want to know more, I recommend reading the paper, searching for "Two dogs aldol", learning about the mechanisms of aldol reaction, baeyer-villiger oxidation and hydrolysis of esters.

Forensic Science International: David Doughty, Ben Painter, Paul E. Pigou, Martin R. Johnston | PDF | Ester | Chemical Reactions

Scribd is the world's largest social reading and publishing site.

www.scribd.com

 

[WillD]

Hi everyone !

I've tried this synthesis twice, and here's my conclusion on this one.

Firstly, I'm far from being a trained chemist, so what I say should be taken with a grain of salt. Feel free to correct what I say.

The reactions and mechanisms are the result of my research and my understanding of synthesis, and are therefore also open to criticism.

I just saw that a lot of people had already discussed the subject, so I hope my post won't be redundant. Also, the link at the end of my post has already been posted on the topic. Sorry if you don't learn anything from my post.


Step 1: crossed aldol condensation :
Normally we use a small excess of MEK in this reaction because ketones can self-condense, but this reaction is thermodynamically devafable, and will be done up to a maximum of 5% in the literature I've been able to find. Nevertheless, according to this paper, benzaldehyde can react with the final product, which would greatly lower the yield, hence the use of excess MEK to make sure that the benzaldehyde reacts with the right molecule. (Moreover, according to the same paper, distillation between crossed aldol condensation and Baeyer-Villiger oxidation is not useful, as the by-products will not react during the Baeyer-Villiger oxidation and can be eliminated with the next distillation). I wondered whether it wouldn't be better to add the benzaldehyde drop by drop, which would make sure there was an excess of MEK, and thus prevent the benzaldehyde from reacting with the newly formed product. And since the aldol self-condensation of ketones is not very favorable, proceeding in this way may be better for yield. But as I said, what I'm saying needs to be verified.

As a catalyst we can normally use either an acid or a base for aldol reactions. I assume, however, that here we're using an acid to avoid a Cannizzaro reaction, because benzaldehyde is non-enolizable. By using an acid catalyst, we go through the formation of an enol instead of the enolate.

As an acid catalyst, I tried a strong addition of concentrated H2SO4 the first time I did this reaction, and the second time I only added a few drops. The difference I noticed between the two was that if too much H2SO4 was added, the product polymerized, making distillation almost impossible due to bumping.

Crossed aldol condensation will lead to 3-methyl-4-phenyl-3-buten-2-one.

For Baeyer-Villiger oxidation, I wanted to try perborate or sodium percarbonate. The only problem I saw with using sodium percarbonate was that it would react with the GAA and gradually neutralize it. And indeed this is a pretty bad idea, having tried it on a small scale. Percarbonate has trouble solubilizing, and needs a medium containing a little more water. Once that's done, you have to be careful not to release too much CO2. Peracetic acid is formed in situ and reacted with 3-methyl-4-phenyl-3-buten-2-one. To make my percarbonate solubilize, I added a little H2O2. But I'd say, if you don't have 50% H2O2, don't waste your time on this synthesis. And that's my conclusion. Although this synthesis may seem attractive, it's tedious and labor-intensive, especially with all those vacuum distillations (I've tried without, it works, but leads to working with high temperatures, and I've even managed to destroy product that way!). So I'd advise anyone to turn to another synthesis method. I managed to get what I think was the desired product in the end, but in my opinion not enough to justify the whole procedure. For those who want to know more, I recommend reading the paper, searching for "Two dogs aldol", learning about the mechanisms of aldol reaction, baeyer-villiger oxidation and hydrolysis of esters.

Forensic Science International: David Doughty, Ben Painter, Paul E. Pigou, Martin R. Johnston | PDF | Ester | Chemical Reactions

Scribd is the world's largest social reading and publishing site.

www.scribd.com

Irving LangmuirExcess MEK also acts as a solvent for the reaction (except what you wrote). The release of a product without distillation is possible after dilution with water (excess mek and other impurities) and extracting the sediment in the form of oil. The oil crystallizes well into an intermediate product after recrystallization with ethanol. At this stage, we get the first stage product without complicated manipulations (it is not necessary to extract chloroform, and in general, the technique in this topic needs to be slightly corrected). We cannot use hydroxide, this will give another by-product as a result.

 

[Irving Langmuir]

Excess MEK also acts as a solvent for the reaction (except what you wrote). The release of a product without distillation is possible after dilution with water (excess mek and other impurities) and extracting the sediment in the form of oil. The oil crystallizes well into an intermediate product after recrystallization with ethanol. At this stage, we get the first stage product without complicated manipulations (it is not necessary to extract chloroform, and in general, the technique in this topic needs to be slightly corrected). We cannot use hydroxide, this will give another by-product as a result.

William D.That's interesting, thank you! What would you correct about the technique in this topic?

 

[Cbison]

Excess MEK also acts as a solvent for the reaction (except what you wrote). The release of a product without distillation is possible after dilution with water (excess mek and other impurities) and extracting the sediment in the form of oil. The oil crystallizes well into an intermediate product after recrystallization with ethanol. At this stage, we get the first stage product without complicated manipulations (it is not necessary to extract chloroform, and in general, the technique in this topic needs to be slightly corrected). We cannot use hydroxide, this will give another by-product as a result.

William D.Kindly share the procedure of obtaining MPB oil from crude mixture if you don’t want to vacuum distill.