Phenylacetone (P2P) synthesis from benzaldehyde with butanone

[Fenster]

Im running the same process at the same stage. Don't expectuch help from the team here. They seem to have abandoned this write up. I think a lot of write ups are just copy pasted.



Consider, that MEK and Benzaldehyde have different molecular weight and density. Therefore 100ml of MEK is not 100g. This only an issue later when you go to add 100g of h202(50%)

There are several measures in this write up where one side of the reaction is stated in grams and the other in MLS. H2O2 I stated in grams of a 50/50 mixture. So you have to account for the water and the peroxide when calculating the MLS from weight. Unless your going to start weighing liquids.

Let me know how you go, when I did .1M reaction I ended up with such poor yields that i couldn't extract the p2p from the tar crap. This write up doesn't really inform you much along the way of what to expect. You can the impression of just extract and distill.

Let me know how you go extracting the MPB tomorrow. Did your Rx mixture go bright red?

 

[Ortist]

This writeup contains a few serious mistakes thats why. In particular the last step is completely wrong. Doing it as describet you'll end up with tar and a few % of p2p

 

[Mo0odi]

Is there an alternative to peroxide hydrogen ?

 

[Ortist]

Original twodogs procedure uses perboric acid made in-situ from acetic acid & sodium perborate. Perboric route is a bit messy and requires filtering

 

[TheNut22]

I used one time performic acid, and it worked, but not as well as peracetic acid.

 

[billythekid]

per boric and GAA makes peracetic

 

[mithyl2]

what is the best way to make 50% Hydrogen peroxide?

does it have to be exactly 50%?

 

[skanderbeg]

YT tutorials on that and do your math with the % peroxide you have. Other than that buy from alfa aesar. Yes it's better to use 50% because it has a lot of water as a stabilizer/diluting agent and can (don't know for sure) interfere with the reaction.

 

[mithyl2]

i saw some of those and the method seems to be boiling off the water so that the % of peroxide increases, but this is very inaccurate.

but if there's an accurate way of doing it, then that will be ok. could you maybe shed some light on this?

better yet, is there an alternative to hydrogen peroxide?

 

[skanderbeg]

Never did the two dogs method don't know about alternatives . But you can open air boil off the water until it reaches about 25% concentration. Afterwards I repeat myself again do your calculations. Fraction distill the water under vacuum (-30inHg is ok) it should boil off at 50-60 celsius. Just do your math on how much water you need to boil off to reach 50% concentration .

 

[mithyl2]

thanks. if there's no substitute chemical then i'll try this method out.

does the hydrogen peroxide have to be exactly 50%?

 

[Ortist]

it is recommended. otherwise you'll end up with really low % peracetic acid. There are charts somewhere on internet about %H2O2 versus % peracetic acid you get. High %H2O2 is essential.

 

[Ortist]

Original twodogs write up does not use peroxide. It uses sodium perborate.
100g of ketone, 143g sodium perborate, 625ml of acetic acid, 50-60 degrees celsius, 6hours mixing time. It is exotermic reaction so check temp and cool if necessary.

 

[mithyl2]

do you think if i distill off more than 50% of the water out of the hydrogen peroxide to make sure i at least have 50%, that would work better? will the reaction be compromised if i use too high a concentration of hydrogen peroxide?

 

[Ortist]

yes you can distill water to make it more concentated. it is a bit dangerous, please watch videos on the youtube on how to concentrate H2O2. do not attempt to make more than 50% as it becomes an explosive

 

[waltjr5858]

Yes as you boil it off you need to weigh the liquid on an accurate small scale and check the density until you get to 50%

 

[Ortist]

This whole synth procedure makes me think that guy who posted it never actually tried it.

1. Better to use 1:2 PhCHO to MEK molar ratio.
2. For each 100g of PhCHO you need roughly 20g of HCL., not just "bubble 1.5hour"
You CAN use aqueous 35%..37% HCL
3. Reaction mixture must be cooled for at least 6 hours after all HCL is added
4. Reaction mixture MUST stay at room temp for AT LEAST 24 hours
5. RM must be washed with water once, sodium bicarbonate once.
6. Distill excess of MEK at atmospheric pressure
7. Distill your product under vacuum.
8. From 1000g of PhCHO you'll get 900g of your ketone at best.

Bayer-Villager:
1. Your amount of acetic acid is insane
2. Peracetic acid must be made in advance, not just "put it all together"

Saponification step:
Absolutely unrealistic yeld. At best you can get 35% w/w but it usually less

 

[handle]

Approximately 45.4 mL of 37% HCl solution to obtain 20 grams of HCl.
Approximately 53.9 mL of 32% HCl solution to obtain 20 grams of HCl.

 

[Ortist]

saponification in aqueous NaOH at 50 degrees ?! Thats really bad idea

 

[gmo]

What temperature is required?

 

[mckennai]

Are you already in try or just asking? I'm almost trying that recipe just Williams guiding and directing me. I think I've done obtaining first intermediate I'had 3butane2one now I'm on acetoxy synthesizing step 2. If u already trying to synthesize Ill be happy to talk and stayin contact with u

 

[gmo]

I tried unsuccessfully once, now I want to start again with the mentioned combined method and the opinions of friends and some simple initiatives. I will be happy to cooperate with you

 

[waltjr5858]

Yeah if you're going to write that's a bad idea you should probably explain why and the correct way with a reference if possible to help those out that are trying to accomplish it....

 

[the money]

I really wish we had a video on P2P synthesis of benzaldehyde and methyl ethyl ketone (MEK) As you know, anyone can supply methyl ethyl ketone (MEK) from stores, there is also a video for you on the synthesis of benzaldehyde from stores.

 

[Katty Korner]

Can oxone be used to replace the hydrogen peroxide? No water, has some buffer usually so it won't be too acidic, but can be gotten without iirc.

 

[Ortist]

yes it can be used. but not just instead oh h2o2. there are several patents on the internet about using oxone in bayer-villiger on unsaturated ketones.

 

[Katty Korner]

Id assume it would be used in place, at least partially, for some of the acetic acid.

I'll look for such patents, thank you

 

[Ortist]

in the step 3 of this method you have to disill p2p under vacuum. there are many side products & tar created on this saponification step. real yeld is around 300g of p2p

 

[Katty Korner]

Id assume it would be used in place, at least partially, for some of the acetic acid.

I'll look for such patents, thank you

 

[lalalander]

Everyone says this method has flaws. Has anyone ever really gotten significant yields with this method?

 

[Ortist]

I used this method many times. Modified a bit. The best results I got was 30ml of P2P from 100ml of benzaldehyde. Also I know a few people who researched this reaction alot; their best results were around 35ml of P2P.

Working method:

1. Methyl-phenyl-butenone prepared as follows: 500ml of benzaldehyde is mixed with 1000ml of MEK. Mixture is cooled in a bucked filled with ice to around +5 degrees.
2. To this is added aqueous HCL, 35-37%, (you have to add 100g of pure HCL which corresponds to about 286ml of 37%HCL)
3. Mix and keep it in a bucket with ice overnight, let the ice melt.
4. Wait 24 hours more
5. Put it in a separatory funnel, discard lower layer.
6. Wash the dark brown-red mixture with 500ml of water, discard water.
7. Distill everything that boils below 150 degrees at atmosferic pressure and discard
8. Distill the rest in vacuum to get a yellow oil

This oil will darken on standing within a week.


Bayer-Villiger:
1. 100ml of above prepared oil add to mixture of 300ml of glacial acetic acid and 100ml of 50% hydrogen peroxide.
2. Heat & stir it at 55 degrees.
3. When reaction starts temperature will go up above 55..60 (about 1..2 hours) : this is the indication to turn OFF heating. If temperaturfe climbs to 70 then cool your flask under running water a bit.
4. Stir until temperature falls back to 50..55 degrees, then turn heating ON again
5. Stir & heat for 6 hours
7. Pour mixture to 1L of water, extract 3 times with 100+100+100ml of DCM
8. Distill DCM off


Saponification:
1. Put Bayer-Villiger product from the step above in a flask with stirring. Slowly add
NaOH solution (30g NaOH, 250ml water, 250ml ethanol). Slowly means dropwise, about 3..5 drops a second. Mixture becomes reddish-orange

2. At the end of addition pH should be above 12
3. To the mixture add acetic acid (any percentage) until neutral pH. Mixture will turn yellow
4. Pour this to 1L of water and extract 3 times with 100+100+100ml of DCM
5. Distill DCM & traces of ethanol off at atmospheric pressure
6. Distill your P2P under vacuum.
7. There will be alot of tar left in a flask

 

[TheNut22]

I totally agree. I'm sorry my frustration comes sometimes pretty fast. Ortist, you know what you're doing. Thanks!

 

[ZMI_AA0B]

Teacher, I failed with your method! Do I need to reflux when heating and stirring 100ml of oil, 100ml of hydrogen peroxide, and 300ml of glacial acetic acid? I didn't use reflux and extracted with dam, only the darker colored lower layer liquid remained

 

[Ortist]

You can also distill P2P with water, but it is very slow. However you MUST distill methyl-phenyl-nutenone under vacuum because there is significant amount of crap and MPB will not distill with water

 

[TheNut22]

OK, and I didn't distill anything. Not MPB, acetoxy, or my P2P, but my downside was that I didn't do the saponification of acetoxy, right. No when I did it right, I got 13 g of dark orange P2P, that I washed a'la Uncle Fester. I got so clean P2P that I see through it. Annnd, it worked in my Leuckart with formamide plus ammonium formate catalyst, and ZnCl2-catalyst (it can be used). I have the better, AlCl3-catalyst for Leuckart, but I was thinking that have I made it wrong. So, with right purification (I purified my acetoxy also, and got clean very sweet smelling yellow oil. And, I read that PDF when they didn't distill P2P and tested the impurities, in P2P, there was impurities, but in VERY low amount.

I do not have even distilling apparatus anymore, because those cheap apparatus i bought, breaks very easily. For example, my magnetic stirrer broke, in my heating mantle, the first week, if I remember correctly. So, I have to buy one whole setup again. Now I have just erlenmeyer, broken glass stick, reflux column, and heating mantle. I also broke my 100 ml measuring flask. DAMN!

Can someone give me advise what kind of apparatus I have to buy to make the vacuum for distilling. I have vacuum holes in those glassses. And they are $24/40. What it means, I don't really know, I think that means the vacuum amount, or what?!

 

[TheNut22]

This was just my polymerized P2P bullshit! And I could not distill my P2P. That's why my Leuckart didn't work any of those times I tried, and oh boy I tried..