Phenylacetone (P2P) synthesis from benzaldehyde with butanone

[MadHatter]

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.

 

[TheNut22]

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

 

[GhostChemist]

plz use English in main topics and use a translator for this

 

[MadHatter]

I guess what I'm really wondering about is the stochiometry of this reaction. In other write-ups of the bayer-williger I can't seem to find this enormous amounts of GAA. Can somebody help me with the rationale? I'm really close to trying this one out, but the amount of GAA is problematic.

 

[billythekid]

this amount of gaa is a lot and my best guess as to why is that preparing Peracetic acid in situ (during the reaction) and without a catalyst is inefficient so the chemist overcompensates to help with this, also GAA is used here as the solvent
by making the peracetic acid days before and testing the available oxygen content you are likely to get better results. This being said, I have seen professionals use this method and only get at best 35 to 65% of finished product. so an inexperienced chemist is likely to get even worse and a newbee is likely to fail or even worse hurt themselves. I recommend reading and studying and start small
make sure you thoroughly clean your finished reaction mix at the end of each step, Do not exceed -5c in the aldol condensation let mek/benzaldehyde stir overnight in the fridge after gassing.
do not exceed 60c in the Bayer villager. and research other oxidizers because I get better results with a different one.

 

[chema333]

Hola amigo me podrías ayudar a cintetisar oxona

 

[Jamroz]

I will prepare hcl gas from sulfuric acid and hydrochloric acid, can anyone tell me what amount I need hcl and h2so4? when i know i have added enough gas?

 

[waltjr5858]

I can tell you in this same reaction Scaled down They used 200 g of benzaldehyde to 300 G of MEK. I'm not sure which one of those that you base your gas addition on but they added until the mixture was 40 G heavier. So again I am not sure whether you can interpolate that with the benzaldehyde or the MEK depending on what scale you're using but I do know the weight came from a good resource. With this reaction on this site they use a 50/50 benzaldehyde MEK. I can try to look around and I'll let you know if I find something concrete

 

[kitboy]

Add more MEK than aldehyde, you can use concentrated sulfuric acid directly.

 

[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

 

[Su sho p]

Do I need chloroform extraction for washing with water? Because there is no chloroform reactant in the upper layer, chloroform is used to extract the reactant in the lower layer

 

[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

 

[lalalander]

That is interesting. Do you have the paper?

 

[handle]

is that the Australian paper?

 

[handle]

Great let's try this one.
Step 1, underway.
45g Benzaldehyde + 200ml M.E.K bubble the HCL gas from 25ml H2SO4 over 25ml Hydrochloric acid. Turned bright red in about 30mins, now stirring.

 

[TheNut22]

46 g benzald. (~95%) + 36.8 g MEK + 45 g hydrochloric acid (18%). 100°C to 115°C degrees.
Time: 4 hours.

I think I'll use these amounts from now on, because I've never gotten such a large organic phase, and I didn't have to put much more reagents. I was going to put all the reagents first in the same amount as before, but when I put accidentally 45 g of hydrochloric acid, even though I had to put the same 30 g. So I added more of the other reagents to the mixture as well.

The amount of MEK was proportionally less, because it ran out of it, but it didn't hurt at all, because judging by the size of the organic phase, it was a good thing. I now also heated at slightly higher temperatures. I've tried warming up also in degrees 120-130°C, but after several experiments I ended up with that degree of about 100°C. Lower temperatures reduced yields.

 

[unclefesteraddams1]

What is the use of crystal solution?
Kristal çözelti ne işe yarar

 

[lalalander]

These crystals are oxidized to form the enol acetate ester of phenylacetone, which is then hydrolyzed to yield phenylacetone.

---

Bu kristalller, oksidasyon reaksiyonu ile fenilasetonun enol asetat esterine okside edilir ve bu ester hidrolize edildiğinde fenilaseton elde edilir.

 

[nokospp]

is these the right color of Methyl phenyl butenone ?
after distilling it under vacuum i receive some of yellow oil and put it on freezer for overnight and i got that yellow crystal

 

[kitboy]

What happens if you add water in the first reaction to eliminate the acid? Two phases form. In the oxidation, water is added with NaOH, and the aqueous phase separates from the organic phase. Doing this can separate the two phases well Is this a bad idea? Does it significantly affect the yield?

 

[Su sho p]

Teacher! After I added hydrogen chloride and stirred it, and then added distilled water, it had already layered. Do we still need chloroform extraction？

 

[Su sho p]

Excuse me, teacher! Do I extract with chloroform, dry with magnesium sulfate, and then directly vacuum distill? Don't you need to distill chloroform first?