Phenylacetone (P2P) synthesis from benzaldehyde with butanone

[MadHatter]

Thank you so much for the easy and detailed synth description!
How about the hydrogen peroxide, could that be substituted? It's a really controlled chemical nowadays, and a bitch to synthesize yourself. Its mainly there as a catalyst in the reaction between the glacial acetic acid and the 3-methyl-4-phenyl-3-buten-2-one, right? What could be a good substitute?

 

[handle]

Peracids will work (lower yields) Baeyer-Villiger oxidation.read the investigation paper above.

 

[TheNut22]

I got 37.28 grams of acetoxyphenylpropene from 52.77 grams of MPB last time with peracetic acid, that I made from 30% H2O2 and glacial acetic acid, and 0.1 moles of H2SO4. That peracetic acid stood in my closet for 3 days before it was used.
But just 13.04 g of P2P from that 37.28 g of acetoxy via base hydrogenation (no heating, just stirring and dropping it in 2,5 hours).

 

[lalalander]

Did you use 50/50 water/alcohol or just water and base?

 

[TheNut22]

Alcohol/water with base.

 

[William Dampier]

yes, 10L of GAA

 

[situ1988]

What concentration of GAA

 

[waltjr5858]

Just by 99% pure GAA from anywhere and that's what you use

 

[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.

 

[waltjr5858]

Toulene is perfectly fine also

 

[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.

 

[waltjr5858]

Why didn't you have P2P those times? What was the failure what did you miss?

 

[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.

 

[UWe9o12jkied91d]

I would say DCM, but I might be wrong
You also easily make chloroform by reacting cold 0* C bleach with acetone in stoechiometric amounts with a small 10% ish molar excess of bleach.Nilered has a video.

 

[waltjr5858]

Imagine how many bottles of bleach you would have to use to make the chloroform needed for any sizable reaction. I do know that toulene works just fine and since that is easily purchasable that's what I would use

 

[Fenster]

I need help!

100g of both Benzaldehyde and MEK were added to a 500ml RBF and chilled to zero. The mixture was put on mag Stir and HCL was bubbled through the solution, quickly at first and then slow and steady once the HCl generator was fine tuned. (HCl over Conc. Sulphuric Acid). The solution turned yellow, then red, followed by very dark red. After 1.5 Hours, gas was removed and let stir at room temperature for 1.5 hours. Added 200ml of distilled water, instantly two layers formed. A dark layer (organic bottom) and a aqueous layer clear yellow. 40ml of DCM was added to the solution.

Here is my problem. The DCM appears to have merged with the organic layer. It's a lovely smelling camphur solution, actually it's a beautiful smell. However I cannot see the DCM layer in the sep funnel. Damn, how the fuck to resolve this?

 

[waltjr5858]

Toulene...

 

[Fenster]

@jokerr I don't think gpatton is interested. I asked for soooo much help and they seemed to just wait until I got frustrated and then disarming language by accusing me of not following procedure. I've have DM the op and no response.

I have the original forensics write up. Might shed some light. This write up is honestly dog shit here.

 

[handle]

Looks like it's a 1:4.44 ratio of benzaldehyde to butanone

 

[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.

 

[Osmosis Vanderwaal]

In the US, what's a good source for benzaldehyde? I know it is in bitter almond extract and imitation cherry and vanilla flavoring, but does anyone have any recommendations for a brand or product or any experience sourcing it? If I could get it under the radar this would be OTC in the US

 

[handle]

Nice easy synthesis: Benzyl alcohol + nitric acid, Tom's lab on you tube. Works well 83% yield.

 

[TucoSalamanca.]

can you write how you synthesise

 

[handle]

1L Rbf add in order the below.
400ml Distilled water,
52.4ml Nitric acid,
4g sodium nitrite,
125ml benyl alcohol.
Strong stirring. Yield 105g

Spoiler: Procedure

Reflux for 4 hours <70c >90c
Cool.
Transfer to Sep funnel.
Dump spent HNO3.
Wash with little water.
Then bicarb.
Then wash with NaCl sol.
105g yield raw.
Vacuum distill benzaldehyde, dry with MgSO4.
Store in Amber bottle, cool ,dry place.

 

[TucoSalamanca.]

what is spent hno3 unload
If I do it with sodium carbonate, how many gr and how many ml should I use washing

 

[TucoSalamanca.]

how many degrees should the dripping be

 

[handle]

Spoiler: Benzaldehyde from Benzyl alcohol

This thread should answer all your questions. In future please use english.

 

[Ketaholiker]

Hello ,

can i go from 3-Methyl-4-phenyl-3-buten-2-one and do a electro oxidation.
Possible?

EP0247526: Electrolytic 3,4-Dimethoxyphenylacetone Preparation - [www.rhodium.ws]

Electrochemical process for converting olefins to ketones

This maybee helps also

Electrochemical Reduction of Nitroalkenes to Oximes and Amines - [www.rhodium.ws]

OTC would be super hope you guys can help electro reduction/oxidation its really cool and unsupect xD

Have a nice day

 

[TheNut22]

All those reagents to make 3-Methyl-4-phenyl-3-buten-2-one are OTC.
I'm not going to name any brand for to obtain that benzaldehyde, because "they" will take them out of those shelves, immediately. Or, even if i'm wrong about that, it's better to be little cautious about those precious reagets.

 

[TheNut22]

BUT, look the benz-hyde from artificial flavouring shelves in stores.

 

[OrgUnikum]

No. This are different oxidations. You need a BV, a Baier Villinger oxidation.

 

[G-Meth ICE]

Ya!ψ(｀∇´)ψThe RM after the reaction of benzaldehyde + MEK + HCI turns black and challenges the distillation of 3-Methyl-4-phenyl-3-buten-2-one with a boiling point of 269! This is the first time I bought a -60kpa vacuum pump for vacuum decompression and successfully obtained the golden yellow liquid 3-Methyl-4-phenyl-3-buten-2-one! But the machine seems to be overheated. Now I can only pause the distillation... Do you want the remaining rm to be completely distilled, right? I don’t want to distill out impurities with higher boiling points and ruin my hard work⋯

 

[TheNut22]

Wow! If that is the benzyldienemethylethylketone (different name to MPB), that looks very pure!
And yes, the reaction contitions will make black organic phase, when the reaction is made right.
It also looks like benzaldehyde, with same colour (boiling point: 178,1°C), and I have the info, that the product, MPB, is yellow, when it's made to oil, but I want to believe that this is the right product, and I don't want to be an asshole. Can it be distilled without a vacuum? Because now I have so much raw and not dry MPB (over 100 grams) and if it can be distilled with simple distillation, I want to make this kind of pure oil with it! Wow! Good work my friend.

 

[Labchef]

Pls show your vacuum pump and how you used it in distillation please.

 

[G-Meth ICE]

Now looking back at the pump I used at that time, I was able to use ultra-high temperature to evaporate and distill out a product with a boiling point of 260 degrees. It was incredible. I remember that the thermometer showed about 220 degrees. You must not do what I did. I suggest you buy an oil-driven vacuum pump and test the glass interface for high-vacuum silicone. Also pay attention to safety during the application process!