P2P synthesis from BMK glycidate ethers

[Saul]

this is the preparation of P2P Phenylacetone CAS 103-79-7 made use of BMK Glycidic Acid ( sodium salt ) CAS 5449-12-7 with main ingredient sulfonic acid strength is 75% CAS 7664-38-2
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we are going to prepare 1 kg of BMK
take a 5 liter double neck flask
add 500ml boiling water . start with the mixer.
now slowly add 1kg of BMK salt. then add 1 liter of sulfonic acid. now connect the reflux and heat the contents of the flask to max temperature. plus minus 130°c. use a powerful mixer
Let it boil in reflux for 4 hours.
take the top layer and pour it into a measuring cup.
let the bottom layer cool and save for next time. ( we have no chemical waste for this preparation method )

now boil 1 liter of water and add it to the measuring cup. use a hand mixer to mix everything.
After mixing for a few minutes, let the measuring cup cool to room temperature.
remove the top white layer (this is water and waste that we don't need)
the bottom layer is P2P purified and ready to use.

ps: in this preparation we don't have to worry about water remaining in our P2P because water weighs less than P2P

ps2: if you keep these ratios, the P2P will have a ph value of 4 .
if you use more sulfonic acid the ph value will drop to 1. Therefore it is not necessary to use too much sulfonic acid.

 

[Costa]

Hi Tor,
What do you do with that bottom layer that you save?:
"let the bottom layer cool and save for next time. ( we have no chemical waste for this preparation method )"
Do make an extraction to get the remaining P2P diluted there? or do you add it to the BMK and fosforic acid in a new process, from the beginning?

 

[Jesse_Pinkman_]

Thx Buddy

 

[edy's]

Ali sells heating socs for few euros .and an old pan from your kitchen saves a shitload of money .together with a REX100 and your done

 

[Saul]

@Costa

1kg Bmk Salt = 700ml P2P

you dont need DCM
You dont need Steam Distillation
You need H2o for purifying and some time ( 24h ) to seperate the final product p2p

 

[Heisenblack]

Should it be pure distilled water or brine solution?

 

[Andrzej]

Is it possible to connect both methods (steam distillation and vacuum distillation)? Or the author meant just standard steam distillation technique?

 

[w2x3f5]

hit water steam distillation works great, you need 10 grams of steam per milliliter of ketone, the steam value fluctuates a lot. Superheated steam distillation works best.
vacuum distillation makes sense if you have a spider attachment, you will be able to fractional the ketone (take for next step only the highest purity ketone body).

 

[G.Patton]

I told about conventional atmosphere distillation in the topic. You can use steam distillation as @w2x3f5 said.

 

[w2x3f5]

please tell me at what pressure / temperature and other nuances you drive off the ketone with water steam in a vacuum. very interesting, since the usual steam race has a very long history. Thank you!

 

[G.Patton]

I use simple steam distillation for P2P at atm pressure.

 

[Andrzej]

1)mixed 20g of 5449-12-7, 60mL of water and 40mL concentrated HCl (hcl added slowly in room temperature) - according to procedure ratio
2)Stirred by 3h in 82-84 C degrees.
3)Extracted 3x20mL DCM and washed by concentrated nacl solution (brine) ; dried b MgSO4; dcm evaporated on water bath.

Obtained very poor yield: 6g of P2P


1) How can I improve the yield?

2) Is concentrated NaCl solution as a "brine" is suitable in this procedure? (What concentration of NaCl is enough?)

3) How much (mL) of brine should be used to wash reaction mixture in this scale?

4) If the purpose of washing by brine is to neutralise the reaction mixture after acid hydrolysis, couldn't be better to use sodium hydrocarbonate solution instead of NaCl?

 

[w2x3f5]

Why is everyone trying to use hydrochloric acid and everyone has a product yield when it does.
Use hydrolysis in concentrated phosphoric acid, do not add water. Personally received an yield of 80 percent.

 

[Acab1312]

Can I agree

 

[Andrzej]

Thank you very much for the advice. I will try and reply what is the result.
What ratio of phosphoric acid to bmk-glycidic acid sodium salt, temperature and reaction time do you apply?
1:1 and 80-90 degrees and 3h or more?

 

[w2x3f5]

1 to 1, take 100 ml of phosphoric acid per 100 grams of glycidate (you need to get a homogeneous mixture without layers). Heating up to 115-120 degrees, not higher. The reaction is not controlled by time, the end of the reaction is determined when the gases cease to be released. Synthesis is faster in the microwave.

 

[w2x3f5]

I used glycidate (more profitable and cheaper), but with sodium salt everything is the same, the yield is about 80 percent of theory. A person from the forum set up the synthesis in the microwave by sodium salt glycidate and got a yield of 60 percent, but he had a number of errors when isolating p2p (the temperature was not higher than 80 degrees, he did not neutralize the mixture, did not extract p2p with a solvent, he only collected the top layer of p2p and overtook it in vacuum ).

 

[Acab1312]

• w2x3f5

Can I agree

 

[hy16a]

How long does it take for the distillation temperature to be 200 degrees during the purification process?

 

[w2x3f5]

what is 200 degrees for??? ketone will go bad, or steam distillation or vacuum distillation

 

[Andrzej]

Yesterday I have tried the method with the microwave and in fact the result is interesting.
In baker mixed 20g 5449-12-7 and 20mL of 85% orto-phosphoric acid.
I put in microwave oven (700W), and set the lowest power. 5 -7 seconds of heating and 10-15 seconds brake for mixing and cooling the mixture because the temperature was too high. In sum 1 minute of active heating.
After heating added 50mL of distilled water.
Than extracted with dietyl ether (3x20mL) and washed with brine (3x100mL).
Dried with magnesium sulphate and evaporated ether:

Obtained very good looking product but only 7g from 20g of powder.
I was try again and heat in microwave longer - 2 minutes but there was no difference - the same yield (I was afraid of overheating because too much heat in microwave result creating solid, transparent glass-like surface which is unable to remove from baker).
Is there any method to improve the yield in microwave? Because now it is still between 30-40%?

 

[41Dxflatline]

I did this yesterday, got almost exactly the same result. One thing I did observe though is when I didn't mix it straight away it seemed more p2p was forming but upon mixing it didn't return to the surface. Some sort of emulsification with the lower layer or a misobservation on my part?

 

[41Dxflatline]

I'm pretty sure he took that photo at room temperature.

 

[w2x3f5]

To be precise, there is a mixture of p2p and glycidic acid, for this reason it does not crystallize at room temperature

 

[Andrzej]

Additional photos.
After taking from microwave oven:

And after adding 50mL of water:

Yield is problem... still between 30-40%

 

[w2x3f5]

In both cases, the reaction did not go to the end, it is impossible to wash the ketone with pure water, either brine, or wash the ketone in an organic solvent (dichloromethane, for example) with salt water.