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