Introduction
It's known that 1-Phenyl-2-propanone (Phenylacetone; BMK; P2P) is a primary precursor to methamphetamine. This method represents modern approach to P2P production from available and legal in some countries precursor hydratropic aldehyde (CAS Number: 93-53-8). Despite the fact that this approach takes some expensive reagents like H2SO4 conc, which is not always available, the synthesis is quite simple and rapid.
Difficulty rating: 3/10
Equipment and glassware:
Difficulty rating: 3/10
Equipment and glassware:
- An ice-water bath;
- Laboratory scale (0.1 g-200 g is suitable);
- Measuring cylinders 100 ml and 20 ml;
- Beakers 2 L x2; 500 ml x2; 100 ml x4;
- Laboratory grade thermometer (-50°C to 50°C);
- Magnetic stirrer;
- Separatory funnel
Reagents:
- Hydratropic aldehyde 90 g (CAS Number: 93-53-8) [98% pure hydrotropic aldehyde from Sigma Aldrich];
- Concentrated sulfuric acid (H2SO4 conc 98%) 400 mL;
- Ice 5 pounds (2.3 kg);
- Distilled water;
- Toluene 100 ml;
- Mixture of ice, ethanol, and salt (NaCl);
P2P Synthesis From Hydratropic Aldehyde Scheme
BMK (P2P; phenylacetone) Synthesis From Hydratropic Aldehyde
1. Pour 400 mL of concentrated sulfuric acid (H2SO4 98%) into the 2L beaker.
2. Weigh hydratropic aldehyde 90 g.
3. Place the sulfuric acid beaker in an ice-water bath or a mixture of ice, ethanol, and salt (NaCl) to lower the temperature further.
4. Reduce the temperature of the sulfuric acid to -16°C.
5. Liquid nitrogen was used for additional cooling. Liquid nitrogen (N2) can replace the ice bath as it lowers the temperature more effectively and lasts longer. Also, dry ice can be used.
6. Once the sulfuric acid reaches -16°C, gradually add the hydratropic aldehyde to the solution with manual and vigorous stirring. This process should take about one hour to ensure complete addition.
7. Monitor the temperature carefully to prevent it from rising more than a few degrees, as higher temperatures significantly reduce the yield. This is why liquid nitrogen was used.
8. The temperature should not drop below -16°C, as the hydratropic aldehyde will freeze, preventing the formation of the BMK product.
9. After 15 minutes, once the reaction is complete, pour the solution onto about 5 pounds (2.3 kg) of ice in another beaker and allow it to concentrate at room temperature.
10. As the mixture reaches room temperature and thickens, an oily layer forms on top of the solution, which takes about one hour to fully separate.
11. Use a separatory funnel (sep funnel) to extract this yellow benzyl methyl ketone (BMK; P2P) top layer.
12. The lower gummy layer is mixed with water 70 ml and toluene 100 ml, then shaken vigorously three times for 15 seconds each in a separatory funnel (another oily layer of BMK containing toluene was extracted).
13. Finally, the product was steam distilled following the method provided on BB, and toluene was removed via vacuum distillation.
14. Pure benzyl methyl ketone (BMK) 60 mL was obtained. Pure BMK (P2P) yield is 75%.
This experiment was performed on a small scale to test feasibility before scaling up. FTIR and 1H-NMR analysis confirmed that the product was benzyl methyl ketone (P2P; phenylacetone).
2. Weigh hydratropic aldehyde 90 g.
3. Place the sulfuric acid beaker in an ice-water bath or a mixture of ice, ethanol, and salt (NaCl) to lower the temperature further.
4. Reduce the temperature of the sulfuric acid to -16°C.
5. Liquid nitrogen was used for additional cooling. Liquid nitrogen (N2) can replace the ice bath as it lowers the temperature more effectively and lasts longer. Also, dry ice can be used.
6. Once the sulfuric acid reaches -16°C, gradually add the hydratropic aldehyde to the solution with manual and vigorous stirring. This process should take about one hour to ensure complete addition.
7. Monitor the temperature carefully to prevent it from rising more than a few degrees, as higher temperatures significantly reduce the yield. This is why liquid nitrogen was used.
8. The temperature should not drop below -16°C, as the hydratropic aldehyde will freeze, preventing the formation of the BMK product.
9. After 15 minutes, once the reaction is complete, pour the solution onto about 5 pounds (2.3 kg) of ice in another beaker and allow it to concentrate at room temperature.
10. As the mixture reaches room temperature and thickens, an oily layer forms on top of the solution, which takes about one hour to fully separate.
11. Use a separatory funnel (sep funnel) to extract this yellow benzyl methyl ketone (BMK; P2P) top layer.
12. The lower gummy layer is mixed with water 70 ml and toluene 100 ml, then shaken vigorously three times for 15 seconds each in a separatory funnel (another oily layer of BMK containing toluene was extracted).
13. Finally, the product was steam distilled following the method provided on BB, and toluene was removed via vacuum distillation.
14. Pure benzyl methyl ketone (BMK) 60 mL was obtained. Pure BMK (P2P) yield is 75%.
This experiment was performed on a small scale to test feasibility before scaling up. FTIR and 1H-NMR analysis confirmed that the product was benzyl methyl ketone (P2P; phenylacetone).
Soruces
- @Ranof ‘s method; <<== Special thanks indeed from BB Forum community to this guy.
- Biddle, Timothy J., et al. "Potential forensic markers from synthetic pathways to 1-phenyl-2-propanone from uncontrolled and controlled substances." Forensic Chemistry 28 (2022): 100410. https://www.sciencedirect.com/science/article/abs/pii/S2468170922000133
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