The following reagents are used:
A solution of 10 g of 1-phenyl-2-nitropropene in 100 ml isopropyl alcohol and 50 ml acetic acid is prepared before starting the synthesis. In addition, 12 g of aluminium foil is cut into small pieces with a paper shredder for the preparation of an aluminium amalgam. It can be cut with scissors or torn with the hands (wearing gloves).
- Preparation of an aqueous alkaline solution. This solution was made in advance so that it is at room temperature at the time of alkalinisation of the main reaction mixture in this video. The alkalinisation is carried out by spontaneous heating. If a freshly made hot aqueous alkaline solution is used, then the temperature will rise further and forced cooling of the reaction mass will be necessary.
- Amalgamation with mercury nitrate. The amalgamated aluminium will reduce 1-phenyl-2-nitropropene to amphetamine. During the amalgamation reaction a small amount of gas is evolved and a grey precipitate is formed. It is important not to miss the moment when the aluminium amalgam is ready. This moment can be determined by the formation of a grey precipitate and by an increase in gas evolution. This occurs within 10-15 minutes from the start of the reaction.
- The water is drained without removing the gauze, the amalgamated aluminium is washed with two portions of cold distilled water. It is worth paying attention to the release of gas bubbles. It is noticeable that the bubbles are smaller and the colour of the liquid is darker in a "correct" amalgam. If the reaction is violent, the bubbles are large and the colour is light, the amalgam is "wrong". This is almost certainly due to a lack of mercury salt. Note that mercury salts are poisonous.
- The most important part of the process is the reduction of 1-phenyl-2-nitropropene by the aluminium amalgam. The reaction is exothermic and takes place with an abundant release of heat. It is necessary to carefully control the temperature during the procedure. If overheating occurs, the reaction flask is cooled in an ice bath. It is allowed to add cold water to the flask. Sometimes the reaction does not start, it is necessary to heat the reaction mass thoroughly and then start the reaction (with a correctly prepared amalgam). Odours of boiling alcohol and acetic acid are released during the reaction. An Allihn reflux condenser is used to capture the vapours. The efficiency of the Allihn reflux condenser can be increased with running cold water, which can be connected to it.
- The reaction flask can be rinsed with a small amount of alcohol and the unreacted aluminium can also be rinsed to collect residues and increase the yield.
- There should be little unreacted aluminium left. The amount of reacted 1-phenyl-2-nitropropene can be determined from the residues.
- Alkalinisation. The reaction is carried out with heat release. Unreacted aluminium residues will additionally react with alkali and heat the mixture, as well as create by-products. A separation into visible layers occurs within 30 minutes after alkalinisation. The pH of the top layer should be 11-12.
- Decanting. The top layer is collected with amphetamine base in alcohol. It can be dried with a small amount of anhydrous magnesium sulphate. The slag can be extracted with a non-polar solvent (ether, benzene, toluene), then the solvent is evaporated.
- Preparation of the sulphuric acid solution in acetone. This solution is necessary for a milder acidification. If concentrated sulphuric acid is used, local overacidification of the product occurs. Therefore, the yield decreases.
- Acidification of the product and obtaining amphetamine sulphate. To the yellow top layer, which was collected in the previous step, a prepared sulphuric acid solution is added dropwise. Salt flakes are formed with each drop of acid solution. This stage is very important, as it is necessary to carefully control the pH to avoid over-acidification. Acidification continues up to a pH of 5.5-6. The overacidified product has a pinkish colour. The product will spoil in case of total overacidification.
- Filtration of the amphetamine sulphate from the solvents in a Büchner funnel under vacuum. The product can be additionally rinsed with cold acetone at this stage by pouring it through the Büchner funnel with the amphetamine sulphate cake.
- Filtration using improvised tools. Any coarse cloth can be used as a filter. The resulting product is dried in a warm, dry place for several hours to remove residual solvents. Storage in a vacuum pack is recommended.
The yield is 60-70%.
- 10 g of 1-Phenyl-2-nitropropene (P2NP)
- 100 ml isopropyl alcohol (IPA)
- 50 ml of glacial acetic acid (AcOH)
- 50 g sodium hydroxide (NaOH)
- 12 g aluminium (in the form of household aluminium foil sheets)
- 0.1 g mercury (II) nitrate (Hg(NO3)2)
- 2 ml of sulphuric acid (H2SO4)
- 50 ml acetone
- Distilled water
- 2 L flat-bottomed flask
- Retort holder and clamp for securing the apparatus (optional)
- Reflux condenser
- Funnel
- Sieve filter (kitchen grade is fine)
- Pasteur syringe or pipette
- pH indicator papers
- Beakers (600 mL x2, 2 L, 1 L, 100 mL x2)
- Vacuum pump
- Laboratory balance (0.1-200 g is suitable)
- 1000 mL and 100 mL measuring cylinders
- Cold water bath
- Glass rod and spatula
- 1 L separatory funnel (optional)
- Laboratory grade thermometer
- Büchner flask and funnel
- Filter paper
A solution of 10 g of 1-phenyl-2-nitropropene in 100 ml isopropyl alcohol and 50 ml acetic acid is prepared before starting the synthesis. In addition, 12 g of aluminium foil is cut into small pieces with a paper shredder for the preparation of an aluminium amalgam. It can be cut with scissors or torn with the hands (wearing gloves).
- Preparation of an aqueous alkaline solution. This solution was made in advance so that it is at room temperature at the time of alkalinisation of the main reaction mixture in this video. The alkalinisation is carried out by spontaneous heating. If a freshly made hot aqueous alkaline solution is used, then the temperature will rise further and forced cooling of the reaction mass will be necessary.
- Amalgamation with mercury nitrate. The amalgamated aluminium will reduce 1-phenyl-2-nitropropene to amphetamine. During the amalgamation reaction a small amount of gas is evolved and a grey precipitate is formed. It is important not to miss the moment when the aluminium amalgam is ready. This moment can be determined by the formation of a grey precipitate and by an increase in gas evolution. This occurs within 10-15 minutes from the start of the reaction.
- The water is drained without removing the gauze, the amalgamated aluminium is washed with two portions of cold distilled water. It is worth paying attention to the release of gas bubbles. It is noticeable that the bubbles are smaller and the colour of the liquid is darker in a "correct" amalgam. If the reaction is violent, the bubbles are large and the colour is light, the amalgam is "wrong". This is almost certainly due to a lack of mercury salt. Note that mercury salts are poisonous.
- The most important part of the process is the reduction of 1-phenyl-2-nitropropene by the aluminium amalgam. The reaction is exothermic and takes place with an abundant release of heat. It is necessary to carefully control the temperature during the procedure. If overheating occurs, the reaction flask is cooled in an ice bath. It is allowed to add cold water to the flask. Sometimes the reaction does not start, it is necessary to heat the reaction mass thoroughly and then start the reaction (with a correctly prepared amalgam). Odours of boiling alcohol and acetic acid are released during the reaction. An Allihn reflux condenser is used to capture the vapours. The efficiency of the Allihn reflux condenser can be increased with running cold water, which can be connected to it.
- The reaction flask can be rinsed with a small amount of alcohol and the unreacted aluminium can also be rinsed to collect residues and increase the yield.
- There should be little unreacted aluminium left. The amount of reacted 1-phenyl-2-nitropropene can be determined from the residues.
- Alkalinisation. The reaction is carried out with heat release. Unreacted aluminium residues will additionally react with alkali and heat the mixture, as well as create by-products. A separation into visible layers occurs within 30 minutes after alkalinisation. The pH of the top layer should be 11-12.
- Decanting. The top layer is collected with amphetamine base in alcohol. It can be dried with a small amount of anhydrous magnesium sulphate. The slag can be extracted with a non-polar solvent (ether, benzene, toluene), then the solvent is evaporated.
- Preparation of the sulphuric acid solution in acetone. This solution is necessary for a milder acidification. If concentrated sulphuric acid is used, local overacidification of the product occurs. Therefore, the yield decreases.
- Acidification of the product and obtaining amphetamine sulphate. To the yellow top layer, which was collected in the previous step, a prepared sulphuric acid solution is added dropwise. Salt flakes are formed with each drop of acid solution. This stage is very important, as it is necessary to carefully control the pH to avoid over-acidification. Acidification continues up to a pH of 5.5-6. The overacidified product has a pinkish colour. The product will spoil in case of total overacidification.
- Filtration of the amphetamine sulphate from the solvents in a Büchner funnel under vacuum. The product can be additionally rinsed with cold acetone at this stage by pouring it through the Büchner funnel with the amphetamine sulphate cake.
- Filtration using improvised tools. Any coarse cloth can be used as a filter. The resulting product is dried in a warm, dry place for several hours to remove residual solvents. Storage in a vacuum pack is recommended.
The yield is 60-70%.