SYNTHESIS OF 4-Bromo-P2NP FROM NITROETHANE AND 4-BromoBENZALDEHYDE
Laboratory tools: 4-liter flat-bottomed flask, glass funnel, 8L pot, cheapest electric cooker, thermometer with 150*C scale, 2x 3000 ml beakers, 1 liter tall beaker, Allihn condenser + hoses and water pump + bowl (bucket) with cold water, 3-liter conical vacuum flask + 150 mm Buchner funnel + 150 mm quality filters + vacuum pump (water aspirator), PP drying trays (cuvettes), container for the obtained product (vacuum desiccator). Electric kettle.
Chemicals: Cyclohexylamine, 4-bromobenzaldehyde, glacial acetic acid (GAA), nitroethane, distilled water, isopropanol
1. Pour 700 ml (622g) of nitroethane into the reaction flask.
2. Cyclohexylamine - 150 ml (108g) is poured into the reaction flask (4L flat bottom flask) for
condensation.
3. Glacial acetic acid (GAA) 300 ml is poured into the reaction flask. Remember that glacial acetic acid turns into a solid below 16*C. It is necessary to keep it in a liquid form.
4. Add 1 kg of 4-bromobenzaldehyde to the reaction flask. This substance is in the form of fine crystals, melting point is 57*C. After heating the mixture to 60*C, everything will melt and go into liquid form.
5. During the reaction, a thick white fog may form - stir the mixture holding the 4L beaker in both hands and vigorously perform spherical movements to mix everything - remember to have good ventilation.
6. Put the 8L pot on the electric stove and put a 1-2 cm high piece of wood in the pot. (this is insulation from the hot bottom of the pot)
7. Put the 4L reaction flask in the pot, attach the neck of the reaction flask to the metal pin in the stand and put the Allihn reflux condenser on the reaction flask.
8. Turn on the water pump to start cooling in the Allihn reflux condenser.
9. Pour water into the electric kettle and boil the water until it starts to boil, then pour this water into the pot with the reaction flask to the height of the mixture poured into the reaction flask. (this process accelerates the stabilization of the expected temperature to 70-80*C.) We put the thermometer in a pot of hot water.
10. We turn on the electric stove to minimum heating and maintain the temperature of 70-80*C for 6 hours.
11. The color should change from light yellow to dark yellow
12. After a while, the reaction mixture is poured into a cooling container (2x 3L beaker). Crystallization time 24 hours. At a temperature of 0 - 4 *C.
13. 4-bromo-P2NP is vacuum filtered on a Büchner funnel and a vacuum flask, after cooling and complete crystallization. It is best to use a circulating vacuum water pump water aspirator because it is resistant to corrosion (acetic acid is a strong corrosive agent)
14. The mother liquor (non-crystallized 4-bromo-P2NP in a vacuum flask) is transferred to another vessel, and the crystallized 4-bromo-P2NP on the Buchner funnel is washed with cold IPA.
15. 4-bromo-P2NP is dried to constant mass at room temperature for one day on a laboratory cuvette. Optionally, you can also use a desiccator and put 4-bromo-P2NP in it, close the desiccator and connect the vacuum - thanks to this, the solvent from 4-bromo-P2NP will initially evaporate strongly.
16. Then, distilled water is added to the non-crystallized 4-bromo-P2NP in the beaker until additional 4-bromo-P2NP crystals are obtained. If there are few crystals, it means that we have obtained a reaction with high efficiency. After adding water, 2 phases are formed: organic at the top and aqueous at the bottom. You can collect the lower layer and freeze it or distill the solvent if necessary, but it is not necessary. Step 11 is optional (additional)
17. We obtain 1072g of 4-bromo-P2NP with a yield of 107%, taking into account 4-bromobenzaldehyde
Additional observations
In this reaction, I used a magnetic stirrer with heating and the reaction took place at 45*C.
Laboratory tools: 4-liter flat-bottomed flask, glass funnel, 8L pot, cheapest electric cooker, thermometer with 150*C scale, 2x 3000 ml beakers, 1 liter tall beaker, Allihn condenser + hoses and water pump + bowl (bucket) with cold water, 3-liter conical vacuum flask + 150 mm Buchner funnel + 150 mm quality filters + vacuum pump (water aspirator), PP drying trays (cuvettes), container for the obtained product (vacuum desiccator). Electric kettle.
Chemicals: Cyclohexylamine, 4-bromobenzaldehyde, glacial acetic acid (GAA), nitroethane, distilled water, isopropanol
1. Pour 700 ml (622g) of nitroethane into the reaction flask.
2. Cyclohexylamine - 150 ml (108g) is poured into the reaction flask (4L flat bottom flask) for
condensation.
3. Glacial acetic acid (GAA) 300 ml is poured into the reaction flask. Remember that glacial acetic acid turns into a solid below 16*C. It is necessary to keep it in a liquid form.
4. Add 1 kg of 4-bromobenzaldehyde to the reaction flask. This substance is in the form of fine crystals, melting point is 57*C. After heating the mixture to 60*C, everything will melt and go into liquid form.
5. During the reaction, a thick white fog may form - stir the mixture holding the 4L beaker in both hands and vigorously perform spherical movements to mix everything - remember to have good ventilation.
6. Put the 8L pot on the electric stove and put a 1-2 cm high piece of wood in the pot. (this is insulation from the hot bottom of the pot)
7. Put the 4L reaction flask in the pot, attach the neck of the reaction flask to the metal pin in the stand and put the Allihn reflux condenser on the reaction flask.
8. Turn on the water pump to start cooling in the Allihn reflux condenser.
9. Pour water into the electric kettle and boil the water until it starts to boil, then pour this water into the pot with the reaction flask to the height of the mixture poured into the reaction flask. (this process accelerates the stabilization of the expected temperature to 70-80*C.) We put the thermometer in a pot of hot water.
10. We turn on the electric stove to minimum heating and maintain the temperature of 70-80*C for 6 hours.
11. The color should change from light yellow to dark yellow
12. After a while, the reaction mixture is poured into a cooling container (2x 3L beaker). Crystallization time 24 hours. At a temperature of 0 - 4 *C.
13. 4-bromo-P2NP is vacuum filtered on a Büchner funnel and a vacuum flask, after cooling and complete crystallization. It is best to use a circulating vacuum water pump water aspirator because it is resistant to corrosion (acetic acid is a strong corrosive agent)
14. The mother liquor (non-crystallized 4-bromo-P2NP in a vacuum flask) is transferred to another vessel, and the crystallized 4-bromo-P2NP on the Buchner funnel is washed with cold IPA.
15. 4-bromo-P2NP is dried to constant mass at room temperature for one day on a laboratory cuvette. Optionally, you can also use a desiccator and put 4-bromo-P2NP in it, close the desiccator and connect the vacuum - thanks to this, the solvent from 4-bromo-P2NP will initially evaporate strongly.
16. Then, distilled water is added to the non-crystallized 4-bromo-P2NP in the beaker until additional 4-bromo-P2NP crystals are obtained. If there are few crystals, it means that we have obtained a reaction with high efficiency. After adding water, 2 phases are formed: organic at the top and aqueous at the bottom. You can collect the lower layer and freeze it or distill the solvent if necessary, but it is not necessary. Step 11 is optional (additional)
17. We obtain 1072g of 4-bromo-P2NP with a yield of 107%, taking into account 4-bromobenzaldehyde
Additional observations
In this reaction, I used a magnetic stirrer with heating and the reaction took place at 45*C.
