P2NP Synthesis Guide

Introduction

1-Phenyl-2-nitropropene (P2NP) is a key intermediate compound commonly used in organic synthesis, particularly in the development of various fine chemicals and research compounds. This P2NP synthesis guide provides a detailed overview of the procedures and materials required for synthesizing P2NP using the Henry condensation reaction between benzaldehyde and nitroethane. Covering both medium- and small-scale synthesis methods—including a conventional reflux process and a microwave-assisted approach—this guide outlines the necessary equipment, reagents, step-by-step instructions, and post-reaction purification techniques such as crystallization and recrystallization. It is intended for individuals with a foundational understanding of laboratory practices and aims to support safe and efficient experimentation in controlled environments.

P2NP Synthesis Guide Medium Scale

Equipment and glassware:

1. 10 L Flask;
2. Retort stand and clamp for securing apparatus (optional);
3. Reflux condenser;
4. Funnel;
5. Vacuum source;
6. Laboratory scale (0.1-500 g is suitable) – optional;
7. Measuring cylinders 1000 mL and 100 mL;
8. Water bath;
9. Glass rod and spatula;
10. Filter paper;
11. Laboratory grade thermometer;
12. Buchner flask and funnel;
13. Bucket 5-10 L.
14. Freezer;

Reagents:

1. Benzaldehyde 1000 ml;
2. Nitroethane 1000 ml;
3. Glacial acetic acid 250 ml;
4. n-Butylamine 50 ml;
5. Isopropyl alcohol (IPA) ~1000 ml;

P2NP Synthesis Guide Medium Scale Steps

1. Benzaldehyde 1000 ml, nitroethane 1000 ml, glacial acetic acid 250 ml and n-butylamine 50 ml are placed into 10 L flask.
2. A reflux condenser is installed onto the flask.
3. The stirrer and heater are turned on. The reaction mixture is heated up to 60 °С.
4. The reaction is conducted during 2-3 hours with constant stirring at 60 °С.
5. The reaction mixture is poured into an empty 5-10 L bucket.
6. Isopropyl alcohol (IPA) 800 ml is poured into the bucket and stirred.
7. The bucket with mixture is put into a freezer for 12 hours, 1-phenyl-2-nitropropene (P2NP) is crystallized.
8. The product P2NP is filtered on a Buchner funnel (suction filtration procedure), washed be a small amount of cold IPA and dried on air (or in vacuum chamber, optional).
   The yield is 65-75%.

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P2NP Synthesis Guide Microwave Small Scale

Equipment and glassware:

1. Beaker 500 ml;
2. Funnel;
3. Vacuum source;
4. Laboratory scale (0.1-500 g is suitable) – optional;
5. Measuring cylinders 50 mL and 100 mL;
6. Glass rod and spatula;
7. Filter paper;
8. Buchner flask and funnel;
9. Freezer;
10. Microwave oven 750 W;

Reagents:

1. Benzaldehyde 100 ml;
2. Nitroethane 100 ml;
3. Glacial acetic acid 25 ml;
4. n-Butylamine 20 ml;
5. Isopropyl alcohol (IPA) ~150 ml;

P2NP Synthesis Guide Microwave Small Scale Steps

1. Benzaldehyde 100 ml, nitroethane 100 ml, glacial acetic acid 25 ml and n-butylamine 20 ml are placed into 500 ml beaker.
2. A rubber glove is put onto the beaker.
3. The beaker is put into a microwave oven.
4. The power of the microwave oven is set up on 750 W. Oven is turned on and the mixture is warmed until the boiling. The mixture is cooled down to the room temperature.
5. Step 4 is repeated several times. Minimum 6 times.
6. Next, IPA 100 ml is added, reaction mixture is stirred and put into a freezer for 12 hours. 1-Phenyl-2-nitropropene (P2NP) is crystallized.
7. The product P2NP is filtered on a Buchner funnel (suction filtration procedure), washed be a small amount of cold IPA and dried on air (or in vacuum chamber, optional).​

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1-Phenyl-2-nitropropene (P2NP) Recrystallization​

1-Phenyl-2-nitropropene (P2NP) can be recrystallized from hexane, methanol, ethanol or isopropanol (IPA).​

Conclusion

The synthesis of 1-Phenyl-2-nitropropene (P2NP) can be effectively carried out using either conventional heating with reflux or a simplified microwave-assisted method, depending on the desired scale and available equipment. With proper technique and safety precautions, both approaches yield consistent results, typically producing 65–75% of purified P2NP. Recrystallization further enhances product purity, making this guide a practical reference for laboratory-scale organic synthesis.

Sources

1. 1-Phenyl-2-nitropropene (P2NP) Video Synthesis From Benzaldehyde and Nitroethane. Henry Reaction. https://bbgate.com/en/threads/1-phenyl-2-nitropropene-p2np-video-synthesis-from-benzaldehyde-and-nitroethane-henry-reaction.52/
2. Xavier, Spectroscopic, and S. Periandy. “Spectroscopic (FT-IR, FT-Raman, UV and NMR) investigation on 1-phenyl-2-nitropropene by quantum computational calculations.” Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 149 (2015): 216-230. https://www.sciencedirect.com/science/article/pii/S1386142515005272