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Org. Synth. 1981, 60, 101
DOI: 10.15227/orgsyn.060.0101
2-NITROPROPENE
[1-Propene, 2-nitro]
Submitted by Masaaki Miyashita, Tetsuji Yanami, and Akira Yoshikoshi1.
Checked by D. Seebach, H. Siegel, and E. Wilka.
1. Procedure
Caution! This procedure should be carried out in a hood since 2-nitropropene is a powerful lachrymator. Nitroolefins have a tendency to undergo "fume-offs" (which can be like explosions) near the end of a distillation, particularly if air is let in on a hot distillation residue (from a vacuum distillation).
A 250 mL, one-necked, round-bottomed flask equipped with a magnetic stirring bar is charged with 96.5 g (0.65 mol) of phthalic anhydride (Note 1) and 52.5 g (0.50 mol) of 2-nitro-1-propanol (Note 2). A 10-cm vacuum-insulated Vigreux column, a stillhead fitted with a thermometer, a condenser, a 50-mL, round-bottomed receiving flask, and a water aspirator are installed in due order, and the reaction vessel is placed in an oil bath and evacuated to 110 mm (Note 3). The bath temperature is raised to 150°C and maintained for 30 min while the phthalic anhydride melts to give a homogeneous solution. The receiving flask is immersed in an ice bath, stirring is started, and the bath temperature is raised to 180°C. As the reaction mixture darkens, green-colored 2-nitropropene is gradually distilled off with water, bp 50–65°C (110 mm). The bath temperature is held at 180–185°C until the distillation ceases (ca. 1 hr). The distillate is transferred into a 50-mL separatory funnel, and the lower layer is separated from water (Note 4) and dried over anhydrous magnesium sulfate. Redistillation under reduced pressure through a 10-cm vacuum-insulated Vigreux column (Note 5) gives 25.0–31.4 g (57–72%) of 2-nitropropene, which is collected in an ice-cooled receiving flask as a transparent green liquid, bp 56–57°C (86 mm), nD20 1.4348 [lit.2 bp 58°C (90 mm), nD19 1.4292, d201.0492] (Note 5). The distilling flask is cooled to room temperature before the vacuum is released.
2. Notes
1. Commercial phthalic anhydride, purchased from Wako Pure Chemical Industries, Ltd. (Japan) or from Fluka AG, Buchs (Switzerland), was used without purification.
2. The checkers purchased 2-nitro-1-propanol (ca. 98% purity) from EGA-Aldrich and used it without further purification. The submitters prepared this reagent from nitroethane and formalin according to the procedure of Feuer,3 yield 70–75%, bp 79–80°C (5 mm).
3. Lower pressure may cause a loss of the product because of its volatility.
4. The layers sometimes do not separate well. In this case a small amount of magnesium sulfate should be added.
5. It is important that the bath temperature be kept as low as possible to avoid fume-off decompositions. In the checked procedure the bath temperature was never allowed to exceed 80°C. Toward the end of the distillation the pressure was reduced to ca. 60 mm to achieve complete distillation. Although pure 2-nitropropene may be stored in a freezer as a low-melting solid for several weeks, it is recommended to prepare it immediately before use since it tends to polymerize and to darken slowly on storage. 2-Nitropropene polymerizes readily in the presence of a trace of alkali.
3. Discussion
The procedure described is essentially the same as that of Buckley and Scaife.2 The yield has been increased from 55.5% up to 72% by using 1.3 mol eq of phthalic anhydride and by carefully controlling the pressure and cooling the receiving flask. Although 2-nitropropene has previously been prepared by pyrolysis of 2-nitro-1-propyl benzoate in 72% overall yield from 2-nitro-1-propanol,4 the present method is preferred for its preparation since the procedure is much simpler and the product is directly obtainable from 2-nitro-1-propanol without first preparing its ester. It is also applicable to the preparation of 1-nitro-1-propene (58%),5,6 2-nitro-1-butene (82%),7 and 2-nitro-2-butene (60%).6,7 In general, aliphatic nitroolefins have the tendency to polymerize readily with alkali.
This preparation is referenced from:

References and Notes
  1. Chemical Research Institute of Non-Aqueous Solutions, Tohoku University, Sendai 980, Japan.
  2. Buckley, G. D.; Scaife, C. W. J. Chem. Soc. 1947, 1471–1472.
  3. Feuer, H.; Miller, R. J. Org. Chem. 1961, 26, 1348–1357.
  4. Blomquist, A. T.; Tapp, W. J.; Johnson, J. R. J. Am. Chem. Soc. 1945, 67, 1519–1524.
  5. Miyashita, M.; Kumazawa, T.; Yoshikoshi, A. J. Chem. Soc., Chem. Commun. 1978, 362–363.
  6. Melton, J.; McMurry, J. E. J. Org. Chem. 1975, 40, 2138–2139.
  7. Miyashita, M.; Yanami, T.; Yoshikoshi, A. J. Am. Chem. Soc. 1976, 98, 4679–4681.

Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)

formalin (50-00-0)

phthalic anhydride (85-44-9)

magnesium sulfate (7487-88-9)

nitroethane (79-24-3)

2-Nitropropene,
1-Propene, 2-nitro (4749-28-4)

2-nitro-1-propanol (2902-96-7)

2-nitro-1-propyl benzoate

1-nitro-1-propene

2-nitro-1-butene

2-nitro-2-butene