Org. Synth. 1953, 33, 41
DOI: 10.15227/orgsyn.033.0041
Submitted by Henry Feuer and Stanley M. Pier1.
Checked by William S. Johnson and Ernest F. Silversmith.
1. Procedure
In a 500-ml. round-bottomed flask fitted with a reflux condenser and a drying tube leading to a gas-absorption trap2 are placed 234 g. (1.1 mole) of phosphorus pentachloride (Note 1) and 65 g. (0.5 mole) of itaconic acid (Note 2). The reagents are mixed by shaking the flask; after a few minutes a vigorous reaction commences, resulting in partial liquefaction of the mixture and copious evolution of hydrogen chloride. When the initial reaction subsides, the mixture is gently heated to cause reflux of phosphorus oxychloride until all the solid dissolves; then heating is continued for an additional 15 minutes (Note 3). The reflux condenser is replaced by a 12-in. Vigreux column, and the phosphorus oxychloride is removed by distillation at reduced pressure provided by a water aspirator (Note 4), the major portion coming over at about 45°/85 mm. When all the phosphorus oxychloride has been removed, the pressure is reduced (vacuum pump) and the material boiling at 70–75°/2 mm. is collected. Liquid boiling in this range weighs 50–55 g., representing a yield of 60–66%. This material, nD20 1.4915, nD25 1.4900, is pure enough for most purposes, but it may be further refined by distillation through a packed column, yielding 47–53 g. of a water-white liquid, nD20 1.4919, boiling at 71–72°/2 mm.
2. Notes
1. The slight molar excess of phosphorus pentachloride has been found to increase the yield of product. It is best to use apparatus with ground-glass joints.
2. Chas. Pfizer and Company technical grade itaconic acid was employed without purification.3
3. Heating for a longer period results in a rather sudden change in color from pale yellow to deep orange or red, and a decrease in yield.
4. Considerable dissolved hydrogen chloride is liberated at this point and passes into the water aspirator. A mechanical vacuum pump should not be used at this stage because it would be damaged by corrosion.
3. Discussion
Itaconyl chloride has been prepared previously only by the reaction of itaconic anhydride with phosphorus pentachloride.4

References and Notes
  1. Purdue University, Lafayette, Indiana.
  2. Org. Syntheses Coll. Vol. 2, 4 (1943).
  3. Org. Syntheses Coll. Vol. 2, 369 (1943).
  4. Petri, Ber., 14, 1635 (1881).

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

hydrogen chloride (7647-01-0)

phosphorus pentachloride (10026-13-8)

Phosphorus Oxychloride (21295-50-1)

Itaconic anhydride (2170-03-8)

Itaconic acid (97-65-4)

Itaconyl chloride (1931-60-8)