A report has been received that a sample of ethyl azodicarboxylate [Org. Syntheses, 28, 59 (1948); Coll. Vol. 3, 375 (1955)] decomposed upon attempted distillation with sufficient violence to shatter the distillation apparatus.It is possible that the explosion may have been due to overchlorination or to insufficient washing of the product with sodium bicarbonate solution. It is recommended that ethyl azodicarboxylate be distilled only behind a safety shield, and protected from direct sources of light.

Additional precautions on the handling of ethyl azodicarboxylate may be found in the most recent procedure published for its preparation in this series.¹