Imidazole → 1,1'-Carbonyldiimidazole

Participants

Reaction Conditions

Reaction Steps

286.0 g of imidazole were introduced into 1200 g of chlorobenzene in a flask fitted with water separator, and 320 g of 50% strength aqueous sodium hydroxide solution were added dropwise. Water was then separated out until the distillate no longer separated into two phases. After 224 ml of water had been separated out in this way, 100 ml of chlorobenzene were removed by distillation. 202 g of phosgene were subsequently passed in at 80-85° C. over the course of one hour. When the addition was complete, the mixture was stirred at 90° C. for a further 1 hour while a vigorous stream of nitrogen was passed through the flask, and the precipitate then present was filtered off at 80° C. and rinsed with 200 g of chlorobenzene at 90° C. The filtrate and the washing liquid were combined and cooled to 0° C. The precipitate which deposited was filtered off, rinsed with 200 g of dry chlorobenzene, and dried at 60° C. under reduced pressure (50 mbar). 290.6 g of carbonyldiimidazole were thus obtained in the form of colorless crystals having a purity of 97%. This corresponded to a yield of 88% of theory.

Provenance & Evidence