Imidazole → 1,1'-Carbonyldiimidazole

Participants

Reaction Conditions

Reaction Steps

286.0 g of imidazole were introduced into 1400 g of chlorobenzene in a flask fitted with column and distillation bridge. 720 g of 30% strength methanolic sodium methoxide solution were added dropwise. First methanol was removed by distillation, followed by 300 ml of chlorobenzene. 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 at 20° C. and dried at 60° C. under reduced pressure (50 mbar). 278.3 g of carbonyldiimidazole were thus obtained in the form of colorless crystals and having a purity of 97.8%. This corresponded to a yield of 84.0% of theory.

Provenance & Evidence