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United States Patent 4495107

Process for producing alkali metal cyanates

EXAMPLE 1

During a one hour period a stirred mixture of urea (60 g, 1.0 mole) and sodium carbonate (63 g, 0.60 mole) in 1,2-dichlorbenzene (300 g) was heated to reflux. While the reaction mixture was heating, water vapor, ammonia and carbon dioxide evolved and were vented to the atmosphere. The reflux temperature, 177° C., was maintained for 2.6 hours, after which the heat was removed and the reaction mixture allowed to cool to room temperature. The cool mixture was filtered and the filter cake dried at 60° C. under reduced pressure for approximately two hours to yield sodium cyanate (74.51 g, 87.5% yield).

EXAMPLE 2

During a one hour period a stirred mixture of urea (60 g, 1.0 mole) and sodium carbonate (63 g, 0.60 mole) in 1,2-dichlorobenzene (300 g) is heated to reflux. While the reaction mixture is heating, water vapor, ammonia and carbon dioxide evolve and are vented to the atmosphere. Reflux is maintained for an additional two hourse, and approximately 30 ml of solvent is then distilled from the reaction mixture to remove any remaining water. Dimethyl sulfate (117 g, 0.928 mole) is added dropwise to the refluxing mixture over a one hour period. The methyl isocyanate (b.p. 40° C.) is collected by fractional distillation as it is produced.

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