METHOD FOR PURIFYING HYDROGEN CYANIDE Russian patent published in 2023 - IPC C01C3/02 C07C253/08 C07C319/20 C07C319/22 C07C323/23 B01D3/00 

FIELD: chemical industry.

SUBSTANCE: method for purifying hydrogen cyanide includes dividing a liquid feed stream 1 containing hydrogen cyanide into at least a first liquid stream 2 and a second liquid stream 3. The first liquid stream 2 at temperature T1 is introduced into the distillation column 4 at a point between the top and bottom of the distillation column. The second liquid stream 3 at temperature T2 is introduced into the distillation column 4 in its upper part. The temperature T2 of the second liquid stream 3 is lower than the temperature T1 of the first liquid stream 2. The distillation column is operated at a temperature of at least 30°C at the top of the distillation column 4. The mass flow ratio of the first liquid stream 2 and the second liquid stream 3 is in the range from 95:5 to 50:50. From the distillation column 4, an upper vapour stream 5 enriched in hydrogen cyanide and a lower stream 6 depleted in hydrogen cyanide are recovered. Also proposed is a method for obtaining 2-hydroxy-4-methylthiobutyronitrile using purified hydrogen cyanide.

EFFECT: inventions make it possible to prevent the accumulation of by-products, such as acetonitrile and acrylonitrile, in the distillation column, and to reduce energy consumption during its operation.

13 cl, 5 dwg, 3 tbl, 2 ex