Refining method of 2,2'-bipyridine

The invention provides a refining method of 2,2'-bipyridyl. The refining method comprises the following steps: (1) adding a 2,2'-bipyridyl reaction solution to a batch rectification column, and evaporating in the rectification column to obtain pyridine first; (2) adjusting the temperature of the top of a primary rectification column to 305 DEG C and the temperature of the bottom of the primary rectification column to 282 DEG C, starting rectification, and when the top pressure of the primary rectification column is 132.0 Pa-1350 Pa, adjusting the reflux ratio to (7:1) to (11:1); (3) condensingrectification gas at the top of the primary rectification column into liquid through a reflux tank at the top of the primary rectification column, and when the rectification gas enters a secondary rectification column, adjusting the temperature at the top of the secondary rectification column to 282 DEG C and the temperature at the bottom of the secondary rectification column to 272 DEG C; (4) condensing the rectificatio