Method for preparing 1,2-dibromo-2,4-dicyanobutane

A method for preparing 1,2-dibromo-2,4-dicyanobutane comprising the steps of:

• mixing 2-methyleneglutaronitrile with methanol to obtain a solution;
• gradually adding bromine to the solution by maintaining the solution temperature below 40° C. to obtain a homogenous reaction mixture;
• warming the homogeneous reaction mixture to about 50°-55° C.;
• gradually adding a 5% sodium bicarbonate solution to the reaction mixture to neutralize the reaction mixture to a pH of 6-7;
• adding water to the reaction mixture to saturate the reaction mixture for crystallization;
• cooling the reaction mixture to about 5° C. to obtain the product in the form of a cake;
• filtering the cake out of the reaction mixture;
• washing the cake with a pre-cooled methanol/water mixture;
• drying the cake in a vacuum oven at 25°-40° C. to obtain the 1,2-dibromo-2,4-dicyanobutane as colorless crystals.