PURPOSE: To provide the subject N-cyclohexylmaleimide causing no discoloration in its hot molten state, and effectively prevented from its thermal polymerization.
CONSTITUTION: The objective thermally stabilized N-cyclohexylmaleimide is obtained by incorporating (A) 100 pts.wt. of N-cyclohexylmaleimide with (B) 0.00001-0.0005 pts.wt. of CUCl2 and (C) 0.01-0.1 pts.wt. of N-cyclohexylmaleamic acid.