A catalyst includes a cyclic imide compound having an N-substituted cyclic imide skeleton represented by following Formula (I): ##STR00001## wherein X is an oxygen atom or a hydroxyl group, and having a solubility parameter of less than or equal to 26 [(MPa).sup.1/2] as determined by Fedors method. The catalyst may further comprise a metallic compound. By allowing (A) a compound capable of forming a radical to react with (B) a radical scavenging compound in the presence of the catalyst, an addition or substitution reaction product between the compound (A) and the compound (B) or a derivative thereof can be obtained.
This application is a Divisional of application Ser. No. 10/092,554 filed on Mar. 8, 2002, now U.S. Pat. No. 6,998,491 B2, and for which priority is claimed under 35 U.S.C. .sctn. 120; and this application claims priority of Application No. 2001-067633 filed in Japan on Mar. 9, 2001 under 35 U.S.C. .sctn. 119; the entire contents of all are hereby incorporated by reference.
