Ammoxidation is a process for producing carbocyclic nitriles or heterocyclic nitriles by reacting a carbocyclic or heterocyclic compound having organic substituent(s), with ammonia and an oxygen-containing gas. Examples of the carbocyclic compounds having organic substituent(s) which are used as a raw material in the present invention, include those compounds having a carbon ring such as benzene, naphthalene, anthracene, cyclohexene, cyclohexane, dihydronaphthalene, tetralin and decalin, and containing as side chains, organic substituent(s) bonded to the carbon ring such as methyl, ethyl, propyl, formyl, acetyl, hydroxymethyl, methoxycarbonyl and alkoxyl. The carbocyclic compounds may further contain inorganic substituent(s) such as halogen, hydroxyl, amino and nitro. Specific examples of the carbocyclic compounds having organic substituent(s) include toluene, xylene, trimethyl benzene, ethyl benzene, methyl naphthalene, dimethyl naphthalene, methyl tetralin, dimethyl tetralin, chlorotoluene, dichlorotoluene, methyl amyrin, cresol and methyl anisole.

Inorganic substituent(s): halogen(-X), hydroxy(-OH), amino(-NH2), nitro(-NO2)[0025] Examples of the heterocyclic compounds having organic substituent(s) which are used as a raw material in the present invention, include those compounds having a hetero ring such as furan, pyrrole, indole, thiophene, pyrazole, imidazole, oxazole, pyran, pyridine, quinoline, isoquinoline, pyrroline, pyrrolidine, imidozoline, imidazoline, piperidine and piperazine, and containing the above organic substituent(s) bonded to the hetero ring. The heterocyclic compounds may also contain as side chains, the same inorganic substituent(s) as described with respect to the above carbocyclic compounds. Specific examples of the heterocyclic compounds having organic substituent(s) include furfural, 2-methyl thiophene, 3-methyl thiophene, 2-formyl thiophene, 4-methyl thiazole, methyl pyridine, dimethyl pyridine, trimethyl pyridine, methyl quinoline, methyl pyrazine, dimethyl pyrazine, methyl piperazine or the like.