Ion-molecule reactions of disbstituted benzene with ion system of acetone and deuterium-labelled acetone under chemical ionization conditions were examined and the fragmentation reactions of the adduct ions formed by the ion-molecule reactions were studied using collision- induced dissociation (CID) technique. It was found that the electron- releasing groups favored the adduct eactions, whereas the electron- withdrawing groups did not. The position and properties of substituted groups affected the relative abundance of the adduct ions. The fragmentation reaction of the adduct ion formed by ortho- phenylenediamine with acetyl ion was simlar to the reductive alkylation reaction of amine in condensed phase.

Key words: BENZENE P, ACETONE, FRAGMENTAION REACTION