The formation of the anilinium ion from the ammonium ion in the ammonia chemical ionization of substituted benzenes

Compounds C 6 H 5 X(X F, Cl, Br, NO 2 , CN, OCH 3 ) have been studied under chemical ionization conditions with ammonia as reagent gas. A pulsed electron beam and time resolved ion collection has allowed the determination of the reaction leading to the formation of [C 6 H 5 NH 3 ] + ( m / z 94). [NH 4 ] + reacts with C 6 H 5 X(X F, Cl, Br) to yield m / z 94 but C 6 H 5 X (X CN, NO 2 ) forms this ion only by reactions involving either [NH 3 ] + or [C 6 H 5 X] + . C 6 H 5 OCH 3 does not form m / z 94.