Two model coals, one containing pyrrolic nitrogen and another containing pyridinic nitrogen, have been used to study N-2 formation from different nitrogen structures during coal pyrolysis. The formation of N-2 during pyrolysis of the model coals with and without a catalyst has been investigated in a fixed-bed reactor at 2.5-10degreesC/min up to 1000degreesC. The pyrolysis results show that calcium and iron catalyze both pyrrolic and pyridinic nitrogen in model coals to N-2. Calcium-catalyzed N-2 formation occurs at temperatures higher than 800degreesC however, the iron catalyzes N-2 formation at temperatures below 800degreesC. The remarkable formation of N-2 results in low residual nitrogen in char. It is suggested that the calcium and iron catalysts catalyze N-2 formation mainly through solid-phase reactions of pyrrolic and pyridinic nitrogen forms in char.