SORPTION AND MAGNETIC SUSCEPTIBILITY STUDIES ON NITRIC OXIDE-ALUMINA GEL SYSTEMS AT SEVERAL TEMPERATURES

Sorptions of nitric oxide by alumina gel were determined at 181, 192, 207 and 273 degrees K. Magnetic susceptibility of the sorbed nitric oxide was followed by a movable magnet. A rapid physical adsorption of the nitric oxide was in each case followed by a slow chemisorption. This was definitely shown by the magnetic studies, for the susceptibility rose rapidly during the physical adsorption and then remained almost constant or fell slightly during the long period of chemisorption. Desorption of the physically sorbed nitric oxide causes the magnetic suscentibility to fall to the starting point. The slow desorption of the chemisorbed gas produces no further change in the susceptibility of the system. Here is a system exhibiting both physical and chemisorption under the same conditions. Further, the rate of chemisorption was found to be faster at lower temperatures, indicating a negative energy of activation if calculated in the usual manner. The data indicate that the transmission coefficient for the chemisorption is very low.