Abstract

The thermal treatment of dipropylamine template occluded within AlPO₄-11 was studied using sample controlled thermal analysis under a residual pressure of 5 × 10⁻³ mbar. Intermediate samples, treated to different temperatures, were studied using FTIR and nitrogen adsorption manometry at 77 K.

The thermal treatment occurs in four steps. The first step (25 °C to 140 °C) corresponds to the dehydration of the hydrated dipropylamine. The second (140 °C to 210 °C) and third (210 °C to 330 °C) steps correspond to the main loss of whole dipropylamine molecules without degradation. A temperature induced evaporation type process would explain such a phenomenon. The final step (330 °C to 470 °C) corresponds to the degradation of a very small amount of dipropylamine in strong interaction with the AlPO₄ framework. The microporosity only becomes available to nitrogen adsorption during this final step.