Preparation of carbon molecular sieves by pyrolytic carbon deposition

The effect of different preparation parameters (pyrolysis temperature, process time, benzene concentration and residence time) on the properties of carbon molecular sieves obtained by pyrolytic carbon deposition from benzene on a microporous activated carbon, has been studied. For a fixed process time of 2 h, the increase of the pyrolysis temperature from 525 to 700 degrees C produced a strong increase of the CO2/CH4 selectivity, reaching a maximum value of 13 for pyrolysis at 700 degrees C. Selectivity also increased with process time (up to 5 h, with the pyrolysis temperature fixed at 650 and 675 degrees C), yielding values as high as 28. The obtained results have allowed to find the optimal preparation parameters for the preparation of CMS with high selectivity.