Hydroconversion of n ‐heptane on platinum/H‐Mordenite catalysts prepared via different routes

Two Pt/H‐mordenite catalysts were prepared via different routes: (a) by impregnating H 2 PtCl 6 in H‐mordenite (HM) (catalyst 1) and (b) in NH 4 HM (catalyst II), followed by drying, calcination and reduction. Catalyst I was found (i) to be more active for n‐heptane hydroconversion, (ii) to be more selective for its isomerisation, (iii) to encounter more diffusion limitation as it yields a larger Thiele modulus, (iv) to give a lower effectiveness factor and (v) to give lower activation energy, E a , values than catalyst II. A study of the pressure effect between 1·5 and 5·5 MNm −2 showed an increase of the catalytic activities to a maximum at 3·0 MNm −2 , followed by a decrease. A compensation effect plot gave a linear relationship between In A (pre‐exponential factor in the Arrhenius equation) and E a at various pressures for n‐heptane hydroconversion and its hydrocracking. High selectivities for central hydrocracking of heptane components and high iso‐butane to n‐butane ratios were obtained on both catalysts.