In this work, some commercial nanoporousbased catalysts, such as USY, beta and mordenite zeolites loaded with Platinum metal acting as bifunctional catalysts, were used for hydroisomerisation experiments in a fixedbed reactor at the atmospheric pressure and at feed space time 5.12 h -1 to hydroisomerise n-heptane over a temperature range of 210-270°C. The study aimed to evaluate the changes with time-on-stream in the catalytic activity, product selectivity and manner of deactivation of metalloaded zeolite catalysts, at constant contact time of 5.13 h -1 and a hydrogen-to-n-heptane molar ratio fixed at 9. Various analytical techniques were used to characterise fresh and aged catalysts. Results show that pore architecture is the most important factor affecting coke formation and deactivation in zeolite catalysts, and those catalysts with three-dimensional pore structures lacking cavities or cages were best able to resist deactivation. In addition, it was found that those catalysts with high Si/Al ratios and those which had been acid-leached or steamed showed better activity, higher selectivity towards isomeric products and better time stability. Moreover, the balance between the number of metal sites and the number of acid sites played an important role in determining the activity, selectivity and stability of the bifunctional catalysts.

The hydroconversion of n-heptane was studied on five USY zeolite samples loaded with 1 wt % Pt. Experiments were performed on a continuous fixed-bed stainless steel reactor at 210À310 °C and pressures up to 15 bar. Three in-house samples were subjected to steaming treatment, and the remaining were acid-leached from a commercial source. The study aimed to evaluate the effect of acid leaching, and its subsequent extraframework alumina (EFAL) species removal, on the performance of bifunctional USY zeolite catalysts during n-heptane transformation. Results have shown that steamed samples generate more cracked products at higher conversions when compared to acid-leached ones, more than likely due to a high presence of EFAL species. The degree of steaming played a role in decreasing cracking tendency at higher pressures, which is attributed to pore structure change and decreasing acidity. In addition, steaming resulted in a catalyst sample capable of generating isomers with blended research octane numbers close to those achieved with a robust commercial catalyst. However, poisoning experiments have shown that these two catalysts are highly sensitive to sulfur and require sulfur-free feeds in order to demonstrate their full capacities. ' EXPERIMENTAL SECTIONThe three in-house USY samples were generated as follows: a parent Y zeolite material with a sodium content of 1.05 wt % was steamed at 425 °C and then underwent a mild ion-exchange treatment with ammonium sulfate (1 M) at 70 °C for 30 min, resulting in a drop in sodium content to 0.24 wt %. The resulting sample was used to generate the three USY samples: first, by

In this work, some commercial and in-house nanoporous-based catalysts, such as USY, beta and mordenite zeolites, and mesoporous aluminosilicate molecular sieves such as MCM-48 and SBA-15, loaded with metals and acting as mono-and bimetallic bifunctional catalysts, were used for hydroisomerisation experiments in a fixedbed reactor at pressures between 1 and 15 bar and at feed space time ranging from 2.57 to 10.26 h-1 (35.14-140.6 kg s mol-1) to hydroisomerise n-heptane over a temperature range of 210-270°C. The effect of post-synthesis treatments of micro-and mesoporous catalysts was examined, regarding their activity, selectivity and stability, such as acid and steam dealumination techniques, acid leaching via a chelating agent, bimetal loading techniques, different platinum loading methods, and composite or hybrid catalyst generation. Results show that pore architecture is the most important factor affecting coke formation and deactivation in zeolite catalysts. It was found that those catalysts with high Si/Al ratios and those which had been acid-leached or steamed showed better activity, higher selectivity towards isomeric products and better time stability. Moreover, the balance between the number of metal sites and the number of acid sites played an important role in determining the activity, selectivity and stability of the bifunctional catalysts. Higher metal loading improves catalytic stability, due to a better balance and closeness of the catalytic functions. Moreover, the bimetallic catalyst improves the formation of smaller metal particles and better dispersion, which may affect selectivity and stability.