The performance of SAPO-18 and SAPO-34 catalysts has been compared during the conversion of ethylene or 1-butene to propylene. This comparison has been made in terms of activity (conversion), selectivity and stability against coke deposition. The SAPOs were synthesized, agglomerated, calcined, characterized and tested in a fixed-bed reactor at 500 °C. The spent catalysts (after 5 h on stream) were characterized to assign the location and nature of coke. The results point to the higher activity and stability of SAPO-18 catalyst in the conversions of each reactant (ethylene or 1-butene), which has been explained on the basis of its acidity, pore topology and above all, the faster diffusion of aromatics causing deactivation. Thus, the SAPO-18 catalyst suffers slower coke deposition, while this coke is of lighter nature (more aliphatic and less aromatic). The advantages of SAPO-18 over SAPO-34 catalyst are more relevant for the transformation of 1-butene, where the propylene selectivity and yield increase over time, as secondary reactions are selectively neglected and coke condensation is slowed down.

在乙烯或1-丁烯转化为丙烯的过程中，已经比较了SAPO-18和SAPO-34催化剂的性能。在活性（转化率），选择性和对焦炭沉积的稳定性方面进行了比较。SAPO在500°C的固定床反应器中合成，凝聚，煅烧，表征和测试。对废催化剂（运行5小时后）进行表征，以确定焦炭的位置和性质。结果表明，SAPO-18催化剂在每种反应物（乙烯或1-丁烯）的转化中具有更高的活性和稳定性，这已基于其酸度，孔拓扑以及最重要的是芳烃的更快扩散进行了解释。导致停用。因此，SAPO-18催化剂的焦炭沉积速度较慢，而这种焦炭的性质较轻（脂肪族较多，芳香族较少）。与SAPO-34催化剂相比，SAPO-18的优势与1-丁烯的转化更为相关，1-丙烯的选择性和收率随时间增加，这是因为选择性地忽略了次要反应，并且降低了焦炭冷凝的速度。