Description:
ZSM-5 zeolite properties
Thermal stability
High thermal stability of ZSM-5 zeolite. This is caused by a skeleton in a stable five-membered ring structure and a high silica to alumina ratio. For example, the sample calcined at 850 ℃ After 2 hours, the crystal structure unchanged. Even can withstand high temperature of 1100 ℃. So far, ZSM-5 zeolites are known to one of the highest qualitative hot temperature. Therefore, it is used in high-temperature process is particularly suitable. For example, use it as a hydrocarbon cracking catalyst, regeneration of the catalyst can withstand passage of time.
Acid resistance
ZSM-5 zeolite has good acid resistance, it is resistant to various acids except hydrofluoric acid.
Steam stability
Wang, IKai other studies have shown that when other zeolites by steam and hot water, and their general structure is destroyed, leading to irreversible deactivation. The Mobil company with ZSM-5 as the conversion of methanol (water is one of the major product) catalyst. This suggests that ZSM-5 to water vapor with good stability. 540 ℃ lower partial pressure of 22mmHg steaming column and HY zeolite HZSM-5 after 24 hours, a crystallinity of HZSM-5 and about 70 percent of fresh catalyst, but under the same conditions, HY zeolite skeleton almost completely damage.
Hydrophobic
ZSM-5 having a high silica to alumina ratio, the smaller the surface charge density. The water molecule is polar, so you will not ZSM-5 is adsorbed. Although water molecules smaller than the diameter of n-hexane, but the amount of adsorption of n-hexane ZSM-5 is generally greater than water.
