| abstract |
The present invention relates to a novel ZSM-5 which provides crystals with a high average silica to alumina ratio at the edges of each microcrystal than at the center, as determined from a narrow slit line scan profile obtained from SEM / EDX or TEM / EDX elemental analysis . Such ZSM-5 crystals are obtained by a production process using L-tartaric acid. The new ZSM-5 configuration provides significantly reduced xylene losses in ethylbenzene dealkylation, especially when silica as the binder and at least one hydrogenation metal selected from platinum, tin, lead, silver, copper and nickel is bonded do. Additional advantages have been found when a combination with a small crystal size of ZSM-5 is used. |