2004 年 83 巻 12 号 p. 1045-1052
Influences of external surface and total areas of some H-mordenites (HM) were examined to elucidate the role of external acid sites in the isopropylation of biphenyl (BP).
The several types of HM (SiO2/Al2O3 ratio: 12-19; BET surface area 480-500 m2/g; external surface area: 0.1-25m2/g) were obtained commercially or synthesized by the methods referred to the literature for ZSM-5 and other zeolites. The selectivity for 4, 4'-diisopropylbiphenyl (4, 4'-DIPB) was almost constant for all HMs in the isopropylation; however, the catalytic activity was varied by samples.
H-Mordenites with different particle size HM [a] (average particle size 2μm; SiO2/Al2O3=18.7; external surface area: 17m2/g) and HM [b] (average particle size 1μm; SiO2/Al2O3=15.7; external surface area: 25m2/g) were dealuminated by the combination of steam treatment at 600°C and acid leaching at 80°C. The selectiv-ity for 4, 4'-DIPB was in the similar level for both series of HMs in the range of SiO2/Al2O3 ratio from 20 to 400. However, the catalytic activity was varied with the ratio.
These results from two types of HMs show that selective formation of 4, 4'-DIPB occurred inside the pores of HMs, that the external acid sites did not play an important role on the shape-selectivity, and that catalytic activities for the isopropylation were influenced by external surface area.
