Effect of oxygen concentration on Catalyst deactivation rate in vapor phase Beckmann rearrangement over acid catalysts

摘要

The addition of a small amount of oxygen (up to 1000 ppm) in helium was effective toimprove the catalytic activity in vapor phase Beckmann rearrangement over the high silicaHZSM-5 modified with the precious metals. At the same time, the catalyst life of the zeoliteincreased using oxygen as the diluent gas. However, oxygen exceed 1.0 % was responsible toaccelerate the dehydrogenation from the coke precursor. The combination of oxygen as thediluent gas and methanol as the diluent solvent was effective to prolong the catalyst life of theacid catalysts including an amorphous SiO_2-Al_2O_3, HZSM-5 type zeolite and porous silicaglass.