Influence of MgO Physically Mixed with Tungsten Oxide Supported Silica Catalyst on Coke Formation

The effect of additional magnesium oxide (MgO) was investigated by using the tungsten oxide supported on silica catalyst (WOx/SiO2) physically mixed with MgO in a weight ratio 1:1. The both fresh and spent catalysts were characterized by FT-Raman spectrometer, UV-Vis spectrometer, X-Ray diffraction (XRD) and temperature programmed oxidation (TPO). The results indicated that the additional MgO could enhance the conversion of trans-2-butene due to isomerization reaction. However, adding MgO would increase the amount of coke deposit on the WOx/SiO2 catalyst. The TPO profile presented two peaks when the WOx/SiO2 catalyst was physically mixed with MgO. The further peak was suggested that came from coke precursor could be produced by isomerization reaction of undesired product. Then, the occurred coke precursor could deposit and form coke on the acid catalyst. Keywords—Coke formation, metathesis, magnesium oxide, physically mix.