The catalytic decomposition of dichlorodifluoromethane(CFC 12) in the presence of water vapour has been carried out on WO 3/Al 2O 3 prepared by impregnating Al(OH) 3 with aqueous ammonium metatungstate followed by dry...The catalytic decomposition of dichlorodifluoromethane(CFC 12) in the presence of water vapour has been carried out on WO 3/Al 2O 3 prepared by impregnating Al(OH) 3 with aqueous ammonium metatungstate followed by drying and calcining at 700 ℃ in air. On WO 3/Al 2O 3 CFC 12 was decomposed completely at 305 ℃, while on simple Al 2O 3 it needed 370 ℃; WO 3 had only a poor activity. NH 3 TPD results showed that this enhancement in activity can be explained in terms of the great acidity of WO 3/Al 2O 3. No by product was detected during decomposition of CFC 12 on WO 3/Al 2O 3, but on unmodified Al 2O 3 CFC 13 was found to be amounted to 4%. The CFC 12 conversion over WO 3/Al 2O 3 at 295 ℃ decreased from 97% to 90% in first 8 h and then took a steady value.展开更多
A new propene production route from 1-butene metathesis has been developed on heterogeneous 10WO3/Al2O3-HY catalysts with different HY contents. It is found that the catalysts play bi-functionally first for the isomer...A new propene production route from 1-butene metathesis has been developed on heterogeneous 10WO3/Al2O3-HY catalysts with different HY contents. It is found that the catalysts play bi-functionally first for the isomerization of 1-butene to 2-butene and then for the cross-metathesis between 1-butene and 2-butene to propene and 2-pentene. The combination of HY zeolite and Al2O3 is prerequisite for the production of propene. The propene yield keeps increasing with the HY content in the range of 10-70 wt%, where 10WO3/Al2O3-70HY exhibits the highest propene yield. The MS-H2-TPR and MS-O2-TPO characterizations indicate that the increase of HY content in the catalysts weakens the interaction between W species and supports, whereas enhance the probability of coking on the metal species and acid sites.展开更多
文摘The catalytic decomposition of dichlorodifluoromethane(CFC 12) in the presence of water vapour has been carried out on WO 3/Al 2O 3 prepared by impregnating Al(OH) 3 with aqueous ammonium metatungstate followed by drying and calcining at 700 ℃ in air. On WO 3/Al 2O 3 CFC 12 was decomposed completely at 305 ℃, while on simple Al 2O 3 it needed 370 ℃; WO 3 had only a poor activity. NH 3 TPD results showed that this enhancement in activity can be explained in terms of the great acidity of WO 3/Al 2O 3. No by product was detected during decomposition of CFC 12 on WO 3/Al 2O 3, but on unmodified Al 2O 3 CFC 13 was found to be amounted to 4%. The CFC 12 conversion over WO 3/Al 2O 3 at 295 ℃ decreased from 97% to 90% in first 8 h and then took a steady value.
基金supported by the National Natural Science Foundation of China (No.20773120)National 973 Project of China (No.2005CB221403)
文摘A new propene production route from 1-butene metathesis has been developed on heterogeneous 10WO3/Al2O3-HY catalysts with different HY contents. It is found that the catalysts play bi-functionally first for the isomerization of 1-butene to 2-butene and then for the cross-metathesis between 1-butene and 2-butene to propene and 2-pentene. The combination of HY zeolite and Al2O3 is prerequisite for the production of propene. The propene yield keeps increasing with the HY content in the range of 10-70 wt%, where 10WO3/Al2O3-70HY exhibits the highest propene yield. The MS-H2-TPR and MS-O2-TPO characterizations indicate that the increase of HY content in the catalysts weakens the interaction between W species and supports, whereas enhance the probability of coking on the metal species and acid sites.
