V. V. Brei

Superacids Based on Zirconium Dioxide

The synthesis of the superacidic materials SO42−/ZrO2 and WO3/ZrO2 is examined. The structure of their acidic centers and their activity in the isomerization and acylation of hydrocarbons are discussed.

Correlation between the Hammett Acid Constants of Oxides and Their Activity in the Dealkylation of Cumene

On the basis of the TPR spectrum of cumene adsorbed on oxide catalysts, the temperature dependence of the maximum rate (Tm) of formation of benzene on the Hammett acidity of the samples has been found to be expressed by the equation H0 = 21.47 − 13.88·103/Tm. From this relationship it is possible to estimate the value of H0 of acid catalysts with a precision of ±1.3 in the range +5 < H0 < −16. The interrelation between the strength of the acid centers of the oxides in terms of H0 and the rate constants of the heterogeneous catalytic reactions occurring with proton transfer is considered.

Effect of crystallinity in HZSM-5-amorphous alumosilica systems on their catalytic properties in the synthesis of dimethoxymethane

Granulated catalysts with 3–5% H-ZSM-5 phase were obtained from a highly dispersed alumosilica and were used for the synthesis of dimethoxymethane (DMM) from methanol and formaldehyde. The activity of these catalysts is greater than the activity of pure zeolite. A linear correlation was found between the yield of DMM and the content of Brönsted acid sites in the catalysts.