Abstract
The formation of the Re2O7Al2O3 catalyst surface in conditions of precatalysis has been investigated by means of various physical and chemical methods. It is suggested that under oxidative conditions a surface aluminum mesoperrhenate, “AlReVIIO5” is obtained. The same structure is formed finally, irrespective of the amount of rhenium deposited, as well as its valence state, combination (oxides, salts), the alumina carrier structure (γ, θ, nonporous) and phase (solid mixture or solution) of the starting materials. The structure is thermal and moisture stable, and is characterized by diffuse reflectance spectra with bands at 235 and 340 nm and a shoulder at 395 nm. It is not readily transformed into metallic rhenium. After reduction the structure can be completely restored under oxidative conditions only. On heating dried samples in an inert gas atmosphere or in vacuo, low-valence Re(VI) and Re(IV) coexist with Re(VII) on the surface. This is also observed under vacuum treatment of the calcined samples. The formation of a surface mesoperrhenate structure is detected on other carriers as well.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
