Chromia zinc-doped

The drop-in replacement selected for the most widely used CFC refrigerant, CCljFj, was 1,1,1,2-tetrafluoroethane, CHjFCFj (Figure 7.2). One of the routes to this compound used the existing technology for the fluorinated chromia-catalyzed route to CCljFCFj followed by a hydrodechlorination step the other used a new zinc-doped chromia catalyst precursor in a two-step process to convert CHQ=CCl2 to CH2FCF3 directly [16]. The doped chromia developed is described later in this chapter. 

The use of a fluorinated zinc-doped chromia catalyst for a large-scale synthesis of CH2FCF3 [28], referred to above, was undoubtedly a factor in generating widespread interest for studying the behavior of doped chromia and supported chromia in the fluorination of... 

XPS and TEM measurements indicate that after fluorination, zinc and nickel, on the surface of these catalysts is present as ZnF2 or NiF2, respectively and these findings support the idea that the Zn(II) and Ni(II) species on doped fluorinated chromias do not become integrated into the surface structure but are, in fact, distinct phases on the surface. 

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