Fluorine-Promoted Catalysts

Enhanced Sulfur Tolerance of Bimetallic PtPd/Al2O3 Catalysts for Hydrogenation of Tetralin by Addition of Fluorine

“…As previously observed [14], the surface oxygen concentration decreased when F was present, as F partially replaced oxygen or hydroxyl groups on the alumina surface [16]. In agreement with the TPR result, the surface chlorine composition decreased as the metal chlorinated species decreased when F was added.…”

“…However, too much acidity could result in hydrogenation selectivity losses [3]. The incorporation of an electronegative atom, e.g., F, can be used to adjust the acidity of the catalyst support, i.e., alumina, as F replaces the surface hydroxyl group [16]. Several papers have reported the benefit of adding F to noble metal catalysts for different applications, e.g., oxidation [17], hydroisomerization [18], and hydrodechlorination [19].…”

FTIR Spectroscopy of Adsorbed Probe Molecules for Analyzing the Surface Properties of Supported Pt (Pd) Catalysts

“…Variation of the acid-base properties of alumina surface is commonly performed by chemical modifying via the introduction of additional anions (halogens, sulfates, phosphates) or cations (alkaline or alkaline earth metals) (Bocanegra et al, 2006;Ghosh & Kydd, 1985;Lisboa et al, 2005;López Cordero et al, 1989;Marceau et al, 1996;Requies et al, 2006;Rombi et al, 2003;Scokart et al, 1979;Wang et al, 1994). These methods complicate the process of catalyst synthesis and can lead to non-reproducible results.…”

Controlled fluorination of clays

“…Several authors have reported on the changes in structure and catalytic properties of montmorillonite after activation by solutions of HF, NaF, KF, NH 4 F, NH 4 HF 2 , (NH 4 ) 3 AlF 6 , (NH 4 ) 2 SiF 6 and CF 3 SO 3 H [13,[15][16][17][18][19][20]. In general, these investigators observed that activation results in an increase in the number of acid centers and, consequently, the application of the material to acid catalysis is facilitated.…”

“…It is known to modify surface acidity and subsequently the reactivity [3][4][5][7][8][9][10]12]. For example, fluorinated alumina is generally more reactive as a catalyst in acid-catalyzed hydrocarbon reactions than alumina itself [13] and fluorinated silica has a higher cumene cracking rate than non-fluorinated silica [14].…”