A molybdenum-95 solid-state NMR study of hydrodesulfurization catalysts. 1. Formation of fresh HDS catalyst precursors by adsorption of polyoxomolybdates onto .gamma.-alumina

Quadrupole Coupling and Anisotropic Shielding from Single-Crystal NMR of the Central Transition for Quadrupolar Nuclei.87Rb NMR of RbClO4and Rb2SO4

“…The present work demonstrates that, for half-integer quadpowders have shown that the magnitudes of the two tensorial rupolar nuclei, the quadrupole-coupling and CSA tensors interactions as well as their relative orientation may be obmay conveniently be determined from single-crystal NMR tained from the lineshape of the central transition (1)(2)(3) or of the central transition for very small CSAs. 87 Rb (I Å 3 2 ) from a spectrum of all transitions (4).…”

“…3 for RbClO 4 tions of the two Hamiltonians in Eq. [1]), using the optiand in Fig. 4 for Rb 2 SO 4 .…”

“…Q and Single-crystal 87 Rb NMR experiments were performed at first-order CSA term H H U (1) s need to be considered (7). In the 130.9 MHz (9.4 T) on a Varian UNITY-400 spectrometer secular approximation, the CSA term takes the form (19) using a homebuilt single-crystal NMR probe recently designed and described elsewhere (15).…”

Evidence of a phase transition of RbHCO3 from high‐resolution solid‐state 13C and 87Rb NMR by comparison with KHCO3

“…We used a double pass in order to dry the air after the air dryer furnished by the normal MAS installation. The freezing time ¾3 h and the long proton relaxation time limited the number of scans collected to [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32].…”

Hydroraffinationskatalysatoren in der Erdölverarbeitung – Stand und Perspektiven

“…[24]. 95 Mo-NMRUntersuchungen adsorbierter Species bestäti-gen diese Annahme [25]. Bei der Imprägnie-rung muss der pH-Wert der Tränklösung unterhalb des isoelektrischen Punktes des Trä-gers liegen (3 bis 6 für Al 2 O 3 und < 2 für SiO 2 ) [26].…”