Showing papers by "John B. Moffat published in 2002"
TL;DR: In this article, the effect of the nature of the cation on the surface and catalytic properties of calcium, strontium, barium and lead hydroxyapatites and dicationic analogs containing lead and stontium or barium has been studied with methanol and deuterated methanoline.
Abstract: The effect of the nature of the cation on the surface and catalytic properties of calcium, strontium, barium and lead hydroxyapatites and dicationic analogs containing lead and strontium or barium has been studied with methanol and deuterated methanol. XRD, XPS and 31P MAS NMR have been used to characterize the samples, and temperature programmed desorption of deuterated methanol has been employed to provide ancillary information. The dehydration/dehydrogenation of methanol is found to depend strongly on the nature of the divalent cation and is related to the binding strengths of methanol on the hydroxyapatites.
13 citations
TL;DR: In this paper, the selectivities of isobutane and 12-molybdophosphoric acid were studied for various loadings, reaction temperatures, contact times and times on-stream.
Abstract: The conversion of isobutane and the selectivities to products are studied on silica-supported 12-tungstophosphoric acid (H 3 PW 12 O 40 , abbreviated as HPW) and 12-molybdophosphoric acid (H 3 PMo 12 O 40 , abbreviated as HPMo) for various loadings, reaction temperatures, contact times and times-on-stream. The conversions and selectivity patterns are markedly dissimilar for the two acids with carbenium ion and hydride transfer processes catalyzed on the former at temperatures as low as 200 °C but not on the latter, a reflection of the stronger acidic sites on the tungsten-containing acid than on 12-molybdophosphoric acid.
7 citations