Title: 1H, 31P NMR MAS, infrared and catalytic studies of heteropolyacid H3PW12O40 supported on MgF2
Abstract: 1H and 31P NMR MAS spectra of heteropolyacid H3PW12O40 (HPA) supported on high dispersed MgF2 suggest the change of the structure of HPA compared with crystal HPA due to interaction with the support. 1H NMR spectra at HPA content below 3 wt% do not reveal the 1H NMR line from protons attached to HPA. In the samples with HPA content larger than 3 wt% the 1H NMR line with δ ≈ 5 ppm was attributed to protons in isolated heteropolyanions bonded with support surface. At HPA contents larger than 20 wt% the crystals of HPA on MgF2 surface are formed; this follows from appearance in 1H NMR spectra of a line at δ = 9.3 ppm typical for crystalline HPA. 31P NMR and IR spectra suggest the destruction of HPA structure at low (less than 3 wt%) loading, and its preservation at larger HPA contents. The 19F NMR signals were found in methanol after dissolving of HPA supported on MgF2. Catalytic measurements show the drastic increase of activity of HPAMgF2 catalysts in reaction of isobutylene oligomerization on increase of HPA content.
Publication Year: 1995
Publication Date: 1995-01-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 35
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