SYNTHESIS AND CHARACTERIZATION OF CHROMIUM SILICALITE

dc.creatorMAMBRIM, JST
dc.creatorPASTORE, HO
dc.creatorDAVANZO, CU
dc.creatorVICHI, EJS
dc.creatorNAKAMURA, O
dc.creatorVARGAS, H
dc.date1993
dc.dateFEB
dc.date2014-12-16T11:33:40Z
dc.date2015-11-26T17:00:02Z
dc.date2014-12-16T11:33:40Z
dc.date2015-11-26T17:00:02Z
dc.date.accessioned2018-03-28T23:47:48Z
dc.date.available2018-03-28T23:47:48Z
dc.identifierChemistry Of Materials. Amer Chemical Soc, v. 5, n. 2, n. 166, n. 173, 1993.
dc.identifier0897-4756
dc.identifierWOS:A1993KN06300004
dc.identifier10.1021/cm00026a004
dc.identifierhttp://www.repositorio.unicamp.br/jspui/handle/REPOSIP/74035
dc.identifierhttp://www.repositorio.unicamp.br/handle/REPOSIP/74035
dc.identifierhttp://repositorio.unicamp.br/jspui/handle/REPOSIP/74035
dc.identifier.urihttp://repositorioslatinoamericanos.uchile.cl/handle/2250/1278367
dc.descriptionInfrared spectroscopy (mid-IR), Si-29 and Al-27 magic angle spinning nuclear magnetic resonance (MAS-NMR), powder X-ray diffraction (PXRD), electron paramagnetic resonance (EPR), and photoacoustic spectroscopy (PAS), in combination, have produced useful information about a series of crystalline MFI-type chromium silicalite, synthesized in a fluoride medium. Aluminum is an impurity and occupies framework sites, as evaluated by the Al-27 MAS-NMR. The mid-IR spectra are very similar to the zeolite ZSM-5 with the addition of a weak band at congruent-to 680 cm-1, which we tentatively assign to symmetric stretching of (Cr-O-Si)n groups. The samples are crystalline materials and have expanded unit cells, as PXRD measurements pointed out. The as-synthesized sample shows a distribution of Cr sites, detected by EPR, comprising structure and channel occlusion sites; the nonstructural sites being extensively oxidized to Cr(VI) species after calcination in the presence of dioxygen. The changes in the photoacoustically measured physical properties, such as nonradiative relaxation time, the thermal diffusivity and optical absorption coefficient of both calcined and noncalcined chromium silicalite samples are also reported.
dc.description5
dc.description2
dc.description166
dc.description173
dc.languageen
dc.publisherAmer Chemical Soc
dc.publisherWashington
dc.relationChemistry Of Materials
dc.relationChem. Mat.
dc.rightsfechado
dc.sourceWeb of Science
dc.subjectThermal-diffusivity
dc.subjectZeolite Catalysts
dc.subjectPhotoacoustic-spectroscopy
dc.subjectZsm-5-type Ferrisilicates
dc.subjectO-compounds
dc.subjectMethanol
dc.subjectConversion
dc.subjectSolids
dc.subjectHydrocarbons
dc.subjectSubstitution
dc.titleSYNTHESIS AND CHARACTERIZATION OF CHROMIUM SILICALITE
dc.typeArtículos de revistas


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