Publication
Multiple-quantum 27Al MAS NMR spectroscopy of microporous AlPO-40 and SAPO-40
| dc.contributor.author | Rocha, J. | |
| dc.contributor.author | Lourenço, J. P. | |
| dc.contributor.author | Ribeiro, M. F. | |
| dc.contributor.author | Fernandez, C. | |
| dc.contributor.author | Amoureux, J. P. | |
| dc.date.accessioned | 2013-01-04T12:18:25Z | |
| dc.date.available | 2013-01-04T12:18:25Z | |
| dc.date.issued | 1997 | |
| dc.date.updated | 2013-01-03T10:16:42Z | |
| dc.description.abstract | Two-dimensional triple- and quintuple-quantum 27AI magic-angle spinning (MO MAS) n.m.r. spectra of microporous AIPO-40 and SAPOBO have been recorded at 9.4 and 14.1 T. The resolution of the 5Q spectra of AIPO-40 is amazing, at least 11 resonances being resolved. The 3lQ spectra further reveal the presence of 2 other much fainter peaks. Because the AIPO-40 aluminium sites have different quadrupole coupling constants the 9.4 T spectra are slightly better resolved than the 14.1 T spectra, suggesting that in MO n.m.r. it may sometimes be advantageous to work at lower magnetic fields. The 3Q spectra of SAPO-40 are poorly resolved displaying a main broad peak and two faint resonances. This is because the introduction of even a small amount of Si into the framework of AIPO-40 generates a distribution of Al sites and a dispersion of chemical shifts. MQ 27AI MAS n.m.r. together with 31P MAS n.m.r. evidence discard an orthorhombic, Pccn, and monoclinic, P172/n, structure for as-prepared or calcined dehydrated AIPO-40, suggesting a space group with even lower symmetry that proposed to date. | por |
| dc.identifier.citation | Rocha, J.; Lourenço, J. P.; Ribeiro, M. F.; Fernandez, C.; Amoureux, J. P. Multiple-quantum 27Al MAS NMR spectroscopy of microporous AlPO-40 and SAPO-40, Zeolites, 19, 156-160, 1997. | por |
| dc.identifier.other | AUT: JLO01215; | |
| dc.identifier.uri | http://hdl.handle.net/10400.1/2052 | |
| dc.language.iso | eng | por |
| dc.peerreviewed | yes | por |
| dc.publisher | Elsevier | por |
| dc.subject | Structure | por |
| dc.subject | Multiple-quantum 27Al MAS NMR | por |
| dc.subject | AlPO-40 | por |
| dc.subject | SAPO-40 | por |
| dc.title | Multiple-quantum 27Al MAS NMR spectroscopy of microporous AlPO-40 and SAPO-40 | por |
| dc.type | journal article | |
| dspace.entity.type | Publication | |
| oaire.citation.endPage | 160 | por |
| oaire.citation.startPage | 156 | por |
| oaire.citation.title | Zeolites | por |
| oaire.citation.volume | 19 | por |
| person.familyName | Lourenço | |
| person.givenName | João P. | |
| person.identifier | 634248 | |
| person.identifier.ciencia-id | F81F-A1F0-2A7C | |
| person.identifier.orcid | 0000-0002-0501-6672 | |
| person.identifier.rid | A-7758-2008 | |
| person.identifier.scopus-author-id | 57195730600 | |
| rcaap.rights | restrictedAccess | por |
| rcaap.type | article | por |
| relation.isAuthorOfPublication | f66ab886-d989-4c1d-9550-527507723c26 | |
| relation.isAuthorOfPublication.latestForDiscovery | f66ab886-d989-4c1d-9550-527507723c26 |