AlPO4-31 derivatives doped with various metals: effects on crystal symmetry and thermal stability

Finger, G. G.; Kornatowski, J.; Jancke, K.; Matschat, Ralf; Baur, W. H.

doi:10.1016/s1387-1811(99)00130-4

Cited by 23 publications

(26 citation statements)

References 23 publications

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“…Phosphorus substitution was later confirmed using several characterization methods [4][5][6][7] and was supported by several catalytic reactions such as hydrocarbon transformations [8][9][10][11][12]. Suggestions for the incorporation of other metals into the AlPO 4 -31 framework can be found in three publications for TAPO-31 [13], ZnAPO-31 [3] and MgAPO-31 [3,14], and catalytic applications are reported for TAPO-31 [15], VAPO-31 [16], MnAPO-31 [8,17], NiAPO-31 [17], ZnAPO-31 [17] and FeAPO-31 [18]. However, no literature reports could be found providing direct evidence for the isomorphous substitution of framework aluminum in AlPO 4 -31 by cobalt or manganese.…”

Section: Introductionmentioning

confidence: 95%

“…The rhombohedral symmetry was also determined for the as-synthesized SAPO-31 [2]. Recently [3], a powder X-ray diffraction pattern, without structure refinement, of as-synthesized AlPO 4 After the incorporation of a small amount of metal (Zn, Mg) into the AlPO 4 -31 framework, the symmetry changed to rhombohedral [3]. This suggests that substitution of framework elements by metals may have occurred.…”

Section: Introductionmentioning

confidence: 99%

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Framework cobalt and manganese in MeAPO-31 (Me=Co, Mn) molecular sieves

Tušar

Mali

Arčon

et al. 2002

Microporous and Mesoporous Materials

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Pure phases of CoAPO-31 and MnAPO-31 were synthesized hydrothermally using di-n-propylamine as a structuredirecting agent. The incorporation of manganese(II) and cobalt(II) into framework aluminum sites of AlPO 4 -31 was suggested from elemental, thermogravimetric and X-ray powder diffraction analysis. Isomorphous aluminum substitution with cobalt(II) was confirmed from static 31 P NMR spectra. UV-VIS and XANES spectra revealed a partial oxidation of framework cobalt(II) and manganese(II) into cobalt(III) and manganese(III) in the calcined MeAPO-31 and thus the presence of redox centers in the products. The generation of acid sites (Brønsted and Lewis) in MeAPO-31 was supported by IR measurements of pyridine and by ammonium adsorption/desorption. The strength of the acid sites in the catalysts studied decreased in the following order: MnAPO-31 > CoAPO-31 > AlPO 4 -31.

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Section: Introductionmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Framework cobalt and manganese in MeAPO-31 (Me=Co, Mn) molecular sieves

Tušar

Mali

Arčon

et al. 2002

Microporous and Mesoporous Materials

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“…In this sense, the modification of AlPO s framework with transition metal (Fe, Co, Ni, Cu and so on) can lead to the elaboration of novel materials with enhanced acidic and/or redox properties . AlPO 4 –5 is a typical aluminophosphate molecular sieve with 3D structure with hexagonal symmetry . Yoshihiro Sugi and Ajayan Vinu et al reported the isopropylation of biphenyl to 4,4´‐DIPB with Co(5)APO‐5 and Ni(5)APO‐5 as catalysts, giving the high selectivity to 4,4´‐DIPB of 65–75%.…”

Section: Introductionmentioning

confidence: 99%

Research on the direct amination of benzene to aniline by NiAlPO₄–5 catalyst

Wang

Yang

Zhang

2019

Applied Organom Chemis

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A series of NiAlPO4–5 molecular sieves have been hydrothermally synthesized and shown high and stable activity in the direct amination of benzene to aniline with hydroxylamine hydrochloride as aminating agent. The as‐synthesized and calcined samples were investigated with XRD, SEM, TG, BET, NH3‐TPD and FT‐IR to explore the crystalline, coordination and location of the incorporated transition metal ions. The results indicated that nickel ions were incorporated into the framework of AlPO4–5 and the as‐synthesized catalysts were highly crystalline, and possessed good thermal stability. Among them, Ni(0.3)AlPO4–5 showed the highest catalytic activity for the direct amination of benzene with the highest aniline yield of 73.2% and 100.0% selectivity to aniline. After the catalyst was reused for 5 times, the activity remained little change.

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“…To our knowledge, no work has been devoted to the influence/effect of very low amounts of heteroatoms, although such materials promise an advantage of more perfect or/and complete incorporation of the metals into framework positions. In previous work, we described the synthesis of MeAPO-31 molecular sieves (ATO structure type) containing trace amounts of Zn, Mg, Mn, Co, Cr, Cd, and Cu as dopants in the structure (one Me heteroatom for up to over 100 unit cells (uc's)). The materials were mainly characterized using X-ray diffraction (XRD) methods to determine the influence of the dopants on the structure symmetry of the crystals and their thermal stability …”

Section: Introductionmentioning

confidence: 99%

Thermoanalytic Studies on Template Removal from MeAPO-31 Doped with Various Metals

2002

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Removal of the template from MeAPO-31 samples doped with trace amounts of Cu, Cd, Cr, Co, Mn, Mg, and Zn (1 Me heteroatom per 5−115 unit cells) was investigated with thermal analysis methods. The findings were contrasted/compared with mass spectroscopy results. The main factor controlling the material properties is the content of heterocenters and not their chemical identity. The position of the high-temperature differential thermogravimetric peak and the intensity ratio between the high- and low-temperature peaks depend linearly on the content of heteroatoms. Both peaks correspond to thermal degradation and not to a simple release of the template molecules. The low-temperature peak comprises desorption of water to a considerable extent. The linear shift of the position of the high-temperature peak with the metal content reflects a composed phenomenon including a number of (thermo)chemical processes and setting free the species formed during decomposition of the template. This release is significantly hindered by the framework heterocenters. In general, the removal of template is a process controlled by the mobility of the exiting species, and it depends primarily on the content of the heterocenters. The crystal dimensions and the calcination atmosphere also have a significant influence.

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AlPO4-31 derivatives doped with various metals: effects on crystal symmetry and thermal stability

Cited by 23 publications

References 23 publications

Framework cobalt and manganese in MeAPO-31 (Me=Co, Mn) molecular sieves

Framework cobalt and manganese in MeAPO-31 (Me=Co, Mn) molecular sieves

Research on the direct amination of benzene to aniline by NiAlPO₄–5 catalyst

Thermoanalytic Studies on Template Removal from MeAPO-31 Doped with Various Metals

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AlPO4-31 derivatives doped with various metals: effects on crystal symmetry and thermal stability

Cited by 23 publications

References 23 publications

Framework cobalt and manganese in MeAPO-31 (Me=Co, Mn) molecular sieves

Framework cobalt and manganese in MeAPO-31 (Me=Co, Mn) molecular sieves

Research on the direct amination of benzene to aniline by NiAlPO4–5 catalyst

Thermoanalytic Studies on Template Removal from MeAPO-31 Doped with Various Metals

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Product

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Research on the direct amination of benzene to aniline by NiAlPO₄–5 catalyst