Formation of crystalline titanium(IV) phosphates from titanium(III) Solutions

Bortun, Anatoly I.; Jaimez, Enrique; Llavona, Ricardo; García, Javier Avilés; Rodrı́guez, Julio

doi:10.1016/0025-5408(95)00019-4

Cited by 54 publications

(38 citation statements)

References 16 publications

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“…Both materials maintain Ti(III) for very long time, especially the phosphate-based one as the gallophosphate slows down but does not prevent its oxidation to Ti(IV), which is completed in a few months [25]. In the same sense, mixtures of TiCl 3 and phosphoric acid are very slowly oxidized even by air [26], in such a way that phosphate anions seems to be particularly suitable to stabilize Ti(III) species in aqueous solution.…”

Section: Introductionmentioning

confidence: 99%

Incorporation of Ti(III) into the AlPO4-5 framework by direct synthesis

Alfayate¹,

Sánchez‐Sánchez²,

Pérez‐Pariente³

2014

Microporous and Mesoporous Materials

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This work focuses on the synthesis and characterization of a conceptually innovative series of TAPO materials, particularly centered in the AFI-structured TAPO-5. Unlike the conventional TAPOs, the so-called Ti(III)APO-5 are prepared by using Ti(III) sources. This strategy aims to avoid the presence of both Ti-O-Al and Ti-O-Ti bonds in TAPOs, undesired for catalytic purposes. The thermodynamic stability of this oxidation state of Ti in water and in the presence of air is low, but the preparation of the gel and the filling of the autoclaves under N 2 atmosphere allowed Ti to maintain its 3+ oxidation state in a considerable proportion in the hydrothermally-crystallized solids. The materials were characterized by powder XRD, ICP chemical analysis, SEM, DR-UV-visible spectroscopy, TGA and 31 P and 27 Al MAS NMR. DR-UV-visible spectroscopy certified the presence of Ti(III) in both tetrahedral and octahedral environments in the as-made samples before being exposed to air, whereas 31 P MAS NMR

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Section: Introductionmentioning

confidence: 99%

Incorporation of Ti(III) into the AlPO4-5 framework by direct synthesis

Alfayate¹,

Sánchez‐Sánchez²,

Pérez‐Pariente³

2014

Microporous and Mesoporous Materials

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show abstract

“…-TPH was obtained by reacting 0.126 moles of titanium trichloride 15% with 0.50 moles of phosphoric acid 85% for four days, in a polyethylene #ask, at 333 K with periodical stirring (19). The solid was separated by centrifugation and washed with bidistilled water until the washing part reached the range of pH 3.5 to 4.0.…”

Section: Methodsmentioning

confidence: 99%

Enthalpy of Interaction and Activation Energy for Thermal Degradation of Modified Forms of Lamellar Titanium Hydrogenphosphate

Nunes

Airoldi

Farias

1999

Journal of Solid State Chemistry

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“…All this indicates a widespread current interest in this topic, but a detailed literature review reveals that only synthesis of crystalline TiP has been explored analytically [4,7,14,15,[18][19][20]. The studies of amorphous TiP ionites remain somewhat isolated and mostly focused on varying the H 3 PO 4 acidity [21][22][23][24].…”

Section: Introductionmentioning

confidence: 96%

“…Variations in the synthetic conditions result in products of different P:Ti ratio and of different levels of crystallinity, and hence different ion-exchange abilities. For example at high P:Ti ratio in the initial solutions the amount of phosphate groups increases [14,15]. In relation to their sorption properties, it has been demonstrated that the cation-exchange capacity of the ionites decreases when the amount of phosphorus (in hydro-and di-hydro-phosphate forms: НРО 4 2− , Н 2 РО 4 − point leads to a decrease of sorption properties as a consequence of Ti(IV) hydrolysis (that initiates at temperatures above 80°C) [13].…”

Section: Introductionmentioning

confidence: 98%