TiF4 : An original and very interesting precursor to the synthesis of titanium containing silicalite-1

Jordà, Elisabet Fuguet i; Tuel, A.; Teissier, R.; Kervennal, J.

doi:10.1016/s0144-2449(97)00067-5

Cited by 67 publications

(28 citation statements)

References 29 publications

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“…The UV/vis spectra of TS‐1 usually have three sets of bands (Figure 3). The band at λ ≈210 nm is attributed to the Ti 4+ O 2− to Ti 3+ O − ligand‐to‐metal charge transfer,39 which is characteristic of tetrahedrally coordinated framework Ti. It was reported that the five‐membered ring formed by tetrahedral Ti with H 2 O 2 and alcohol can oxidize propene to propene oxide (PO).…”

Section: Resultsmentioning

confidence: 99%

Enhanced Catalytic Performance of Titanium Silicalite‐1 in Tuning the Crystal Size in the Range 1200–200 nm in a Tetrapropylammonium Bromide System

et al. 2015

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A facile method for the size‐controllable synthesis of titanium silicalite‐1 (TS‐1) is presented. A tetrapropylammonium bromide hydrothermal system was used, and the amount of seeds (silicalite‐1 suspension) and crystallization time were tuned to control the crystal size. The crystal size could be adjusted from 200 to 1200 nm by varying the seed amount from 12 to 0.05 wt %. Crystallization time plays a less important role than the seed amount on the crystal size. TS‐1 samples with different crystal sizes were characterized and evaluated in propene epoxidation. The catalytic activity and selectivity of propene oxide are enhanced by decreasing the crystal size from 1200 to 200 nm because the diffusion limitation is eliminated gradually. The seed is significant for this system, as a lack of seeds leads to poor crystallization and low catalytic activity. The mechanism of the seed function was studied by simulating the transformation process of the seed in the TS‐1 synthesis system.

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Section: Resultsmentioning

confidence: 99%

Enhanced Catalytic Performance of Titanium Silicalite‐1 in Tuning the Crystal Size in the Range 1200–200 nm in a Tetrapropylammonium Bromide System

et al. 2015

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“…in the tetrahedral environment [55,56]. The absorption signals between 240 and 290 nm are attributed to the penta-coordinated titanium or small TiO 2 clusters through the quantum size effect, which is usually called nonframework Ti [57]. The board band at 300-330 nm is assigned to anatase TiO 2 [58].…”

Section: Resultsmentioning

confidence: 99%

Effect of triethylamine treatment of titanium silicalite-1 on cyclohexanone ammoximation in a continuous system

Zhang

Wang

et al. 2014

Reac Kinet Mech Cat

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TS-1 has been hydrothermally treated by aqueous solutions of triethylamine, characterized by a number of techniques and studied in the ammoximation of cyclohexanone with NH 3 and H 2 O 2 in a continuous system. Some irregular hollow cavities are created after the treatment by desilication. The catalytic activities of TS-1 are not affected, but the catalyst stabilities significantly increase after the treatment, which can be attributed to the generation of the cavities. The treatment conditions are optimized, with the catalyst stability being extended to ten times of the conventional TS-1. After the treatment, triethylamine can be separated simply through distillation and recycled. The causes of deactivation are elucidated to be the deposition of higher weight byproducts formed on the surface of the catalysts and the deactivated TS-1 can be effectively regenerated through calcination in air.

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“…Moreover, Kooyman et al (97) attempted to synthesize TS-1 in the presence of fluoride (using TiF 3 and the rutile modification of TiO 2 as precursors) but observed anatase impurities, with evidence arising from extended X-ray absorption fine structure (EXAFS) data that were consistent with octahedral-and thus extraframework-titanium. Jorda et al (12) used TiF 4 for the synthesis and conclusively demonstrated that it is possible to synthesize TS-1 by using the air-and water-stable TiF 4 . These authors were able to incorporate up to two titanium atoms per unit cell, corresponding to a Ti/(Ti + Si) ratio of 0.2, but their samples contained trace amounts of residual fluoride from the synthesis.…”

Section: General Synthesis Proceduresmentioning

confidence: 99%

Science and Technology of Framework Metal-Containing Zeotype Catalysts

Németh

Bare

2014

Advances in Catalysis

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TiF4 : An original and very interesting precursor to the synthesis of titanium containing silicalite-1

Cited by 67 publications

References 29 publications

Enhanced Catalytic Performance of Titanium Silicalite‐1 in Tuning the Crystal Size in the Range 1200–200 nm in a Tetrapropylammonium Bromide System

Enhanced Catalytic Performance of Titanium Silicalite‐1 in Tuning the Crystal Size in the Range 1200–200 nm in a Tetrapropylammonium Bromide System

Effect of triethylamine treatment of titanium silicalite-1 on cyclohexanone ammoximation in a continuous system

Science and Technology of Framework Metal-Containing Zeotype Catalysts

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