Preparation, optical properties and catalytic activity of TiO 2 @Pd nanoparticles as heterogeneous and reusable catalysts for ligand-free Heck coupling reaction

Nasrollahzadeh, Mahmoud; Azarian, A.; Ehsani, Ali; Khalaj, Mehdi

doi:10.1016/j.molcata.2014.06.033

Cited by 49 publications

(8 citation statements)

References 31 publications

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“…UV-vis spectral analysis was recorded on a double-beam spectrophotometer (Hitachi, U-2900). The microstructure of the phasors of incident, reflected and transmitted electric fields are given as [32][33][34][35][36][37][38]:…”

Section: Introductionmentioning

confidence: 99%

Electrosynthesis, optical modeling and electrocatalytic activity of Ni-MWCNT-PT nanocomposite film

Ehsani

Vaziri-Rad

Babaei

et al. 2015

Electrochimica Acta

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Section: Introductionmentioning

confidence: 99%

Electrosynthesis, optical modeling and electrocatalytic activity of Ni-MWCNT-PT nanocomposite film

Ehsani

Vaziri-Rad

Babaei

et al. 2015

Electrochimica Acta

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“…NaOAc improved yields in the presence of the polar DMF ( Table 2, entry (6)). Inorganic bases recorded poor yields due to relative insolubility effects of the inorganic bases in the organic reaction matrix [13]. There was no conversion achieved when the reaction was carried out in the absence of a base.…”

Section: Effect Of Basesmentioning

confidence: 99%

“…To help address the problem of recovery and recycling of the catalyst, different support materials have been and are still being investigated. The most attractive is Pd on carbon or carbon nanotubes [9][10][11]: Pd on metal oxide such as MgO, Al 2 O 3 , ZnO, ZrO 2 , and TiO 2 [5,[12][13][14][15], Pd on zeolites [16], Pd encapsulated in large organic structures (dendrimers) [17], and Pd on block copolymer micelles [18]. The supports tend to arrest Pd on the surface of a solid material or in an organic matrix, making it possible to stabilize the catalytically active palladium species and prevent sintering.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Characterization of Pd Modified TiO₂ Nanofiber Catalyst for Carbon–Carbon Coupling Heck Reaction

Nyangasi

Andala

Onindo

et al. 2017

Journal of Nanomaterials

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TiO 2 fibers were prepared through electrospinning of poly methyl methacrylate (PMMA) and titanium isopropoxide (TIP) solution followed by calcination of fibers in air at 500 ∘ C. Cetyltrimethylammonium bromide (CTAB) protected palladium nanoparticles (Pd NPs) prepared through reduction method were successfully adsorbed on the TiO 2 nanofibers (NF). Combined studies of X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) indicated that the synthesized Pd/TiO 2 had anatase. BET indicated that the synthesized TiO 2 and Pd/TiO 2 had a surface area of 53.4 and 43.4 m 2 /g, respectively. The activity and selectivity of 1 mol% Pd/TiO 2 in the Heck reaction have been investigated towards the Mizoroki-Heck carbon-carbon cross-coupling of bromobenzene (ArBr) and styrene. Temperature, time, solvent, and base were optimized and catalyst was recycled thrice.1 H NMR and 13 C NMR indicated that stilbene, a known compound from literature, was obtained in various Heck reactions at temperatures between 100 ∘ C and 140 ∘ C but the recyclability was limited due to some palladium leaching and catalyst poisoning which probably arose from some residual carbon from the polymer. The catalyst was found to be highly active under air atmosphere with reaction temperatures up to 140 ∘ C. Optimized reaction condition resulted in 89.7% conversions with a TON of 1993.4 and TOF value of 332.2 hr −1 .

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“…Some TiO 2 -supported Pd catalysts have been applied to various organic and inorganic reactions such as the Suzuki-Miyaura reaction [42][43][44][45][46][47][48][49][50], hydrogenation [51][52][53][54][55][56][57][58] and Heck reaction [59]. However, the effect on the catalyst activity, depending on the difference of the TiO 2 crystal forms of TiO 2 -supported Pd catalysts toward cross-coupling reactions, has never been systematically evaluated, except for a report related to the oxidative homo coupling reaction of 4-methylpyridines in the presence of Pd oxide-loaded TiO 2 (PdO/TiO 2 ) as a catalyst [60].…”

Section: Introductionmentioning

confidence: 99%

Development of Titanium Dioxide-Supported Pd Catalysts for Ligand-Free Suzuki–Miyaura Coupling of Aryl Chlorides

et al. 2019

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The catalyst activities of various heterogeneous palladium catalysts supported by anatase-, rutile- and brookite-type titanium oxide for ligand-free Suzuki–Miyaura cross-coupling reactions of aryl chlorides were evaluated. Palladium acetate [Pd(OAc)2], supported on anatase-type titanium oxide (TiO2) via acetonitrile solution impregnation process without reduction [Pd/TiO2 (anatase-type)], demonstrated the highest catalyst activity in comparison to those of other titanium oxide (rutile- or brookite-type) supported Pd(OAc)2 without reduction and reduced Pd/TiO2 (anatase-type) [Pd(red)/TiO2 (anatase-type)]. Various aryl chloride and bromide derivatives were smoothly coupled with arylboronic acids including heteroarylboronic acids in the presence of 5–10 mol% Pd/TiO2 (anatase-type) without the addition of any ligands. Although the fresh Pd/TiO2 (anatase-type) catalyst was surprisingly comprised of ca. 1:2 mixture of palladium(II) and palladium(0) species according to X-ray photoelectron spectroscopy (XPS), in spite of no reduction process, significant further increment of palladium(0) species was observed during the Suzuki–Miyaura coupling reaction, and Pd/TiO2 (anatase-type) was converted into a catalyst, which contained palladium(0) species as the main component [ca. 1:5 mixture of palladium(II) and palladium(0) species]. Therefore, the reduction via the electron donation process to the palladium(II) species may have occurred during the reaction on anatase-type titanium oxide.

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Preparation, optical properties and catalytic activity of TiO 2 @Pd nanoparticles as heterogeneous and reusable catalysts for ligand-free Heck coupling reaction

Cited by 49 publications

References 31 publications

Electrosynthesis, optical modeling and electrocatalytic activity of Ni-MWCNT-PT nanocomposite film

Electrosynthesis, optical modeling and electrocatalytic activity of Ni-MWCNT-PT nanocomposite film

Preparation and Characterization of Pd Modified TiO₂ Nanofiber Catalyst for Carbon–Carbon Coupling Heck Reaction

Development of Titanium Dioxide-Supported Pd Catalysts for Ligand-Free Suzuki–Miyaura Coupling of Aryl Chlorides

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Preparation, optical properties and catalytic activity of TiO 2 @Pd nanoparticles as heterogeneous and reusable catalysts for ligand-free Heck coupling reaction

Cited by 49 publications

References 31 publications

Electrosynthesis, optical modeling and electrocatalytic activity of Ni-MWCNT-PT nanocomposite film

Electrosynthesis, optical modeling and electrocatalytic activity of Ni-MWCNT-PT nanocomposite film

Preparation and Characterization of Pd Modified TiO2 Nanofiber Catalyst for Carbon–Carbon Coupling Heck Reaction

Development of Titanium Dioxide-Supported Pd Catalysts for Ligand-Free Suzuki–Miyaura Coupling of Aryl Chlorides

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Preparation and Characterization of Pd Modified TiO₂ Nanofiber Catalyst for Carbon–Carbon Coupling Heck Reaction