Sulfated Zirconia: An Efficient and Reusable Heterogeneous Catalyst in the Friedel–Crafts Acylation Reaction of 3-Methylindole

Vargas, Darío A.; Méndez, Leticia; Cánepa, Alicia S.; Bravo, Rodolfo D.

doi:10.1007/s10562-017-2057-x

Cited by 8 publications

(4 citation statements)

References 36 publications

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“…The bands at 1130 and 1225 cm −1 corresponded to the S=O vibrations in the bridging bidentate sulfate coordinated to Zr 4+ , while those at 995, 1030, and 1076 cm −1 corresponded to the S–O stretching vibrations [ 45 , 46 ]. In addition, the band observed at 1628 cm −1 was attributed to the bending vibrations of adsorbed water [ 47 ]. Notably, the intensity of the bands from S–O stretching vibrations (1030 and 1076 cm −1 ) for the 5SZ( y ) samples was enhanced with an increase in the calcination temperature owing to the crystallization of the tetragonal ZrO 2 phase ( Figure 3 a).…”

Section: Resultsmentioning

confidence: 99%

Production of H2-Free Carbon Monoxide from Formic Acid Dehydration: The Catalytic Role of Acid Sites in Sulfated Zirconia

et al. 2022

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The formic acid (CH2O2) decomposition over sulfated zirconia (SZ) catalysts prepared under different synthesis conditions, such as calcination temperature (500–650 °C) and sulfate loading (0–20 wt.%), was investigated. Three sulfate species (tridentate, bridging bidentate, and pyrosulfate) on the SZ catalysts were characterized by using temperature-programmed decomposition (TPDE), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The acidic properties of the SZ catalysts were investigated by the temperature-programmed desorption of iso-propanol (IPA-TPD) and pyridine-adsorbed infrared (Py-IR) spectroscopy and correlated with their catalytic properties in formic acid decomposition. The relative contributions of Brønsted and Lewis acid sites to the formic acid dehydration were compared, and optimal synthetic conditions, such as calcination temperature and sulfate loading, were proposed.

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Section: Resultsmentioning

confidence: 99%

Production of H2-Free Carbon Monoxide from Formic Acid Dehydration: The Catalytic Role of Acid Sites in Sulfated Zirconia

et al. 2022

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“…As shown in Figure 8, a broad peak at 3427 cm −1 corresponds to the hydroxo-and aquo-OH stretching vibrations of hydroxyl groups, and adsorbed water is accompanied by the band at 1632 cm −1 [9] [32]. The weak bands at 2925 cm −1 can be assigned to the bending/scissoring and stretching vibration of C-H and CH 3 groups [9] [33] [34].…”

Section: Irmentioning

confidence: 99%

The Physico-Chemical Characterization of Mesoporous Sulfated Zirconia Nanoparticles Prepared under Structure-Directing-Free for <i>n</i>-Hexane Isomerization

Gongyi¹,

Chen²,

Xu³

2020

JMMCE

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This article describes the physico-chemical characterization of the sulfated zirconia catalysts prepared from zirconyl chloride, acetic acid and ammonium persulfate system under structure-directing-free and calcined at 650˚C. The catalysts were characterized via an array of characterization techniques such as surface acidity and texture measurements, X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-VIS), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDXS), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), thermogravimetric measurement (TG) coupled with a quadrupole mass spectrometer (MS), inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and/or mass spectrometry (ICP-MS). It is clear from TG-MS, ICP-AES, and IR analyses that the precursor of the catalyst is a sulphur species-doped zirconium oxy-hydroxyl acetate complex. The presence of zirconium-bound sulfate groups results in the superacidity of the catalyst and hence high activity in n-hexane isomerization.It is shown from nitrogen adsorption and desorption, FESEM, and HRTEM measurements that the materials exhibit mesoporous and nanocrystalline structure.

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“…The starting material, 1-(3-methyl-1H-indol-2-yl) ketones 1, was obtained from 3-methylindole by Friedel-Crafts acylation using acylating agents and Amberlyst 15 resins or sulfated zirconia as a heterogeneous catalyst, by applying a method recently developed by us. [35,36] Scheme 2.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Complex Ureas with Brominated Heterocyclic Intermediates

2023

Self Cite

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Herein we present an efficient method to synthesize novel complex ureas from simple ureas, with potential pharmacological activity. First, 3-methylindole ketones are protected via a two-phase N-tosylation reaction catalyzed by NBu 4 HSO 4 as the PTC. Second, an NBS bromination of the terminal methyl group is performed with high selectivity and very good yields. Finally, complex novel and promising ureas are synthesized in 46 %-92 % yields using non-base-catalyzed substitution reactions with simple monosubstituted and disubstituted ureas. All products were easily purified through column chromatography and/or crystallization. The overall procedure produces very high yields and selectivity for bromination.

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Sulfated Zirconia: An Efficient and Reusable Heterogeneous Catalyst in the Friedel–Crafts Acylation Reaction of 3-Methylindole

Cited by 8 publications

References 36 publications

Production of H2-Free Carbon Monoxide from Formic Acid Dehydration: The Catalytic Role of Acid Sites in Sulfated Zirconia

Production of H2-Free Carbon Monoxide from Formic Acid Dehydration: The Catalytic Role of Acid Sites in Sulfated Zirconia

The Physico-Chemical Characterization of Mesoporous Sulfated Zirconia Nanoparticles Prepared under Structure-Directing-Free for <i>n</i>-Hexane Isomerization

Synthesis of Complex Ureas with Brominated Heterocyclic Intermediates

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Sulfated Zirconia: An Efficient and Reusable Heterogeneous Catalyst in the Friedel–Crafts Acylation Reaction of 3-Methylindole

Cited by 8 publications

References 36 publications

Production of H2-Free Carbon Monoxide from Formic Acid Dehydration: The Catalytic Role of Acid Sites in Sulfated Zirconia

Production of H2-Free Carbon Monoxide from Formic Acid Dehydration: The Catalytic Role of Acid Sites in Sulfated Zirconia

The Physico-Chemical Characterization of Mesoporous Sulfated Zirconia Nanoparticles Prepared under Structure-Directing-Free for &lt;i&gt;n&lt;/i&gt;-Hexane Isomerization

Synthesis of Complex Ureas with Brominated Heterocyclic Intermediates

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The Physico-Chemical Characterization of Mesoporous Sulfated Zirconia Nanoparticles Prepared under Structure-Directing-Free for <i>n</i>-Hexane Isomerization