Silica supported Brönsted acids as catalyst in organic transformations: A comprehensive review

Kaur, Manpreet; Sharma, Sahil; Bedi, Preet Mohinder Singh

doi:10.1016/s1872-2067(14)60299-0

Cited by 65 publications

(14 citation statements)

References 105 publications

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“…Iron oxide magnetic core-shell nanoparticles have been prepared in various ways and have been modified by functional groups with catalytic properties [ 12 ]. Silica is one of the best coatings used for the synthesis of iron oxide core-shell nanoparticles because of stability, biocompatibility, functionality and resistance to acid or high temperature [ 13 , 14 ]. The acid catalytic properties of iron oxide@SiO 2 nanoparticles can be exceeded by the modification of the surface of nanoparticles with acid functional groups, such as HBF 4 [ 15 ], sulfuric acid [ 16 ], R-NHMe 2 ][H 2 PO 4 ] [ 17 ] and sulfonic acid [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

The synthesis and characterization of Fe2O3@SiO2–SO3H nanofibers as a novel magnetic core-shell catalyst for formamidine and formamide synthesis

Ziyadi

Baghali²,

Heydari

2021

Heliyon

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Over the past several decades, the fabrication of novel ceramic nanofibers applicable in different areas has been a frequent focus of scientists around the world. Aiming to introduce novel ceramic core-shell nanofibers as a magnetic solid acid catalyst, Fe 2 O 3 @SiO 2 –SO 3 H magnetic nanofibers were prepared in this study using a modification of Fe 2 O 3 @SiO 2 core-shell nanofibers with chlorosulfonic acid to increase the acidic properties of these ceramic nanofibers. The products were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray spectroscope (EDS), vibrating sample magnetometer (VSM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The prepared nanofibers were used as catalysts in formamide and formamidine synthesis. The treatment of aqueous formic acid using diverse amines with a catalytic amount of Fe 2 O 3 @SiO 2 –SO 3 H nanofibers as a reusable, magnetic and heterogeneous catalyst produced high yields of corresponding formamides at room temperature. Likewise, the reaction of diverse amines with triethyl orthoformate led to the synthesis of formamidine derivatives in excellent yields using this novel catalyst. The catalytic system was able to be recovered and reused at least five times without any catalytic activity loss. Thus, novel core-shell nanofibers can act as efficient solid acid catalysts in different organic reactions capable of being reused several times due to their easy separation by applying magnet.

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Section: Introductionmentioning

confidence: 99%

The synthesis and characterization of Fe2O3@SiO2–SO3H nanofibers as a novel magnetic core-shell catalyst for formamidine and formamide synthesis

Ziyadi

Baghali²,

Heydari

2021

Heliyon

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“…Heteropolyacids (HPAs), especially silicotungstic acid (HSiW), phosphotungstic acid (HPW) and phosphomolybdic acid (HPMo), are well‐proved active species for aldol condensation reactions due to the presence of Brønsted acid sites . Due to the disadvantages of low thermal stability and surface area (<10 m 2 g −1 ), an available and inexpensive silica aerogel is used to support the HPAs for the purpose of a higher competitiveness in commercial applications.…”

Section: Introductionmentioning

confidence: 99%

Acrylic acid synthesis via condensation of acetic acid and formaldehyde catalyzed by silica aerogel‐supported SiW/PW/PMo oxides

Shen

Yin

et al. 2020

J of Chemical Tech & Biotech

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BACKGROUND: The demand for acrylic acid continues to increase rapidly due to its widespread application. The traditional production of acrylic acid originates from non-sustainable propylene oxidation. Considering the environmental requirements and economic sustainable development, it is of great significance to exploit new routes to replace the petrochemical route.RESULTS: Comparison of silica aerogel-supported SiW/PW/PMo catalysts shows that PW/SiO 2 catalyst with 30 wt% loading and calcined at 450°C provides the best performance for the condensation of acetic acid and formaldehyde. Increasing the reaction temperature from 340 to 400°C leads to the best acrylic acid selectivities of 87.1-84.2% at formaldehyde conversions of 35.7-45.2%. CONCLUSIONS: The catalytic performance of PW/SiO 2 catalyst increases with increasing PW loading. The acidic and basic sites of the catalyst, especially the weak ones, are of vital importance to the synthesis of acrylic acid via the aldol condensation of acetic acid and formaldehyde.

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“…Also silicasupported reagent, H2SO4 / SiO2 for its ease of preparation, low cost, high efficiency and environmental benignness, 6 has already been used in cylcoadditions, 7 Beckmann rearrangements, 8 glycosylations, 9 condensations, 10 esterification, 11 acetylation of (+)cedrol compound, 12 synthesis of 2,4,5-triaryl-1H-imidazoles, 13 and as catalyst in organic transformations: a comprehensive review. 14 On the other hand, during our continuing efforts to develop convenient approaches to synthesize heterocycle compounds, 15 we revealed that H2SO4/SiO2 was a high-efficient and recyclable catalyst for preparing the quinoxaline derivatives in a synthetically practical procedure (stoichiometric ratios of starting materials and short reaction times) with relatively widely functional group compatibility in ethylene glycol at ambient temperature (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%

Ethylene glycol and H2SO4 / SiO2 as a green medium for the preparation of quinoxaline derivatives at room temperature

Bashirzadeh¹,

Behbahani²

2020

ECB

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Silica supported Brönsted acids as catalyst in organic transformations: A comprehensive review

Cited by 65 publications

References 105 publications

The synthesis and characterization of Fe2O3@SiO2–SO3H nanofibers as a novel magnetic core-shell catalyst for formamidine and formamide synthesis

The synthesis and characterization of Fe2O3@SiO2–SO3H nanofibers as a novel magnetic core-shell catalyst for formamidine and formamide synthesis

Acrylic acid synthesis via condensation of acetic acid and formaldehyde catalyzed by silica aerogel‐supported SiW/PW/PMo oxides

Ethylene glycol and H2SO4 / SiO2 as a green medium for the preparation of quinoxaline derivatives at room temperature

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