Nickel salt of phosphomolybdic acid as a bi-functional homogeneous recyclable catalyst for base free transformation of aldehyde into ester

Patel, Anjali; Patel, Jay

doi:10.1039/d0ra04119j

Cited by 16 publications

(4 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[78] While in the UV spectrum of the Co 2 SiW 12 O 40 the maximum absorption was 215 nm, for all the other salts it was shifted toward a lower wavelength. [ 79] Conversely, a second absorption band was noticed around 260 nm, which was attributed to charge transfer from bridges Oxygen atoms to W atoms (i. e., dπ-pπ-dπ of WÀ OÀ W bridging). [80] However, the "d-d" transitions absorption bands that are typical when the transition metal cations are present are weak and normally appear at a higher wavelength, at the visible spectrum region.…”

Section: Chemistryselectmentioning

confidence: 99%

How the Cobalt Position in the Keggin Anion Impacts the Activity of Tungstate Catalysts in the Furfural Acetalization with Alkyl Alcohols

Silva

Ferreira

et al. 2022

ChemistrySelect

View full text Add to dashboard Cite

Keggin heteropolyacids (HPAs) comprise a class of versatile catalysts, which have properties that can be easily adjusted through modification in their structure, such as the protons exchange, the removal or one or more MO unity (i. e., W or Mo) followed by doping with transition metals, or even less frequently, the substitution of heteroatom (i. e., P or Si). In this work, these effects were assessed by modifying the structure of silicotungstic acid (i. e., H4SiW12O40) with Co2+ cations. A series of Cobalt‐polyoxometalates (i. e., Co2SiW12O40, K6CoW12O40, K8SiW11O39, K6SiCoW11O39, K8CoW11CoO39) were synthesized and catalytically evaluated in furfural acetalization with alkyl alcohols. Spectroscopy analyses (i. e., UV‐Vis, FT‐IR, EDS), powder X‐ray diffraction patterns, scan electronic microscopy images, surface area, porosity, and thermal analyses provided the main physicochemical properties of the synthesized salts. Acidity properties were assessed by potentiometric titration and adsorbed Py‐FT‐IR spectroscopy. The impact of temperature, nature, and catalyst loading, and type of alcohol were investigated. The K6CoW12O40 salt was the most active and selective catalyst. We paid special attention to correlating the catalyst activity with its composition and properties.

show abstract

Section: Chemistryselectmentioning

confidence: 99%

How the Cobalt Position in the Keggin Anion Impacts the Activity of Tungstate Catalysts in the Furfural Acetalization with Alkyl Alcohols

Silva

Ferreira

et al. 2022

ChemistrySelect

View full text Add to dashboard Cite

show abstract

“…In the supplemental material, we compared the UV-Vis spectra of three Keggin suppose that the absorption band involving charge transfer from terminal Oxygen atoms was also shifted toward lower wavelength, which is out of spectral range analyzed [51].…”

Section: Characterization Of Heteropoly Saltsmentioning

confidence: 99%

Copper Phosphotungstate-Catalyzed Microwave-Assisted Synthesis of 5-Hydroxymethylfurfural In A Biphasic System

Castro

Lopes

Fernandes

et al. 2021

Preprint

View full text Add to dashboard Cite

In this paper, we have described a novel route to produce 5-hydroxymethylfurfural (HMF), a valuable platform-molecule obtained from biomass, using transition metal-exchanged Keggin heteropolyacid salts as catalysts, in microwave-assisted reactions carried out in a water-ethyl acetate biphasic system. To avoid the use of homogenous Brønsted acid catalysts, which are corrosive and difficult to be reused, we have exchanged the protons of the Keggin heteropolyacids by transition metal cations. These salts were evaluated in the fructose dehydration, being the Cu3/2PW12O40 the most active and selective catalyst, achieving 81 % of HMF yield, after 15 min reaction at 413 K under microwave irradiation (MWI). The effects of metal cation, anion, and heteropolyanion present in the catalyst were evaluated. The greatest efficiency of Cu3/2PW12O40 was attributed to its high Lewis acidity strength, which allows that it coordinate with water molecules, consequently generating H3O+ ions in the reaction medium. Even though the catalyst has been water-soluble, it was easily reused removing the extracting phase, and adding a new load of the substrate to the remaining aqueous phase. This way, it was successfully reused without loss activity.

show abstract

“…Many attempts were made to overcome these limitations and improve the yields, shortening reaction time [20] and increasing selectivity for the desired product [21]. Many Lewis acid catalysts like SbCl 3 [22], Cu(OTf) 2 [23], ZrCl 4 , FeCl 3 [24], SnCl 2 , InBr 3 [25,26], ZnBr 2 [27], and Mg(ClO 4 ) 2 [28,29] were proved the capability in promoting the Biginelli reaction. However, many issues associated with their use are the high cost, long reaction time, and moderated yield.…”

Section: Introductionmentioning

confidence: 99%

Cobalt perchlorate hexahydrate catalyzed one‐pot synthesis of dihydropyrimidin‐ones/‐thiones through sonochemistry and its mechanistic study using density functional theory calculations

Ambatwar,

Kumar,

Agarwal

et al. 2023

Journal of Heterocyclic Chem

View full text Add to dashboard Cite

A cobalt(II) perchlorate hexahydrate coordinated synthesis of dihydropyrimidin‐ones and ‐thiones through sonochemistry is developed. Herein, the reaction was demonstrated as a simple, efficient, and one‐pot method for synthesizing a series of interesting 3,4‐dihydropyrimidin‐2(1H)‐ones. Further, the reaction mechanism was investigated using mass spectrometry and density functional theory calculations suggesting that a Lewis acid character of cobalt(II) perchlorate hexahydrate plays a crucial role in coordinating carbonyl functionalities and stabilizing the polar intermediates like imine–enamine which further led to cyclized dihydropyrimidin‐ones and ‐thiones. This methodology was further explored to synthesize a gram‐scale synthesis of monastrol drug, a kinase inhibitor.

show abstract

Nickel salt of phosphomolybdic acid as a bi-functional homogeneous recyclable catalyst for base free transformation of aldehyde into ester

Abstract: A Ni salt of phosphomolybdic acid (NiHPMA) was synthesized, characterized and evaluated for bi-functional activity via conversion of benzaldehyde to ethyl benzoate. The role of Mo-peroxo and Ni-oxo was confirmed by UV-visible/Raman spectroscopy.

Cited by 16 publications

References 72 publications

How the Cobalt Position in the Keggin Anion Impacts the Activity of Tungstate Catalysts in the Furfural Acetalization with Alkyl Alcohols

How the Cobalt Position in the Keggin Anion Impacts the Activity of Tungstate Catalysts in the Furfural Acetalization with Alkyl Alcohols

Copper Phosphotungstate-Catalyzed Microwave-Assisted Synthesis of 5-Hydroxymethylfurfural In A Biphasic System

Cobalt perchlorate hexahydrate catalyzed one‐pot synthesis of dihydropyrimidin‐ones/‐thiones through sonochemistry and its mechanistic study using density functional theory calculations

Contact Info

Product

Resources

About