Recent Advances in Using Niobium Compounds as Catalysts in Organic Chemistry

Arpini, Bruno H.; Bartolomeu, Aloísio de Andrade; Andrade, Carlos Kleber Z.; Silva‐Filho, Luiz Carlos da; Lacerda, Valdemar

doi:10.2174/157017941205150821125817

Cited by 25 publications

(12 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Niobium-containing materials are widely studied as solid catalysts for heterogeneous processes including sustainable organic synthesis [1]. Nb2O5/SiO2 catalysts are active in sugar dehydration [2][3][4][5], methanol oxidation [6], glycerol dehydration to acrolein [7] and oxidation reactions with aqueous H2O2 [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Effect of the niobium state on the properties of NbSiBEA as bifunctional catalysts for gas- and liquid-phase tandem processes

Kyriienko

Larina

Popovych

et al. 2016

Journal of Molecular Catalysis A: Chemical

View full text Add to dashboard Cite

International audienceNbSiBEA zeolites contained isolated framework mononuclear Nb(V) (Nb0.7SiBEA) and a mixture of framework mononuclear and extra-framework polynuclear Nb(V) (Nb2.0SiBEA) were prepared by two-step postsynthesis method as evidenced by XRD, NMR, DR UV–vis and FTIR. DR UV–vis showed that two types of framework mononuclear Nb(V) are present in Nb0.7SiBEA, while Nb2.0SiBEA mainly contained isolated mononuclear Nb(V) in the framework of zeolite and polynuclear Nb(V) in the extra-framework position. FTIR with pyridine and 2,6-di-tert-butylpyridine as probe molecules showed that major amount Lewis and weak Brønsted acidic sites are formed by incorporation of niobium in the framework of zeolites as mononuclear Nb(V). The catalytic properties of Nb-containing zeolites were investigated in tandem processes of ethanol conversion into 1,3-butadiene (gas-phase) and synthesis of unsymmetrical ethers from aromatic aldehyde and aliphatic alcohol (liquid-phase). It has been found that Nb0.7SiBEA catalyst, containing only isolated framework mononuclear Nb(V) is more active than Nb2.0SiBEA in the conversion of ethanol and ethanol/acetaldehyde mixture into 1,3-butadiene, MPV reduction of crotonaldehyde with ethanol and etherification of 4-methoxybenzyl alcohol with 2-butanol. The higher specific activity (turnover number/frequency) of Nb0.7SiBEA than Nb2.0SiBEA catalyst has been revealed for gas- and liquid-phase tandem processes

show abstract

Section: Introductionmentioning

confidence: 99%

Effect of the niobium state on the properties of NbSiBEA as bifunctional catalysts for gas- and liquid-phase tandem processes

Kyriienko

Larina

Popovych

et al. 2016

Journal of Molecular Catalysis A: Chemical

View full text Add to dashboard Cite

show abstract

“…10,11 Thus, niobium-containing materials have been proposed as effective catalysts in the dehydration of alcohols, oxidation, hydrolysis, alkylation, esterification, photocatalysis and isomerization. [12][13][14][15][16][17][18][19][20][21] Ammonium niobium oxalate (AmNO, NH 4 [NbO(C 2 O 4 ) 2 (H 2 O) x ]•nH 2 O) is used as a niobium precursor in the preparation of functionalized materials, including ceramics, optical lenses, high purity niobium oxides, tin films and catalysts. Compared with NbCl 5 , this niobium salt is cheap, easy to handle and not sensitive to air or moisture.…”

Section: Introductionmentioning

confidence: 99%

Simple Niobium Catalysts Applied in Reflux and Ultrasound-Assisted Systems for Biofuel Synthesis

Arpini

Cubides-Román

Javarini

et al. 2019

J. Braz. Chem. Soc.

Self Cite

View full text Add to dashboard Cite

Using niobium compounds as heterogeneous catalysts in biodiesel production is a promising methodology from economic and environmental viewpoints. However, the application of niobium catalysts still is a challenge due to the high temperatures and pressures for moderate biofuel yields. Therefore, easily handled and applied materials have been developed to optimize biofuel production, which is the goal of this study. Nb 2 O 5 and ammonium niobium oxalate (AmNO) were activated in reflux and ultrasound-assisted system. Nb 2 O 5 showed better activity under reflux, using methanol. The characterizations conclude that the Lewis-acid sites are determinant for higher conversion rather than surface area. AmNO has better activity also in the reflux system at 70 °C, against 170 °C for Nb 2 O 5 , reaching above 70% conversion. In addition, reactions in ultrasound-assisted systems are also appealing due to the lower time and temperature, with conversion rates above 40%. Both catalysts showed interesting results under milder conditions than those in the literature.

show abstract

“…However, they are not always cost competitive nor easily scaled up. As part of our research interests on synthetic methodologies using NbCl 5 [40][41][42][43][44][45][46][47][48][49][50], we report a new approach for the functionalization of 4formylphthalonitrile (1) with substituted anilines and terminal phenylacetylenes via a multicomponent reaction (MCR) promoted by NbCl 5 in the presence of p-chloranil.…”

Section: Introductionmentioning

confidence: 99%

Multicomponent reactions mediated by NbCl 5 for the synthesis of phthalonitrile-quinoline dyads: Methodology, scope, mechanistic insights and applications in phthalocyanine synthesis

et al. 2018

View full text Add to dashboard Cite

Herein, we demonstrate the efficiency of NbCl 5 to promote a multicomponent reaction (MCR) for the synthesis of a library of phthalonitrile-quinoline dyads, which are very useful and new functionalized building blocks for phthalocyanine (PC) synthesis. Experimental mechanistic insights on the key MCR process are described, using a deuterated reagent, clearly showing the pericyclic nature of a hetero-Diels-Alder reaction. Examples of phthalocyanine (PC) syntheses were performed in order to demonstrate the versatility of the phthalonitrile-quinoline dyads. Preliminary photophysical measurements show that our phthalonitrile library is very promising for the production of new molecular scaffolds of PC derivatives with potential applications.

show abstract

Recent Advances in Using Niobium Compounds as Catalysts in Organic Chemistry

Cited by 25 publications

References 0 publications

Effect of the niobium state on the properties of NbSiBEA as bifunctional catalysts for gas- and liquid-phase tandem processes

Effect of the niobium state on the properties of NbSiBEA as bifunctional catalysts for gas- and liquid-phase tandem processes

Simple Niobium Catalysts Applied in Reflux and Ultrasound-Assisted Systems for Biofuel Synthesis

Multicomponent reactions mediated by NbCl 5 for the synthesis of phthalonitrile-quinoline dyads: Methodology, scope, mechanistic insights and applications in phthalocyanine synthesis

Contact Info

Product

Resources

About