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13 pages, 4010 KiB

Open AccessFeature PaperArticle

Binuclear Dioxomolybdenum(VI) Complex Based on Bis(2-pyridinecarboxamide) Ligand as Effective Catalyst for Fuel Desulfurization

by Fátima Mirante, Catarina N. Dias, André Silva, Sandra Gago and Salete S. Balula

Catalysts 2024, 14(5), 305; https://doi.org/10.3390/catal14050305 - 04 May 2024

Viewed by 215

Abstract

A binuclear dioxomolybdenum catalyst [(MoO₂Cl₂)₂(L)] (1) (with L (1S,2S)-N,N′-bis(2-pyridinecarboxamide)-1,2-cyclohexane) was prepared and used as catalyst for the desulfurization of a multicomponent model fuel containing the most refractory [...] Read more.

A binuclear dioxomolybdenum catalyst [(MoO₂Cl₂)₂(L)] (1) (with L (1S,2S)-N,N′-bis(2-pyridinecarboxamide)-1,2-cyclohexane) was prepared and used as catalyst for the desulfurization of a multicomponent model fuel containing the most refractory sulfur compounds in real fuels. This complex was shown to have a high efficiency to oxidize the aromatic benzothiophene derivative compounds present in fuels, mainly using a biphasic 1:1 model fuel/MeOH system. This process conciliates catalytic oxidative and extractive desulfurization, resulting in the oxidation of the sulfur compounds in the polar organic solvent. The oxidative catalytic performance of (1) was shown to be influenced by the presence of water in the system. Using 50% aq. H₂O₂, it was possible to reuse the catalyst and the extraction solvent, MeOH, during ten consecutive cycles without loss of desulfurization efficiency. Full article

(This article belongs to the Special Issue Advances in Green Catalysis for Sustainable Organic Synthesis, 2nd Edition)

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16 pages, 2383 KiB

Open AccessFeature PaperArticle

Highly Efficient and Magnetically Recyclable Non-Noble Metal Fly Ash-Based Catalysts for 4-Nitrophenol Reduction

by Iwona Kuźniarska-Biernacka, Inês Ferreira, Marta Monteiro, Ana Cláudia Santos, Bruno Valentim, Alexandra Guedes, João H. Belo, João P. Araújo, Cristina Freire and Andreia F. Peixoto

Catalysts 2024, 14(1), 3; https://doi.org/10.3390/catal14010003 - 19 Dec 2023

Cited by 1 | Viewed by 947

Abstract

4-nitrophenol (4-NPh) is a harmful compound produced in large amounts in the chemical industry, and its reduction to aminophenol (4-APh) using noble metals as catalysts is one of the most studied processes. The development of noble metal-free catalysts represents an economic advantage in [...] Read more.

4-nitrophenol (4-NPh) is a harmful compound produced in large amounts in the chemical industry, and its reduction to aminophenol (4-APh) using noble metals as catalysts is one of the most studied processes. The development of noble metal-free catalysts represents an economic advantage in large-scale applications and contributes to the sustainability of raw materials. Coal fly ash (FA), a major waste stream from coal combustion, contains an easily recoverable magnetic fraction (FA_mag sample) composed of Fe-rich particles that could substitute noble metal catalysts in 4-NPh reduction, with the concomitant advantage of being easily recovered via magnetic separation. For this purpose, a new composite material containing copper ferrite nanoparticles (FA_mag@CS@CuFe) was prepared via a facile, environmentally friendly and cost-effective method based on three components: FA_mag as the core, a biobased polymer chitosan (CS) as the linker and copper ferrite CuFe₂O₄ nanoparticles (CuFe) as the active sites. The structure, morphology, composition and magnetic properties of the FA_mag@CS@CuFe material were studied to assess the efficiency of the preparation. It was found that the biopolymer prevented the aggregation of CuFe nanoparticles and enabled a synergistically outstanding activity towards the reduction of 4-NPh in comparison to the pristine FA_mag and bare CuFe nanoparticles. The FA_mag@CS@CuFe catalyst showed efficiency and stability in the conversion of 4-NPh of up to 95% in 3 min over four consecutive cycles. Such remarkable catalytic results demonstrate the potential of this catalyst as a substitute for expensive noble metals. Full article

(This article belongs to the Special Issue Advances in Green Catalysis for Sustainable Organic Synthesis, 2nd Edition)

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16 pages, 5511 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

A Mild and Sustainable Procedure for the Functionalization of Morpholin-2-Ones by Oxidative Imidation Reactions

by Ana Maria Faisca Phillips and Armando J. L. Pombeiro

Catalysts 2023, 13(7), 1072; https://doi.org/10.3390/catal13071072 - 05 Jul 2023

Viewed by 941

Abstract

Nitrogen-containing heterocycles such as morpholin-2-ones are structural elements of many biologically active substances, as well as useful synthetic intermediates. To be able to functionalize them regioselectively in an easy, atom-efficient, and environmentally friendly manner is highly desirable. A procedure for cross-dehydrogenative coupling between [...] Read more.

Nitrogen-containing heterocycles such as morpholin-2-ones are structural elements of many biologically active substances, as well as useful synthetic intermediates. To be able to functionalize them regioselectively in an easy, atom-efficient, and environmentally friendly manner is highly desirable. A procedure for cross-dehydrogenative coupling between morpholinones and cyclic imides was developed addressing these requirements. An earth-abundant metal catalyst, copper(I) chloride, in the presence of acetic acid, and with molecular oxygen as the sole oxidant, operating under mild conditions, afforded the desired C–N coupled products in high yields. Besides being potentially biologically active, as many members of both families of compounds are, the products themselves may be suitable substrates for functionalized polymers, e.g., poly(β-aminoesters) or even for PROTACs. Full article

(This article belongs to the Special Issue Advances in Green Catalysis for Sustainable Organic Synthesis, 2nd Edition)

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12 pages, 1165 KiB

Open AccessArticle

Highlights on the General Preference for Multi-Over Mono-Coupling in the Suzuki–Miyaura Reaction

by Carlos F. R. A. C. Lima, Marco A. L. Lima, J. Ricardo M. Pinto, M. Gabriela T. C. Ribeiro, Artur M. S. Silva and Luís M. N. B. F. Santos

Catalysts 2023, 13(6), 928; https://doi.org/10.3390/catal13060928 - 24 May 2023

Viewed by 1361

Abstract

A systematic synthetic study was performed to explain the usual trend in selectivity towards multi-coupling, over mono-coupling, in Suzuki–Miyaura reactions. This preference was observed under different reaction conditions: for various halobenzenes, using substituents on the boronic acid, and changing the catalyst and temperature. [...] Read more.

A systematic synthetic study was performed to explain the usual trend in selectivity towards multi-coupling, over mono-coupling, in Suzuki–Miyaura reactions. This preference was observed under different reaction conditions: for various halobenzenes, using substituents on the boronic acid, and changing the catalyst and temperature. Moreover, this reaction selectivity was found to increase for more reactive systems towards oxidative addition and more diluted media. The results constitute experimental evidence that the formation of the totally substituted coupling product is kinetically favoured by a reaction path location—the proximity between the regenerated catalyst and the newly formed coupling intermediate promotes the subsequent reaction. Full article

(This article belongs to the Special Issue Advances in Green Catalysis for Sustainable Organic Synthesis, 2nd Edition)

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Review

Jump to: Research

35 pages, 7530 KiB

Open AccessReview

Recent Advances in Catalyst Design for Carboxylation Using CO₂ as the C1 Feedstock

by Sagarkumar Rajendrakumar Shah, Nayan Jyoti Mazumdar, Ander Centeno-Pedrazo, Dhanapati Deka, Nancy Artioli and Haresh Manyar

Catalysts 2023, 13(12), 1489; https://doi.org/10.3390/catal13121489 - 30 Nov 2023

Cited by 2 | Viewed by 1726

Abstract

Carbon dioxide is ideal for carboxylation reactions as a renewable and sustainable C1 feedstock and has significant recognition owing to its low cost, non-toxicity, and high abundance. To depreciate the environmental concentration of CO₂, which causes the greenhouse gas effect, developing [...] Read more.

Carbon dioxide is ideal for carboxylation reactions as a renewable and sustainable C1 feedstock and has significant recognition owing to its low cost, non-toxicity, and high abundance. To depreciate the environmental concentration of CO₂, which causes the greenhouse gas effect, developing new catalytic protocols for organic synthesis in CO₂ utilization is of great importance. This review focuses on carboxylation reactions using CO₂ as a C1 feedstock to synthesize value-added functionalized carboxylic acids and their corresponding derivatives via catalytically generated allyl metal intermediates, photoredox catalysis, and electrocatalysis with a focus on recent developments and opportunities in catalyst design for carboxylation reactions. In this article, we describe recent developments in the carboxylation of C–H bonds, alkenes, and alkynes using CO₂ as the C1 source for various reactions under different conditions, as well as the potential direction for the further development of CO₂ utilization in organic synthesis. Full article

(This article belongs to the Special Issue Advances in Green Catalysis for Sustainable Organic Synthesis, 2nd Edition)

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27 pages, 8427 KiB

Open AccessFeature PaperReview

Bimetallic (or Multimetallic) Synthesis of N-Heterocycles

by Ana Rita Reis, Nuno Viduedo, Daniel Raydan and Maria Manuel B. Marques

Catalysts 2023, 13(9), 1268; https://doi.org/10.3390/catal13091268 - 02 Sep 2023

Cited by 2 | Viewed by 1681

Abstract

Bimetallic (or multimetallic) catalysis has emerged as a powerful tool in modern chemical synthesis, offering improved reaction control and versatility. This review focuses on the recent developments in bimetallic sequential catalysis for the synthesis of nitrogen heterocycles, which are essential building blocks in [...] Read more.

Bimetallic (or multimetallic) catalysis has emerged as a powerful tool in modern chemical synthesis, offering improved reaction control and versatility. This review focuses on the recent developments in bimetallic sequential catalysis for the synthesis of nitrogen heterocycles, which are essential building blocks in pharmaceuticals and fine chemicals. The cooperative action of two (sometimes more) different metal catalysts enables intricate control over reaction pathways, enhancing the selectivity and efficiency of the synthesis of N-heterocyclic compounds. By activating less reactive substrates, this multimetal catalytic strategy opens new synthetic possibilities for challenging compounds. The use of catalytic materials in bimetallic systems reduces waste and improves atom efficiency, aligning with green chemistry principles. With a diverse range of metal combinations and reaction conditions, bimetallic catalysis provides access to a broad array of N-heterocyclic compounds with various functionalities. This paper highlights the significant progress made in the past decade in this topic, emphasizing the promising potential of bimetallic catalysis in drug discovery and the fine chemical industries. Full article

(This article belongs to the Special Issue Advances in Green Catalysis for Sustainable Organic Synthesis, 2nd Edition)

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26 pages, 11108 KiB

Open AccessFeature PaperReview

The Asymmetric Petasis Borono-Mannich Reaction: Insights on the Last 15 Years

by Carolina Marques and Pedro Brandão

Catalysts 2023, 13(6), 1022; https://doi.org/10.3390/catal13061022 - 19 Jun 2023

Cited by 1 | Viewed by 1844

Abstract

The Petasis borono-Mannich reaction, commonly described as the Petasis reaction, was one of the latest famous multicomponent reactions described in the literature. Currently celebrating its 30th anniversary since it was first reported by Petasis and Akritopoulou in 1993, this reaction has emerged as [...] Read more.

The Petasis borono-Mannich reaction, commonly described as the Petasis reaction, was one of the latest famous multicomponent reactions described in the literature. Currently celebrating its 30th anniversary since it was first reported by Petasis and Akritopoulou in 1993, this reaction has emerged as a powerful tool for the synthesis of biologically relevant molecules (such as substituted amines or amino acids), among others. This three-component catalyst-free reaction (the classic model), involving the coupling of an aldehyde, an amine, and a boronic acid, enables the synthesis of polysubstituted amine-containing molecules. Several accounts regarding the catalyst-free version using different carbonyl, amine, and boron-type components have been reported thus far. In contrast, the asymmetric version is still in its infancy since it was first reported in 2007. In this work, we aim to review the asymmetric versions of the Petasis reaction reported over the last 15 years, considering the chiral pool approach (asymmetric induction by one reaction component) and the use of catalysts (organocatalysts, transition-metal catalysts, and others) to access enantiomeric and diastereomeric pure amino-derivatives. Insights regarding the catalyzed Petasis reaction and consequent sustainable synthesis will be highlighted. Full article

(This article belongs to the Special Issue Advances in Green Catalysis for Sustainable Organic Synthesis, 2nd Edition)

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24 pages, 4661 KiB

Open AccessReview

Green Chemistry in Organic Synthesis: Recent Update on Green Catalytic Approaches in Synthesis of 1,2,4-Thiadiazoles

by Laila Rubab, Ayesha Anum, Sami A. Al-Hussain, Ali Irfan, Sajjad Ahmad, Sami Ullah, Aamal A. Al-Mutairi and Magdi E. A. Zaki

Catalysts 2022, 12(11), 1329; https://doi.org/10.3390/catal12111329 - 29 Oct 2022

Cited by 17 | Viewed by 3980

Abstract

Green (sustainable) chemistry provides a framework for chemists, pharmacists, medicinal chemists and chemical engineers to design processes, protocols and synthetic methodologies to make their contribution to the broad spectrum of global sustainability. Green synthetic conditions, especially catalysis, are the pillar of green chemistry. [...] Read more.

Green (sustainable) chemistry provides a framework for chemists, pharmacists, medicinal chemists and chemical engineers to design processes, protocols and synthetic methodologies to make their contribution to the broad spectrum of global sustainability. Green synthetic conditions, especially catalysis, are the pillar of green chemistry. Green chemistry principles help synthetic chemists overcome the problems of conventional synthesis, such as slow reaction rates, unhealthy solvents and catalysts and the long duration of reaction completion time, and envision solutions by developing environmentally benign catalysts, green solvents, use of microwave and ultrasonic radiations, solvent-free, grinding and chemo-mechanical approaches. 1,2,4-thiadiazole is a privileged structural motif that belongs to the class of nitrogen–sulfur-containing heterocycles with diverse medicinal and pharmaceutical applications. This comprehensive review systemizes types of green solvents, green catalysts, ideal green organic synthesis characteristics and the green synthetic approaches, such as microwave irradiation, ultrasound, ionic liquids, solvent-free, metal-free conditions, green solvents and heterogeneous catalysis to construct different 1,2,4-thiadiazoles scaffolds. Full article

(This article belongs to the Special Issue Advances in Green Catalysis for Sustainable Organic Synthesis, 2nd Edition)

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