K-10 montmorillonite-catalyzed solid phase diazotizations: environmentally benign coupling of diazonium salts with aromatic hydrocarbons to biaryls DOI
Garima Pandey, Béla Török

Green Chemistry, Journal Year: 2017, Volume and Issue: 19(22), P. 5390 - 5395

Published: Jan. 1, 2017

A new heterogeneous catalytic diazotization and subsequent coupling of diazonium salts with aromatics for the synthesis biaryls is described.

Language: Английский

Green Synthesis of Aromatic Nitrogen-Containing Heterocycles by Catalytic and Non-Traditional Activation Methods DOI Creative Commons

R. Bernadett Vlocskó,

Guoshu Xie, Béla Török

et al.

Molecules, Journal Year: 2023, Volume and Issue: 28(10), P. 4153 - 4153

Published: May 17, 2023

Recent advances in the environmentally benign synthesis of aromatic N-heterocycles are reviewed, focusing primarily on application catalytic methods and non-traditional activation. This account features two main parts: preparation single ring N-heterocycles, their condensed analogs. Both groups include compounds with one, more N-atoms. Due to large number protocols, this focuses providing representative examples feature available methods.

Language: Английский

Citations

17
Organic Synthesis Using Environmentally Benign Acid Catalysis DOI
Anne Kokel, Christian Schäfer, Béla Török

et al.

Current Organic Synthesis, Journal Year: 2019, Volume and Issue: 16(4), P. 615 - 649

Published: Feb. 8, 2019

Recent advances in the application of environmentally benign acid catalysts organic synthesis are reviewed. The work includes three main parts; (i) description catalysts, (ii) with heterogeneous and (iii) homogeneous catalysts. first part provides a brief overview both solid acids (metal oxides, zeolites, clays, ion-exchange resins, metal-organic framework based catalysts) those that soluble green solvents (water, alcohols) at same time could be regenerated after reactions triflates, heteropoly acids, acidic organocatalysts etc.). sections review broad array most common practical such as Friedel-Crafts related (acylation, alkylations, hydroxyalkylations, halogenations, nitrations etc.), multicomponent reactions, rearrangements ring transformations (cyclizations, opening). Both catalytic parts include an asymmetric catalysis chiral Lewis Brønsted acids. Although processes discussed, emphasis is placed on applications commercially available well sustainable nature; thus individual examples critically reviewed regarding their contribution to synthesis.

Language: Английский

Citations

46
Heterogeneous Catalytic Upgrading of Biofuranic Aldehydes to Alcohols DOI Creative Commons

Jingxuan Long,

Yufei Xu,

Wenfeng Zhao

et al.

Frontiers in Chemistry, Journal Year: 2019, Volume and Issue: 7

Published: July 26, 2019

Heterogeneous catalytic conversion of lignocellulosic components into valuable chemicals and biofuels is one the promising ways for biomass valorization, which well meets green chemistry metrics, can alleviate environmental economic issues caused by rapid depletion fossil fuels. Among identified derivatives, furfural (FF) 5-hydroxymethylfurfural (HMF) stand out as rich building blocks be directly produced from pentose hexose sugars, respectively. In past decades, much attention has been attracted to selective hydrogenation FF using various heterogeneous catalysts. This review evaluates recent progress developing different materials, such noble/non-noble metal particles, solid acids/bases, alkali salts, efficient reduction bio-based furanic aldehydes alcohols. Emphasis laid on insights challenges encountered in those transformation processes, along with focus understanding reaction mechanisms clarify role specific active species. Brief outlook also made further optimization systems processes upgrading biofuranic compounds.

Language: Английский

Citations

39
A multicomponent, facile and catalyst-free microwave-assisted protocol for the synthesis of pyrazolo-[3,4-b]-quinolines under green conditions DOI Creative Commons
Mandlenkosi Robert Khumalo,

Surya Narayana Maddila,

Suresh Maddila

et al.

RSC Advances, Journal Year: 2019, Volume and Issue: 9(53), P. 30768 - 30772

Published: Jan. 1, 2019

A facile, swift and ecofriendly microwave-assisted multi-component/one-pot protocol is designed for the synthesis of novel pyrazolo-[3,4-b]-quinolines at ambient temperature in aqueous ethanol as a reaction medium. The 18 pyrazolo-[3,4-b]-quinoline derivatives were synthesized by fusion chosen aryl aldehyde, dimedone 5-amino-3-methyl-1-phenylpyrazole excellent yields (91-98%). All molecular structures confirmed 1H-NMR, 15N-NMR, 13C-NMR, HRMS data analysis. Operational simplicity, easy handling, one-step simple workup procedure, mild conditions, short time (≤10 min), high selectivity no by-product formation are striking features protocol.

Language: Английский

Citations

37
Microwave-assisted liquefaction of carbohydrates for 5-hydroxymethylfurfural using tungstophosphoric acid encapsulated dendritic fibrous mesoporous silica as a catalyst DOI
Srinivasan Vinju Vasudevan,

Xianghai Kong,

Mengjie Cao

et al.

The Science of The Total Environment, Journal Year: 2020, Volume and Issue: 760, P. 143379 - 143379

Published: Nov. 1, 2020

Language: Английский

Citations

37
Regiospecificity in Ligand-Free Pd-Catalyzed C–H Arylation of Indoles: LiHMDS as Base and Transient Directing Group DOI
Y. Mohr, Marc Renom‐Carrasco,

Clément Demarcy

et al.

ACS Catalysis, Journal Year: 2020, Volume and Issue: 10(4), P. 2713 - 2719

Published: Jan. 28, 2020

A highly efficient catalyst–base pair for the C–H arylation of free (NH)-indoles in C-3 position is reported. Ligand-free palladium acetate coupled with lithium hexamethyldisilazide (LiHMDS) catalyzed regiospecific, i.e. 100% regioselective, indoles high turnover numbers. This catalytic system has been successfully applied to a wide range substrates, including various functional aryl halides and indolic cores. The unique role LiHMDS as both base unexpected transient directing group revealed experimentally elucidated computationally, line Heck-type insertion–elimination mechanism.

Language: Английский

Citations

36
Microflow chemistry and its electrification for sustainable chemical manufacturing DOI Creative Commons
Tai-Ying Chen,

Yung Wei Hsiao,

Montgomery Baker-Fales

et al.

Chemical Science, Journal Year: 2022, Volume and Issue: 13(36), P. 10644 - 10685

Published: Jan. 1, 2022

This review presents the recent advancements in utilizing microflow systems combined with plasma and microwave heating for sustainable manufacturing. The technology holds promise increasing process efficiency while minimizing carbon footprint.

Language: Английский

Citations

20
Production of Triacetin by Microwave Assisted Esterification of Glycerol Using Activated Natural Zeolite DOI Creative Commons

H. Marwan,

Eti Indarti,

Darmadi Darmadi

et al.

BULLETIN OF CHEMICAL REACTION ENGINEERING AND CATALYSIS, Journal Year: 2019, Volume and Issue: 14(3), P. 672 - 677

Published: June 3, 2019

Triacetin, an alternative biodiesel additive, was prepared by esterification of glycerol with acetic acid in the presence chemically activated natural zeolite. The carried out a small reaction flask under microwave irradiation. catalyst characterized for its morphology SEM and chemical composition X-ray Diffraction (XRD). Scanning Electron Microscopy (SEM) micrograph indicates improved surface area zeolite, while XRD analysis shows increase Si/Al ratio from zeolite to 6.042 crystallinity value 12.23%. Fourier Transform Infra Red (FTIR) obtained showed that microwave-heated samples have esters group spectrum triacetin at 1702 cm-1. conversion more than 95% molar reactants 1:9 loading 3%. selectivities monoacetin, diacetin were 80.1%, 15.4%, 4.5% 60 minutes, 43.0%, 48.6%, 8.3% 90 minutes. It took place consecutive steps use allows proceeding milder condition.

Language: Английский

Citations

31
Simplified, fast, and efficient microwave assisted chemical recycling of poly (ethylene terephthalate) waste DOI Creative Commons
Karzan H. Zangana,

A. Fernandez,

Justin D. Holmes

et al.

Materials Today Communications, Journal Year: 2022, Volume and Issue: 33, P. 104588 - 104588

Published: Oct. 25, 2022

The widespread adoption of chemical recycling poly (ethylene terephthalate) (PET) is hampered by long reaction times, high energy consumption and the use metal catalysts that are either toxic or cost prohibitive for industrial use. Herein, we report a simple PET glycolytic process combines an environmentally friendly cheap heterogenous catalyst, calcium oxide (CaO) with microwave irradiation to obtain monomer bis(2-hydroxyethyl) terephthalate (BHET), which can be easily separated crystallisation. After optimisation, depolymerisation waste was achieved in 3.5 min under atmospheric pressure, highly crystalline BHET yield 75%. To our knowledge, this fastest heterogeneous reported literature to-date, using eco- catalyst. Moreover, catalyst avoiding need product precipitation water addition, CaO ethylene glycol materials were reused, thus validating protocol as potential green scalable route recycling.

Language: Английский

Citations

19
An efficient and environmentally benign domino protocol for the synthesis of spirodihydropyridines using europium-doped ZnO nanoparticles as recyclable and reusable heterogeneous catalyst DOI
Asha Verma, Surendra Kumar Saini, Lalita Kumari

et al.

Research on Chemical Intermediates, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 24, 2025

Language: Английский

Citations

0