A facile synthesis of clay – graphene oxide nanocomposite catalysts for solvent free multicomponent Biginelli reaction

Narayanan, Divya P.; Gopalakrishnan, Anila; Yaakob, Zahira; Sugunan, S.; Narayanan, Binitha N.

doi:10.1016/j.arabjc.2017.04.011

Cited by 60 publications

(23 citation statements)

References 70 publications

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“…In continuation of our research works on the development of highly efficient green heterogeneous catalysts for MCRs, [34][35][36][37] herein we report the use of novel CHA -twisted graphene nanocomposites for multicomponent Biginelli reaction. To the best our knowledge, this is the first report on in situ exfoliation of graphite to graphene with further composite formation using ash derived from naturally available waste materials.…”

Section: Introductionmentioning

confidence: 99%

A Green Approach for the Synthesis of Coconut Husk Ash –Twisted Graphene Nanocomposites: Novel Catalysts for Solvent‐Free Biginelli Reaction

et al. 2019

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Herein we report an easy, scalable, cost‐effective and green synthesis of twisted graphene from bulk graphite by a ball milling technique with the in situ formation of novel coconut husk ash (CHA) ‐ twisted graphene nanocomposite and its catalytic application towards multicomponent Biginelli reaction. Here the ash derived from naturally available waste material (coconut husk) is effectively used as an exfoliating agent for the scissoring of graphene layers from bulk graphite for the first time. The elemental analysis data obtained by inductively coupled plasma atomic emission spectroscopy (ICP‐AES) provided useful information regarding the composition of CHA and the nanocomposites. The X‐ray diffraction (XRD) patterns confirmed the exfoliation of graphite into graphene layers. Raman spectroscopic analysis evaluated the quality and the nature of graphene layers in the composites. X‐ray photoelectron spectroscopy (XPS) analysis confirmed the bonding between the graphene layers and CHA particles. Transmission electron microscopy (TEM) images revealed the presence of few layered graphene as well as twisted graphene in the composites. The CHA – twisted graphene nanocomposite is found to be an excellent reusable catalyst for Biginelli reaction with a higher yield of 3,4‐dihydropyrimidinones within short duration of reaction.

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Section: Introductionmentioning

confidence: 99%

A Green Approach for the Synthesis of Coconut Husk Ash –Twisted Graphene Nanocomposites: Novel Catalysts for Solvent‐Free Biginelli Reaction

et al. 2019

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“…Compared with the XPS spectra of clay-GO nanocomposite before thermal treatment, the Si/Al-O-C and Si-O-Al bonds in the spectra of Si(2p) and Al(2p) appeared after thermal treatment. This implies that covalent bonding formed between the clay and GO, which is critical for the reinforcement efficiency of graphene [29]. It is also worth noting that the large area of the Si-O-C peak suggests the broad dispersion of GO in the nanocomposite.…”

Section: Resultsmentioning

confidence: 94%

“…Before sintering, the characteristic peaks of 3695 cm −1 , 3618 cm −1 and 3445 cm −1 reflect the stretching vibration of -OH: 3695 cm −1 corresponds to the -OH vibration in the kaolinite interlayer, 3618 cm −1 corresponds to the -OH vibration between the kaolinite silicon layer and the aluminum layer, and 3445 cm −1 corresponds to the vibration of -OH in the absorbed water in the sample [4,30,31]. Besides, the characteristic peak 1626 cm −1 represents the bending vibration of -OH in absorbed water and the vibration of aromatic C=C in GO [29,31]. After sintering, the characteristic peaks at 3695 cm −1 , 3618 cm −1 and 3445 cm −1 disappeared due to dehydration and dehydroxylation during heating [4,27,31].…”

Section: Resultsmentioning

confidence: 99%

“…Only a weak peak near 1626 cm −1 can be obtained, which is the vibration of aromatic C=C in GO. Before sintering, the peaks in the FTIR spectra corresponding to 1043 cm −1 , 774 cm -1 , 691 cm −1 , and 476 cm −1 are generated by Si-O vibration in quartz and kaolinite [29,31]. A peak of 917 cm −1 is generated by the bending vibration of Al-OH, and 535 cm −1 is generated by the vibration of Al-O in the kaolinite [27].…”

Section: Resultsmentioning

confidence: 99%

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Self-Heating Graphene Nanocomposite Bricks: A Case Study in China

Tang

Gong

et al. 2020

Materials

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In cold climate regions, the energy associated with indoor heating constitutes a large portion of energy consumption. Increasing energy utilization efficiency is critically important for both economic and environmental reasons. Directly converting electrical energy to thermal energy using joule heating construction elements can save energy and investment to the water pipelines which have been extensively used for indoor heating in China. The fired brick has been extensively used to make pavements, walls and other masonry. Taking advantage of the high dispersion quality of graphene oxide (GO) in water, as well as the firing process used to make fired bricks, graphene nanocomposite bricks with excellent electrical properties and improved mechanical performance were prepared in China. The compressive strength of the bricks showed a substantial increase from 3.15 MPa to 7.21 MPa when GO concentration was 0.1 wt.%. Through applying 5 volts of electrical field within 5 minutes, the nanocomposites can be heated from room temperature to 60 °C, 110 °C and 160 °C for the nanocomposite bricks with graphene concentration of 3 wt.%, 4 wt.% and 5 wt.%, respectively, due to the extremely low percolation threshold (~0.5 wt.%) and high conductivity (10 Ω·cm at 1 wt.%). The sheets were connected more tightly when the GO content was increased. The thermal efficiency can reach up to 88% based on the applied voltage, measured resistance and temperature rise curves.

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“…Even though these methods are effective, many of them are associated with drawbacks such as harsh reaction conditions such as strongly acidic condition, prolonged reaction times, meticulous work-up protocols, expensive and moisture sensitive starting materials and unsatisfactory yields. Even though, Biginelli reaction has history of over a century, and lot of work is being published by the researchers in the recent past, [17][18][19] there is a lack literature precedent for the use of gem-dibromomethylarene as substrates for the synthesis of 5-unsubstituted 3,4-dihydropyrimidin-2-ones and thiones. The substitution of aldehyde component with another functional group has not been explored so far.…”

Section: Introductionmentioning

confidence: 99%

Biginelli‐type reaction: Efficient synthesis of 5‐unsubstituted 3,4‐dihydropyrimidin‐2‐ones and thiones fromgem‐dibromomethylarenes

Vinaya¹,

Kotturappa²,

Manjunath³

et al. 2020

Journal of Heterocyclic Chem

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In the present study, we are reporting a simple and efficient method for the one‐pot synthesis of the biologically important heterocyclic molecules 5‐unsubstituted 3,4‐dihydropyrimidin‐2‐ones and thiones using gem‐dibromomethylarenes, oxalacetic acid, and urea or thiourea. Gem‐dibromomethylarenes are used as aldehyde equivalent for the efficient synthesis of 3,4‐dihydropyrimidin‐2‐ones/thiones. This reaction offers advantages for the synthesis of these compounds, including ready availability of the starting materials, experimental simplicity and in good yields. Besides, the synthesized molecules are interesting for their biological and pharmacological actions.

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A facile synthesis of clay – graphene oxide nanocomposite catalysts for solvent free multicomponent Biginelli reaction

Cited by 60 publications

References 70 publications

A Green Approach for the Synthesis of Coconut Husk Ash –Twisted Graphene Nanocomposites: Novel Catalysts for Solvent‐Free Biginelli Reaction

A Green Approach for the Synthesis of Coconut Husk Ash –Twisted Graphene Nanocomposites: Novel Catalysts for Solvent‐Free Biginelli Reaction

Self-Heating Graphene Nanocomposite Bricks: A Case Study in China

Biginelli‐type reaction: Efficient synthesis of 5‐unsubstituted 3,4‐dihydropyrimidin‐2‐ones and thiones fromgem‐dibromomethylarenes

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