scholarly journals Trimesic Acid-Functionalized Chitosan: A Novel And Efficient Multifunctional Organocatalyst For Green Synthesis of Polyhydroquinolines And Acridinediones Under Mild Conditions

2021 ◽  
Author(s):  
Rahman Beiranvand ◽  
Mohammad G. Dekamin
Keyword(s):  
Active Sites ◽  
Simple Procedure ◽  
Xrd Analysis ◽  
Significant Loss ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Trimesic Acid ◽  
Mild Conditions ◽  
Hantzsch Condensation

Abstract Trimesic acid-functionalized chitosan (Cs/ECH-TMA) material was prepared through a simple procedure by using chitosan (Cs), epichlorohydrin (ECH) and trimesic acid (TMA). The obtained bio-based Cs/ECH-TMA material was characterized using energy-dispersive X-ray (EDX) and Fourier-transform infrared spectroscopy (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) analysis. The Cs/ECH-TMA material was successfully used, as a multifunctional heterogeneous and sustainable catalyst, for efficient and expeditious synthesis of medicinally important polyhydroquinoline (PHQ) and polyhydroacridinedione (PHA) scaffolds through the Hantzsch condensation in a one-pot reaction. Indeed, the heterogeneous Cs/ECH-TMA material can be considered as a synergistic multifunctional organocatalyst due to the presence of a large number of acidic active sites in its structure as well as hydrophilicity. Both PHQs and PHAs were synthesized in the presence of biodegradable heterogeneous Cs/ECH-TMA catalytic system from their corresponding substrates in EtOH under reflux conditions and high to quantitative yields. The Cs/ECH-TMA catalyst is recyclable and can be reused at least four times without significant loss of its catalytic activity.

Carboxyl graphene reinforced melamine-based polyamide nanocomposites

2021 ◽  
pp. 089270572110514
Author(s):  
Himanshu V Madhad ◽  
Dilip V Vasava
Keyword(s):  
Electron Microscopy ◽  
Decomposition Temperature ◽  
Differential Scanning Calorimetric ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Mild Conditions ◽  
Thermal Stability Of ◽  
Infrared Techniques ◽  
Scanning Electron

Over the years, various types of techniques have been used for the synthesis of nanocomposites. In this work, melamine-based polyamide (PA) was synthesized using a one-pot polycondensation method under mild conditions. carboxyl graphene (CG)/PA nanocomposites (CGMPA) were prepared by CG nanofiller loadings of 1, 3, and 5 wt.% via delamination/adsorption approach. The prepared CGMPA nanocomposites were characterized using different analyses, such as Fourier transform infrared techniques (FTIR), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), differential scanning calorimetric (DSC), and thermogravimetric analysis (TGA). The effects of the CG on the thermal properties of the CGMPA nanocomposites were significant. The results showed that the melting temperature (Tm) of neat PA and CGMPA were increased from 378°C to 393°C suggested better dispersion of CG in PA matrix. The decomposition temperature of PA was increased from 451°C to 463°C in CGMPA nanocomposites indicates the better thermal stability of PA matrix by addition of CG.

scholarly journals Ferrocene-Containing Ionic Liquid Supported on Silica Nanospheres (SiO2@Imid-Cl@Fc) as a Mild and Efficient Heterogeneous Catalyst for the Synthesis of Pyrano[3,2-b]Pyran Derivatives Under Ultrasound Irradiation

2018 ◽  
Vol 42 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Reza Teimuri-Mofrad ◽  
Somayeh Esmati ◽  
Masoumeh Rabiei ◽  
Mahdi Gholamhosseini-Nazari
Keyword(s):  
Ionic Liquid ◽  
Reaction Times ◽  
Aromatic Aldehydes ◽  
Ultrasound Irradiation ◽  
Xrd Analysis ◽  
Catalytic Performance ◽  
Significant Loss ◽  
One Pot ◽  
X Ray ◽  
Three Component Reaction

A novel heterogeneous silica nanosphere-supported ferrocene-containing ionic liquid catalyst (SiO2@Imid-Cl@Fc) was designed and synthesised and was systematically characterised by Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) analysis. The catalytic activity of the SiO2@Imid-Cl@Fc catalyst was tested in a one-pot, three-component reaction of malononitrile and kojic acid with 15 aromatic aldehydes at room temperature under ultrasound irradiation. The products were pyrano[3,2-b]pyran derivatives, four of which are new. The catalyst exhibited good catalytic performance over short reaction times (15–20 min) and could be recycled at least five times without significant loss of activity.

scholarly journals Enhancement of Mercury Removal by Utilizing Catalytic Chelation Technique

2020 ◽  
Vol 10 (5) ◽  
pp. 6354-6364
Keyword(s):  
Heavy Metals ◽  
Active Sites ◽  
Catalyst Surface ◽  
Chelating Agent ◽  
Xrd Analysis ◽  
Mercury Removal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cold Vapor Atomic Absorption ◽  
Time Of Reaction

Discharge of heavy metals released from industries has adverse effects on the environment. The development of a method that can safely remove heavy metals is still challenging. Therefore, the aim of this study is to propose catalytic chelation technique for the removal of mercury (Hg). Removal of Hg was carried out using the sodium acetate (CH3COONa) as the chelating agent and catalyzed by the heterogeneous alumina supported calcium oxide (CaO/Al2O3). The optimization was performed by applying the Response Surface Methodology (RSM) with the pH ranging from 7 to 10, a dosage of chelating agent from 400 ppm to 600 ppm, temperature from 33.5 to 37.5 oC, and time of reaction from 1 to 5 h. Hg content analysis was carried out using Flow Injection Mercury System based on cold vapor atomic absorption spectroscopy. X-ray diffraction (XRD) analysis revealed the presence of active sites on the catalyst. Field Emission Scanning Electron Microscopy (FESEM) analysis represented the formation of homogeneous particles on the catalyst surface. The Brunauer-Emmett-Teller (BET), Energy Dispersive X-Ray (EDX), and Fourier-transform Infrared Spectroscopy (FTIR) confirmed the surface area, the elemental composition, and functional groups of the catalyst, respectively. Moreover, the proposed method successfully achieved ±99 % of Hg removal.

scholarly journals Copper(II) Anchored on Amine-Functionalized MMT: A Highly Efficient Catalytic System for the One-Pot Synthesis of Bispyrano[2,3-c]pyrazole Derivatives

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Majid Ahmadzadeh ◽  
Masoud Sadeghi ◽  
Javad Safari
Keyword(s):  
Condensation Reaction ◽  
Significant Loss ◽  
Pyrazole Derivatives ◽  
X Ray Diffraction ◽  
Phenyl Hydrazine ◽  
One Pot ◽  
X Ray ◽  
Amine Functionalized ◽  
The One ◽  
High Yields

In this study, preparation of pyridine-2-carboimine copper complex immobilized on amine-functionalized nanoclay montmorillonite K10 was reported. The products were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and thermogravimetric analysis (TGA). The catalytic activity of this new nanocatalyst, as a natural, renewable, inexpensive, and heterogeneous catalyst, was very effective for the four-component condensation reaction of hydrazine hydrate (or phenyl hydrazine), malononitrile, β-ketoester, and terephthalaldehyde (or isophthalaldehyde) toward the synthesis of multisubstituted bispyrano[2,3-c]pyrazole derivatives. From the viewpoint of green chemistry, the advantages of this approach are accessibility, simplicity, and high yields synthesis. The catalyst was recycled and reused four times without significant loss of activity.

scholarly journals ZnO-Activated Carbon Blended as a Catalyst for Oxidative Desulfurization of Dibenzothiophene

2021 ◽  
Vol 16 (4) ◽  
pp. 881-887
Author(s):  
Wega Trisunaryanti ◽  
Maria Ulfa ◽  
Yatim Lailun Nikmah ◽  
Satriyo Dibyo Sumbogo ◽  
Safa Annissa Novianti ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Reaction Time ◽  
Surface Area ◽  
Simple Procedure ◽  
Oxidative Desulfurization ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Desulfurization Process ◽  
Physical Blending

The problem of sulfur content in heavy oil is a challenge for researchers to meet the needs of environmentally friendly fuels. The catalyst preparation plays an important role in the desulfurization process. The synthesis of ZnO-activated carbon as a catalyst and its activity in oxidative desulfurization (ODS) reaction has been successfully carried out. In this work, the ZnO and activated carbon (AC) were blended by a solid-solid reaction. The ZnO, AC, and ZnO-AC were then characterized using acidity test with pyridine vapor adsorption, Fourier Transform Infra-Red (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscope-Energy Dispersive X-Ray (SEM-EDX), and Surface Area Analyzer (SAA). ODS of dibenzothiophene (DBT) reaction was performed by using H2O2 under variation of the reaction time (30, 60, 120, and 150 min) for the ZnO-AC catalyst. The efficiency of ODS-DBT was analyzed by a UV-Visible spectrophotometer. The XRD analysis result showed that ZnO-AC blended displays new crystal peaks of Zn in the AC diffractogram. The surface area (734.351 m2/g) and acidity (4.8780 mmol/g) of ZnO-AC were higher than ZnO and AC themselves. ZnO-AC produced the highest efficiency of ODS-DBT which was 93.83% in the reaction time of 120 min. Therefore, the simple procedure of this physical blending was proved effective to homogenize between ZnO and AC into ZnO-AC so that it has good physicochemical properties as an ODS-DBT catalyst. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

scholarly journals One-pot Selective Conversion of Biomass-derived Furfural into Cyclopentanone/Cyclopentanol over TiO2 Supported Bimetallic Ni-M (M = Co, Fe) Catalysts

2020 ◽  
Vol 15 (1) ◽  
pp. 231-241 ◽  
Author(s):  
Maria Dewi Astuti ◽  
Ditya Kristina ◽  
Rodiansono Rodiansono ◽  
Dwi Rasy Mujiyanti
Keyword(s):  
Acid Site ◽  
Xrd Analysis ◽  
Acid Sites ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
One Pot ◽  
X Ray ◽  
Selective Conversion ◽  
Temperature Programmed ◽  
High Yields

One-pot selective conversion of biomass-derived furfural (FFald) into cyclopentanone (CPO) or cyclopentanol (CPL) using bimetallic nickel-based supported on TiO2 (denoted as Ni-M(3.0)/TiO2; M = Co and Fe; 3.0 is Ni/M molar ratio) have been investigated. Catalysts were synthesized via a hydrothermal method at 150 °C for 24 h, followed by H2 reduction at 450 °C for 1.5 h. X-ray Diffraction (XRD) analysis  showed that the formation of Ni-Co alloy phase at 2θ = 44.2° for Ni-Co(3.0)/TiO2 and Ni-Fe alloy at 2θ = 44.1° for Ni-Fe(3.0)/TiO2. The amount of acid sites was measured by using ammonia-temperature programmed desorption (NH3-TPD). Ni-Co(3.0)/TiO2 has three NH3 desorption peaks at 180 °C, 353 °C, and 569 °C with acid site amounts of 1.30 µmol.g-1, 1.0 µmol.g-1, and 2.0 µmol.g-1,        respectively. On the other hand, Ni-Fe(3.0)/TiO2 consisted of NH3 desorption peaks at 214 °C and 626 °C with acid site amounts of 3.3 µmol.g-1and 2.0 µmol.g-1, respectively. Both Ni-Co(3.0)/TiO2 and Ni-Fe(3.0)/TiO2 catalysts were found to be active for the selective hydrogenation of FFald to furfuryl alcohol (FFalc) at low temperature of 110 °C, H2 3.0 MPa, 3 h with FFalc selectivity of 81.1% and 82.9%, respectively. High yields of CPO (27.2%) and CPL (41.0%) were achieved upon Ni-Fe(3.0)/TiO2 when the reaction temperature was increased to 170 °C, 3.0 MPa of H2, and a reaction time of 6 h. The yield of CPO+CPL on the reused catalyst decreased slightly after the second reaction run, but the activity was maintained for at least three consecutive runs. Copyright © 2020 BCREC Group. All rights reserved

Identification of acid-insoluble filter-plugging compounds and optimal acid-washing procedures for tubular backpulse pressure filters

TAPPI Journal ◽  
2011 ◽  
Vol 10 (1) ◽  
pp. 17-23
Author(s):  
KEVIN TAYLOR ◽  
RICH ADDERLY ◽  
GAVIN BAXTER
Keyword(s):  
Calcium Sulfate ◽  
Membrane Filter ◽  
Sulfamic Acid ◽  
Xrd Analysis ◽  
Metal Sulfides ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gypsum Formation ◽  
Acid Washing ◽  
Hydrolysis Of

Over time, performance of tubular backpulse pressure filters in kraft mills deteriorates, even with regular acid washing. Unscheduled filter replacement due to filter plugging results in significant costs and may result in mill downtime. We identified acid-insoluble filter-plugging materials by scanning electron microscope/energy-dispersion X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) analysis in both polypropylene and Gore-Tex™ membrane filter socks. The major filter-plugging components were calcium sulfate (gypsum), calcium phosphate (hydroxylapatite), aluminosilicate clays, metal sulfides, and carbon. We carried out detailed sample analysis of both the standard acid-washing procedure and a modified procedure. Filter plugging by gypsum and metal sulfides appeared to occur because of the acid-washing procedure. Gypsum formation on the filter resulted from significant hydrolysis of sulfamic acid solution at temperatures greater than 130°F. Modification of the acid-washing procedure greatly reduced the amount of gypsum and addition of a surfactant to the acid reduced wash time and mobilized some of the carbon from the filter. With surfactant, acid washing was 95% complete after 40 min.

An unusual reaction of a bridged triterpenoid α-diketone with acetic anhydride

1991 ◽  
Vol 56 (12) ◽  
pp. 2917-2935 ◽  
Author(s):  
Eva Klinotová ◽  
Václav Křeček ◽  
Jiří Klinot ◽  
Miloš Buděšínský ◽  
Jaroslav Podlaha ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Acetic Anhydride ◽  
Spectral Methods ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mild Conditions ◽  
Condensation Products ◽  
Unsaturated Lactones ◽  
C Nmr

3β-Acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) reacts with acetic anhydride in pyridine under very mild conditions affording β-lactone IVa and γ-lactones Va and VIIa as condensation products. On reaction with pyridine, lactones Va and VIIa undergo elimination of acetic acid to give unsaturated lactones VIIIa and IXa, respectively. Similarly, the condensation of 20β,28-epoxy-21,22-dioxo-18α,19βH-ursan-3β-yl acetate (IIIb) with acetic anhydride leads to β-lactone IVb and γ-lactone Vb; the latter on heating with pyridine affords unsaturated lactone VIIIb and 21-methylene-22-ketone Xb. The structure of the obtained compounds was derived using spectral methods, particularly 1H and 13C NMR spectroscopy; structure of lactone IVa was confirmed by X-ray diffraction.

Role of the Structure and Electronic Properties of Fe2O3-MoO3 Catalyst on the Dehydration of Isopropyl Alcohol

1993 ◽  
Vol 58 (7) ◽  
pp. 1591-1599 ◽  
Author(s):  
Abd El-Aziz A. Said
Keyword(s):  
Active Sites ◽  
Isopropyl Alcohol ◽  
Oxide Catalyst ◽  
Flow System ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalyst Composition ◽  
Surface Active

Molybdenum oxide catalyst doped or mixed with (1 - 50) mole % Fe3+ ions were prepared. The structure of the original samples and the samples calcined at 400 °C were characterized using DTA, X-ray diffraction and IR spectra. Measurements of the electrical conductivity of calcined samples with and without isopropyl alcohol revealed that the conductance increases on increasing the content of Fe3+ ions up to 50 mole %. The activation energies of charge carriers were determined in presence and absence of the alcohol. The catalytic dehydration of isopropyl alcohol was carried out at 250 °C using a flow system. The results obtained showed that the doped or mixed catalysts are active and selective towards propene formation. However, the catalyst containing 40 mole % Fe3+ ions exhibited the highest activity and selectivity. Correlations were attempted to the catalyst composition with their electronic and catalytic properties. Probable mechanism for the dehydration process is proposed in terms of surface active sites.

Physicochemical and Catalytic Properties of Spinels Formed by Solid-Solid Interaction Between Fe2O3and V2O5

1996 ◽  
Vol 61 (8) ◽  
pp. 1131-1140 ◽  
Author(s):  
Abd El-Aziz Ahmed Said
Keyword(s):  
Vanadium Oxide ◽  
Active Sites ◽  
Catalyst Surface ◽  
Catalytic Properties ◽  
Flow System ◽  
Oxide Catalysts ◽  
X Ray Diffraction ◽  
Selective Catalyst ◽  
X Ray ◽  
Solid Catalysts

Vanadium oxide catalysts doped or mixed with 1-50 mole % Fe3+ ions were prepared. The structure of the original samples and those calcined from 200 up to 500 °C were characterized by TG, DTA, IR and X-ray diffraction. The SBET values and texture of the solid catalysts were investigated. The catalytic dehydration-dehydrogenation of isopropanol was carried out at 200 °C using a flow system. The results obtained showed an observable decrease in the activity of V2O5 on the addition of Fe3+ ions. Moreover, Fe2V4O13 is the more active and selective catalyst than FeVO4 spinels. The results were correlated with the active sites created on the catalyst surface.

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