scholarly journals Layered double hydroxides Cu-Al: Synthetic and catalytic applications in the alkylation reaction of indole with benzaldehydes

2016 ◽  
Vol 19 (4) ◽  
pp. 95-102
Author(s):  
Truc Hoang Thanh Nguyen ◽  
Phuong Hoang Tran ◽  
Chinh Quoc Nguyen

Layered double hydroxides derived Cu-Al metal oxides were found to be an efficient catalytic reagent for the reaction of indole benzaldehydes. In this report, we prepared series of (Cu/Al)-CO3 layered double hydroxides with the unchanging ratio of Cu/Al = 3 : 1 and it was subsequently calcinated in air at 500 oC. The materials were characterized by means of Inductively Coupled Plasma emission (ICP), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and, thermogravimetry (TG). The materials were calcinated at 500 oC and tested as catalysts in the alkylation reaction of indole with benzaldehydes.

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 454 ◽  
Author(s):  
Esthela Ramos-Ramírez ◽  
Francisco Tzompantzi-Morales ◽  
Norma Gutiérrez-Ortega ◽  
Héctor G. Mojica-Calvillo ◽  
Julio Castillo-Rodríguez

In recent years, the search for solutions for the treatment of water pollution by toxic compounds such as phenols and chlorophenols has been increasing. Phenols and their derivatives are widely used in the manufacture of pesticides, insecticides, paper, and wood preservers, among other things. Chlorophenols are partially biodegradable but not directly photodegradable by sunlight and are extremely toxic—especially 2,4,6-trichlorophenol, which is considered to be potentially carcinogenic. As a viable proposal to be applied in the treatment of water contaminated with 2,4,6-trichlorophenol, this paper presents an application study of the thermally activated Mg/Fe layered double hydroxides as photocatalysts for the mineralization of this contaminant. Activated Mg/Fe layered double hydroxides were characterized by X-ray diffraction, thermal analysis, N2 physisorption, and scanning electron microscopy with X-ray dispersive energy. The results of the photocatalytic degradation of 2,4,6-trichlorophenol in aqueous solution showed good photocatalytic activity, with an efficiency of degradation of up to 93% and mineralization of 82%; degradation values which are higher than that of TiO2-P25, which only reached 18% degradation. The degradation capacity is attributed to the structure of the MgO–MgFe2O4 oxides derived from double laminate hydroxide Mg/Fe. A path of degradation based on a mechanism of superoxide and hollow radicals is proposed.


Molecules ◽  
2019 ◽  
Vol 24 (15) ◽  
pp. 2695 ◽  
Author(s):  
Mhadmhan ◽  
Marquez-Medina ◽  
Romero ◽  
Reubroycharoen ◽  
Luque

We have successfully incorporated iron species into mesoporous aluminosilicates (AlSBA15) using a simple mechanochemical milling method. The catalysts were characterized by nitrogen physisorption, inductively coupled plasma mass spectrometry (ICP-MS), pyridine (PY) and 2,6-dimethylpyridine (DMPY) pulse chromatography titration, powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). The catalysts were tested in the N-alkylation reaction of aniline with benzyl alcohol for imine production. According to the results, the iron sources, acidity of catalyst and reaction conditions were important factors influencing the reaction. The catalyst showed excellent catalytic performance, achieving 97% of aniline conversion and 96% of imine selectivity under optimized conditions.


Clay Minerals ◽  
2017 ◽  
Vol 52 (2) ◽  
pp. 203-215 ◽  
Author(s):  
Kaouther Abderrazek ◽  
Najoua Frini Srasra ◽  
Ezzeddine Srasra

Abstract[Zn-Al] layered double hydroxides (LDH) with cationic molar ratios of R = Zn/Al 1–5 were synthesized by the coprecipitation method at constant pH = 10. The samples synthesized and their derived forms obtained after calcination at 500°C and at 900°C (denoted Zn-Al-R, Zn-Al-R-500 and Zn-Al-R-900, respectively), were characterized by X-ray diffraction (XRD), inductively coupled plasmamass spectrometry, scanning electron microscopy, energy-dispersive X-ray spectroscopy, diffuse reflectance spectroscopy and nitrogen physisorption at −196°C. The XRD study showed: (1) the presence of accessory ZnO with the LDH in samples synthesized with R ≥ 3; and (2) the lamellar structure was destroyed at 500°C which made room for a poorly ordered ZnO phase, while calcination at 900°C yielded well crystallized ZnO and ZnAl2O4. The photocatalytic activity of the calcined and the unheated samples was evaluated for the decolourization of methylene blue. The photocatalytic activity was dependent on the cationic ratio R and on the calcination temperature. The sample Zn-Al-3 displayed maximum photocatalytic activity. Calcination at 500 and 900°C improved the photocatalytic activity of LDH synthesized at R = 1 and 2.


Catalysts ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 81
Author(s):  
José Castanheiro

Glycerol acetalization with citral was studied using a heteropolyacid (tungstophosphoric acid) supported on KIT-6, as a catalyst, at 100 °C. Different catalysts were synthesized. Catalysts were characterized by scanning electron microscopy (SEM), inductively coupled plasma (ICP), X-ray diffraction (XRD), attenuated total refletion-Fourier transform infrared spectroscopy (ATR-FTIR), and potentiometric titrations. At a fixed time, the glycerol conversion increased with the H3PW12O40 (PW) on KIT-6. PW4-KIT-6 material had a higher conversion than other catalysts. The optimization of glycerol’s acetalization with citral was studied under the PW4-KIT-6 catalyst. After 5 h, it was found that, at T = 100 °C, with m = 0.3 g of solid, molar glycerol:citral = 1:2.25, the conversion of glycerol was 89%. Moreover, the PW4-KTI-6 catalyst showed good catalytic stability.


2019 ◽  
Vol 38 (1) ◽  
pp. 137-157 ◽  
Author(s):  
Qiaojing Zhao ◽  
Yongjie Niu ◽  
Zhizhong Xie ◽  
Kuangming Zhang ◽  
Jinming Zhou ◽  
...  

Coal seams 41 and 42 of the Heshan Coalfield belong to superhigh-organic-sulfur coals. In order to study the geochemical characteristics of the coals, 15 coal samples and 6 rock samples were collected from both coal seams and the roof/floor rocks. The samples were investigated by using conventional microscopy, inductively coupled plasma mass spectroscopy, X-ray diffraction, X-ray fluorescence, and scanning electron microscopy with an energy-dispersive X-ray spectroscopy. The results show that minerals in the coals are dominated by kaolinite and a mixed layer illite/smectite and illite; small ratios of pyrite, quartz, chlorite, smectite, calcite, and dolomite are also present. Under the microscope, these pyrites occur as framboidal, euhedral, homogeneous, anhedral, nodular, and fine dissemination shapes. In Shicun Mine, the trace elements Li, Y, Zr, Sn, Sm, and Tb are enriched; Zn and Ba are depleted. However, in the Heliluoshan Mine, Mo is significantly enriched; Li, Zr, Cs, and U are enriched; and Co and Ba are depleted. The occurrence of Li and Ga is associated mainly with organic matter and sulfate minerals. U and Mo occur in silicate minerals, carbonate minerals, illite, I/S, and pyrite. A reducing environment is beneficial for the enrichment of V, Cr, Mn, Ni, Mo, Cd, and U. The abundances of sulfur in Heshan were controlled mainly by the degree of seawater influence and hydrothermal activities.


Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 736 ◽  
Author(s):  
Aurelija Smalenskaite ◽  
Lina Pavasaryte ◽  
Thomas Yang ◽  
Aivaras Kareiva

The Mg3/Al and Mg3/Al0.99Eu0.01 layered double hydroxides (LDHs) were fabricated using a sol-gel chemistry approach and intercalated with different anions through ion exchange procedure. The influence of the origin of organic anion (oxalate, laurate, malonate, succinate, tartrate, benzoate, 1,3,5-benzentricarboxylate (BTC), 4-methylbenzoate (MB), 4-dimethylaminobenzoate (DMB) and 4-biphenylacetonate (BPhAc)) on the evolution of the chemical composition of the inorganic-organic LDHs system has been investigated. The obtained results indicated that the type and arrangement of organic guests between layers of the LDHs influence Eu3+ luminescence in the synthesized different hybrid inorganic–organic matrixes. For the characterization of synthesis products X-ray diffraction (XRD) analysis, infrared (FTIR) spectroscopy, fluorescence spectroscopy (FLS), and scanning electron microscopy (SEM), were used.


2016 ◽  
Vol 94 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Kamellia Nejati ◽  
Azam Mokhtari ◽  
Fatemeh Khodam ◽  
Zolfaghar Rezvani

In the present work, layered double hydroxides of Mg–Al were synthesized with nitrate interlayer anions in the presence of different types of amines such as ethylenediamine, dimethylamine, and trimethylamine, without a N2 atmosphere, from a homogeneous solution using the coprecipitation method. The concentration of the different types of amines and pH of the solution were adjusted to produce high-purity and -crystallinity samples. The structure and morphology of layered double hydroxides were characterized and investigated by powder X-ray Diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and thermogravimetric analysis techniques. The analyses showed that with increasing amine concentration, both crystallinity and purity of the samples increase at pH 10.5.


2006 ◽  
Vol 118 ◽  
pp. 639-644
Author(s):  
Hye Sung Kim ◽  
Su Chak Ryu

Hydroxyapatite (Ca10(PO4)6(OH)2, HAp) powders is synthesized using the mixed powders of CaCO3 refined from oyster shells and phosphoric acid (H3PO4-98%, Daejung) as starting materials. The characteristic evaluation and chemical analysis of the synthesized powders is performed by X-ray diffraction (XRD), Fourier-transformed infra-red spectroscopy (FT-IR), and inductively-coupled plasma atomic emission spectroscopy (ICPAES). XRD analysis of synthetic powder by heat treatment at 1300°C for 2hrs shows only HAp peaks corresponding to stoichiometric HAp. It is confirmed by ICP-AES test that impurities such as Zn, In, Ti, Ba, Cd, Pb, and Mn, is not detected at all, but small amounts of Ti and Be is observed (0.099ppm Ti and 0.002ppm Ba). Variation of bone density is measured by giving medication of HAp powder with drinking water into human body continuously for three month. After the medication, the bone density is higher than the medication before. This means that HAp powder made from this process can be used as improver of bone density.


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