Synthesis of (E)-2-(1H-tetrazole-5-yl)-3-phenylacrylenenitrile Derivatives Under Green Conditions Catalyzed by New Thermally Stable Magnetic Periodic Mesoporous Ognosilica Embedded With ZnO Nanoparticles

Author(s):  
Sajedeh Safapoor ◽  
Mohammad G. Dekamin ◽  
Arezoo Akbari ◽  
M. Reza Naimi-Jamal

Abstract ZnO nanoparticles embedded on the surface of magnetic isocyanurate-based periodic mesoporous organosilica (Fe3O4@PMO-ICS–ZnO) was prepared through modified environmental-benign procedure for the first time and was properly characterized by appropriate spectroscopic and analytical methods or techniques used for mesoporous materials. The new thermally stable Fe3O4@PMO-ICS–ZnO materials with proper active sites, uniform particle size and surface area were investigated for the synthesis of medicinally important tetrazole derivatives through cascade condensation and concerted reactions as a representative of the Click Chemistry concept. The desired 5-substituted-1H-tetrazole derivatives were smoothly prepared in high to quantitative yields and good purity under green conditions. Low catalyst loading, very short reaction time and the use of green solvents such as EtOH and water instead of carcinogenic DMF as well as the possibility of easy separation and recyclability of the catalyst for at least five consecutive runs without significant loss of its activity are notable advantages of this new protocols compared to other recent introduced procedures.

2020 ◽  
Vol 64 (3) ◽  
Author(s):  
Hu Yu Lin ◽  
Bing Liu Xiao ◽  
Yang Liu

Abstract. A novel type of multifunctional nanocatalysts (La-/Sm-PMO-ILCl) based on the immobilization of benzotriazolium ionic liquid and further incorporation of samarium acetate or lanthanum acetate onto periodic mesoporous organosilica were afforded for the cycloaddition of CO2 and epoxides to produce cyclic carbonates. In consequence of the intramolecular synergistic effect between samarium sites of periodic mesoporous organosilica and homogeneously dispersed basic sites of ionic liquid, the powerful catalyst Sm-PMO-ILCl offered superior catalytic performance with ultra high yields and selectivities in the cycloaddition reaction without the addition of any solvent and cocatalyst. Moreover, the catalyst Sm-PMO-ILCl could be easily recovered by filtration and reused for at least five runs without any significant loss of its catalytic activity. Resumen. Se prepararon nuevos nano catalizadores (La-(Sm-PMO-ILC1) por la vía de inmovilización del líquido iónico benzotriazolium y adición se acetato de samario o acetato de lantano en organosilice mesoporosa. Los catalizadores se evaluaron en la ciclo adición de CO2 y epóxidos para producir carbonatos cíclicos. El efecto sinérgico intramolecular entre los sitios de samario de la organosilice y los sitios básicos del líquido iónico homogéneamente distribuidos inducen una alta actividad catalítica en el catalizador Sm-PMO-ILC1. Así, con este catalizador se obtuvo alta conversión y selectividad en la reacción de ciclo adición, sin agregar solvente ni co-catalizador. Además, el catalizador Sm-PMO-ILC1 podría recuperarse fácilmente por filtración y reusado por al menos 5 corridas sin pérdida significativa de su actividad catalítica.


Author(s):  
Norshahidatul Akmar Mohd Shohaimi ◽  
Norfakhriah Jelani ◽  
Ahmad Zamani Ab Halim ◽  
Nor Hakimin Abdullah ◽  
Nurasmat Mohd Shukri

: The presence of relatively high naphthenic acid in crude oil may contribute to the major corrosion in oil pipelines and distillation units in crude oil refineries. Thus, high concentration Naphthenic Acids crude oil is considered tobe of low quality and is marketed at lower prices. In order to overcome this problem, neutralization method had been developed to reduce the TAN value in crude oil. In this study, crude oil from Petronas Penapisan Melaka was investigated. The parameters studied were reagent concentration, catalyst loading, calcination temperature and reusability of the potential catalyst. Basic chemical used were 2- methylimidazole in polyethylene glycol (PEG 600) with concentration 100, 500 and 1000 ppm. Cerium oxide-based catalysts supported onto alumina prepared with different calcination temperatures. The catalyst was characterized by using Brunauer-Emmett-Teller (BET), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetry Analysis-Differential Thermal Gravity (TGA-DTG) to study physical properties of the catalyst. The Ce/Al2O3 catalyst calcined at 1000°C was the best catalyst due to larger surface area formation which lead to increment of active sites thus will boost the catalytic activity. The result showed that the Ce/Al2O3 catalyst meet Petronas requirement as the TAN value reduced to 0.6 mgKOH/g from original TAN value of 4.22 mgKOH/g. The best reduction of TAN was achieved by using catalyst loading of 0.39% and reagent of 1000 ppm.


Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 482
Author(s):  
Hilmar Guzmán ◽  
Federica Zammillo ◽  
Daniela Roldán ◽  
Camilla Galletti ◽  
Nunzio Russo ◽  
...  

Electrochemical CO2 reduction is a promising carbon capture and utilisation technology. Herein, a continuous flow gas diffusion electrode (GDE)-cell configuration has been studied to convert CO2 via electrochemical reduction under atmospheric conditions. To this purpose, Cu-based electrocatalysts immobilised on a porous and conductive GDE have been tested. Many system variables have been evaluated to find the most promising conditions able to lead to increased production of CO2 reduction liquid products, specifically: applied potentials, catalyst loading, Nafion content, KHCO3 electrolyte concentration, and the presence of metal oxides, like ZnO or/and Al2O3. In particular, the CO productivity increased at the lowest Nafion content of 15%, leading to syngas with an H2/CO ratio of ~1. Meanwhile, at the highest Nafion content (45%), C2+ products formation has been increased, and the CO selectivity has been decreased by 80%. The reported results revealed that the liquid crossover through the GDE highly impacts CO2 diffusion to the catalyst active sites, thus reducing the CO2 conversion efficiency. Through mathematical modelling, it has been confirmed that the increase of the local pH, coupled to the electrode-wetting, promotes the formation of bicarbonate species that deactivate the catalysts surface, hindering the mechanisms for the C2+ liquid products generation. These results want to shine the spotlight on kinetics and transport limitations, shifting the focus from catalytic activity of materials to other involved factors.


2021 ◽  
Vol 287 ◽  
pp. 119965
Author(s):  
Yasutomo Goto ◽  
Ken-ichi Yamanaka ◽  
Masataka Ohashi ◽  
Yoshifumi Maegawa ◽  
Shinji Inagaki

2019 ◽  
Vol 30 (4) ◽  
pp. 929-932 ◽  
Author(s):  
Xiaodan Su ◽  
Jun Tao ◽  
Qing Wang ◽  
Peng Xu ◽  
Wei Luo ◽  
...  

2019 ◽  
Vol 7 (26) ◽  
pp. 8109-8119 ◽  
Author(s):  
Anna M. Kaczmarek ◽  
Pascal Van Der Voort

Nano-sized PMOs grafted with lanthanides show selective ion sensing for Pb2+ and Cr3+ and strong solvatochromism allowing their use as protic and aprotic solvent sensors.


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