A novel silver nanoparticle embedded mesoporous polyaniline (mPANI/Ag) nanocomposite as a recyclable catalyst in the acylation of amines and alcohols under solvent free conditions

RSC Advances ◽  
2014 ◽  
Vol 4 (80) ◽  
pp. 42670-42681 ◽  
Author(s):  
Usha Mandi ◽  
Anupam Singha Roy ◽  
Biplab Banerjee ◽  
Sk. Manirul Islam

Highly dispersed silver nanoparticles (Ag NPs) have been embedded into a mesoporous organic polymer (mPANI) and the material showed high catalytic activity in the acylation of amines and alcohols using acetic acid.

Catalysts ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 252 ◽  
Author(s):  
Gabriela Dobras ◽  
Kornela Kasperczyk ◽  
Sebastian Jurczyk ◽  
Beata Orlińska

N-Hydroxyphthalimide was immobilized via ester bond on commercially available silica gel (SiOCONHPI) and then coated with various ionic liquids containing dissolved CoCl2 (SiOCONHPI@CoCl2@IL). New catalysts were characterized by means of FT IR spectroscopy, elemental analysis, SEM and TGA analysis and used in ethylbenzene oxidation with oxygen under mild solvent-free conditions (80 °C, 0.1 MPa). High catalytic activity of SiOCONHPI was proved. In comparison to a non-catalytic reaction, a two-fold increase in conversion of ethylbenzene was observed (from 4.7% to 8.6%). Coating of SiOCONHPI with [bmim][OcOSO3], [bmim][Cl] and [bmim][CF3SO3] containing CoCl2 enabled to increase the catalytic activity in relation to systems in which IL and CoCl2 were added directly to reaction mixture. The highest conversion of ethylbenzene was obtained while SiOCONHPI@CoCl2@[bmim][OcOSO3] were used (12.1%). Catalysts recovery and reuse was also studied.


2019 ◽  
Vol 6 (1) ◽  
pp. 317-325 ◽  
Author(s):  
Yixing Li ◽  
Xiao Zhang ◽  
Ping Xu ◽  
Zimin Jiang ◽  
Jianmin Sun

Novel Zn(PZDC)(ATZ) with Lewis acid–base sites exhibited strong resistance to acids/alkalis and moisture and possessed high catalytic activity for CO2 transformation.


RSC Advances ◽  
2015 ◽  
Vol 5 (17) ◽  
pp. 13239-13245 ◽  
Author(s):  
D. A. Islam ◽  
D. Borah ◽  
H. Acharya

Monodisperse silver nanoparticles supported layered double hydroxides (Ag NPs–LDH) were preferentially deposited on the outer surfaces of pillared LDH offered a high catalytic activity on alcohol oxidation.


NANO ◽  
2018 ◽  
Vol 13 (01) ◽  
pp. 1850003 ◽  
Author(s):  
Yueyue Hao ◽  
Nan Zhang ◽  
Jing Luo ◽  
Xiaoya Liu

In this work, a facile, environmental-friendly and cost-effective method was developed to prepare silver nanoparticles (Ag NPs) in aqueous solution at room temperature. In our approach, tannic acid was employed as the reducing agent and stabilizer simultaneously, avoiding the usage of any toxic agent. The tannic acid derived silver nanoparticles (TA-Ag NPs) were fully characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and thermogravimetric analyzer (TGA). The particle size of the synthesized TA-Ag NPs is tunable from 6.5[Formula: see text]nm to 19.2[Formula: see text]nm with narrow distribution by varying the molar ratio of TA to silver precursor. Efficient reduction of methylene blue (MB) catalyzed by TA-Ag NPs was observed, which was dependent upon the particle size of TA-Ag NPs or the TA concentration used for synthesis. By optimizing the TA concentration, complete reduction of MB was accomplished by TA-Ag NPs within 8[Formula: see text]min. The high catalytic activity of TA-Ag NPs was attributed to their nanosize and good dispersity as well as the electrostatic interaction between TA and MB which induces rapid enrichment of MB towards TA-Ag NPs, creating a locally concentrated layer of MB. Considering the facile and environmental-friendly preparation procedure and excellent catalytic activity, TA-Ag NPs are green, efficient and highly economical candidates for the catalysis of organic dyes and extendable of other reducible contaminants as well.


2012 ◽  
Vol 9 (2) ◽  
pp. 786-790 ◽  
Author(s):  
A. Hassankhani ◽  
E. Mosaddegh ◽  
S. Y. Ebrahimipour

An efficient and environmentally benign protocol for the one-pot, three-component synthesis of 12-aryl-8,9,10,12-tetrahydro-benzo[a]xanthen-11-one derivatives by condensation of aryl aldehydes, 2-naphthol and dimedone using H4SiW12O40(SiWA) as a reusable catalyst with high catalytic activity was reported. The reaction was carried out at 100 ºC under solvent-free conditions within 15-40 min in 82-91% yield.


2021 ◽  
Author(s):  
Qi-An Huang ◽  
Asahi Haruta ◽  
Yuhya Kumamoto ◽  
Haruno Murayama ◽  
Eiji Yamamoto ◽  
...  

Abstract Heterogeneous acid and base catalysts play a crucial role in many important chemical processes. Hard Lewis and Brønsted acid catalysts like silica-alumina and zeolites have been widely applied in numerous reactions; however, developing reusable and active soft Lewis acid catalysts remain a challenge. Herein, we demonstrate for the first time that a highly dispersed supported platinum catalyst can act as a heterogeneous soft Lewis acid. High turnover numbers and reusability were observed in the isomerization of allylic esters under solvent-free conditions. Moreover, the as-prepared catalysts are characterized by X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) analyses, revealing that the highly dispersed Pt clusters with Pt–Cl bonds play a key role in the high activity. The residual chloride anion enhances the Lewis acidity of the Pt metal center and thus improves the catalytic activity. Simultaneously, the high catalytic activity of Pt/CeO2 with residual chloride and the soft Lewis acid mechanism are also proved by density functional theory (DFT) calculations based on the model reaction.


2019 ◽  
Vol 16 (7) ◽  
pp. 1040-1054
Author(s):  
Fatemeh K. Damghani ◽  
Seied A. Pourmousavi ◽  
Hamzeh Kiyani

Background: Carbon-based sulfonated catalysts have several advantages but their separation by filtration is still a challenge. On the other hand, the synthesis of magnetic sulfonated carbon nanoparticle indicated that the magnetic separation could be an efficient way to separate the catalyst from the reaction mixture. Objective: In order to synthesize a separable magnetic Fe3O4@C-SO3H nanoparticle (MNPs) with high catalytic activity in organic transformation, three environmental-benign and low-cost sulfonic acidfunctionalized magnetic nanoparticle (Fe3O4@C-SO3H) were successfully synthesized. Materials and Methods: The Nano catalysts were prepared by solvothermal carbonization of Sucrose (Suc), Starch (Sta) or Cellulose (Cel) in the presence of Fe3O4 Nanoparticle and then grafting of the sulfonic groups on the surface of resulted Fe3O4@C nanoparticles in the presence of p-Toluenesulfonic. Then the Nano catalysts were characterized using XRD, FESEM and FT-IR. Results: Three Fe3O4@C-SO3H were successfully synthesized. The resulted MNPs were used for the synthesis of benzo [4, 5] imidazo[1, 2-a]-pyrimidine derivatives, 2/-aminobenzothiazolomethylnaphthols and 1-amidoalkyl-2-naphthols under solvent-free conditions in excellent yields. It was found that high catalytic activity and easy magnetic separation from the reaction mixture are important achievement with regard to the efficiency and reusability of the catalyst in synthesis. Conclusion: The MNPs were synthesized and used as an efficient catalysts for the one-pot synthesis of benzo [4, 5] imidazo[1, 2-a]-pyrimidine derivatives, 2/-aminobenzothiazolomethylnaphthols, and 1-amidoalkyl-2- naphthols under solvent-free conditions in excellent yields. High catalytic activity and easy magnetic separation from the reaction mixture are two factors for evaluating the performance of Fe3O4@C-SO3H nanoparticles in the organic transformations.


Author(s):  
Mohsen Nikoorazm ◽  
Maryam Khanmoradi ◽  
Masoumeh Sayadian

Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.


Nanoscale ◽  
2018 ◽  
Vol 10 (26) ◽  
pp. 12487-12496 ◽  
Author(s):  
Haichao Duan ◽  
Yu Yang ◽  
Jianhua Lü ◽  
Changli Lü

We report a facile, mussel-inspired construction of a thermo-responsive diblock copolymer-anchored rGO support for superfine PdNPs with high catalytic activity.


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