96238-12-9Relevant academic research and scientific papers
Phosphorous acid functionalized polyacrylonitrile fibers with a polarity tunable surface micro-environment for one-pot C-C and C-N bond formation reactions
Xu, Gang,Wang, Lu,Li, Mengmeng,Tao, Minli,Zhang, Wenqin
, p. 5818 - 5830 (2017)
The preparation and application of fiber catalysts have attracted much attention. However, research on the effect of the micro-environment of fiber catalysts on the catalytic activities though of special importance is limited. In this work, a novel strategy for the synthesis of phosphoric acid-functionalized polyacrylonitrile fibers with a polarity tunable surface micro-environment by hydrophobic groups for one-pot C-C and C-N bond formation reactions is reported. The special hydrophobic surface micro-environment of the fiber catalysts is proven to promote the catalytic activities impressively in cyclocondensation of β-ketoesters with 2-aminobenzamides, the Knoevenagel condensation as well as the multi-component Biginelli reactions in green solvents. Both the surface synergy of the catalytic sites and hydrophobic auxiliary groups (benzyl or n-butyl) in the surface of fiber catalysts and interface acceleration in reaction medium play an important role in the highly efficient promotion of catalytic activity. Thereby a surface synergistic mechanism is proposed to explain the micro-environment effect. In addition, the fiber catalysts could be simply separated from the reaction system using tweezers and directly used in the next cycle without further treatment. Importantly, even after 10 reaction cycles in water or ethanol, there is no significant loss in their catalytic activity. The results indicate that the phosphoric acid functionalized fibers show green and sustainable potential for industrial production.
Successive oxidation-condensation reactions using a multifunctional gold-supported nanocomposite (Au/MgCe-HDO)
Chandra, Ramesh,Kumar, Loveneesh,Kumar, Rupesh,Sehrawat, Hitesh,Tomar, Ravi,Verma, Nishant
, p. 3472 - 3481 (2022/02/21)
The application of gold-supported nanocomposites is useful in clinical diagnostics because of their ability to provide bio-compatible and sensitive detection systems. A gold-supported magnesium hydroxide and cerium oxide nanocomposite framework (Au/MgCe-HDO) was synthesized and characterized via XRD, XPS, SEM, DLS, TEM, and TGA techniques. The nanocomposite was used as a selective catalyst for the aerobic oxidation of alcohols under mild reaction conditions followed by successive condensation reactions, like Knoevenagel and Claisen-Schmidt condensation. Substituted benzyl alcohols were converted into the corresponding carbonyl compounds in the presence of the Au/MgCe-HDO nanocomposite with O2 gas and toluene as a solvent. We observed that, upon the addition of malononitrile/ethyl cyanoacetate/acetophenone to the catalyst in the aerobic oxidation reaction, the reaction proceeds to produce the corresponding desired condensation product with up to 95% yield.
Highly Active Copper(I)-Chalcogenone Catalyzed Knoevenagel Condensation Reaction Using Various Aldehydes and Active Methylene Compounds
Mannarsamy, Maruthupandi,Prabusankar, Ganesan
, (2021/10/05)
First copper(I) chalcogenones catalysed Knoevenagel Condensation reactions have been reported. No illustration of the utilization of this copper-chalcogenone complex class in Knoevenagel Condensation catalysis can be found. Thus, copper(I) bis(benzimidazole-2-chalcogenone) catalysts [Cu(L1)4]+BF4? (1) and [Cu(L2)4]+BF4? (2) (L1 = bis(1-isopropyl-benzimidazole-2-selone)-3-ethyl; L2 = bis(1-isopropyl-benzimidazole-2-thione)-3-ethyl) have been utilized as catalysts in the Knoevenagel Condensation reactions. These copper(I) chalcogenone catalysts have shown high efficiency for the catalytic Knoevenagel Condensation of aryl aldehydes and active methylene compounds. In particular, complex 2, exhibit the best catalytic activities. The scope of the catalytic reactions has been investigated with 22 different molecules. The excellent catalytic activity has been depicted for various types of substrates with either electron-rich or deficient aryl aldehydes. The present investigation features relatively mild reaction conditions with good functional group tolerance and excellent yields. Graphic Abstract: The first copper(I)-chalcogenone complexes catalysed Knoevenagel Condensation reactions?have also been investigated, and revealed the best catalytic activities. [Figure not available: see fulltext.]
Biguanide-functionalized hierarchical porous covalent organic frameworks for efficient catalysis of condensation reactions
Feng, Huiru,Gong, Kai,Li, Cunhao,Li, Haoran,Wang, Yunyun,Zhang, Daquan,Zhang, Huimin
, (2021/07/21)
Covalent organic frameworks (COFs) can be rationally designed with desired physicochemical properties for a far-ranging application in catalytic systems. Herein, a biguanide-functionalized covalent organic framework was designed and prepared via N-alkylat
Highly active zinc oxide-supported lithium oxide catalyst for solvent-free Knoevenagel condensation
Basude, Manohar,Bhongiri, Yadagiri,Masula, Keshavulu,Pasala, Vijay Kumar,Puppala, Veerasomaiah,Sunkara, Prasad
, (2021/07/09)
Li2O/ZnO catalyst was prepared by wet impregnation method and characterized by XRD, SEM, EDX, FTIR, BET surface area and UV-Vis diffuse reflectance spectroscopy. This study revealed a decrease in average particle size and change in the shape of
Engineering cellulose into water soluble poly(protic ionic liquid) electrolytes in the DBU/CO2/DMSO solvent system as an organocatalyst for the Knoevenagel condensation reaction
Shen, Yuqing,Yuan, Chaoping,Zhu, Xianyi,Chen, Qin,Lu, Shenjun,Xie, Haibo
, p. 9922 - 9934 (2021/12/24)
The facile design and preparation of polyelectrolytes is a frontier topic in the fields of polymer science, energy storage devices and catalysis. Herein, linear water soluble cellulosic poly(protic ionic liquid) (CPIL) electrolytes were facilely and atom economically prepared after the dissolution of cellulose in the newly developed DBU/CO2/DMSO solvent system, followed by the simple addition of succinic anhydride under mild conditions. The DBU not only participated in the dissolution of cellulose as a solvent component, but also acted as an organocatalyst for the acylation reaction of cellulose with succinic anhydride, as well as a cation component in the targeted CPIL electrolytes. The reaction was optimized, and the effect of the reaction conditions on the chemical and physical properties of the CPILs was investigated. And then, as a proof of concept, the CPIL electrolyte aqueous solution was successfully used as the catalytic reaction media for the Knoevenagel condensation reaction. It was found that the reaction was homogeneous at the beginning, and the products could precipitate out from the media with the proceeding of the reaction, thus affording satisfactory filtration yields ranging from 56.7% to 93.8%. The solution properties of the CPIL aqueous solution were primarily investigated towards an in-depth understanding of the catalytic mechanism, by which a synergetic catalytic mechanism of the CPILs was proposed, and the reaction started with a nucleophilic addition reaction, and was then followed by a fast dehydration reaction. Finally, the direct reusability potential of the CPIL aqueous solution after the product filtration was also primarily investigated for the Knoevenagel condensation reaction.
Bis [hydrazinium (1+)] hexafluoridosilicate:(N2H5)2SiF6 novel hybrid crystal as an efficient, reusable and environmentally friendly heterogeneous catalyst for Knoevenagel condensation and synthesis of biscoumari
El hajri, Fatima,Benzekri, Zakaria,Sibous, Sarra,Ouasri, Ali,Boukhris, Said,Hassikou, Amina,Rhandour, Ali,Souizi, Abdelaziz
, (2021/02/03)
A simple, effective, green and nontoxic protocol was used for the Knoevenagel condensation and the biscoumarin derivatives synthesis. It have demonstrated that the use of a new hybrid crystal as a heterogeneous catalyst makes it possible to obtain several
Overcoming acid–base copolymer neutralization using mesoporous carbon and its catalytic activity in the tandem deacetalization–Knoevenagel condensation reaction
Javad Kalbasi, Roozbeh,Rahmati, Fatemeh,Mazaheri, Omid
, p. 3413 - 3430 (2020/05/16)
Abstract: Acid–base copolymer materials are of considerable interest because of their fundamental implications for acid–base bifunctional catalysis applications. However, quenching the acid and base sites of the copolymer with each other in free radical polymerizations is still challenging. Herein, we demonstrate that the polymerization of styrenesulfonic acid-co-4-vinylpyridine into the mesoporous carbon material (i.e., CMK-3) can control the chain growth polymerization and result in decreasing the interaction of the acid–base sites. The results showed that by using CMK-3, 40% of the acid and base sites of the copolymer remain in their original form while 60% of acid and base sites convert to the pyridinium and sulfonate forms. Furthermore, it is demonstrated that this material can be processed as a heterogeneous bifunctional acid–base catalyst in the tandem one-pot acid–base reaction (i.e., deacetalization–Knoevenagel condensation reaction) with a high catalytic activity in aqueous media. Graphic abstract: [Figure not available: see fulltext.].
A facile microwave-assisted Knoevenagel condensation of various aldehydes and ketones using amine-functionalized metal organic frameworks
Lee, Ik-Mo,Lumbiny, Bilkis Jahan,Taher, Abu
, (2020/07/16)
An amine-functionalized metal organic framework (MOF) was used as highly efficient and recyclable heterogeneous catalyst for Knoevenagel condensation of various aromatic aldehydes and ketones in ethanol. The catalytic efficiency was demonstrated by the hi
Synthesis of highly substituted tetrahydroquinolines using ethyl cyanoacetate: Via aza-Michael-Michael addition
Chen, Chinpiao,Lee, Gene-Hsian,Palanimuthu, Arunan
, p. 13591 - 13600 (2020/04/23)
A three-component cascade reaction involving 2-alkenyl aniline, aldehydes, and ethyl cyanoacetate in the presence of DBU to synthesize highly substituted 1,2,3,4-tetrahydroquinolines is reported. The reaction proceeded through the Knoevenagel condensation
