2141-62-0Relevant articles and documents
Memory effect of hydrotalcites and its impact on cyanoethylation reaction
Teodorescu,Pǎlǎdu?ǎ,Pavel
, p. 2055 - 2059 (2013)
The aim of this work is to study the changes of hydrotalcites structure when is subjected to gradual multiple calcination/hydration treatments in the presence of water or alkaline solution with the same composition like in co-precipitation step and then to analyze its influence on the catalytic activity in the cyanoethylation reaction between ethanol and acrylonitrile with the main product being beta-ethoxypropionitrile according to these treatment. The samples were characterized by elemental analysis, XRD, DRIFT, CO 2-TPD.
KOtBu-Catalyzed Michael Addition Reactions Under Mild and Solvent-Free Conditions
Thiyagarajan, Subramanian,Krishnakumar, Varadhan,Gunanathan, Chidambaram
supporting information, p. 518 - 523 (2020/02/04)
Designed transition metal complexes predominantly catalyze Michael addition reactions. Inorganic and organic base-catalyzed Michael addition reactions have been reported. However, known base-catalyzed reactions suffer from the requirement of solvents, additives, high pressure and also side-reactions. Herein, we demonstrate a mild and environmentally friendly strategy of readily available KOtBu-catalyzed Michael addition reactions. This simple inorganic base efficiently catalyzes the Michael addition of underexplored acrylonitriles, esters and amides with (oxa-, aza-, and thia-) heteroatom nucleophiles. This catalytic process proceeds under solvent-free conditions and at room temperature. Notably, this protocol offers an easy operational procedure, broad substrate scope with excellent selectivity, reaction scalability and excellent TON (>9900). Preliminary mechanistic studies revealed that the reaction follows an ionic mechanism. Formal synthesis of promazine is demonstrated using this catalytic protocol.
Preparation method of 3-ethoxypropylamine
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Paragraph 0016; 0020; 0022; 0024, (2019/03/08)
The invention discloses a preparation method of 3-ethoxypropylamine. The preparation method comprises the following steps: 1) adding a catalyst A and ethanol into a reactor; 2) controlling the temperature of the reactor and dripping acrylonitrile; 3) preparing 3-ethoxy propionitrile with the content of more than 97%; 4) hydrogenating the prepared 3-ethoxy propionitrile in the presence of a catalyst B, hydrogen and an inhibitor; and 5) after the hydrogenation is qualified, carrying out vacuum vacuum distillation to obtain a finished product with a content greater than 99.5%. The preparation method has high selectivity, and excessive ethanol and the catalysts A and B in the process can be recycled, thus further reducing the production cost and reducing the discharge amount of waste liquid.
Formation of a New, Strongly Basic Nitrogen Anion by Metal Oxide Modification
Tamura, Masazumi,Kishi, Ryota,Nakayama, Akira,Nakagawa, Yoshinao,Hasegawa, Jun-Ya,Tomishige, Keiichi
, p. 11857 - 11867 (2017/09/08)
Development of new hybrid materials having unique and unprecedented catalytic properties is a challenge for chemists, and heterogeneous-homogeneous hybrid catalysts have attracted much attention because of the preferable and exceptional properties that are highly expected to result from combination of the components. Base catalysts are widely used in organic synthesis as key materials, and a new class of base catalysts has made a large impact from academic and industrial viewpoints. Here, a principle for creating a new strong base by hybridization of homogeneous and heterogeneous components is presented. It is based on the modification of organic compounds with metal oxides by using the acid-base property of metal oxides. Based on kinetic and DFT studies, combination of CeO2 and 2-cyanopyridine drastically enhanced the basicity of 2-cyanopyridine by a factor of about 109 (～9 by pKa (in CH3CN)), and the pKa was estimated to be ～21, which locates it in the superbase category. 2-Cyanopyridine and CeO2 formed a unique adsorption complex via two interaction modes: (i) coordinative interaction between the Ce atom of CeO2 and the N atom of the pyridine ring in 2-cyanopyridine, and (ii) covalent interaction between the surface O atom of CeO2 and the C atom of the CN group in 2-cyanopyridine by addition of the lattice oxygen of CeO2 to the CN group of 2-cyanopyridine. These interactions established a new, strongly basic site of N- over the CeO2 surface.
Catalytic Olefin hydroalkoxylation by nano particles of pollucite
Zamanian, Sara,Kharat, Ali Nemati
, p. 981 - 986 (2015/06/25)
The catalytic hydroalkoxylation of α,β-unsaturated esters, nitriles, and ethers with aliphatic and aromatic alcohols over pollucite using thermal and microwave-assisted methods was investigated. To study the effect of the alcohol structures on the mechanism of the hydroalkoxylation reaction, different alcohols, such as methanol to butanol, cyclohexanol, phenol, and 2-ethylhexanol were used. The activities of pollucite, in contrast to other basic solids, were scarcely affected by the presence of air and moisture. The correlation between alcohol acidity and reaction activity is discussed. The prepared pollucite was characterized by X-ray diffraction, volumetric nitrogen adsorption surface area analysis, and CO2 temperature-programmed desorption. Scanning electron microscopy analysis revealed that the size of the modified nano catalyst particles was under 40nm.
Oxa-Michael addition promoted by the aqueous sodium carbonate
Guo, Shi-Huan,Xing, Sheng-Zhu,Mao, Shuai,Gao, Ya-Ru,Chen, Wen-Liang,Wang, Yong-Qiang
supporting information, p. 6718 - 6720 (2014/12/11)
An efficient Michael addition of alcohols to activated alkenes promoted by sodium carbonate with water as reaction medium has been developed. The reaction provides a general, economical and environmentally friendly approach for the synthesis of β-alkoxycarbonyl compounds.
Addition of alcohols to acrylic compounds catalyzed by Mg-Al LDH
Teodorescu,Deaconu,Bartha,Z?voianu,Pavel
, p. 117 - 122 (2014/03/21)
This study reports the preparation of hydrotalcite with Mg/Al molar ratio 3 by co-precipitation under low suprasaturation conditions of Mg and Al nitrated solutions with Na2CO3 and NaOH at pH 10. The solid was thermally decomposed at 460°C in air atmosphere in order to obtain mixed oxides which, by means of memory effect, can reconstruct the hydrotalcite structure by hydration with bidistilled water. The hydrotalcite and reconstructed samples by memory effect were characterized by elemental analysis, powder XRD, DRIFT and TG-DTG. Determination of the catalysts surface base sites was made using a method based on the irreversible adsorption of organic acids with different pKa values and N2 adsorption-desorption isotherms. The catalytic activity of these solids was evaluated in 1,4-addition of saturated linear alcohols to different acrylic compounds. All these reactions arose with high selectivity in the desired product. No by-products were detected by means of GC-MS chromatography and 1H NMR.
Cyanoethylation of alcohols and amines by cesium-modified zeolite y
Zamanian, Sara,Kharat, Ali Nemati
, p. 264 - 269 (2014/03/21)
Zeolite Y modified by cesium and magnesium ions was prepared by ion-exchange and impregnation methods, and its activity in the cyanoethylation of aliphatic and aromatic alcohols and amines was investigated. During the preparation of some samples, the transformation of zeolite Y into a pollucite-type phase occurred. This phase exhibited good activity in the cyanoethylation of aliphatic alcohols. The prepared solids modified by the impregnation method were more active than the ion-exchanged solids. The activities of the catalysts, in contrast to other basic solids, were scarcely affected by the presence of air or moisture. A correlation between catalyst basicity and catalytic activity is discussed. The catalysts were characterized by X-ray diffraction, volumetric nitrogen adsorption surface area measurement, and CO2 temperature-programmed desorption. Scanning electron microscopy revealed that the particles of the modified nanocatalysts were 40 nm. The reaction of acrylonitrile with linear alcohols in the presence of the catalysts was accelerated by microwave irradiation.
Solid sodium stannate as a high-efficiency superbase catalyst for anti-Markovnikov hydroamination and hydroalkoxylation of electron-deficient olefins under mild conditions
Zhang, Shuguo,Wei, Yudan,Yin, Shuangfeng,Au, Chak-Tong
, p. 712 - 716 (2013/01/09)
A solid superbase with H- above 26.5 has been obtained through thermal treatment of sodium stannate hydrate. It was found to be an efficient catalyst for anti-Markovnikov hydroamination and hydroalkoxylation of electron-deficient olefins under mild conditions.
Heck reactions catalyzed by Pd(0)-PVP nanoparticles under conventional and microwave heating
Martins, Daniela De L.,Alvarez, Heiddy M.,Aguiar, Lúcia C.S.,Antunes, Octavio A.C.
experimental part, p. 47 - 53 (2012/04/11)
Pd(0) nanoparticles stabilized by polyvinylpyrrolidone (Pd-PVP) with a diameter of 3-6 nm in ethanol catalyzed Heck coupling of iodobenzene with different alkenes under microwave heating. Products were obtained in good yields (62-99%) and good selectivity to the E-isomers. Microwave heating proved to be superior to conventional heating, providing products in higher yields and selectivities in short times (12 min).
