Synthesis and characterization of the novel diamine‐functionalized Fe3O4@SiO2 nanocatalyst and its application for one‐pot three‐component synthesis of chromenes

Fe₃O₄@SiO₂@propyltriethoxysilane@o‐phenylendiamine as an environmentally‐benign functionalized silica‐coated magnetic organometallic nanomaterial has been synthesized and characterized by Fourier transforms infrared (FT‐IR) spectroscopy, scanning electron microscopy (SEM) images and energy dispersive X‐ray (EDX) and vibrating sample magnetometer (VSM) analyses. Then, its catalytic activity was investigated for the one‐pot three‐component condensation reaction between dimedone, malononitrile and various substituted aromatic aldehydes to afford the corresponding 2‐amino‐4H‐chromene derivatives under mild reaction conditions. This nanocatalyst can be easily recovered from the reaction mixture by using a magnet and reused for at least five times without significant decrease in catalytic activity.     

Host (Nanocavity of Aluminium-Incorporated Mesoporous KIT-6)–guest (12-tungesto(molybdato) Phosphoric Acid) Nanocomposite Material: Efficient and Reusable Catalysts for the Hosomi–Sakurai Three-Component Coupling Reaction

Abstract

The immobilization of heteropoly acids (HPAs) into the Al-functionalized KIT-6 mesoporous molecular sieve has been carried out to see the effect of Al-KIT-6 as a host matrix on the HPA activities. These modified mesoporous molecular sieves are effective catalysts for the Hosomi–Sakurai three-component coupling reaction via condensation of aldehydes, silyl ethers, and allylsilanes.

Supplemental materials are available for this paper. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

A Simple Synthesis of Stable Phosphoranes Derived from Imidazole Derivatives

Stable crystalline phosphorus ylides were obtained in excellent yields from the 1:1:1 addition reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, in the presence of strong NH-acids, such as imidazole, 2-methylimidazole, 4-methylimidazole, 2-ethylimidazole, benzimidazole, and 5,6-dimethylbezimidazole. These stable ylides exist in solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon–carbon partial double bond resulting from the conjugation of the ylide moiety with the adjacent carbonyl group.     

Electrochemical platform for simultaneous determination of levodopa,acetaminophen and tyrosine using a graphene and ferrocene modified carbon paste electrode

Microchimica Acta - A carbon paste electrode (CPE) was modified with graphene and ethyl 2-(4-ferrocenyl-[1,2,3]triazol-1-yl) acetate (EFTA) and used for electrocatalytic oxidation of levodopa....     

APPROXIMATE SOLUTION OF A p-th ROOT FUNCTIONAL EQUATION IN NON-ARCHIMEDEAN (2,β)-BANACH SPACES

In this paper, using the Brzdek's fixed point theorem [9,Theorem 1] in non-Archimedean(2,β)-Banach spaces, we prove some stability and hyperstability results for an p-th root functional equation ■where p∈{1, …, 5}, a_1,…, a_k are fixed nonzero reals when p ∈ {1,3,5} and are fixed positive reals when p ∈{2,4}.     

Zn and Zr co-doped M-type strontium hexaferrite: Synthesis,characterization and hyperthermia application

In the present study, hard ferromagnetic (M-type strontium hexaferrite) SrFe₁₂O₁₉ was co-doped by Zn and Zr for magnetic hyperthermia applications. As a result of the high concentration of single domain SrFe₁₂O₁₉ nanoparticles (suspended in the ferrofluid), they found a large hydrodynamic diameter, which caused a long-time Brownian relaxation under the AC magnetic field. On the other hand, increasing the Zn-Zr content (low concentration of SrFe₁₂O₁₉) led to a drop in anisotropy, which coincided with a short-time N´eel relaxation. All of the substituted samples with a multi-disperse state in ferrofluid exhibited an almost equal amount of the N´eel and Brownian effects. Consequently, the magnetic saturation (M_s) was considered as the dominant factor in the specific absorption rate (SAR) of the substituted samples. Transformation to the mono-disperse state was followed by the decrease of the Brownian relaxation time and hence the increase of the SAR. The interesting point in mono-disperse state was the heat generation of pure SrFe₁₂O₁₉ under the AC magnetic field as a result of the decrement of the Brownian relaxation time.     

The Processing of Pyrolysis Fuel Oil by Dielectric Barrier Discharge Plasma Torch

In present paper, an atmospheric-pressure low-temperature plasma treatment of pyrolysis fuel oil (PFO) was investigated in dielectric barrier discharge plasma torch reactor. The effect of the applied voltage and the volume of feedstock, as the main parameters, on the cracking of PFO were studied. By increasing the applied voltage from 10 to 16 kV, the production rate of hydrocarbons containing methane, ethylene, acetylene, propane, propylene, and C₄ rise 18 times. In this case, the production rate of hydrogen increases by approximately 14 times and reaches 7.27 × 10^?3 mol/min for 16 kV. In the feedstock volume investigation, based on limitation of reactor volume, the production rate of hydrocarbons decreased from 0.44 × 10^?3 to 0.15 × 10^?3 mol/min by increasing volume of feedstock from 1 to 5 cc.