Interfacial reactions between impurities and slag onset of Si purification by slag addition

The interfacial reactions between impurities (Al and Ti) and slag onset of Si purification by 51 mol% SiO2–34 mol% CaO–15 mol% MgO slag addition were studied to enhance impurity removal efficiency from Si. The Al distribution behavior at the Si/Slag interface was investigated; a short reaction time (10 s) resulted in the formation of successive SiO2–CaO–MgO–Al2O3 layers in the slag with a thickness of 10 µm; increasing the reaction time (60 s) resulted in the entire ternary slag being changed into SiO2–CaO–MgO–Al2O3 quaternary slag due to the diffusion of Al2O3. It was shown that the highest impurity removal rate of Al could be achieved at the onset of the slag refining process. Based on the Ti distribution at the Si/slag interface, the slag refinement with 51 mol% SiO2–34 mol% CaO–15 mol% MgO had no effect on Ti removal.

Preparation and Characterization of Novel Polymer-Based Heterogeneous MPg-C3N4 Catalyst and Its Application in Multi-Component Reactions

Magnetic polyvinyl alcohol-based g-C3N4 composite (MPg-C3N4) was synthesized as a heterogeneous catalyst. It was characterized by various analyses such as FT-IR, XRD, FE-SEM, TGA, EDX, and VSM. For showing the catalytic merits of MPg-C3N4, it was used in the synthesis of acridinedione and 4H-chromene derivatives in a highly efficient yield. Various aldehyde derivatives were used to show the merits of the MPg-C3N4. High yield, short reaction time, easy separation, mild condition reaction, simple purification, non-toxic solvents, and reusability are the advantages of using polymer-based heterogeneous MPg-C3N4 catalyst to synthesize acridinedione and 4H-chromene derivatives. Also, the intended products were purified by simple crystallization.

Synthesis, Characterization and Catalytic Potency of Zn-based MOF for Knoevenagel Condensation Reaction

A Zn based metal organic framework with pyridine 2, 5-dicarboxylate (Zn-based MOF) were prepared as a reusable heterogeneous catalyst using solvothermal method. Zn-based MOF was used as heterogeneous catalyst for synthesis 5-arylidene malononitrile in ethanol under reflux condition. The attractive features of present method are mild reaction condition, short reaction time, simplicity, easy separation of catalyst and excellent yield. Keywords: Metal organic framework, heterogeneous catalyst, solvothermal method.

4-(Dimethylamino)pyridine as an Efficient Catalyst for One-Pot Synthesis of 1,4-Pyranonaphthoquinone Derivatives viaMicrowave-Assisted Sequential Three Component Reaction in Green Solvent

Novel 1,4-pyranonaphthoquinone derivatives were successfully synthesized via the microwave-assisted three-component reaction of 1,4-naphthoquinone, malononitrile, and various arylaldehydes in ethanol in the presence of 4-(dimethylamino)pyridine (DMAP) as a catalyst, and subsequently evaluated in terms of their antimicrobial and antifungal activities. This synthetic procedure has the notable advantages of environmental friendliness, short reaction time, good yield, and convenient operation.

Chickpea Leaf Exudates: A Highly Efficient Natural Brønsted Acidic Medium for the Synthesis of Pyran-annulated Heterocycles

: We reported Chickpea leaf exudates (CLE) as a Brønsted acid type naturally available biodegradable, ecofriendly and reusable reaction medium for highly efficient and facile one-pot synthesis of pyran annulated heterocyclic systems like 7-aryl-benzopyrano[4,3-b]benzopyran-6,8-diones, tetrahydrobenzo[b]pyran and dihydropyrano[c]chromenes scaffolds. The analogous products were obtained via tandem Knoevengel-Michael addition and cyclocondensation reaction in ethanol at room temperature with 90-96 % yields in a short reaction time. Moreover, the reaction media containing Bronsted acids can be easily recovered and reused upto five times with a slight decrease in product yields.

Synthesis and Inhibition Activity Study of Triazinyl-Substituted Amino(alkyl)-benzenesulfonamide Conjugates with Polar and Hydrophobic Amino Acids as Inhibitors of Human Carbonic Anhydrases I, II, IV, IX, and XII

Primary sulfonamide derivatives with various heterocycles represent the most widespread group of potential human carbonic anhydrase (hCA) inhibitors with high affinity and selectivity towards specific isozymes from the hCA family. In this work, new 4-aminomethyl- and aminoethyl-benzenesulfonamide derivatives with 1,3,5-triazine disubstituted with a pair of identical amino acids, possessing a polar (Ser, Thr, Asn, Gln) and non-polar (Ala, Tyr, Trp) side chain, have been synthesized. The optimized synthetic, purification, and isolation procedures provided several pronounced benefits such as a short reaction time (in sodium bicarbonate aqueous medium), satisfactory yields for the majority of new products (20.6–91.8%, average 60.4%), an effective, well defined semi-preparative RP-C18 liquid chromatography (LC) isolation of desired products with a high purity (>97%), as well as preservation of green chemistry principles. These newly synthesized conjugates, plus their 4-aminobenzenesulfonamide analogues prepared previously, have been investigated in in vitro inhibition studies towards hCA I, II, IV and tumor-associated isozymes IX and XII. The experimental results revealed the strongest inhibition of hCA XII with low nanomolar inhibitory constants (Kis) for the derivatives with amino acids possessing non-polar side chains (7.5–9.6 nM). Various derivatives were also promising for some other isozymes.

C-H Amination of Nitro Aza-Heterocyclic Compounds by Vicarious Nucleophilic Substitution

This manuscript describes the C-H amination of a variety of nitro aza-heterocyclic compounds by Vicarious Nucleophilic Substitution (VNS) methodology with 4-amino-1,2,4-triazole (ATA). The aminated products were characterized by NMR, MS and single-crystal X-ray diffraction. Among the substrates examined, moderate to excellent yield (30-88%) and good regioselectivity (ortho/para position of the nitro) are exhibited. This protocol offers the advantages of mild conditions, short reaction time (only 2-4 h) with inexpensive, commercially available and less toxic amination reagent, no additional catalysts or reagents needed. Possible reaction mechanism was also discussed.

Study of the Three-Component Reactions of 2-Alkynylbenzaldehydes, Aniline, and Dialkyl Phosphites—The Significance of the Catalyst System

New, practical approaches for the synthesis of α-amino (2-alkynylphenyl)-methylphosphonates and 1,2-dihydroisoquinolin-1-ylphosphonates were developed. By the propylphosphonic anhydride (T3P®)-mediated Kabachnik–Fields reaction of 2-alkynylbenzaldehydes, aniline, and dialkyl phosphites, α-amino (2-alkynylphenyl)-methylphosphonates were obtained selectively in high yields. The method developed is a simple operation and did not require a chromatographic separation since the products could be isolated from the reaction mixture by a simple extraction. At the same time, 2,3-disubstituted-1,2-dihydroisoquinolin-1-ylphosphonates could be prepared effectively from the same kinds of starting materials (2-alkynylbenzaldehydes, aniline, and dialkyl phosphites) at 60 °C in a short reaction time by changing the catalyst for CuCl. Therefore, it was proved that the catalyst system applied played a crucial role with respect to the reaction outcome.

Fe3O4@chitosan-tannic acid bionanocomposite as a novel nanocatalyst for the synthesis of pyranopyrazoles

Recently magnetic nanocatalyst has attracted considerable attention because of its unique properties, including high performance, easy separation from the reaction mixture, and recyclability. In this study, a novel magnetic bionanocomposite was synthesized with chitosan and tannic acid as a natural material. The synthesized bionanocatalyst was characterized by essential analysis. Fe3O4@chitosan-tannic acid as a heterogeneous nanocatalyst was successfully applied to synthesize pyranopyrazole and its derivatives by a one-pot four-component reaction of malononitrile, ethyl acetoacetate, hydrazine hydrate, and various aromatic aldehyde. At the end of the reaction, the nanocatalyst was separated from the reaction mixture and was reused several times with no significant decrease in its catalytic performance. Simple purification of products, the ability for recovering and reusing the nanocatalyst, eco-friendliness, high yields of pure products, mild reaction conditions, short reaction time, non-toxicity, economically affordable are some of the advantages of using the fabricated nanocatalyst in the synthesis of pyranopyrazole.

NiO nanoparticles: A highly efficient catalyst for the one-pot three-component synthesis of pyrano [2, 3-d] pyrimidine derivatives in green media.

: NiO nanoparticles are utilized to effectively strengthen annulated pyrano [2, 3- d] pyrimidine synthesis through primary Knoevenagel, following Micheal and ultimate heterocyclization reactions of aldehyde, malononitrile, and barbituric acid. The characteristics of NiO nanoparticles are identified using advanced techniques, such as IR, UV, EDX, XRD, SEM, and TEM. The nano-NiO particles are mostly below < 100 nm in size with uniform spherical shapes. The adopted approach is advantages thanks to its simple processing, relatively short reaction time, often good to high average yields, convenient workability, and environmental friendliness.