Reusable Medium Research Articles

Green Synthetic Approach for Catalyst-free Synthesis of 2-Amino-4H-chromenes Promoted by Glycerol as a Reusable Medium

Green Synthetic Approach for Catalyst-free Synthesis of 2-Amino-4H-chromenes Promoted by Glycerol as a Reusable Medium

Behaviors of Perfluorocarbon Emulsion during Dissolution of Oxide Layers.

This study investigates the dissolution behavior of oxide layers containing radionuclides using perfluorocarbon (PFC) emulsion as a reusable medium. Chemicals such as PFC, anionic surfactant, and H2SO4 are used for preparing the PFC emulsion, and emulsified using an ultrasonication process. The FTIR results show O–H stretching that is formed by the interaction of the carboxyl group of the anionic surfactant with the hydroxyl group of water containing H2SO4, and find that the H2SO4 can be homogeneously dispersed in the PFC–anionic surfactant–H2SO4 emulsion. The dissolution test of the simulated Cr2O3 specimen is conducted using PFC emulsion containing KMnO4. Through the weight losses of specimens and Scanning Electron Microscope-Energy Dispersive X-ray Spectrometer (SEM-EDS) analysis, it is confirmed that the Cr2O3 layer on the SUS304 specimen is easily dissolved using PFC emulsion. During the dissolution of the Cr2O3, it is observed that the dispersed H2SO4–KMnO4 became unstable and separated from PFC emulsion. Based on these results, the behavior of the PFC emulsion during the dissolution of the oxide layer is explained.

Synthesis of β-keto-sulfones using alkyl/aryl sulphinates in ionic liquids [bmim-BF4] as an efficient and reusable reaction medium

Synthesis of β-keto-sulfones using alkyl/aryl sulphinates in ionic liquids [bmim-BF4] as an efficient and reusable reaction medium

Heterogeneous SO3H@Fe3O4 magnetic nanocatalyst as an efficient and reusable medium for the synthesis of 3,3′‐(arylmethylene)‐bis‐(4‐hydroxycoumarin), bis‐(indolyl)‐methane, and 1,8‐dioxo‐octahydroxanthene derivatives

AbstractThis work aimed to synthesize a new heterogeneous catalyst (SO3H@Fe3O4 magnetic nanoparticles) and the study of its catalytic behavior in synthesizing 3,3′‐(arylmethylene)‐bis‐(4‐hydroxycoumarin), bis‐(indolyl)‐methane, and 1,8‐dioxo‐octahydroxanthene derivatives. The characterization of obtained material has been performed by means of Fourier‐transform infrared spectroscopy, thermogravimetric analysis, X‐ray diffraction, vibrating sample magnetometer, and transmission electron microscopy. The main properties of this new methodology, compared to earlier ones, are the short times of reaction, mild reaction conditions, simple recovery of the catalyst by permanent magnetic field, excellent yields, and reusability of the catalyst for a minimum of six runs.

Solvent-mediated Highly Efficient Synthesis of [1,2,4]triazolo/benzimidazoloquinazolinone Derivatives.

An efficient and catalyst-free procedure for the synthesis of [1,2,4]triazolo/benzimidazolo quinazolinones has been developed in 2,2,2-trifluoroethanol or deep eutectic solvent(DESs) as a clean reaction media. All of the obtained products are known compounds and identified by IR, 1HNMR,13CNMR, and melting points. Various products were obtained in good to excellent yields under reaction conditions. We have efficiently developed a practical and catalyst-free approach for the synthesis of [1,2,4]triazolo/benzimidazolo quinazolinones employing TFE as a clean and reusable media.

Incorporation of hydrogel as a sensing medium for recycle of sensing material in chemical sensors

A hydrogel, produced with agarose extracted from seaweed, was introduced as a reusable medium in ultrasensitive sensors employing conducting polymer nanomaterials and aptamers. A basic dopamine (DA) sensor was constructed by placing a hydrogel, containing a sensing material composed of aptamer-linked carboxylated polypyrrole nanotubes (PPy-COOH NTs), onto a micropatterned gold electrode. The hydrogel provided a benign electrochemical environment, facilitated specific interactions between DA and the PPy-COOH NT sensing material, and simplified the retrieval of PPy-COOH NTs after detection. It was demonstrated that the agarose hydrogel was successfully employed as a sensing medium for detection of DA, providing a benign environment for the electrode type sensor. PPy-COOH NTs were recovered by simply heating the hydrogel in water. The hydrogel also afforded stable signal intensity after repeated use with a limit of detection of 1nmol and a clear, stable signal up to 100nmol DA. This work provides relevant information for future research on reusable or recyclable sensors.

Ionic liquid-promoted multicomponent synthesis of fused tetrazolo[1,5-a]pyrimidines as α-glucosidase inhibitors

A simple and facile synthesis of fused tetrazolo[1,5-a]pyrimidine derivatives based on the multicomponent reaction of acetophenone, dimethylformamidedimethylacetal and 5-aminotetrazole is described. A green chemical synthesis has been achieved by using1-butyl-3-methylimidazolium hydrogen sulfate [Bmim]HSO4 ionic liquid as a reusable medium. Short synthetic route, operational simplicity, good yields, eco-friendliness and recyclability of the ionic liquid are the advantages of this method. The synthesized compounds were screened for α-glucosidase inhibitory activity using yeast maltase (MAL12) as a model enzyme. Inhibition and kinetic studies have shown that compounds 4d and 4g are found to be active showing comparable inhibitory potency with acarbose. Further docking studies of the derivatives with MAL12 homology model identified a similar binding mode consistent with the binding of acarbose. These studies along with in silico predicted ADMET properties suggest that these molecules could represent a new scaffold that may be useful for the development of new anti-diabetic drugs.

Choline chloride and itaconic acid-based deep eutectic solvent as an efficient and reusable medium for the preparation of 13-aryl-5H-dibenzo[b,i]xanthene-5,7,12,14(13H)-tetraones

Choline chloride and itaconic acid-based deep eutectic solvent has been identified as an effective catalyst and reaction medium for synthesis of 13-aryl-5H-dibenzo[b,i]xanthene-5,7,12,14(13H)-tetraones by condensation of 2-hydroxynaphthalene-1,4-dione with various aldehydes. The reaction conditions are mild and environmentally friendly.

Ligand-free heck coupling and homocoupling of aryl halides in the presence of tetrabutylammonium nitrate

Tetrabutylammonium nitrate is reported as an effective reusable medium, suitable reducing and stabilizing agent for the Heck coupling reaction of aryl iodides and bromides with styrene and n-butyl acrylate. The efficient phosphine-free, palladium-catalyzed homocoupling reaction of aryl iodides and bromides is also demonstrated in the presence of tetrabutylammonium nitrate. The ionic liquid, still containing Pd (0) complex, is easily recovered and reused in several runs without losing its efficiency.

Aqueous hydrotrope: an efficient and reusable medium for a green one-pot, diversity-oriented synthesis of quinazolinone derivatives.

A library of quinazolinones was prepared by the one-pot three-component reaction of isatoic anhydride, ammonium salts/amines, and various electrophiles using aqueous hydrotropic solution as an efficient, economical, reusable, and green medium giving good to excellent yields of products in very short time. The method offers a versatile way for the development of diversity-oriented synthesis of quinazolinones.

Copper ingrained poly(ethylene)glycols as cost effective and reusable media for selective 1-decene/n-decane separation

Liquid range polyethylene glycols containing copper ions have been used as recyclable extractive media for the selective separation of 1-decene from a mixture of 1-decene and n-decane.

Effect of ohmic heating on tomato peeling

Current industrial methods of tomato peeling are lye and steam peeling, both of which suffer from various disadvantages; caustic, high pH waste with the former, and excessive water use with the latter. In this study, ohmic peeling was attempted to potentially address these problems. Tomatoes were ohmically heated in NaCl solution under various conditions of field strength, initial temperature and number of tomatoes, resulting in peeling with greatly reduced lye concentrations. Field strength, NaCl concentration, initial temperature and fruit concentration all significantly influenced peel cracking time. Results indicated that in terms of quality of peeling, the best conditions of ohmic peeling were: 0.01 g/100 ml NaCl with 8060 and 9680 V/m, and 0.03 g/100 ml NaCl with 6450 and 8060 V/m. These conditions showed potential for processing because they required a reasonably short time (approximately 1 min). Further, the potential to preheat the media to 40 °C or more with reusable media could further shorten the peeling time.

Application of Dissociation Extraction in Oxidation Degradation Reaction of Lignin

A novel approach was developed in order to use lignin as a renewable resource for the production of high added-value aromatic aldehydes. The mixed phosphate solution was used as a reusable medium, and the desired products were separated by the method of the dissociation extraction during the reaction, which prevented the products aromatic aldehydes from oxidizing and increased their yields. The conversion of lignin reached 100%, and the total yield of aromatic aldehydes (vanillin, syringaldehyde and 4-hydroxybenzaldehyde) was 25.8%. Compared with the traditional solvent NaOH aqueous solution, this process gave some advantages to the reaction including less corrosive and environmental problems, easy product separation and purification, and recyclability of solvent.

Solvent-free silica-promoted multicomponent condensation: synthesis of highly functionalized piperidines

Silica gel has been found to be an efficient and reusable medium for the synthesis of diastereospecific functionalized piperidines in good to high yields by a one-pot three-component condensation of aldehyde, amine and β-ketoester under solvent-free conditions at room temperature. Using this environmentally benign, non-inflammable and non-toxic reaction medium, the non-chromatographic purification, reusability of the silica gel, and operational simplicity are the notable advantages of the present method. The procedure is applicable for large-scale synthesis of piperidines derivatives and represents a green synthetic protocol.

L-(+)-Tartaric acid and choline chloride based deep eutectic solvent: An efficient and reusable medium for synthesis of N-substituted pyrroles via Clauson-Kaas reaction

l-(+)-Tartaric acid–choline chloride based deep eutectic solvent has been found to be an effective promoted medium for Clauson-Kaas reaction of aromatic amines and 2,5-dimethoxytetrahydrofuran. Structurally diverse N-substituted pyrroles were obtained in high to excellent yields under mild conditions. The deep eutectic solvent is inexpensive, non-toxic, reusable and biodegradable.

ChemInform Abstract: An Eco‐Compatible Synthesis of Medicinally Important Novel Class of Trispiroheterocyclic Framework Using 2,2,2‐Trifluoroethanol as a Reusable Medium.

Abstract11 Trispirocompounds of type (IV) and (VI) are prepared and screened for their antifungal and antimycobacterial activities.

Amine-based ionic liquids (R3N+PPh2) as a reusable reaction medium and Pd(II) ligand in Heck reactions of aryl halides with styrene and n-butyl acrylate

Amine-based ionic liquids (R3N+PPh2) are reported as an effective reusable medium, suitable Pd(II) ligand and also reducing agent for the Heck coupling reaction of aryl iodides and bromides with styrene and n-butyl acrylate. The ionic liquid, still containing its corresponding Pd(0) complex, was easily recovered and reused in several runs without losing its efficiency.

An eco-compatible synthesis of medicinally important novel class of trispiroheterocyclic framework using 2,2,2-trifluoroethanol as a reusable medium

A highly practical and efficient regio- and stereoselective synthesis of novel trispiropyrrolidine/thiapyrrolizidine derivatives have been accomplished via multi-component reaction of 7,9-bis[(E)arylidene]-1,4-dioxa-spiro[4,5]decane-8-ones, sarcosine/1,3-thiazolane-4-carboxylic acid and substituted isatins using 2,2,2-trifluoroethanol as a solvent. This new protocol has the advantages of environmental friendliness, higher atom economy, shorter reaction time and convenient operation. The structure and relative stereochemistry of spiro product was established by single crystal X-ray analysis and spectroscopic techniques. Synthesized compounds have been screened for their ‘in vitro’ antifungal and antimycobacterial activity against Mycobacterium tuberculosis H37Rv.

ChemInform Abstract: A Facile and Efficient Synthesis of 2‐Amino‐3‐cyano‐4H‐chromenes and Tetrahydrobenzo[b]pyrans Using 2,2,2‐Trifluoroethanol as a Metal‐Free and Reusable Medium.

AbstractCompounds (IV) are purified by recrystallization.

ChemInform Abstract: Magnetic Recording Materials Since 1975

Abstract When information is to be recorded and stored on a re-usable medium, magnetic recording, in one form or another, has been and is today the dominant technology. Magnetic particles or thin films having a coercivity of several hundred oersteds, are easily capable of retaining a magnetic pattern of recorded information (at densities of tens of thousands of bits/inch and track densities of thousands of tracks/inch) for hundreds of years and yet when desired, the pattern can be changed by simply writing the new information over the old. Since the recording process requires only a change in direction of the electron spins, the process is infinitely reversible and the new information may be read immediately with no development process being required. This paper deals with developments of the magnetic (and some important non-magnetic) properties of recording media that have occurred since 1975. It describes their current embodiment in particles of cobalt-modified iron oxides, chromium dioxide, barium ferrite and metals and in thin films of metals, alloys and oxides. The curious and currently unexplained aspects of the behavior of these important materials is noted.