Basic Alumina Research Articles

Microwave Assisted Green Synthesis and Entomological Characteristic Studies of Novel Chromium(III) complexes of dithiocarbamates derived from glycine, alanine, proline, Valine and Norvaline α-amino acids

A series of chromium (III) complexes derived from α-amino acids, of the type Cr[S2CNHCH(R)COOH]3 (where R = H, CH3, C3H5, CH(CH3)2, (CH2)2CH3), were synthesized by microwave irradiation (solvent free and solid support) methods. Among solid supported microwave irradiation better yields are obtained in acidic alumina as compared to silica, neutral alumina, and basic alumina. The α-amino acid-metal complexes were characterized by FT-IR and UV–Vis spectrophotometers to determine the complex formation. The synthesized tris (dithiocarbamato) chromium(III) complexes showed plurality of uses as microbiocides and insecticide for controlling undesirable microorganisms and pests in crop protection, protection of materials, household, veterinary pests, pest management and control in vegetable crops, ornamental plants, floriculture, medicinal and economic plants apart from being cytotoxic. The present paper is focused on the insecticidal activity of the title compounds found to be effective against Spedoptera litura larva and Tetranychus urticae in entomological studies.

A simple polyacrylamide gel route for the synthesis of MgAl2O4 nanoparticles with different metal sources as an efficient adsorbent: Neural network algorithm simulation, equilibrium, kinetics and thermodynamic studies

• A polyacrylamide gel method have been used to synthesize the MgAl 2 O 4 nanoparticles. • An artificial neural network model of phase purity of MgAl 2 O 4 was constructed. • The microstructure and adsorption performance of MgAl 2 O 4 nanoparticles were compared. • An adsorption mechanism of MgAl 2 O 4 nanoparticles was proposed. The MgAl 2 O 4 nanoparticles with different particle sizes prepared by a polyacrylamide gel method with different metal salts as raw materials which was used to study its efficiency as an adsorbent for removal of Congo red, acid orange 7 and acid fuchsin from wastewater. It was difficult to obtain pure MgAl 2 O 4 nanoparticles with basic magnesium carbonate or aluminum acetate coupled with other metal salts. Based on the molecular weight, coordination number, ion radius and the number of water of crystallization for the metal salt and the phase purity of the target product, a neural network prediction model was established to predict the effect of synthesis parameters on the phase purity of MgAl 2 O 4 . The microstructure characterization confirmed that the minimum particle size of MgAl 2 O 4 nanoparticles prepared with aluminum nitrate and magnesium sulfate as metal salts was about 22 nm, and the maximum particle size of MgAl 2 O 4 nanoparticles prepared with aluminum nitrate and magnesium chloride as metal salts was about 50 nm. Adsorption experiments of MgAl 2 O 4 nanoparticles were performed as a function of process parameters: various dyes including Congo red, acid orange 7 and acid fuchsin, adsorption time, particles size, initial dye concentration, initial adsorbent concentration, pH value and reaction temperature. The thermodynamic studies showed that the adsorption of MgAl 2 O 4 nanoparticles for removal of Congo red from wastewater is an exothermic and spontaneous process. The maximum adsorption capacity of 89.043 mg/g for the MgAl 2 O 4 nanoparticles was found at 1 g/L of initial adsorbent concentration, 100 mg/L of initial dye concentration, 6.9 of pH, and 299.8 K of temperature for removal of Congo red from wastewater. The adsorption of Congo red, acid orange 7 and acid fuchsin can be assigned to the synergistic effect of electrostatic interaction, pore filling and ion exchange. This present work provides a technical reference for the synthesis of other metal oxide nanoparticles using metal salts with different acid groups.

Joining of hybrid semi-finished products from sheet metal by orbital forming

Contrary demands like a reduction of carbon dioxide emissions and an increase in functionality are facing the manufacturing industry with growing challenges. When processing functional components, like synchronizer rings, conventional process chains, like shearing and subsequent joining, are reaching their limits due to an increased complexity of the components and a lack in efficiency, referring to the long process time. To meet these challenges, the strategy of lightweight construction combines the application of lightweight materials with efficient manufacturing processes and an innovative product design. One possibility within lightweight construction is the utilization of load-adapted hybrid components, featuring different material strength classes. In previous research, the process of orbital forming is used to manufacture semi-finished products with a varying thickness profile due to the specific radial material flow. This material flow should now be used to realize a permanent joint between materials of two different strength levels. Therefore, the process of orbital forming is modified to manufacture hybrid semi-finished products from a dual-phase steel DP600 and a naturally rigid aluminum alloy EN AW 5754, both with an initial thickness of 2.0 mm. Different joint geometries are cut by laser into a steel ring and the part is coaxially positioned around a basic aluminum disc inside a die and subsequently formed. The joint is investigated regarding the geometrical and mechanical properties, comparing a radial cross-section and the micro hardness distribution. In order to reveal the potential of orbital forming for a combined forming and joining operation, the axial as well as the peeling strength of the multi-material components are investigated and evaluated.

Kinetics of microwave liquid-phase desorption with chemical dissociation: SO2 desorption of basic aluminum sulfate desulfurization rich liquid

BackgroundReaction kinetics was an important tool for quantitative expression of micro-chemical processes. In this study, a kinetic evaluation method of microwave liquid-phase desorption mechanism was established, which was of great value to reveal the non-thermal effect of microwave desorption. MethodsDesorption kinetics of basic aluminum sulfate (aluminum base) desulfurization rich liquid were monitored with a microwave simultaneous cooling system. The effect of microwave power on its chemical reaction was investigated by linear and nonlinear regression analysis. Significant findingsThe kinetic analysis showed that the pre-exponential factor and activation energy decreased with the increase of microwave power, and the dependence on microwave power was more consistent with the first-order linear model and the second-order polynomial model. At the same temperature, the microwave desorption rate was 1.3–2.6 times that of water bath thermal desorption. At the same desorption reaction rate, the microwave desorption temperature was 10 K–20 K lower than that of thermal desorption. Compared with thermal desorption, although the reaction order did not change under different microwave power, the pre-exponential factor and activation energy decreased, and the reaction rate constant was about 1.1–2.1 times that of the same temperature.

Diterpenoid alkaloids from roots of Aconitum kongboense

The chemical constituents from the roots of Aconitum kongboense were studied. Twenty-five diterpenoid alkaloids were isolated from the 95% methanol extract of the roots of A. kongboense by silica gel, reverse-phase silica gel and basic alumina column chromatography. They included a new aconitine-type diterpenoid alkaloid, named as kongboensenine(1), and twenty-four known ones(2-25), i.e., acotarine F(2), acotarine G(3), 14-acetyltalatisamine(4), talatisamine(5), indaconitine(6), yunaconitine(7), chasmanine(8), 6-epi-foresticine(9), homochasmanine(10), 8-deacetyl-yunaconitine(11), chasmaconitine(12), ajaconine(13), franchetine(14), ezochasmanine(15), crassicautine(16), 14-O-deacylcrassicausine(17), genicunine A(18), falconeridine(19), sachaconitine(20), liljestrandisine(21), 8-methyl-14-acetyltalatisamine(22), kongboendine(23), 14-benzoylchasmanine(24) and pseudaconine(25). Their structures were elucidated by common spectroscopic methods including high-resolution electrospray ionization mass spectrometry(HR-ESI-MS) and nuclear magnetic resonance(NMR) techniques. Compounds 2-4, 10, 13, 15-19 and 21-22 were isolated from this plant for the first time. Experimental results showed that all compounds did not have a significant inhibitory activity against acetylcholinesterase(AChE).

Anodic Dissolution of Copper in the Acidic and Basic Aluminum Chloride 1-Ethyl-3-methylimidazolium Chloride Ionic Liquid

The anodic dissolution of copper was investigated at a copper RDE in the Lewis acidic and basic composition regions of the room-temperature AlCl3-EtMeImCl ionic liquid (IL) to assess the utility of chloroaluminate liquids as solvents for the electrochemical machining and electropolishing of copper. In the Lewis acidic IL (60 mol % AlCl3), the dissolution of Cu0 proceeds under mixed kinetic-mass transport control with an exchange current density of 7.00 mA cm−2 at 306 K and an apparent activation free energy of 19.7 kJ mol−1. A formal potential of 0.843 V was obtained for the Cu+/Cu0 reaction from potentiometric measurements. In the basic IL (< 50 mol % AlCl3), potentiometric measurements showed that the oxidation of Cu0 resulted in the formation of [CuCl2]−. In this case, the formal potential of the [CuCl2]−/Cu0 reaction is −0.412 V. At small positive overpotentials, the reaction exhibited mixed control and was first order in the chloride concentration, indicating that only a single Cl− is involved in the RDS. However, at more positive overpotentials, the reaction transitions to mass transport control, and a well-defined limiting current is observed for the anodization process. This limiting current scales linearly with the free chloride concentration in the IL.

Physicochemical and Calorimetric Study of Aluminocopiapite and Thermodynamic Properties of Copiapite-Group Minerals

The natural basic aqueous aluminum and iron sulfate, aluminocopiapite (Al0.60 $${\text{Fe}}_{{0.07}}^{{3 + }}$$ ) $${\text{Fe}}_{{4.00}}^{{3 + }}$$ [SO4]6.03(OH)1.95 ⋅ 19.54H2O (Blyava, South Urals, Russia), was studied using powder X‑ray diffraction, infrared and Mossbauer spectroscopy, and thermal analysis. The enthalpy of formation from the elements $${{\Delta }_{f}}H_{{el}}^{0}$$ (298.15 K) = −11 826 ± 58 kJ/mol was determined by high-temperature melt solution calorimetry on a Tian-Calvet high-temperature heat-flux microcalorimeter “Setaram” (France). Standard entropies and Gibbs energies of formation were estimated for the studied aluminocopiapite and other copiapite-group minerals.

Low and Stable Secondary Electron Yields of Alodine-Treated Aluminum Alloys Under Continuous Electron Bombardment

High secondary electron yields of aluminum (Al) alloys limit the performances of high-power microwave devices and even extremely degrade their lifetimes. In this work, a strategy of alodine treatment for Al alloys was proposed to achieve a goal of the secondary electron emission suppression under continuous electron bombardment. It was found that a porous chromate conversion film including the mixture of basic chromium chromate and alumina with a mean pore size of 69.1 nm was formed on the surface of the Al alloy treated by alodine solution. On the basis of the secondary electron yield (SEY) measurement results, this alodine treatment brings about a reduction of maximal SEY of the Al alloy from 1.67 to 1.33 with a ratio of 20.4% and has just a remarkably tiny SEY change within 0.01~0.03 under 240-min continuous electron bombardment.

Microwave desorption mechanism and microwave effect based on SO2 chemical dissociation and mass transfer of basic aluminium sulfate desulfurization rich liquid

A microwave liquid-phase desorption technique for enhancing mass transfer with chemical dissociation has been proposed for the first time.

Reactivity of Aluminum and Titanium Oxides under the Conditions of the Synthesis of Strontium and Barium Titanates in Water Fluid Media

Strontium and barium titanates deposited on a porous support (α-Al2O3) are synthesized by the treatment of previously deposited precursors (titanium oxide, strontium nitrate, or barium nitrite) in a water fluid medium at 400°C. The obtained samples are characterized by X-ray powder diffraction (XRD) analysis and scanning electron microscopy (SEM) with energy-dispersive X-ray (EDX) spectroscopy. It is found that, in the presence of titanium oxide, α-Al2O3 is partially hydrated to form basic aluminum hydroxide AlO(OH) (boehmite), which is not detected by XRD after the treatment of α-Al2O3 in a water fluid. SEM with EDX spectroscopy demonstrates that strontium ions under the conditions of the treatment in a water fluid preferably interact with titanium oxide to form SrTiO3, although the aluminum oxide content in the samples is much higher. The conditions are determined for obtaining systems with different spatial distributions of the supported component inside the granules of the support by varying the procedure of its preliminary impregnation with the titanium oxide precursor.

Mechanochemically Induced Chalcogenation of Bicyclic Arenes under Solvent‐, Ligand‐, Metal‐, and Oxidant‐Free Conditions

AbstractA convenient method has been developed for the synthesis of biarenyl chalcogenides through the interaction of bicyclic arenes and diaryl dichalcogenides on the surface of basic alumina under ball milling without any metal catalyst or solvent. This methodology shows wide substrate scope and is of high potential in organic synthesis due to its green aspects of ease of operation, shorter reaction time, ambient conditions and high yields.

Raising the COx Methanation Activity of a Ru/γ-Al2 O3 Catalyst by Activated Modification of Metal-Support Interactions.

Ru/Al2O3 is a highly stable, but less active catalyst for methanation reactions. Herein we report an effective approach to significantly improve its performance in the methanation of CO2/H2 mixtures. Highly active and stable Ru/γ‐Al2O3 catalysts were prepared by high‐temperature treatment in the reductive reaction gas. Operando/in situ spectroscopy and STEM imaging reveals that the strongly improved activity, by factors of 5 and 14 for CO and CO2 methanation, is accompanied by a flattening of the Ru nanoparticles and the formation of highly basic hydroxylated alumina sites. We propose a modification of the metal–support interactions (MSIs) as the origin of the increased activity, caused by modification of the Al2O3 surface in the reductive atmosphere and an increased thermal mobility of the Ru nanoparticles, allowing their transfer to modified surface sites.

Exploration of ceramic supports to be used in membrane reactors for hydrogen production and separation

The objective of this study is to develop ceramic supports employed in the preparation of catalytic membrane reactor using less catalyst and lower temperature and enabling H2 production and separation together through the dry reforming of methane. For this reason, nine different ceramic supports are fabricated by using three different types of activated alumina (acidic, basic and neutral) and three different Si/Al molar ratios at two different calcination temperatures in order to investigate the surface acidity and basicity effect of supports to be used with impregnated Rh catalyst for rising the activity to CH4, CO2 and sensitivity to coke formation encountered with Ni-based catalysts. Subsequently, the effect of those variations on supports is determined by using XRD, SEM and BET instruments, in addition to this, H2 permeability test of five supports having high BET surface areas is also performed with using constant volume-variable pressure technique at the temperatures of between 25 and 250 °C. Acidic alumina sintered at 600 °C and containing Si/Al ratio of 0.648 represented the highest hydrogen permeability with higher activity, whereas, neutral alumina calcined at the temperature of 600 °C having Si/Al ratio of 0.555 gave the highest activity with the lower hydrogen permeability, while basic alumina sintered at the temperature of 600 °C and including Si/Al ratio of 0.648 imparted lower activity with higher hydrogen permeability.

Alumina-K3PO4 Solid Supported Microwave Synthesis of 1, 3-diaryl-2- propene-1-one Derivatives as a Prominent Antioxidant Scavenger

Background: The various industrial processes have a diverse effect on the environment through pollution. In view of these observations, some environmentally benign synthetically protocols have developed under green chemistry. For rapid and sustainable synthesis, the microwave irradiation (MI) has gained popularity as a powerful tool compared to conventional synthesis. The present study describes the synthesis of novel substituted 1, 3-diaryl-2-propene-1-one derivative using alumina supported K3PO4-MWI combination. Objective: Chalcones are important compounds which are widely spread in nature like in fruits, vegetables, tea, spices, etc. The 2’-hydroxy derivative of chalcones plays an important role in the synthesis of bioactive compounds. The present communication deals with a convenient and rapid synthesis of 1, 3-diaryl-2-propene-1-one under the support of alumina-tripotassium phosphate and microwave irradiation. Our efforts are focused on the introduction of typical and easier route for the synthesis of title compounds using a microwave. All synthesized chalcones have been screened and evaluated for the antioxidant activity by DPPH and nitric oxide radical scavenging. Some of these compounds are found to be more potent scavengers and may lead to the development of a new class of antioxidants. Methods: The α, β-unsaturated carbonyl functionality contains two electrophilic centers allowing them to undergo addition and cyclization reactions with different nucleophiles. In the literature survey, we found that Chalcones were synthesized using tripotassium phosphate catalyst under refluxing by a conventional method. A novel method for the synthesis of 1, 3-diaryl-2-propene-1-one via Claisen Schmidt has been introduced by reacting substituted 2’- hydroxyl acetonaphthones with substituted aromatic aldehydes under the support of basic alumina –tripotassium phosphate via microwave radiations. Formation of corresponding Chalcones was confirmed by spectral studies followed by their screening for antioxidant activity. The scavenging activity is expressed in terms of % inhibition and IC50 value (μg/ml). Results: The structures of newly synthesized Chalcones were confirmed and in good agreement with obtained spectral analysis such as IR, NMR, Mass and elemental analysis. Commercially available basic alumina and tripotassium phosphate in combination of microwave were utilized and found to be effective, convenient route for the synthesis of 1, 3-diaryl-2-propene-1-one derivatives with desirable yields in short reaction time (5-12 min). The results of antioxidant activity revealed that the IC50 value for compounds 3a, 3d, 3e, 3f, 3g, 3h, 3j, 3l and 3n are lower than that of standard ascorbic acid to scavenge DPPH radical. This indicates that these compounds are more significant scavengers in comparison with standard drug. On the other hand, compounds 3a, 3b, 3c, 3d, 3g, 3l and 3n are more potent scavengers for NO free radical. Conclusion: We have introduced an efficient, ecofriendly, simple and fast microwave assisted method using basic alumina-tripotassium phosphate for the synthesis of 1, 3-diaryl-2-propene-1- one derivatives. Microwave irradiation provides an effective way for the preparation of Chalcones in terms of several advantages as a simple procedure, short reaction time, milder reaction condition, cleaner reaction and excellent yield. The scavenging activity of chalcones against DPPH and NO free radicals showed excellent properties of antioxidants.

An efficient basic alumina supported continuous flow synthesis of chromene derivatives

Abstract An efficient basic alumina supported continuous flow method was developed for the synthesis of various chromene derivatives by one-pot three component condensation of arylaldehydes, malononitrile and dimidone using basic alumina as solid supported catalyst under continuous flow. This protocol offer various advantages such as mild reaction condition, simple work-up procedure, avoids the usage of strong acid catalysts, re-usability of catalyst, and produces higher yields in shorter reaction time with high selectivity. Chromene derivatives were characterized by different spectral analysis such as IR, 1HNMR, 13CNMR, mass spectrometry and elemental analysis.

The bioavailability of ingested 26Al-labelled aluminium and aluminium compounds in the rat

The fractional uptake of ingested aluminium and aluminium compounds (aluminium citrate, aluminium nitrate, aluminium chloride, aluminium sulphate, aluminium hydroxide, aluminium oxide, aluminium metal, powdered aluminium pot electrolyte, acidic sodium aluminium phosphate (SALP), basic sodium aluminium phosphate (Kasal), sodium aluminium silicate and FD&C red 40 aluminium lake) from the gastro-intestinal tract of adult female rats was measured. This was determined by comparing retained body burden of 26Al at seven days post-admistration of an i.v. injection of 26Al-labelled aluminium citrate with that retained following the gastric admistration of 26Al-labelled test compounds as either solutions or suspended solid. The calculated percentage uptake of 26Al for all the aluminium solutions was similar: aluminium citrate 0.08%, aluminium chloride 0.05%, aluminium nitrate 0.05% and aluminium sulphate 0.21%. The uptake of 26Al administered as insoluble particulates was lower: 0.03% for aluminium hydroxide; 0.02% for aluminium oxide; 0.04% for powdered pot electrolyte; 0.12% for sodium aluminium silicate; and 0.09% for FD&C red 40 aluminium lake. For aluminium metal, SALP and Kasal the amount of 26Al present in the rats was insufficient to determine uptake and was less than 0.03%. The results produced for aluminium citrate, aluminium hydroxide and aluminium sulphate are close to those published for man.

Experimental Study on the Phase Equilibrium of Copper Matte and Silica-Saturated FeOx-SiO2-Based Slags in Pyrometallurgical WEEE Processing

The effects of the amphoteric and basic oxides alumina and lime on the phase equilibria of copper matte and silica-saturated slags were investigated at 1300 °C and P_{{{text{SO}}_{ 2} }} = 0.1 atm in a controlled CO-CO2-SO2-Ar gas atmosphere using a high-temperature isothermal equilibration technique followed by rapid quenching. The equilibrium phase compositions were obtained by Electron Probe X-ray Microanalysis. The relationship between the copper concentration in matte and the oxygen partial pressure, iron, and sulfur in matte was quantified. The pure iron-silicate slag exhibited the highest copper loss in slag, although the addition of alumina and lime decreased its value by approximately a quarter and a half, respectively, at a matte grade of 65 wt pct Cu. In contrast, copper and sulfur were highly distributed in the matte phase, and their deportment to the matte was favored by addition of alumina and lime.

Recovery of Precious Metals (Au, Ag, Pt, and Pd) from Urban Mining Through Copper Smelting

With the aim of investigating deportments of precious metals in pyrometallurgical processing of waste electrical and electronic equipment, the distributions of selected precious metals (gold, silver, platinum, and palladium) between copper matte and three different silica-saturated slags (pure FeOx-SiO2, FeOx-SiO2-Al2O3, and FeOx-SiO2-Al2O3-CaO slag) were investigated at 1300 °C in controlled flowing CO-CO2-SO2-Ar gas atmosphere by a high-temperature isothermal equilibration technique. The phase compositions were analyzed by Electron Probe X-ray Microanalysis and Laser Ablation-High Resolution Inductively Coupled Plasma-Mass Spectrometry. It was shown that the distribution coefficients of gold, platinum, and palladium between matte and slag (Lm/s(Me) = [Me]in matte/(Me)in slag) were very high and increased with increasing matte grade. The distributions to the matte phase were increased by adding basic oxides alumina and lime into the acidic silicate slags. The experimentally measured distribution coefficients Lm/s(Me) followed the order of platinum > palladium > gold > silver. The present experimental results can be used for upgrading thermodynamic databases for the complex recycling processes through nonferrous smelting.

Synthesis of 1,4,5-Trisubstituted 1,2,3-Triazoles Through a One-Pot Three Component Reaction of Boronic Acids, Sodium Azide and Active Methylene Compounds Under Ball-Milling Conditions

In this study, we report a mild and efficient one-pot synthesis of 1,4,5-trisubstituted 1,2,3-triazoles via a three-component reaction of aryl boronic acids with sodium azide and active methylene compounds under ball-milling condition. In order to determine optimized reaction conditions, several grinding auxiliaries (basic, neutral and acidic alumina, silica gel, K10 and KSF), bases (DBU, DABCO, piperidine, triethylamine, potassium t-butoxide and potassium carbonate) and copper salts under ball-milling conditions were examined. Using the optimized condition procedure, a wide variety of 1,4,5-trisubstituted 1,2,3-triazole derivatives were prepared in very good yields. All products were well-characterized by 1H-NMR and 13C-NMR spectroscopy. This environmentally friendly protocol offers several advantages including high yields of products, relatively short reaction time and simple work-up procedure.

Evaluation of the Removal Efficiency of PCBs from Five Wastewater Treatment Plants in Jordan

The levels of persistent organic pollutants, polychlorinated biphenyls (PCBs), were investigated in influent, effluent, and sludge of five wastewater treatment plants (WWTPs) in Jordan. Concentrations of 12 dioxin-like PCBs were determined. The extraction of PCBs from wastewater samples was done by solvent extraction using dichloromethane/hexane 1:1 mixture. The concentrated extracts were sequentially subjected to multilayer silica gel, basic alumina, and florisil chromatography columns for further cleanup. Sludge samples were extracted in a Soxhlet apparatus, using petroleum ether. PCB determination has been completed using gas chromatography equipped with mass spectrometry detector. The total concentrations of PCBs in influent samples ranged from 34.65 to 228.3 ng L−1, in effluent samples from 16.1 to 123.88 ng L−1, and in the sludge samples from 51.1 to 223.85 ng kg−1. In three of the investigated wastewater treatment plants, the amount of PCBs in sludge exceeded the limit proposed by European Union legislation. The total removal efficiencies of the total PCBs were evaluated and ranged from 34.8 to 88.1% for Aqaba and Abu-Nsair WWTP, respectively. The values of incremental lifetime cancer risk due to exposure to PCBs in sludge samples were also estimated in this study, and they ranged from 2.415 × 10−7 to 1.193 × 10−6 for adults. The number of people suspected to have cancer due to the exposure to the sludge of the WWTPs in Jordan is between 4 and 20 out of ten million.