Aluminum Amalgam Research Articles

Improving Discharge Voltage of Al-Air Batteries by Ga3+ Additives in NaCl-Based Electrolyte.

The application of NaCl-based aluminum-air batteries is limited due to the passivation of the aluminum anode. In an effort to solve this problem, this work studied the influence of different concentrations of Ga3+ additives on the discharge behavior of Al in the NaCl electrolyte. The results of both experiments and theoretical calculations have shown that commercial purity aluminum could be significantly activated by Ga3+. Based on microstructure observations and electrochemical impedance spectroscopy, the influence activation mechanism of Ga3+ on the discharge behavior of commercial purity Al is clarified. The addition of Ga3+ biased the surface charge of aluminum along the activation direction, forming activation sites, and then destroyed the surface passivation film. Due to the formation of a gallium–aluminum amalgam, the Al-air battery had the best discharge characteristics in the electrolyte with 0.2 M Ga3+, and its discharge voltage reached 0.9734 V with a remarkable increase compared with that of NaCl solution (0.4228 V). Therefore, Ga3+ additive is a promising choice for NaCl-based Al-air batteries to improve their discharge voltage.

An investigation on microstructural evolution and mechanical properties of Zn coating as interlayer on Mg-Al alloys using diffusion bonding

Diffusion bonding is the joining of two or more similar or dissimilar pieces of metals combined under pressure at elevated temperatures for a specific time. During the period, atoms diffuse between the two metals across the interface. The energy needed for the atomic movement entirely dependable on the stress applied and temperature. This is also extensible to non-metals, ceramics and intermetallic Compounds (IMC’s). The traditional method of fusion state welding processes have some disadvantages such as the production of less heat affected zone, distortion of the base metals etc. In the present investigation, 7075 Al and AZ80 Mg alloys combined together which the effects of holding time and holding temperature are related to diffusion and are being studied for mechanical and metallurgical properties. Henceforth, the morphologies were found by optical microscopy and SEM (Li et al., 2009) [1]. Zinc coated AZ 80 magnesium combination and AA 7075 aluminum amalgam were treated to receive the preliminaries of diffusion bonding for various process parameters (Pragatheswaran et al., 2019) [10]. A bonding temperature of 350 to 450 °C, a bonding pressure of 2 MPa to 25 MPa and a holding season of 5 min to 150 min resulted in a dispersion between the zinc coated AZ80 Magnesium/AA7075 Aluminium alloys (Pragatheswaran et al., 2019) [10]. It can be noted that for the zinc coated samples the lower temperatures of 325 °C resulted in non-bonded layer and similarly at lower pressure of 2 MPa and lower time duration resulted in non-bonded layer whereas for non-coated and zinc coated layer of lower temperature resulted in better bonded nature.

Chemoenzymatic route to stereodefined 2-(azidophenyl)oxazolines for click chemistry

Aryl-substituted esters of a racemic diprotected 2-azido-1-alkanol were submitted to the Staudinger/aza-Wittig reaction in order to assess scope and establish conditions for their cyclization to the corresponding 2,4,5-trisubstituted oxazolines. Following the cyclization study, the (2R,3R)-antipode of the azidoalkanol was obtained in high ee by incubation of the corresponding racemic azidoacetate with pig liver esterase (PLE). The p-nitrobenzoate of the enantioenriched 2-azido-1-alcohol was cyclized by the Staudinger/aza-Wittig to give the corresponding (4R,5R)-disubstituted-2-(4-nitrophenyl) oxazoline. Selective reduction of the nitrophenyloxazoline to the corresponding aminophenyloxazoline using aluminum amalgam followed by direct azidation of the 2-(4-aminophenyl) moiety provided the corresponding (4R,5R)-2-(4-azidophenyl) oxazoline derivative. The azidophenyl oxazoline was reacted with a proven click partner 4-ethynylfluorobenzene under copper/sodium ascorbate mediation to provide the click triazole product in high yield.

Applicability of aluminum amalgam to the reduction of arylnitro groups

An array of arylnitro compounds with various functionality were treated with freshly-prepared aluminum amalgam in THF/water solution and resulted in the corresponding arylamines. The Al(Hg)-mediated reductions are relatively rapid with consumption of the amalgam and disappearance of starting material occurring over 20–30 min. The workup of the reductions involves only removal of the insoluble by-products by filtration followed by concentration. Only in some cases is chromatography required to secure the pure product. The desired arylamines are furnished in quantities of 25–100 mg, which in some cases, could be taken on to the next reaction without further purification. Reductions of 4-nitrobenzyl derivatives of carbohydrates or nucleosides were selective in affording the corresponding 4-aminobenzyl products. To show applicability in click chemistry, selected aminobenzyl products are directly azidated to yield products that were then used in click reactions to afford the corresponding 1,2,3-triazoles.

Mechanical and Metallurgical Characterization of Al Ceramic MMC

Aluminum amalgam MMCs are ahead of time abundant acknowledgment for vehicle, modern, and aviation application due to their low thickness, high and great basic quality inflexibility. In the present work, an exertion is made to plan and assess the mechanical properties of Al6061-SiC/Graphite half breed composites. The composites were primed by means of stir casting process in which amount of fortification is varied from 2-10% in steps of 3, 5, 7 wt%. The primed composites are characterized as per standards. The scattered Graphite and SiC in Al6061 combination contributed in improving the rigidity of the composites. The SEMs of the examples showed uniform conveyance of the fortification particles in the lattice with no voids.

Modelling and Structural Analysis of Three-Dimensional Wing

This paper attempts to discover the structural behavior of the wing imperiled to flowing loads through the voyage. The study uses a method in the form of finite element analysis of wing flexure distortion. As a first step, two wing models are established by captivating factual features, wing assembly, and plan principles into consideration. The gathering wing prototypical entails of tinny membrane, two poles, and multi-ribs. Two spars which consist of primary and secondary spars. NACA 23015 is chosen as the baseline aerofoil as this is identical alike to the tailored aerofoil being castoff in Airbus A320. Two rods mostly endure the twisting moment and trim strength, which is finished of titanium contaminant to ensure enough inflexibility. The covering and wing spars are made of aluminum amalgam to lessen the structural heaviness. Later, a static structural investigation is smeared, and the overall distortion, comparable elastic strain, and corresponding Von-Mises tension are obtained to analyze the mechanical behavior of the wing. Furthermore, modal investigation is being supported out to determine the natural rate of recurrence, as well as the modal shape of the three orders, which are acquired through the pre-stress modal analysis. The outcomes of the modal scrutiny aid engineers decrease excitation on the natural occurrences and avert the wing from the flurry. In view of the results obtained from the study, designers can emphasize consolidation and analysis the stress attentiveness range and huge distortion area. In conclusion, the recreation consequences indicate that the arrangement is possible and improves the information grade of the lifting surface.

Effect of Mechanical Analysis of Magnesium AZ 80 Alloy and Aluminium 7075 Alloy using Diffusion Bonding

The vital issue when joining magnesium combination (Mg) and aluminum composite (Al) exists in the presence of development of oxide movies and fragile intermetallic inside the bond district. Be that as it may, dispersion welding is acclimated be a piece of these amalgams while not a great deal of issue. In this examination, an endeavor was made to break down the mechanical properties, for example, lap shear quality, Ram rigidity and microhardness for dispersion holding of AZ80 magnesium (Mg) and AA7075 aluminum (Al) disparate materials. The holding nature of the joints was checked by microstructure examination. This work is directed to get better understanding and portrayal of the dissemination holding of comparative and different metals. It additionally meant to acquire ideal parameters for dispersion holding of aluminum covering over magnesium composite with Aluminum amalgam. This work is led to get better understanding and portrayal of the dispersion holding of comparable and different metals. It additionally intended to get ideal parameters for dispersion holding of aluminum covering over magnesium composite with aluminum amalgam. These two metals are jointed inside the kick the bucket in the wake of completing surface treatment.

Preparation and Characterization of Alumina Nanofibers by Gas-Solid Reaction Method

Using gas-solid reaction method, the non-crystalline alumina nanofibers with different morphology and aspect ratios could exuberantly grow by feeding air into one closed box or bubbling air into several organic liquids which contained the thin aluminum amalgam sheet at room temperature. Their diameters were about 2-10nm, whereas the length-diameter ratios were distributed widely. The diameters and length could be controlled by adjusting the kinds of the organic reagent. The as-grown nanofibers were then heat-treated at temperatures range from 300 to 1000°C. The results of X-ray diffraction and thermo-gravimetric analysis indicated the γ-Al2O3 nanofibers would be produced at 500°C and the α-Al2O3 particles could be obtained at about 1000°C. The electron micrographs suggested the nanofibers growth direction was randomly in the air or organic solutions, except for growing regular naonofibers in polyoxyalklene-400. The growth mechanics of alumina nanofibers were briefly discussed.

Voltammetry of Aluminum Nanoparticles in Aqueous Media with Hanging Mercury Drop Electrode

AbstractThe method of linear cyclic voltammetry with hanging mercury drop eletctrode allows to follow the behaviour of aluminum nanoparticles in aqueous dispersions. The particles gradually react with the dispersion medium to form aluminum hydroxide over various intermediate aggregates depending on composition of the dispersing solution. Voltammetry shows adsorption at the electrode of some of the reaction intermediates and formation of aluminum amalgam when the bared metallic core contacts the electrode.

ChemInform Abstract: An Efficient Method to Construct the A,B-Rings Component Toward Total Syntheses of Phycocyanobilin and Its Derivative as a Photoprobe.

Total syntheses of phycocyanobilin and its derivative bearing a photoreactive group at the D-ring were accomplished by developing a new and efficient method for the construction of A,B-rings component, which consists of the Wittig-type new coupling reaction of 4-(1-methoxyethyl or 1-tosylethyl)-3-methyl-5-tosyl-1,5-dihydro-2H-pyrrol-2-one and a 2-formyl pyrrole derivative in the presence of nBu3P and a base, followed by reduction with aluminum amalgam and a subsequent acid or base treatment.

2-Substituted nitrones and isomeric hydroxylamines – obtained via aluminium amalgam reduction of nitro nitriles and ketones—a new access to convenient intermediates for nitroso carbonyl compounds preparation

Substituted five-membered cyclic nitrones (pyrroline N-oxides) have been obtained in good to high yields from tertiary γ-nitro ketones and nitriles employing aluminium amalgam as a reducing agent in moist diethyl ether or THF. Attempts to obtain cyclic amino nitrones from α- or β-nitro nitriles failed and only the corresponding hydroxylamines have been isolated. Both nitrones and hydroxylamines have been used for synthesis of tertiary C-nitroso nitriles or ketones.

A convenient synthesis of deuterium labeled tertiary aliphatic nitro ketones and nitriles – starting materials for preparation of deuterated cyclic nitrones, isomeric hydroxylamines, and corresponding C-nitroso compounds

Tertiary aliphatic β- and γ-nitro nitriles and ketones deuterated in (several) selected positions had been synthesized. The deuterated nitro compounds served as a starting material for the corresponding deuterium labeled nitrones or hydroxylamines (reducing with aluminum amalgam). Further oxidation of the last two groups of compounds with sodium periodate or m-CPBA afforded the relevant deuterated tertiary C-nitroso compounds.

Elemental analysis of 3,4-methylenedioxymethamphetamine (MDMA): A tool to determine the synthesis method and trace links

The elemental composition of 3,4-methylenedioxymethamphetamine (MDMA) powders and tablets was determined. The objective was the identification of the synthesis method and application of the elemental profile in comparative analysis. The developed analytical method comprised the digestion of a sample followed by quantitative analysis with inductive coupled plasma mass spectrometry (ICP-MS) and inductive coupled plasma atomic emission spectroscopy (ICP-AES). The sample collection consisted of a unique set of MDMA powders (57) from illicit production sites and MDMA tablets (97) taken from large seizures (over 500 tablets) in the Netherlands. The production method of MDMA could be determined for 89 of the 97 tablets. In 84 cases reductive amination using Pt as the catalyst was used, in four cases reductive amination using NaBH 4 or a similar reducing agent was employed and one mixed sample (Pt and B) was found. None of the MDMA tablets were assigned to the aluminium amalgam method. Using the elemental profile, 13 links were identified within the 97 MDMA tablets using cluster analysis based on Pearson correlations. Of these links 10 were corroborated by additional analyses.

Al/Hg – mediated Reductive Dimerisation of 3-methoxycarbonyl-4-oxo-4H-1-benzopyran

Aluminium amalgam – mediated reductive dimerisation of 3-methoxycarbonyl-4-oxo-4H-1-benzopyran produced two sets of diastereomeric bichromones coupled through 2,2′ and 2,4′- positions; the latter set of diastereomers underwent diastereoconvergent dehydration to produce Z-3,3′-dimethoxycabonyl-3H-2,4′-bi[1-benzopyran-2-ylidene]-4-one.

Studies related to carba-pyranoses: synthesis of acetylated derivatives of 4-amino-2,4-dideoxy-3-O-(β-d-glucopyranosyl)-β-l-(and β-d-) altrocarba-pyranose from ad-glucose template

Methyl (E)-3-nitroacrylate 15, the X-ray analysis of which is reported here, is prepared from methyl acrylate by a new route involving sequential reactions with mercury(II) chloride-sodium nitrite, bromine and sodium acetate. The dienophile 15 reacts with Danishefsky's diene 17 to give, after acidic hydrolysis, a 67 : 33 mixture of the ketones rac-18 and rac-19. With (E)-1-(2',3',4',6'-tetra-O-acetyl-beta-D-glucopyranosyloxy)-3-(trimethylsiloxy)buta-1,3-diene 1, it affords, after hydrolysis, a 42 : 18 : 28 : 12 mixture of the ketones 30, 31, 32 and 33. The alcohol 36, obtained by sodium borohydride reduction of the ketone 30, is converted into the monocarba-disaccharide 35 by the action of aluminium amalgam, lithium aluminium hydride and acetic anhydride. Similarly, the alcohol 41, derived from the ketone 32, is transformed into the monocarba-disaccharide 40; the structure of the alcohol 41 is secured by an X-ray analysis. The isolation of a mixture of the acetoxyamino and acetylamino derivatives 38 and 39 from the reaction of the alcohol 36 with aluminium amalgam and acetic anhydride indicates that the nitro function is converted into the hydroxylamino and amino groups by the reducing agent. The cyclohexane rings of the ketones rac-18, rac-19, 30, 31 and 33 adopt the expected chair conformations. Thus, the methoxycarbonyl, nitro and oxy substituents are equatorially orientated in the ketones rac-18 and 30; in the ketones rac-19, 31 and 33, the methoxycarbonyl and nitro groups occupy equatorial dispositions and the oxy substituent is axially orientated. The cyclohexane ring of the ketone 32 (which bears a diastereomeric relationship to that of the ketone 30) displays unexpected conformational properties, that are attributed to a significant population of the chair conformer with axial arrangements of the methoxycarbonyl, nitro and oxy groups.

Conjugate Additions of o‐Iodoanilines and Methyl Anthranilates to Acetylenic Sulfones. A New Route to Quinolones Including First Syntheses of Two Alkaloids from the Medicinal Herb Ruta chalepensis.

AbstractFor Abstract see ChemInform Abstract in Full Text.

(‐)‐β‐Narcotine: A Facile Synthesis and the Degradation with Ethyl Chloroformate.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthetic approach to the AB ring system of ouabain.

Several novel hydroxylated cis-decalin derivatives, potential intermediates for the synthesis of the AB ring system of the important cardiotonic steroid ouabain, have been synthesized from commercially available starting materials. The first step in the preparation of these highly functionalized intermediates is a Robinson annulation of the beta-keto ester 6 and the 4-silyl-3-buten-2-one 5 to furnish the octalone 4 with good diastereoselectivity in fair yield (due to competition with a novel silicon-to-carbon phenyl migration). Reduction of the epoxy alcohol 3 (derived from 4 in two high-yielding steps) with LiAlH(4) gave a mixture of the desired triol 11 along with the product of an unusual reductive opening at the tertiary carbon, namely the triol 12. A plausible mechanism for this unusual reduction is presented as are possible methods for avoiding it. In particular, reduction of the corrresponding epoxy ketone 15 with aluminum amalgam proceeded in good yield to give the hydroxy ketone 16. Also reduction of the epoxide ester having the inverted stereochemistry at C3 afforded the desired tertiary alcohol 33 in good yield. Another approach using the beta,gamma-unsaturated ketal 38 permitted the formation of the tertiary alcohol 40. Fleming oxidation of the related, very functionalized silane 39 afforded the desired 1beta-alcohol 41 in fair yield. Finally a novel rearrangement was observed when the epoxy alcohol 24 was treated with DIBAL to effect loss of the angular hydroxymethyl group to produce the tetrasubstitued alkene 29 in high yield.

Conjugate additions of o-iodoanilines and methyl anthranilates to acetylenic sulfones. A new route to quinolones including first syntheses of two alkaloids from the medicinal herb Ruta chalepensis.

A novel synthesis of 2-substituted 4-quinolones was developed on the basis of the conjugate additions of appropriately ortho-substituted anilines to acetylenic sulfones followed by intramolecular acylation of the corresponding sulfone-stabilized anions. Conjugate additions of variously substituted anilines to alkyl-substituted acetylenic sulfones generally proceeded slowly and in poor yield, especially when the aniline contained an electron-withdrawing substituent such as an ester group. In some cases, the reactions were enhanced by the presence of DMAP and the use of an excess of the sulfone in aqueous DMF. N-Formylanilines proved superior to free anilines. The products were either vinyl or allyl sulfones, depending on the conditions and the structure of the reactants. The acetylenic sulfone exists in equilibrium with its allenic and propargylic isomers under base-catalyzed conditions. Therefore, any of the three unsaturated sulfones can serve as the starting material for the conjugate additions. o-Iodoanilines proved superior to methyl anthranilate derivatives and underwent conjugate additions smoothly. The products were subjected to palladium-catalyzed carbonylation in methanol, and the resulting methyl esters were cyclized by treatment with strong bases such as LiHMDS or LiTMP, followed by reductive desulfonylation with aluminum amalgam. The resulting 2-substituted 4-quinolones included the naturally occurring medicinal compounds 1 and 2 and the O-methyl derivative 3.

(-)-β-Narcotine: A Facile Synthesis and the Degradation with Ethyl Choroformate

<TEX>$(-)-\beta-Narcotine$</TEX> (6), a phthalideisoquinoline alkaloid, was synthesized conveniently by the direct condensation of cotarnine (1) and iodomeconine (2) prepared by aromatic iodination using thallium trifluoroacetate/KI and by the successive reduction of resulting <TEX>$iodo-{\beta}-narcotine$</TEX> (5) with aluminum amalgam. Its structure including a stereochemistry was confirmed by instrumental analyses. This synthetic alkaloid was degraded with ethyl chloroformate at room temperature to afford the chloro-carbamate 6b as a crystalline intermediate, which was unexpectedly converted into the carbinol 8 by exchange of Cl with OH of water contained in the solvents and the ethoxy-carbamate 9, probably because of ethanol added to chloroform as a solvent stabilizer during the purification by column chromatography.