Recrystallization Technique Research Articles

Recrystallization of deformed metal nanoparticles

Despite great advances in the fabrication methods of metal nanoparticles with various sizes and shapes, the available tools for manipulating their microstructure and morphology still remain limited. In the present work we introduce the age-old metallurgical technique of recrystallization to the synthesis of metallic nanoparticles. We uniaxially compressed a large number of single crystalline and defect free Pt nanoparticles obtained by solid-state dewetting and annealed them at the temperature of 1000 °C. Our findings reveal that, while the as-dewetted particles exhibited similar shapes and crystallographic orientations, the plastic deformation and annealing led to a diverse range of shapes, microstructures, and orientations among the particles. We categorized the particles into four distinct types based on their appearance: slanted, terraced, “Danish pastry”, and broken particles. Finally, we propose a differentiation mechanism responsible for this diversification, which relies on a combination of recrystallization, surface step formation, and solid-state dewetting processes.

Unravelling the Effect of Sodium Doping on Li2MnO3 nanostructured Cathode Materials

The quest to develop affordable, high-performance electrode materials for lithium-ion batteries in electric vehicles is driving scientific innovation forward. Li2MnO3, as a prospective high-capacity (459 mAh.g-1) cathode, suffers from capacity degradation and voltage decay during the cycling process. Nanostructuring and incorporating sodium ions into lithium sites can mitigate voltage decay by limiting transition metal migration, impeding oxygen loss, and improving lithium diffusion by lowering the activation energy of Li-rich layered host materials. Herein, sodium-incorporated nonospherical structures of the form Li2-xNaxMnO3 (0 ≤ x ≤ 2), generated through the amorphisation and recrystallisation (A+R) technique show remarkable structural stability and enhanced Li-ion mobility owing to the enlarged lithium lattice upon sodium entrance. Specifically, the Li1.95Na0.05NaO3 nanosphere, displays more stable Li+/Mn4+ layers which will greatly contribute to its capacity. The microstructures associated with this configuration show well-ordered layers with high lithium kinetics and lower activation energy compared to pristine Li2MnO3. Characterisation of the x-ray diffraction (XRD) patterns revealed peak broadening along with the shifting of peaks at 2Θ~38 to the right due to the enlarged lithium layers occupied by sodium ions to facilitate lithium diffusion. Moreover, the undesired phase transformation from layered to spinel was observed at a later stage of charge for the sodium-doped systems, suggesting that the presence of sodium stabilizes the structure and minimizes the migration of manganese into lithium layers. These findings may lead to solutions for problems such as structural instability, lattice oxygen loss, and capacity decay in layered lithium oxide materials.

Analyzing the Implementation of Practicum Organic Compound Separation and Purification in the Chemistry Education Study Program

Students acquire various skills in the laboratory through scientific development practices such as demonstrations and experiments. The primary objective of this study is to gather empirical data regarding the implementation of organic compound separation and purification techniques at tertiary educational institutions to examine their efficacy as a proactive step to facilitate ongoing educational endeavors. The elements discussed include the practicum topics completed, the organic chemistry instruments and equipment possessed, how the practicum is conducted, and the problems and their resolutions. This study’s respondents included course instructors, chemistry lab assistants, and students previously attending practicum content. This study used a qualitative research methodology to analyze multiple chemistry education study programs across various locations in Indonesia. Data collecting methods include open-closed surveys, observation, and documentation. The findings indicated that the separation and purification practicum topic incorporates concepts related to separation and purification, employing extraction, chromatography, distillation, sublimation, and recrystallization techniques. Some chemistry education programs needed adequate instrumentation for organic chemistry. In addition, the wet laboratory practicum for separating and purifying the studied organic compounds are yet to be completed as per the planned topics. Green chemistry and project-based learning have been largely implemented in the practicum, but the micro-scale concept, which can help reduce practicum waste, are yet to be implemented. Inadequate tools and materials for the practicum, as well as inadequate reference materials, are some of the obstacles that hinder the practicum’s efficiency. Hence, there is a want for pragmatic instruments that can effectively cater to the demands of ongoing education. This practicum set should facilitate using green chemistry and micro-scale, focusing on minimizing pollution that can harm the environment. Keywords: practicum organic, compound separation, purification, chemistry education

Multi-step synthesis of novel 2-methyl-3-carboxamide-4-quinolones and an enhanced sampling simulation method to identify potentiators for cystic fibrosis

Cystic fibrosis (CF) is a life-threatening hereditary disease caused by mutations in the CF trans membrane conductance regulator (CFTR) gene. The commonly utilized medication for CF is a potentiator that restores CFTR function by stabilizing the channel in open conformation. A multistep synthesis method has been demonstrated here for synthesizing 2-methyl-3-carboxamide-4-quinolones having potential activities on CF. The synthesized molecules were obtained in quantitative yield and purified using recrystallization techniques without column purification. An extensive computational analysis was carried out to access the potential of 2-methyl-3-carboxamide-4-quinolones as potentiators. The computational analysis using molecular docking, classical and membrane-embedded molecular dynamics simulations in different lipid environments, and MM-PBSA revealed that the molecule 4d formed a stable complex. The binding free energies from umbrella sampling simulations for standard molecules ivacaftor and GPLG1837 were −26.133 kJ/mol and −28.471 kJ/mol, respectively, while for 4d a lower free energy value was obtained (−37.852 kJ/mol), which further strengthened the candidature of 4d as a promising potentiator molecule. This research identified a hit molecule that could be utilized further in in-vitro and in-vivo studies to establish it as a potentiator against CF and also provided a suitable and efficient synthesis method for the pharmaceutical industries.

Mixed Halide Formation in Lead‐Free Antimony‐Based Halide Perovskite for Boosted CO2 Photoreduction: Beyond Band Gap Tuning

AbstractPhotocatalytic conversion of carbon dioxide (CO2) into value‐added fuels is a vastly promising anthropogenic chemical carbon cycle to combat the greenhouse effect while meeting the ever‐increasing energy demand. Recently, lead‐based halide perovskites have demonstrated great potential in various applications including photochemical reduction of CO2. However, in view of lead toxicity, the exploration of a lead‐free alternative is crucial for long term application. Herein, a series of lead‐free mixed halide perovskites Cs3Sb2ClxBr9−x (0 ≤ x ≤ 9) is prepared via a facile antisolvent recrystallization technique, where the incorporation of a secondary halide enhances the charge transfer and separation while allowing precise tuning of bandgap between 2.59 and 2.90 eV. Theoretical calculations further reveal that the formation of mixed Cl/Br halides engenders favorable charge redistribution due to lower octahedral distortion, which in turn strengthens CO2 adsorption and activation. Under visible light illumination, the optimal dual halide perovskite, Cs3Sb2Cl4Br5 manifests substantial twofold and fourfold enhancements of CH4 yield over the single halide perovskite, Cs3Sb2Br9 and Cs3Sb2Cl9, respectively. In brief, this study provides a compelling demonstration of lead‐free mixed halide perovskites for photocatalytic CO2 reduction, and it is anticipated to drive further application of perovskite‐based photocatalysts toward a diverse range of artificial photoredox reactions.

Preparation and in vitro evaluation of hesperidin nanoparticles by antisolvent recrystallization in a double homogenate system.

Hesperidin nanoparticles (HNPs) were made for the first time employing an antisolvent recrystallization technique in a double homogenate system with positive and negative clockwise rotation in order to completely use the underutilized nutritional components in citrus peel. Dimethyl sulfoxide (DMSO), ethanol, and deionized water were used as the solvents and antisolvents in the hesperidin solution preparation. Hesperidin solution concentration of 60.26mg/mL, homogenization speed of 8257rpm, antisolvent-to-solvent volume ratio of 6.93mL/mL, and homogenization time of 3.15min were the ideal experimental conditions. HNPs have to be at least 72.24nm in size. The structures of the produced hesperidin samples and the raw hesperidin powder were identical, according to the findings of the FTIR, XRD, and TG characterization tests. The HNP sample had an in vitro absorption rate that was 5.63 and 4.23 times greater than that of the raw hesperidin powder, respectively. It was discovered that DMSO was more suited than ethanol for creating HNP particles. In the realms of dietary supplements, therapeutic applications, and health promotion, the HNPs produced by the ARDH technology would be a potential formulation on increasing uses for a wider range of nutraceuticals (synergistic).

A Comparative study on Annealing and phase transition effect in SS 304 and SSLNA from low Nickel Austenite to Martensite

The critical investigation for the study of Stainless Steel (SS) properties modification by annealing process is carried out by three different phases. Generally Annealing of metals improves the straining element of that metal and makes it soften to elongation. The SS metals have been variedly used as utensils in the house wares. The drawability index for the SS has naturally evident with the mixture of alloying elements in it. Standard composition consists of considerable percentage of Nickel (Ni) in it say 8% in SS 304. The resource and availability of Ni in India is marginably reduces in recent years. To compensate the absence of Ni with 8% annealing process in different types of SS metals deployed including new standards SSLNA (Low Ni Austenitic grade of SS) in Steel Authority of India Limited. As discussed the three phases were, Coating of Metals during annealing, Morphological/structural modification using recrystallisation and Sample preparation technique for the softening process. This review entirely aims to improve the metallurgical characteristics of SS with low Ni composition.

Experimental and numerical investigations on feasibility of inorganic KSnCl3 perovskite absorber and SWCNT-HTL for solar cells

Inorganic metal halide perovskite materials have attracted remarkable attention as light harvesters because of their promising optoelectronic merits and photovoltaic features like tunable band gaps, high charge carrier mobilities and greater absorption coefficients. In order to explore new inorganic perovskite materials for use in optoelectronic devices Potassium Tin Chloride (KSnCl3) has been experimentally synthesized using a supersaturated recrystallization technique at ambient conditions. The resultant nanoparticle (NP) specimens were analyzed for optical and structural properties by characteristic available techniques including scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and UV visible spectroscopy. Experimental investigations about structure reveals that KSnCl3 crystallizes in orthorhombic phase with particle size of 400–500 nm. SEM showed better crystallization and EDX confirmed the accurate structural composition. UV–Visible analysis indicated a prominent absorption peak at 504 nm, and the band gap is 2.70 eV. Theoretical investigations of KSnCl3 were also carried out via AB-initio calculations in Wein2k simulation program using modified Becke Johnson (mBJ) and generalized gradient approximations (GGA). Optical properties like extinction coefficient k (ω), complex parts of dielectric constant (ε1, ε2), reflectivity R (ω), refractive index n (ω), optical conductivity L (ω) and absorption coefficient α (ω) were examined and it was observed that . theoretical investigations were consistent with experimental findings. Incorporation of KSnCl3 as an absorber material along with single walled carbon nanotubes as p-type materials in (AZO/IGZO/KSnCl3/CIGS/SWCNT/Au) solar cell configuration have been investigated by SCAPS-1D simulation package. Open circuit voltage (Voc) of 0.9914 V, short circuit current density (Jsc) of 47.32067 mA/cm2 and a remarkable efficiency of 36.823% with has been predicted. Thermally stable KSnCl3 may become potential source in manufacturing of photovoltaic and optoelectronic applications on large scale.

Simulated synthesis and atomic-level structural characterization of LiNi2O4

LiMn2O4 is a promising cathode material for advancing lithium-ion batteries due to its high-rate capabilities and high operating voltages. However, it suffers capacity fading due to the loss of manganese and lattice instabilities linked to Mn3+ during cycling. The simulated synthesis technique has been used to generate LiNi2O4 models rich in microstructural features that evolve during the crystal growth process. The microstructural features can be linked to the electrochemical performance and properties of LiNi2O4, which will guide the doping of LiMn2O4 spinel with Ni. Substitution of a small amount of manganese with nickel has been proposed as one of the solutions for reducing capacity loss. The LiNi2O4 spinel structure was synthesized successfully with the simulated amorphization and recrystallization technique. The RDF functions indicated the average Ni – O bond length of ~1.925 Å which is comparable to the Ni – O average bond length of ~1.923 Å synthesized by Thomas M.G.SR and co-workers.

Genistein microparticles prepared by antisolvent recrystallization with low-speed homogenization process

To create genistein particles, a brand-new antisolvent recrystallization technique was employed. The response surface approach was utilized to optimize the single factor test findings, which were acquired via the preliminary tests. The ideal liquid-to-liquid ratio was 9, the solution concentration was 21 mg/mL, the nozzle diameter was 700 μm, the feed rate was 39.65 mL/min, and the homogenization rate was 1500 rpm. The smallest mean particle size measured was 202.782 nm. SEM was used to study the powder's morphology, while thermal analysis and infrared imaging were used to evaluate its characteristics. The homogeneous antisolvent recrystallization method-prepared GMP has a better dissolving rate and stronger antioxidant activity when compared to genistein powder. The antisolvent recrystallization approach used in this study, which uses low-speed homogenizing instead of conventional grinding and homogenizing, can successfully reduce particle size, improve bioavailability, and use less energy. This topic may thus be made popular because it has real-world applications.

Analysing the Implications of Charging on Nanostructured Li2MnO3 Cathode Materials for Lithium-Ion Battery Performance.

Capacity degradation and voltage fade of Li2MnO3 during cycling are the limiting factors for its practical use as a high-capacity lithium-ion battery cathode. Here, the simulated amorphisation and recrystallisation (A + R) technique is used, for generating nanoporous Li2MnO3 models of different lattice sizes (73 Å and 75 Å), under molecular dynamics (MD) simulations. Charging was carried out by removing oxygen and lithium ions, with oxygen charge compensated for, to restrain the release of oxygen, resulting in Li2−xMnO3−x composites. Detailed analysis of these composites reveals that the models crystallised into multiple grains, with grain boundaries increasing with decreasing Li/O content, and the complex internal microstructures depicted a wealth of defects, leading to the evolution of distorted cubic spinel LiMn2O4, Li2MnO3, and LiMnO2 polymorphs. The X-ray diffraction (XRD) patterns for the simulated systems revealed peak broadening in comparison with calculated XRD, also, the emergence of peak 2Θ ~ 18–25° and peak 2Θ ~ 29° were associated with the spinel phase. Lithium ions diffuse better on the nanoporous 73 Å structures than on the nanoporous 75 Å structures. Particularly, the Li1.00MnO2.00 shows a high diffusion coefficient value, compared to all concentrations. This study shed insights on the structural behaviour of Li2MnO3 cathodes during the charging mechanism, involving the concurrent removal of lithium and oxygen.

Improved extraction and recrystallization of high-quality aleuritic acid from natural resins using a modified technique

ABSTRACT The current extraction procedures for aleuritic acid from natural resins (seedlacs) are time-consuming and provide a variable yield of 10–20% with a purity of 70–94%. Furthermore, the perfume industries do not consider this low purity level to be a viable starting material for commercial purposes, since it necessitates further purification by multistage crystallization, resulting in 40–50% aleuritic acid losses. The current study developed a modified extraction method that combines alkaline hydrolysis with a salting-out mechanism and a polarity-manipulated solvent system suited for purification via a single-step recrystallization procedure. The extraction method consistently produces 17–18 grams of aleuritic acid per 100 grams of fresh resins, with a purity of > 99% and a melting point of 100 0C. Furthermore, the developed recrystallization technique resulted in a recovered yield of 85–95%, unlike the traditional recrystallization techniques, which results in yield losses of 40–50%. The purity of aleuritic acid was determined using HPLC equipped with an RI detector, and the melting points and crystals were characterized using Differential Scanning Calorimetry and Field Emission Scanning Electron Microscope. The new approach was less expensive, more ecologically friendly, and provides standard-quality aleuritic acid while using fewer chemicals.

Highly economic and waste valorization strategy for multicomponent and Knoevenagel reactions using water extract of tamarind seed ash.

The application of solid organic waste-originated products in the preparation of synthetically and biologically significant compounds in aqueous media or pure water is a highly desired task in chemical synthesis that shows an effective solution to the circular economy and sustainable environment. In this article, we describe our research on the development of highly economic and sustainable protocols for the synthesis of biologically important oxygen-heterocycles (using a multicomponent reaction) and synthetically important olefins (via the Knoevenagel condensation reaction) using water extract of tamarind seed ash (WETS) as catalyst and aqueous reaction medium. The reactions are carried out at room temperature (RT) under toxic/problematic/volatile organic solvent-free conditions. Products of the current methods have been purified by using recrystallization technique. WETS was characterized from its FTIR, powder XRD, SEM, and EDAX data. Problematic and non-renewable solvents were avoided throughout the process from their synthesis to purification. The utilization of solid organic waste-originated catalyst and aqueous media, avoid of non-renewable substances as catalysts, media, separation solvents and promoters, and unobligating heating conditions can surely attract the attention of chemists towards exploring the waste-based products in chemical transformations.

Isolation, characterization and in vitro antioxidant activity screening of pure compound from black pepper (Piper nigrum).

The present study's aims of isolation, characterization and in vitro antioxidant activity screening of pure compound from Black pepper (Piper nigrum) were investigated. Nowadays, scientific exploration of medicinal plants from natural sources has become the prime concern globally. All the crude drugs that have been isolated from natural plant origin (herbs, root, stem, bark, fruit and flower) have great significance in drug discovery as well as a lead compound to demonstrate great synergistic effect on pharmacology. For this research work, methanol was selected as a mother solvent, and the crude methanolic extract of black pepper was partitioned in between the solvent chloroform and di-ethyl-ether. A crystal fraction has been eradicated from the chloroform extract of black pepper (Piper nigrum). The crystal compound (C1) was isolated and purified by using thin layer chromatography (TLC) and recrystallization technique. The purified crystal compound (C1) isolated from black pepper possesses a strong in vitro antioxidant activity. The IC50 value of crystal compound (C1) was 4.1µg/ml where the standard one had 3.2µg/ml. Physical, phytochemical and chromatographical characterization of pure crystal compound (C1) has been explored, and from the analysis of all characteristics, it was found that, crystal compound (C1) might have resembling features of the standard Piperine of black pepper. The overall research work was really remarkable and introduced a convenient way of isolating pure compound from the natural source which will be a great referential resource in isolating crude drugs for future analysis.

Combined experimental and computational study of Al2O3 catalyzed transamidation of secondary amides with amines.

Amides are the most extensively used substances in both synthetic organic and bioorganic chemistry. Unfortunately, the traditional synthesis of amides suffers from some important drawbacks, including low atom efficiency, high catalyst loading, separation of products from the reaction mixture and production of byproducts. Al2O3 is an amphoteric catalyst that activates the carbonyl carbon of the secondary amide group and helps the C–N cleavage of the reactant amide group by attacking the N–H hydrogen. By using the concepts of amphoteric properties of Al2O3, amides were synthesized from secondary amides and amines in the presence of triethylamine solvent. Several aliphatic and aromatic amines were used for the transamidation of N-methylbenzamide in the presence of the Al2O3 catalyst. Moreover, using the Gaussian09 software at the DFT level, HUMO, LUMO and the intrinsic reaction coordinates (IRCs) have also been calculated to find out the transition state of the reaction and energy. In this study, five successful compounds were synthesized by the transamidation of secondary amides with amines using a reusable Al2O3 catalyst. The catalyst was reused several times with no significant loss in its catalytic activity. The products were purified by recrystallization and column chromatography techniques. This catalytic method is effective for the simultaneous activation of the carbonyl group and N–H bond by using the Al2O3 catalyst.

Accessing new polymorphs and solvates through solvothermal recrystallization.

In high-pressure structural chemistry, recrystallization techniques have been shown to be a powerful way of generating new polymorphs and solvates. A recent study by Olejniczak et al. [IUCrJ (2022), 9, 49-54] on the pyridazine-based compound 6-chloro-1,2,3,4-tetrazolo[1,5-b]pyridazine (C4H2N5Cl or CTP) uses these solvothermal techniques to establish the phase behaviour of CTP and the effects of partial hydration.

All-inorganic perovskite quantum dots-based electrospun polyacrylonitrile fiber for ultra-sensitive trace-recording

All-inorganic dual-phase CsPbBr3-Cs4PbBr6 quantum dots (CPB QDs)-based polyacrylonitrile (PAN) fiber synthesized by supersaturated recrystallization and electrospinning technique possesses characteristics of homogeneous morphology, high crystallinity and solution sensitivity. Under 365 nm laser excitation, CPB@PAN fiber exhibits surprising trace-recording capability attributing to the splash-enhanced fluorescence (FL) performance with a narrow-band emission at 477–515 nm. In the process of ethanol anhydrous (EA) and water splashing, the CPB@PAN fiber presents conspicuous blue and green emission when contacting with EA and water, and maintains intense blue and green FL for more than 4 months. These experimental and theoretical findings provide a facile technology for the development of biological protection display, biotic detection and moisture-proof forewarning based on the trace-recording performance of CPB@PAN fiber.

Isolation of trymiristin from Myristica fragrans for natural product chemistry laboratory

This study aims generated natural products chemistry project laboratory for student in order to isolation trymiristin from Myristica fragrans. The skill of isolating trimyristin will be useful for students to obtain natural whitening raw materials derived from nutmeg. Various studies on the isolation can be used in natural products laboratory project. Students are directed to study literature related to trymiristin isolation procedures. Students practice skills of extraction, fractionation, purification, and structure elucidation of trymiristin. They were asked to design the laboratory activities. Manipulation of the liquor by soxhletation and recrystallization techniques proved to be a simple method to isolate trymiristin in low resource laboratory setting. The trymiristin was treated with structure elucidation NMR and infrared spectrometry. The laboratory method, comprising for 3 hours laboratory sessions, was a simple way for the students to understand the process of isolating trymiristin.

An eco-friendly innovative halide and metal-free basic ionic liquid catalyzed synthesis of tetrahydrobenzo [b] pyran derivatives in aqueous media: A sustainable protocol

A novel imidazolium-based highly efficient, recoverable, and reusable basic ionic liquid [PEMIM][OH] was synthesized using a very simple approach. This ionic liquid was employed as a catalyst for the multicomponent synthesis of tetrahydrobenzo[b]pyran derivatives by the condensation of dimedone, malononitrile and various substituted aldehydes as key starting materials in aqueous media. Novelty, the efficacy of the catalyst, high yields of desired products, greener approach, high atom economy and use of aqueous media make this protocol worthwhile. The inventive idea of employing halide and a metal-free ionic liquid catalyst establishes this as a sustainable process. The cost-effective isolation of pure, high yielded desired product by sidestepping the column and recrystallization technique was also demonstrated in this protocol. A plausible mechanism for the formation of tetrahydrobenzo [b] pyran is proposed. The novel catalyst and synthesized compounds were characterized by using various analytical techniques such as FTIR, 1H NMR, 13C NMR, DEPT-135, LC-Mass, Elemental, HSQC, HPLC, TG-DSC, TG-DTG and single crystal XRD analysis.

Synthesis of GaN Crystals by Nitrogen Pressure-Controlled Recrystallization Technique in Na Alloy Melt

GaN crystals are synthesized by recrystallization technique in Na-Li-Ca alloy melt under different N2 pressure. X-ray powder diffraction results confirm that the structure of crystals is GaN with wurtzite type and there still have raw powders remaining. The total mass of GaN decreases with the nitrogen pressure reduces. No GaN crystals are found in the solution under N2 pressure of 0.4 MPa. The morphologies of the crystal are mainly prism and pyramid. The size of the crystal increases when closer to the liquid surface. Raman spectra indicates that these crystals are stress-free and crystal grown at 3.6 MPa has high structural quality or low impurity concentrations. The results reveal that the solubility and supersaturation of the solution are controlled by N2 pressure. The principle of GaN crystal synthesis by recrystallization is discussed.