Solution combustion synthesis of NaFePO4 and its electrochemical performance

In the current research work, submicron size single-phase NaFePO₄ (NFP) nanoparticles are successfully synthesized using the solution combustion method. The calcination of as synthesized NFP powder is done at 700 °C for 5h in the air atmosphere and it shows the maricite phase crystallized into an orthorhombic structure with a surface area of 9.29 m²/g.  The intermolecular vibrations of the (PO₄)³⁻ group are identified in the FTIR spectra. The XPS spectra of NFP confirms the presence of Fe and P in +2 and +5 oxidation states, respectively. The coin cell assembled using calcined NFP powder shows a pair of redox peaks at 2.42 and 2.69 V vs. Na/Na⁺ owing to Na-ion insertion and extraction. NFP material delivers a specific capacity of 28 mAh/g at 0.1 C with 92% capacity retention after 35 cycles.     

反式和顺式-1,2-二氰-(4-乙基苯)乙烯结构的谱学分析

合成了2种新型的可溶性四氮杂卟啉中间体:反式-1,2-二氰-(4-乙基苯)乙烯和顺式-1,2-二氰-(4-乙基苯)乙烯.通过UV-Vis,FTIR,GC/MS,1H NMR等方法对这2种化合物的结构进行了表征,给出了它们完整的结构信息.分析比较了顺、反异构体结构上的差异,分析两者的紫外-可见光谱(UV-Vis)、红外光谱(FTIR)和核磁共振光谱(1H NMR)谱图的差异及其产生原因.     

Ultrasound irradiation effect on morphological and adsorptive properties of a nanoscale 3D Zn-coordination polymer and derived oxide

In this work, Zn-based coordination polymer [Zn₂(1,3-bdc)bzim₂]_n was successfully synthesized by the sonochemical method using a 13 mm probe-type ultrasound operating at 20 kHz and amplitudes of 30, 40 and 50% corresponding to an acoustic power of 5.5, 8.6, and 10.3 W, respectively. Additionally, a sample was prepared by the slow-diffusion method for comparison. The samples were characterized by FTIR, PXRD, SEM, and BET techniques. The influence of the time and sonication amplitude on the yield of the reaction, crystallite size, and morphology were also studied. It was found that the sonochemical method provided the desired product in 83.9% within 20 min of sonication using the highest level of sonication amplitude. Moreover, this approach resulted in regular, controlled morphology, smaller particles, and higher surface area of the Zn-sample and derived oxide, than the slow diffusion method. The samples prepared by different methodologies were tested for the adsorption of BTEX (benzene, toluene, ethylbenzene, and xylenes) components in six different systems, and the uptakes were quantified by ¹³C NMR spectroscopy. Both samples showed excellent adsorption of benzene, 119.8 mmol/g, and 88.1 mmol/g, for the coordination polymers prepared via the sonochemical and slow-diffusion methods, respectively, corresponding to 63.9%, and 46.9%. These results are in agreement with the non-polar surface of these samples.     

Ultrasound-assisted depolymerization of kappa-carrageenan and characterization of degradation product

Degradation of polysaccharides to afford low-molecular-weight oligosaccharides have been shown to produce new bioactivities that are not present in the starting material. The simplicity of ultrasonic treatment in the degradation of a polysaccharide, such as κ-carrageenan, offers practical advantage in producing degraded products with lower molecular weight that may have new interesting potential activities. This study embarked on investigating the effects in molecular weights and structural changes of κ-carrageenan under varying ultrasonic conditions. Molecular weight (MW) monitoring of ultrasonically-treated κ-carrageenan at various conditions were done by gel permeation chromatography. The product formed using the optimized condition was characterized using FTIR and NMR. The decrease in MW has been shown to be dependent on low concentration (5.0 mg mL⁻¹), high amplitude (85%), and long treatment time (180 mins) to afford a degraded κ-carrageenan with average molecular weight (AMW) of 41,864 Da, which is a 96.33% reduction from the raw sample with initial AMW of 1,139,927 Da. Structural analysis reveals that most of the peaks of the raw κ-carrageenan was retained with minor change. 1D and 2D NMR analyses showed that the sonic process afforded a product where the sulfate group at the G4S-4 position was cleaved forming a methylene in the G4S ring. The results would be useful in the structure–activity relationship of κ-carrageenan oligosaccharides and in understanding the effect in the various potential applications of degraded κ-carrageenan.     

Sonochemical synthesis of aluminium and aluminium hybrids for remediation of toxic metals

Spherical shaped nano-size aluminium oxide and its hybrids with indole and indole derivatives have been synthesized using sol–gel and post grafting methods coupled with sonication (Branson Digital SonifierS-250D; 20 kHz; 40%) for the remediation of toxic metals (lead and mercury). Different spectroscopic techniques (FTIR, SEM, BET, XRD, and XPS) have been applied to assess the properties of synthesized aluminium oxide and its hybrids. FTIR spectra showed the absorption bands of aluminium oxide (Al-O-Al) and aluminium hybrids (Al-O-C) at 800–400 cm⁻¹ and 1650–1100 cm⁻¹ region, respectively. SEM showed spherical shaped clusters of aluminium oxide which changed into the net-shape structure after the hybrid synthesis. It is worth noting that sonication energy increases the total surface area of aluminium oxide when it gets hybridized with indole and its derivatives from 82 m²/g to 167 m²/g; it also improved the product yield from 68% to 78%. Simultaneously, FTIR, SEM and BET analysis of non-sonicated aluminium oxide and its hybrids were also recorded for comparison. While XRD and XPS analysis were only conducted for sonicated aluminium oxide and its hybrids to manifest the structural and compositional properties. XRD patterns indexed as the cubic crystal system with an average 41 nm crystallite size of sonicated aluminium oxide which remains unaffected after hybrid synthesis. A survey scan under XPS confirmed the presence of all expected elements (aluminium, oxygen, carbon, nitrogen) and deconvolution of each recorded peak showed binding of element with its neighboring elements. The performance of aluminium oxide and its hybrids synthesize with and without sonication are also evaluated using a time-dependent batch adsorption protocol optimize for one hour. The maximum adsorption of lead (37%) and mercury (40%) are found onto sonicated aluminium oxide. The sonicated aluminium hybrids showed 43–63% of lead and 55–67% of mercury at pH 7. The fitness of experimental data using adsorption kinetics and isotherms revealed that adsorption follows Pseudo-second-order kinetic, Langmuir, and Freundlich isotherms.     

Investigation of the effect of acid dopant on the physical properties of polyaniline prepared using microwave irradiation

The microwave (MW) synthesis of polyaniline (PANI) is performed using potassium iodate (KIO₃) as oxidizing agent in different concentrations of aqueous hydrochloric acid (HCl) at 8 and 93 W applied microwave power for duration of 10 min. The morphological and structural changes in synthesized MW PANI samples are investigated using Scanning Electron Microscopy (SEM) and Fourier transform Infrared Spectroscopy (FTIR). With decreasing pH of the reaction medium the morphology of MW PANI samples changed from slab-like with a small amount of fibrils to porous products which consist of short, rod-like structures. The FTIR spectra confirm that the microwave generated materials structurally consist of PANI, but aniline oligomer peaks are observed in the FTIR at 725 and 686 cm⁻¹ for MW PANI synthesized using 0.5 M aqueous HCl. The influence of acid dopant on the spin concentration of MW PANI synthesized at 8 and 93 W are examined.     

Ultrasound irradiation as an effective tool in synthesis of the slag-based catalysts for carboxymethylation

Waste minimization strategy was applied in the current work for synthesis of the catalysts from industrial solid waste, namely desulfurization slag. The starting slag material comprising CaCO₃, Ca(OH)₂, SiO₂, Al₂O₃, Fe₂O₃, and TiO₂ was processed by various treating agents systematically varying the synthesis parameters. A novel efficient technique – ultrasound irradiation, was applied as an additional synthesis step for intensification of the slag dissolution and crystallization of the new phases. Physico-chemical properties of the starting materials and synthesized catalysts were evaluated by several analytical techniques. Treatment of the industrial slag possessing initially poor crystal morphology and a low surface area (6 m²/g) resulted in formation of highly-crystalline catalysts with well-developed structural properties. Surface area was increased up to 49 m²/g. High basicity of the neat slag as well as materials synthesized on its basis makes possible application of these materials in the reactions requiring basic active sites. Catalytic performance of the synthesized catalysts was elucidated in the synthesis of carbonate esters by carboxymethylation of cinnamyl alcohol with dimethyl carbonate carried out at 150 °C in a batch mode. Ultrasonication of the slag had a positive effect on the catalytic activity. Synthesized catalysts while exhibiting similar selectivity to the desired product (ca. 84%), demonstrated a trend of activity increase for materials prepared using ultrasonication pretreatment. The choice of the treating agent also played an important role in the catalytic performance. The highest selectivity to the desired cinnamyl methyl carbonate (88%) together with the highest activity (TOF₃₅ = 3.89*10⁻⁷ (mol/g*s)) was achieved over the material synthesized using 0.6 M NaOH solution as the treating agent with the ultrasound pre-treatment at 80 W for 4 h.     

Peroxydisulfate-assisted sonocatalytic degradation of metribuzin by La-doped ZnFe layered double hydroxide

Metribuzin is an herbicide that easily contaminates ground and surface water. Herein, La-doped ZnFe layered double hydroxide (LDH) was synthesized for the first time and used for the degradation of metribuzin via ultrasonic (US) assisted peroxydisulfate (PDS) activation. The synthesized LDH had a lamellar structure, an average thickness of 26 nm, and showed mesoporous characteristics, including specific surface area 110.93 m² g⁻¹, pore volume 0.27 cm³ g⁻¹, and pore diameter 9.67 nm. The degradation efficiency of the US/La-doped ZnFe LDH/PDS process (79.1 %) was much greater than those of the sole processes, and the synergy factor was calculated as 3.73. The impact of the reactive species on the sonocatalytic process was evaluated using different scavengers. After four consecutive cycles, 10.8 % loss occurred in the sonocatalytic activity of the La-doped LDH. Moreover, the efficiency of the US/La-doped LDH/PDS process was studied with respect to the degradation of metribuzin in a wastewater matrix. According to GC–MS analysis, six by-products were detected during the degradation of metribuzin. Our results indicate that the US/La-doped ZnFe LDH/PDS process has great potential for efficient degradation of metribuzin-contaminated water and wastewater.     

A photosensitive copolymer for the gate insulator of organic thin-film transistors

A novel cross-linkable copolymer for the gate insulators of organic thin-film transistors (OTFTs) was synthesized by free radical copolymerization with methyl methacrylate and ethylene methylacrylate cinnamoylate. Copolymers of molecular weights (Mn: 109200–160000 g mol⁻¹) and polydispersities (1.59–2.24) were characterized by FTIR and NMR. Spin-coated thin films had smooth surfaces with the root-mean-square (RMS) surface roughness of 0.23 nm, 0.41 nm, respectively, before and after UV irradiation. Exposure of the copolymers to UV light produced cross-linking of the polymeric chains that could be confirmed by comparing the FTIR and UV spectra recorded prior and after irradiation. Moreover, the vanadyl-phthalocyanine (VOPc) OTFTs with the photosensitive copolymer as gate insulator were fabricated and found to exhibit a carrier mobility of 0.25 cm²/V s, an on/off ratio of 10⁴.     

Electrolytic preparation of CaB<Subscript>6</Subscript> by molten salt technique

Calcium hexaboride (CaB₆) crystals with high melting point (2,235 °C) have been conveniently synthesized at low temperature (900 °C) from molten salt electrolysis. The synthesis was carried out using CaO–B₂O₃–LiF melt under argon atmosphere. Electrochemical experiments were carried out in an inconel reactor to having a high purity graphite crucible, which served as an electrolyte holding vessel as well as the anode. An electropolished molybdenum rod was employed as the cathode. The electrolysis was performed at 900 °C under argon atmosphere at current densities ranging from 0.5 to 1.5 A/cm² at 1:6 M ratios of calcium and boron content. After the electrolysis, the cathode product was removed and cleaned using dilute HCl solution followed by triple distilled water. Characterization of the crystalline product by TG/DTA, XRD, CHNS, EDAX, XPS, EPR, and SEM were reported. From the studies, it has been observed that CaB₆ can be synthesized at all current densities and the products have some impurities.     

Ultrasound-assisted solid Lewis acid-catalyzed transesterification of Lesquerella fendleri oil for biodiesel synthesis

Biodiesel, a mixture of fatty acid methyl esters (FAME), is bio-renewable, non-toxic, biodegradable, and is an attractive alternative to petroleum diesel. This work studied the sonochemical transesterification of Lesquerella fendleri oil (LFO) using inexpensive solid Lewis acid (LA) catalysts with an aim to reduce environmental pollution and dependance on non-renewable fuel sources. Due to the presence of hydroxy fatty acid methyl esters (HFAME) in LFO (∼60%), in addition to producing biofuel it can also be used to generate chemically important estolides and cyclic lactones. AlCl₃, SnCl₂, and Sn(CH₃COO)₂ showed catalytic activity using direct immersion ultrasound (DI-US) among a list of LA catalysts investigated, with AlCl₃ being the best catalyst. Ultrasound increased the reaction rate by facilitating carbocation formation of glyceridic carbons. Experiments were carried out at room temperature in a solvent range from 3:1 to 18:1 methanol-to-oil molar ratio and catalyst loading from 1 wt% to 6 wt% over 10 to 60 min sonication time at 48% ultrasound amplitude (roughly 17 W/cm²). Complete conversion (>99%) was achieved in 40 min with 5 wt% AlCl₃ catalyst. A statistical regression analysis with STATA 14.0 software was performed to optimize process parameters. Chemical characterizations of the compounds were performed with nuclear magnetic resonance (NMR) spectroscopy (¹H NMR & ¹³C NMR), and % conversion of FAMEs was calculated from the ¹H NMR spectra. The fatty acid profile was determined by GC-FID and GC–MS analysis. FT-IR spectroscopic analysis and thermogravimetric analysis (TGA) were performed to investigate the infrared absorption pattern of the compound and the volatility difference between Lesquerella fendleri biodiesel and oil under nitrogen atmosphere. Results indicate that this is a fast, green, energy-efficient, sustainable, and industrially applicable method for biodiesel production from LFO.     

Conductivity or rheology? Tradeoff for competing properties in the fabrication of a gel polymer electrolyte based on chitosan-barbiturate derivative

Chitosan-barbiturate (Ch-Ba) derivative was synthesized to afford organosolubility. Attachment of Ba onto the Ch backbone was confirmed by ¹H NMR with peaks at 8.2 and 11.1 ppm, and FTIR with bands at 1679 and 1739 cm^?1 belonging to the Ba ring. This derivative was used as a host polymer in the preparation of gel polymer electrolytes. The components of the gel consist of tetrapropylammonium iodide (TPAI) as the salt, SiO₂ nanofiller (NF) as the mechanical stabilizer, and dimethyl sulfoxide (DMSO) as the solvent. The necessary formulation required to produce the gel was studied using response surface models by means of artificial neural networks. Electrochemical and rheological behaviors were studied and the simulated model predicted conductivities were as high as 8.51 mS cm^?1 while still maintaining a solid-like gel structure in the region where storage modulus dominated loss modulus, G″/G′?<?1.     

Synthesis and characterization of novel nano-size polyreactive yellow 107

The reactive yellow 107 was polymerized by chemical oxidation method using potassium persulfate. The polymer was characterized by UV-VIS and Fourier transform infrared spectroscopy (FTIR) spectral studies. The peaks at 2,922 and 2,852 cm⁻¹ in the FTIR spectrum of polyreactive yellow 107 are assigned to the symmetric and asymmetric stretching vibrations of CH₂. The peak observed at 1,583 cm⁻¹ for polyreactive yellow 107 may be assigned to the stretching vibration of C=O, N=N, and C=C, 1,347 cm⁻¹ stretching vibration of C–N. The stretching vibrations of sulfone and sulfonic acid of S=O groups show a strong broad peak at 1,091 and 1,051 cm⁻¹. The conductivity of the polymer was determined to be 5.57 × 10⁻⁵ S cm⁻¹. The solubility of the chemically polymerized powder was ascertained and polyreactive yellow 107 showed good solubility in N,N-dimethyl formamide and dimethyl sulfoxide. The X-ray diffraction studies revealed the formation of nano-sized (84 nm) crystalline polymer. Using X-ray diffraction, behavior strain and dislocation density was also calculated. Scanning electron microscope analysis showed uniform crystalline nature of the polymer (200 nm). The thermogravimetric analysis, differential thermal analysis, and differential scanning calorimetry studies revealed good thermal stability of the polymer.     

Esterification of sodium 4-hydroxybenzoate by ultrasound-assisted solid–liquid phase-transfer catalysis using dual-site phase-transfer catalyst

The catalytic esterification of sodium 4-hydroxybenzoate with benzyl bromide by ultrasound-assisted solid–liquid phase-transfer catalysis (U-SLPTC) was investigated using the novel dual-site phase-transfer catalyst 4,4′-bis(tributylammoniomethyl)-1,1′-biphenyl dichloride (BTBAMBC), which was synthesized from the reaction of 4,4′-bis(chloromethyl)-1,1′-biphenyl and tributylamine. Without catalyst and in the absence of water, the product yield at 60 °C was only 0.36% in 30 min of reaction even under ultrasound irradiation (28 kHz/300 W) and 250 rpm of stirring speed. When 1 cm³ of water and 0.5 mmol of BTBAMBC were added, the yield increased to 84.3%. The catalytic intermediate 4,4′-bis(tributylammoniomethyl)-1,1′-biphenyl di-4-hydroxybenzoate was also synthesized to verify the intrinsic reaction which was mainly conducted in the quasi-aqueous phase locating between solid and organic phases. Pseudo-first-order kinetic equation was used to correlate the overall reaction, and the apparent rate coefficient with ultrasound (28 kHz/300 W) was 0.1057 min⁻¹, with 88% higher than that (0.0563 min⁻¹) without ultrasound. The esterification under ultrasonic irradiation using BTBAMBC by solid–liquid phase-transfer catalysis was developed.     

Carbon nanostructures synthesized by arc discharge between carbon and iron electrodes in liquid nitrogen

An idea of using pure iron and graphite electrodes was employed for synthesizing carbon nanoparticles by arc discharge in liquid nitrogen. The synthesized products consist of multiwalled carbon nanotubes (MW–CNT), carbon nanohorns (CNH), and carbon nanocapsules (CNC) with core–shell structure. Effect of metallic cathode and discharge current on product structure and yield had been experimentally investigated. Typical evidence of transmission electron microscopic images revealed that under some certain conditions of discharge in liquid nitrogen the synthesized products mainly consisted of CNCs with mean diameter of 50–400 nm. When conventional graphitic electrodes were employed, CNHs with some MW–CNTs were mainly synthesized. Meanwhile, MW–CNTs with diameter of 8–25 nm and length 150–250 nm became less selectively synthesized as cathode deposit under the condition of discharge in liquid nitrogen with higher arc current. The production yield of carbon nanoparticles synthesized by either carbon–carbon or carbon–iron electrodes became also lower with an increase in the arc current.     

Unraveling the carbene chemistry of oxymethylene ethers: Experimental investigation and kinetic modeling of the high-temperature pyrolysis of OME-2

Oxymethylene ethers (OMEs) form an interesting family of synthetic compounds to replace fossil fuels. This alternative liquid energy carrier can contribute to a circular carbon economy when produced via carbon capture and utilization technology using renewable electricity. Despite the potential to reduce greenhouse gas and particulate matter emissions and their ideal ignition characteristics, little is known about the thermal decomposition behavior of OMEs. In this work, new insights are obtained in the pyrolysis chemistry of oxymethylene ether-2 (OME-2) and the role of carbenes by performing experiments at high temperatures (> 850 K) in a tubular quartz reactor. The used continuous bench-scale pyrolysis unit has a dedicated on-line analysis section including comprehensive two-dimensional gas chromatography (GC $\times$ GC) coupled with flame ionization detection (FID) and mass spectroscopy (MS) to identify and quantify the full product spectrum over the complete temperature range. The reactor temperature was varied between 850 and 1150 K at a fixed pressure of 0.15 MPa and residence times of 400 to 850 ms. The major products are dimethoxymethane, formaldehyde, methyl formate, methane, CO₂, CO and H₂. Minor intermediate compounds comprise dimethyl ether, formic anhydride, formic acid, methoxymethyl formate and methoxymethanol. The yields of compounds with carbon-carbon bonds are low since no such bonds originally occur in OME-2. Precursors of aromatic compounds and soot particles are absent in the reactor effluent. The experimental results are simulated with a new first principles-based kinetic model for pyrolysis and combustion of OME-2. This model can predict the experimental trends of major products on average within the experimental uncertainty margin of ± 10% relative for major product species. A reaction pathway and sensitivity analysis are presented to highlight the importance of the carbenes for initiation of the radical chemistry under pyrolysis conditions.     

Validated spectrophotometric method for the determination,spectroscopic characterization and thermal structural analysis of duloxetine with 1,2-naphthoquinone-4-sulphonate

A novel, selective, sensitive and simple spectrophotometric method was developed and validated for the determination of the antidepressant duloxetine hydrochloride in pharmaceutical preparation. The method was based on the reaction of duloxetine hydrochloride with 1,2-naphthoquinone-4-sulphonate (NQS) in alkaline media to yield orange colored product. The formation of this complex was also confirmed by UV-visible, FTIR, ¹H NMR, Mass spectra techniques and thermal analysis. This method was validated for various parameters according to ICH guidelines. Beer’s law is obeyed in a range of 5.0–60 μg/mL at the maximum absorption wavelength of 480 nm. The detection limit is 0.99 μg/mL and the recovery rate is in a range of 98.10–99.57%. The proposed methods was validated and applied to the determination of duloxetine hydrochloride in pharmaceutical preparation. The results were statistically analyzed and compared to those of a reference UV spectrophotometric method.     

Sonochemical approach for synthesis of zinc oxide-poly methyl methacrylate hybrid nanoparticles and its application in corrosion inhibition

Hybrid nanoparticles (HNPs) with zinc oxide and polymethyl metha acrylate (inorganic/ polymer) were synthesized through the exploitation of ultrasound approach. The synthesized HNPs were further characterized employing transmission electron microscopy and x-ray diffraction. ZnO-PMMA based HNPs exhibit excellent protection properties to mild steel from corrosion when gets exposed to acidic condition. Electrochemical impendence spectroscopy (EIS) analysis was accomplished to evaluate the corrosion inhibition performance of MS panel coated with 2 wt% or 4 wt% of HNPs and its comparison with bare panel and that of loaded with only standard epoxy coating., Tafel plot and Nyquist plot analysis depicted that the corrosion current density (I_corr) decreases from 16.7 A/m² for bare material to 0.103 A/m² for 4% coating of HNPs. Applied potential (E_corr) values shifted from negative to positive side. These results were further supported by qualitative analysis. The images taken over a period of time indicated the increase in lifetime of MS panel from 2 to 3 days for bare panel to 10 days for HNPs coated panel, showing that ZnO-PMMA HNPs have potential application in metal protection from corrosion by forming a passive layer.     

Growth and characterization of a new organic nonlinear optical crystal: Vanillylideneaniline

Vanillylideneaniline with chemical formula C₁₄H₁₃NO₂ (VAN), a second order nonlinear optical (SONLO) organic single crystal was synthesized and grown for the first time from dimethyl formamide (DMF) employing slow solvent evaporation technique. Single crystal X-ray diffraction data reveals that the crystal belongs to noncentrosymmetric orthorhombic space group C222₁. The high-resolution diffraction curve containing single peak with full width at half maximum (FWHM) of 62 arc s ascertains VAN was perfectly crystallized and free from structural grain boundaries. The formation of the material was confirmed quantitatively by FTIR, ₁H¹ and ¹³C NMR spectral analyses. The UV–vis–NIR spectrum reveals the percentage of the transmission of VAN crystal in the entire region. The variations of dielectric constant (?_r) and dielectric loss (D) with frequency at different temperatures were investigated. The SHG of VAN crystal is confirmed by Kurtz Powder technique. The mechanical strength of the crystal was estimated by Vickers hardness test. VAN has yield strength of 8.70 MPa. Thus the grown organic VAN single crystal can be recommended as a promising candidate for SONLO application and device fabrication technology.     

Synthesis and electroluminescent characterization of a symmetric starburst orange-red light material

A new symmetric starburst orange-red light material, tris(4-(2-(N-butyl-1,8-naphthalimide)ethynyl)phenyl)amine (TNGT), was designed and synthesized. It shows a high fluorescence quantum yield and a slight concentration-quenching effect. A high brightness (6600 cd/m²) and a high current efficiency [4.57 cd/A (at 420 cd/m²)] with CIE (0.59, 0.40) were achieved at a relatively high doping concentration (20 wt%) in a TNGT-based OLED.