Concentration Of Acetylacetone Research Articles

Digital colorimetric detection of ammonium in water samples after microextraction procedure using deep eutectic solvent, based on DLLME method

In this study, we have presented a simple, cost-effective, and efficient method for quantifying ammonium ions based on digital colorimetry using a smartphone. Firstly, ammonium ions are converted into a yellow-colored derivative in an alkaline medium in the presence of acetylacetone and formaldehyde. Then, the colored compound is extracted using the dispersive liquid–liquid microextraction (DLLME) technique and its color intensity was measured using a smartphone as RGB Color Detector. For this purpose, a novel deep green eutectic solvent including tetrapropylammonium bromide (TPABr) and 3-methyl-1-butanol (isoamyl alcohol) was employed, with a molar ratio of 1:6. The impact of key variables on the derivatization and microextraction processes, including solution pH, concentration of acetylacetone and formaldehyde, temperature, reaction time, and extraction solvent volume, was thoroughly investigated and optimized. In the optimized conditions, the method was found to be linear in the range of 0.15–5.00 µg mL−1 with a limit of detection of 0.05 µg mL−1 (S/N = 3). Moreover, the proposed method was successfully applied for the determination of ammonium ions in environmental water samples, fish pond, and aquarium water samples, with recoveries ranging from 94.7 to 106.7 %.

Combustion synthesis of Eu2O3 nanomaterials with tunable phase composition and morphology

Combustion reactions in europium nitrate – acetylacetone – 2-methoxyethanol solutions and gels were investigated to produce europium (III) oxide (Eu2O3) nanocrystalline materials and thin films. Thermal analyses of solutions indicated that the 2-methoxyethanol solvent also acts as a fuel in the absence of acetylacetone. Adding acetylacetone increases the overall heat of the reaction. Thermal analysis results revealed that the slow oxidation of unburned hydrocarbon residues follows the primary combustion reaction. Time-temperature profile measurements of the bulk combustion synthesis process in air and nitrogen atmospheres enabled the extraction of the maximum reaction temperature and the heating and cooling rates in the combustion zone. Several direct correlations exist between measured combustion parameters and the phase composition of the products. Combustion in air results in mixed-phase cubic and monoclinic nanocrystalline Eu2O3. Increasing the acetylacetone concentration in solutions increases the synthesis temperature and decreases the quantity of cubic Eu2O3. The reaction of solutions in a nitrogen atmosphere or diluted with Eu2O3 provides control of the product phase composition and reduces the quantity of the monoclinic phase. Transmission electron microscopy imaging shows that the Eu2O3 end products are highly porous aggregates of nanocrystalline particles. Electrospraying of reactive solutions onto different substrates followed by short annealing makes the preparation of Eu2O3 materials with diverse morphologies possible.

Effect of the addition of O2 on copper etching using high density plasma of acetylacetonate/Ar

In the present study, the high density plasma etching of copper thin films masked with SiO2 was conducted using an acetylacetone/O2/Ar gas mixture. As the concentration of acetylacetone increased, the etch rates for the copper film decreased but the etch selectivity increased. The addition of O2 gas to the acetylacetone/Ar mixture greatly improved the etch profile without the redeposition on the sidewalls of the copper film. This was attributed to the formation of copper compounds containing oxygen with the assistance of a polymeric protection layer. Good etch profile for the copper film was obtained using an acetylacetone/O2/Ar gas mixture with a 4:1 vol ratio of acetylacetone to O2. The proposed acetylacetone/O2/Ar gas mixture thus represents a potential candidate gas for the dry etching of copper films.

EFFECT OF ACETYL ACETONE ON RADICAL POLYMERIZATION OF VINYL MONOMERS INITIATED BY BENZOYL PEROXIDE

The radical polymerization of styrene and methyl methacrylate (MMA) initiated by benzoyl peroxide (BР) with the addition of 10, 20, 50, and 80% of acetylacetone (AA) mixed with a monomer was studied. It was found that the rate of the polymerization process increases in the presence of a certain amount of AA in the system (³ 50% of the monomer). This is due to the fact that AA accelerates the decomposition of BP, while removing it from the system in the form of non-radical products, and the initiating function is performed by acetylacetonate radicals, which are formed upon interaction with BP. The incorporation of acac fragments into the polymer chain has been proved by IR and 1H NMR spectroscopy. It was found that these groups in the composition of the polymer interact with the p-system of benzene rings of polystyrene. The second reason for the accelerating action is the formation of complexes between the monomer and AA, in which the additive has an acceptor effect, leading to the facilitation of the breaking of double bonds in the monomer. It was shown that MMA has a stronger effect on AA polymerization, because forms stronger complexes with the enol form of AA, which requires a longer time for the radical to leave the complex. In this regard, during its polymerization, induction periods are observed, the duration of which is directly proportional to the concentration of AA in a mixture with MMA. It was revealed that another feature of the effect of AA on radical polymerization is its participation in chain transfer reactions, which does not decrease the rate of the process, but only leads to a decrease in the molecular weight of the products. This makes it an effective regulator of polymer molecular weights. The paper proposes a scheme for the polymerization of vinyl monomers, initiated by BP with the addition of AA.

Green antisolvent additive engineering to improve the performance of perovskite solar cells

High-quality perovskite films with larger grain size and fewer defects is a prerequisite for high-performance perovskite solar cells (PSCs). Antisolvent-assisted crystallization is an effective approach to obtain compact and uniform perovskite films; however, the majority of antisolvents currently applied have strong toxicity, and the control of perovskite crystallization is not easy through single antisolvent. In this work, a green antisolvent of ethyl acetate (EA) with acetylacetone (AA) additive is used to fine-tune perovskite crystallization and passivate defect, which produces uniform and compact CH3NH3PbI3 perovskite films having larger grain and fewer grain boundaries and reduced defect density. Meanwhile, the interfacial hydrophobic characteristic of the perovskite films is enhanced. At the optimized concentration of AA in EA, the power conversion efficiency (PCE) of the CH3NH3PbI3 PSCs was improved from 19.2% to 21.1% and their stability in air was also enhanced. These results present a green antisolvent additive engineering strategy to enhance the crystallinity, passivate defects, and fabricate efficient and stable PSCs.

Highly efficient cataluminescence gas sensor based on nanosized h-BN for trace acetylacetone detection

Nonmetallic nanocatalysts have demonstrated powerful potential in cataluminescence (CTL) sensing fields. In this study, an original method for the fabrication of a CTL gas sensor was developed to detect acetylacetone based on nanosized hexagonal boron nitride (h-BN). The luminescence characteristics and optimum operating temperature, wavelength, and carrier gas flow rate parameters for the h-BN sensor were studied in detail. Compared with other common gases (such as cyclohexanone, acetaldehyde, and acetone), the fabricated sensor demonstrated a high selectivity and sensitivity toward acetylacetone. This was verified by density functional theory calculations, which were consistent with the experimental results. The CTL intensity and concentration of acetylacetone had a linear relationship in the range of 0.050–20 μg ml−1 (r = 0.9989) with a low detection limit of 16 ng ml−1 (S/N = 3). The developed sensor was applied to analyze spiked samples, and satisfactory recoveries for acetylacetone of 82.2%–118% were obtained with excellent reproducibility (2.8%–11%). These results indicated that the system has excellent sensing properties including a high selectivity, sensitivity, and stability, proving its broad application prospects for detecting acetylacetone.

Solvothermal Synthesis of Monodisperse Porous Zirconia Spheres with Large Surface Area

We developed non‐aggregated monodisperse ZrO2 porous spheres by a one‐pot single‐step solvothermal synthesis. A mixture of zirconium(IV) tetra‐n‐butoxide as a metal source and acetylacetone as an additive in ethanol was heated up to 300 °C in a 10 mL batch type reactor to yield perfectly monodisperse porous spheres of ZrO2 in almost quantitative yield with large surface area of 301 m2/g as well as nano‐concave‐convex surface structure. Especially, the concentration of acetylacetone was crucial in the reaction to form beautiful spheres. The reaction was easily scaled‐up to 500 mL autoclave scale yielding porous spheres with 244 m2/g specific surface area. The monodisperse ZrO2 porous spheres worked as an effective catalyst support comprising Ni nanoparticles, exhibiting in excellent dispersibility of the Ni nanoparticles. The resultant monodisperse ZrO2 porous spheres were tested as a catalyst for highly exothermic CO2 methanation, resulting in superior catalytic activity and thermal tolerance during repeated heating‐cooling cycles of three‐run tests.

Solution-combustion-based nickel oxide hole transport layers via fuel regulation in inverted planar perovskite solar cells

In recent years, metal oxide hole transporting layers (HTLs) have been commonly used in inverted planar perovskite solar cells. Due to high optical transmittance, better long-term stability, and suitable energy band characteristics, NiOx HTLs have been intensively studied. The NiOx materials prepared by solution-combustion method with characteristics of self-energy generation and exothermic reaction have received much attention, which significantly reduces the reaction temperature compared with the traditional sol–gel methods. In this paper, a NiOx film with better conductivity and enhanced carrier extraction was obtained by adjusting the fuel concentration in the nickel oxide precursor solution. It was also confirmed that perovskite film was improved with larger grain size and reduced trap-state densities. As a consequence, by using the 10 ul/ml optimal concentration of acetylacetone in the NiOx precursor solution, the inverted planar perovskite solar cells achieved a maximum power conversion efficiency of 14.37%.

Mechanism of the atmospheric chemical transformation of acetylacetone and its implications in night-time second organic aerosol formation

Recently, a high concentration of acetylacetone (AcAc) has been measured in China, and its day-time chemistry with OH reaction has been evaluated. The phenomenon has profound implications in air pollution, human health and climate change. To systematically understand the atmospheric chemistry of AcAc and its role in the atmosphere, the night-time chemistry of AcAc with O3 and NO3 radical were investigated in this work in detail using density functional theory. The results show that for O3- and NO3-initiated atmospheric oxidation reactions of AcAc, the barrier energies of O3/NO3-addition are found to be much lower than those of H-abstraction, suggesting that O3/NO3-addition to AcAc is a major contributing pathway in the atmospheric chemical transformation reactions. The total degradation rate constants were calculated to be 2.36 × 10−17 and 1.92 × 10−17 cm3 molecule−1 s−1 for the O3- and NO3-initiated oxidation of AcAc at 298 K, respectively. The half-life of AcAc+O3 in some polluted areas (such as, Pearl River Delta and Yangtze River Delta) is close to 3 h under typical tropospheric conditions. Due to its short half-life, the ozonolysis of AcAc plays a more significant role in the night-time hours, leading to fast transformations to form primary ozonides (POZs). A prompt, thermal decomposition of POZs occurred to yield methylglyoxal, acetic acid and Criegee intermediates, which mainly contributed to the formation of secondary organic aerosol (SOA). Subsequently, using the high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS), a non-negligible concentration of AcAc was measured in the field observation during the night-time in Nanjing, China. The obtained results reveal that the atmospheric oxidation of AcAc can successively contribute to the formation of SOA under polluted environments regardless of the time (day-time or night-time). This is due to its high reactivity to tropospheric oxidant species (such as, O3 and NO3 radicals at night-time).

Impact of Acetyl Acetone on Zinc Uptake and Oxidative Stress in Cucumber (Cucumis sativus)

The purpose of this research is to determine the impacts of acetyl acetone on zinc uptake and oxidative stress in cucumber (Cucumis sativus) seedlings grown in hydroponic solutions. Thirty seedlings of cucumber were collected from Kura local government area Kano, Kano state. Concentrations of Zn2+ in the hydroponics were varied from 0.000 to 0.025 mol dm-3 and of acetyl acetone were also varied from 0.000 to 0.025 mol dm-3. The seedlings were replanted and kept at Department of Agriculture Kano University of Science and Technology, Wudil garden. The weight of plants increased significantly (p<0.05) with concentration of Zn2+ in the absence of acetyl acetone and highly insignificantly (p>0.05) with concentration of acetyl acetone in the absence of Zn2+. In the presence of acetyl acetone and Zn2+ plant weight decreased highly insignificant (p>0.05). Leaf fall was observed from plants in all hydroponic, the number of falling leaves was insignificant (p>0.05) with concentration of Zn2+ but it is insignificant (p>0.05) with concentration of acetyl acetone and highly insignificant in the presence of acetyl acetone and Zn2+ (p>0.05). The volume of the solution decreased highly significant (p<0.05) with concentration of Zn2+ and significant with concentration of acetyl acetone (p<0.05) the volume also increased insignificantly in the presence of acetyl acetone and Zn2+ (p>0.05). The pH values of treated hydroponics before replanting and after harvest were insignificant with increased in the concentration of Zn2+ (p>0.05). Both shoot and root zinc accumulated were insignificant at lower concentration of Zn2+ (p>0.05) and significant at higher concentration of Zn2+ (p<0.05). The zinc translocation factor decreased highly insignificantly (p>0.05) at lower concentration of Zn2+ and significant at higher concentration of Zn2+ (p>0.05) in treated plants compared to control. The chlorophyll, carotenoid and proline content varied in the presence and absence of acetyl acetone and or combination of the two, with (p<0.05) or (p>0.05).

Thin Layer Chromatography-A Tool to Investigate Kinetics of Michael Addition Reaction

Thin layer chromatography (TLC), a tool for defining identity, purity, and quantitation of a compound, has also been proved useful for monitoring the progress of a chemical reaction. However, the technique is yet to be exploited for investigating the kinetics of a reaction systematically. In this work, we used TLC for measuring the time for consumption of a reactant in Michael addition reaction of acetylacetone with 2-cyclohexene-1-one. Average rate of the model reaction was determined using a definite initial concentration of acetylacetone for a series of catalyst systems like NaOH, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), DBU based protic ionic liquids (PILs) 1,8-diazabicyclo[5.4.0]undec-7-ene-8-ium hydroxide ([HDBU]OH) and 1,8-diazabicyclo[5.4.0]undec-7-ene-8-ium acetate ([HDBU]CH3COO), a DBU based aprotic ionic liquid (AIL), 8-hexyl-1,8-diazabicyclo [5.4.0]undec-7-ene-8-ium hydroxide ([C6DBU]OH), and binary systems of the ionic liquids with molecular solvents, such as, water, DBU, and acetic acid. The kinetic data on the performance of the chosen catalysts were interpreted on the basis of the established mechanism of the reaction. Finally, the prospect of the method based on TLC as a suitable technique for kinetic study of chemical reactions has been discussed.

Spectrophotometric Determination of Formaldehyde in Seawater Samples after In-situ Derivatization and Dispersive Liquid-Liquid Microextraction

In this paper, a simple dispersive liquid-liquid microextraction for the extraction and pre-concentration of formaldehyde in seawater samples followed with spectrophotometric is proposed. Formaldehyde was derivatized in situ with acetyl acetone in the presence of ammonium acetate in a single step. Then it was collected into a mixture of ethanol (disperser solvent) and chloroform (extracting solvent). Experimental parameters which have an influence on the extraction, including type and volume of extracting and disperser solvent, pH of sample solution, the concentration of acetyl acetone and ammonium acetate, reaction time and temperature were evaluated and optimized. Under optimal experimental conditions, good linearity was observedin the range of 1-500 µg/Lfor the analyte with a limit of detection of 0.29 µg/L. The proposed method was applied to the analysis of real seawater samples. For spiked samples, good recoveries in the range of 97.7-101.5% were obtained. The relative standard deviations were below 2.1%. Using this method, formaldehyde content in seawater from several locations in Chabahar Bay (southeast Iran) were determined in the range of 1.4 to 4.8 µg/L.

Monodispersibility and size control in the preparation of spherical titania particles by thermal hydrolysis of TiCl4 in various solvents

Spherical anatase TiO2 particles were successfully synthesized by the thermal hydrolysis of TiCl4 in various solvents. In the case of n-propanol, isopropanol, and acetone with an RH ratio of 3, spherical titania particles were produced. In contrast, spherical TiO2 particles did not form in methanol and ethanol because of their high dielectric constants. In this study, different oscillators (an oven, and isothermal and ultrasonic oscillators) were used to prepare titania prior to studying the morphology and particle size. The spherical TiO2 particles prepared using the ultrasonic oscillator were much smaller than those obtained using the other heating methods, because of the lower temperature gradient in the solution; however, a narrower size distribution of particles was observed in the TiO2 prepared in an oven. The presence of acetylacetone as a dispersing agent in the starting solutions significantly reduced the particle size. The optimum concentration of acetylacetone of 0.8mg/cm3 resulted in more uniform TiO2 spheres with an average particle size of 1.4µm.

Chlorine Dioxide–Iodine–Acetylacetone Oscillation Reaction Investigated by UV–Vis and Online FTIR Spectrophotometric Methods

In order to study the chemical oscillatory behavior and mechanism of a new chlorine dioxide–iodine–acetylacetone reaction system, a series of experiments were carried out by using UV–Vis and online FTIR spectrophotometric methods. The initial concentrations of acetylacetone, chlorine dioxide, iodine, sulfuric acid, and the pH value have considerable influence on the oscillations observed at wavelength of 350 nm for the starch–triiodide ion complex (\({\text{QI}{_{3}^-}}\)). There is a pre-oscillatory or induction stage, the amplitude and the number of oscillations are associated with the initial concentration of reactants. Equations were obtained for the starch–triiodide ion complex (\({\text{QI}{_{3}^-}}\)) reaction rate change with reaction time and the initial concentrations in the oscillation stage. The oscillation reaction can be accelerated by increasing the reaction temperature. The apparent activation energies at the induction stage and the oscillation stage are 45.64 and 12.39 kJ·mol−1, respectively. The intermediates were detected by the online FTIR analysis. Based upon the experimental data in this work and in the literature, a plausible reaction mechanism was proposed for the oscillation reaction.

Sodium chlorite – iodide – acetylacetone oscillation reaction investigated by UV-Vis spectrophotometry

A new sodium chlorite – iodide – acetylacetone chemical oscillatory reaction has been studied by the UV-Vis spectrophotometric method. The initial concentrations of acetylacetone, sodium chlorite, iodide, and sulfuric acid and the pH value have great influence on the oscillation observed at a wavelength of 570 nm for the starch–triiodide complex. There is a pre-oscillatory or induction stage and the amplitude and number of oscillations depend on the initial concentration of the reactants. Equations for the starch–triiodide complex reaction rate change with reaction time and the initial concentrations in the oscillation stage were obtained. The induction time decreases linearly with the initial concentration of acetylacetone or sodium chlorite but increases linearly with the initial concentration of sulfuric acid. The oscillation reaction can be accelerated by increasing the reaction temperature. The apparent activation energies at the induction stage and the oscillation stage were 61.02 and 61.36 kJ/mol, respectively, indicating that the two stages have similar reaction mechanisms. Generating the enol isomer by keto–enol tautomerism is an important step to constrain the time of the induction period.

Potential of acetylacetone as a mediator for Trametes versicolor laccase in enzymatic transformation of organic pollutants

Low-cost and environmentally friendly mediators could facilitate the application of laccase (EC 1.10.3.2) in variant biotechnological processes. Acetylacetone (AA) represents an inexpensive and low toxic small molecular diketone that has been proven as an effective mediator for laccase in free radical polymerization. However, the potential of AA as a mediator for laccase in pollutant detoxification and/or degradation is still unknown. In this work, the roles of AA in laccase-induced polymerization and transformation were investigated. AA was demonstrated to be a highly efficient mediator in the laccase-induced grafting copolymerization of acrylamide and chitosan. The efficacy of AA in the laccase-induced decoloration of malachite green (MG) was compared with that of the widely used 1-hydroxybenzotriazole (HBT). The laccase-AA system had the highest turnover number (TON, 39.1 μmol/U), followed by the laccase-only system (28.5 μmol/U), while the TON of the laccase-HBT system was the lowest (14.9 μmol/U). The pseudo-first-order transformation rate constant (k 1) of MG in the laccase-AA system was up to 0.283 h(-1) under the given conditions, while the k 1 of AA caused by laccase was only 0.008 h(-1). In the five-cycle run, the concentration of AA remained stable. The larger TON of the laccase-AA system and the stability of AA in the cycling runs demonstrate that AA was more recyclable than HBT in the LMS, leading to a prolonged serving life of laccase. These results suggest that AA might be a potential redox mediator for laccase.

Liquid-phase microextraction with in-drop derivatization combined with microvolume fluorospectrometry for free and hydrolyzed formaldehyde determination in textile samples

A new miniaturized methodology based on the combination of headspace single drop microextraction and microvolume fluorospectrometry is proposed in this work for the determination of free and hydrolyzed formaldehyde in textile samples. The proposed method is based on the extraction and in-drop derivatization of free and hydrolyzed formaldehyde using the Hantzsch reaction. The effect of experimental variables affecting the performance of the proposed method, such as fluorescence parameters, nature of the extractant phase composition (including acetylacetone concentration, pH, ammonium acetate concentration and presence of an organic solvent), sample temperature, NaCl concentration and microextraction time was carefully investigated. Under optimized conditions, instrumental detection and quantification limits were 26 and 87 μg L −1, respectively, whereas procedural detection and quantification limits were 1.0 and 3.5 mg kg −1, respectively. Repeatability, expressed as relative standard deviation, was 4.6% ( n = 9). The method was successfully applied to the determination of free and hydrolyzed formaldehyde in several textile samples, the found results being in good agreement with those obtained with the EN ISO 14184-1:1998 method.

One-step growth of gold nanorods using a β-diketone reducing agent

The synthesis and characterisation of gold nanorods have been carried out by reduction of the gold salt HAuCl4. This has been done using a single reducing agent, acetylacetone, rather than the two reducing agents, sodium borohydride and ascorbic acid, normally required by standard wet chemistry methods of gold nanorod formation. Using this novel method, the nanorods were synthesised at several different pH values which were found to greatly affect both the rate at which the nanorods form and their physical dimensions. The concentrations of acetylacetone and silver nitrate used relative to the gold salt were found to alter the aspect ratio of the nanorods formed. Rods with an average length of 42 nm and an aspect ratio of 4.6 can be easily and reproducibly formed at pH 10 using this method. Nanorods formed under optimum conditions were investigated using TEM.

Anatase Titanium Dioxide Crystallization by a Hydrolysis Reaction of Titanium Alkoxide without Annealing

The crystallization of anatase titanium dioxide (TiO2) was achieved by a hydrolysis reaction of titanium alkoxide without annealing. The hydrolysis reaction rates of tetraethyl orthotitanate were indicated by a function of the concentration of acetylacetone added. The degree of crystallinity of the product particles was influenced by the amounts of acetylacetone and seed crystals. Anatase TiO2 was crystallized by restraining the rapid increase in supersaturation of TiO2 and the consequent nucleation of amorphous TiO2. The degree of crystallinity of the product particles also changed with the types of seed crystals used, and was strongly influenced by the specific surface areas of the seed crystals.

Physico-chemical control of sol–gel transition of titanium alkoxide-based materials studied by rheology

Viscoelastic characterization of titania-based sol–gel materials are investigated. Small amplitude oscillatory measurements are used to determine the gelation time tg and the critical exponent of the frequency dependence of the loss and storage moduli. The scaling exponent is analyzed in order to estimate a fractal dimension at tg. Hydrolysis molar ratio, titanium concentration and temperature parameters have an effect on the gelation time but not on the structure of the critical gel (gel at gelation time). However the acetylacetone concentration used as an inhibitor to control the reactivity of titanium seems to modify both the kinetic process and the gel structure.