Showing papers on "Isopropyl alcohol published in 2021"

Highly selective dehydration of methanol over metal-organic frameworks (MOFs)-derived ZnO@Carbon

Abstract: The methanol-to-dimethyl ether (MTD) process has been considered one of the potential methods for manufacturing environmentally friendly fuel, i.e., dimethyl ether (DME). The process requires an efficient, stable, and sustainable catalyst. Herein, metal-organic frameworks (MOF-5, zinc-terephthalate framework) and ZIF-8 (zeolitic imidazolate framework, zinc-imidazolate) were used as sacrificial precursors for the fabrication of MOF-derived ZnO@carbon (ZnO@C) via carbonization at different temperatures. The materials were characterized using X-ray diffraction (XRD), thermal analysis (thermogravimetric analysis (TGA) and differential thermal analysis (DTA)), X-ray photoelectron spectroscopy (XPS), Fourier transforms infrared (FT-IR), and nitrogen adsorption-desorption isotherms. The material's acidity was evaluated using isopropyl alcohol dehydration, chemisorption, and pyridine-temperature programming desorption (TPD) analysis. Data analysis reveals that the acidity of ZnO@C is due to Bronsted acidic sites of weak and intermediate strength. ZnO@C catalysts showed an excellent catalytic conversion (100%) towards DME via methanol dehydration with a selectivity of 100%. They displayed a high conversion and selectivity, increasing the percentage of methanol in the reacting stream and gas hourly space velocity (GHSV). They can be recycled several times with high catalytic activity and long-term stability for 160 h.

Effects of ethylene glycol contents on phase formation, magnetic properties and photocatalytic activity of CuFe2O4/Cu2O/Cu nanocomposite powders synthesized by solvothermal method

Abstract: In this research, CuFe2O4/Cu2O/Cu nanocomposites were synthesized by the solvothermal method. The consequences of ethylene glycol (ET) as a solvent on phase formation, morphology, and magnetic properties were studied. The powders showed high photocatalytic activity using methylene blue (MB) dye under visible light, and 99.1% degradation was observed without the utilization of H2O2. Various kinetic factors such as pH, catalyst dosage, and initial dye concentration were investigated. It was found that by increasing pH to 9, the highest amount of degradation was obtained. It had also been observed that as the catalyst dosage decreased from 0.2 to 0.1 g, the degradation rate increased from 31.7% to 99.1%. Quenching tests within the presence of •O2− radical scavenger (benzoquinone), •OH− radical scavenger (isopropyl alcohol), and h+ radical scavenger (ammonium oxalate) showed that the main oxidizing species were •O2− radicals. Furthermore, the magnetic measurements showed that the prepared powders had enough magnetic properties to recycle photocatalysts following water treatment.

Stability of Per- and Polyfluoroalkyl Substances in Solvents Relevant to Environmental and Toxicological Analysis.

Abstract: Per- and polyfluoroalkyl substances (PFASs) are widely used anthropogenic chemicals. For environmental and toxicological analysis, it is important to understand the stability of PFASs, including novel per- and polyfluoroalkyl ether acids (PFEAs), in commonly used solvents. In this study, we investigated the effects of PFAS characteristics, solvent type, water-to-organic solvent ratio, and temperature on the stability of 21 PFASs including 18 PFEAs. None of the studied PFASs showed measurable degradation in deionized water, methanol, or isopropyl alcohol over 30 days; however, nine PFEAs degraded in the polar aprotic solvents acetonitrile, acetone, and dimethyl sulfoxide (DMSO). PFEA degradation followed first-order kinetics, and first-order rate constants increased with increasing temperature and with decreasing water-to-organic solvent ratio. Monoethers with a carboxylic acid functional group adjacent to a tertiary carbon (>CF-COOH) degraded more rapidly than multiethers in which the carboxylic acid moiety was adjacent to repeating -CF2O- groups. In contrast, monoethers with a carboxylic acid moiety adjacent to a secondary carbon (-CF2-COOH) were stable in all tested solvents. Using high-resolution mass spectrometry, we determined that PFEAs with a >CF-COOH group were stoichiometrically decarboxylated in aprotic solvents and formed products with a >CFH group; e.g., hexafluoropropylene oxide-dimer acid (HFPO-DA or GenX), HFPO-trimer acid, and HFPO-tetramer acid were stoichiometrically converted to Fluoroethers E-1, E-2, and E-3, respectively. PFEA degradation results highlight the importance of solvent choice when preparing dosing solutions and performing extractions for environmental and toxicological assessments of PFEAs.

Equilibrium Solubility Determination and Dissolution Property Analysis of 5,6-Dimethoxy-1-indanone in 15 Pure Solvents from 283.15 to 323.15 K

Abstract: The equilibrium solubility of 5,6-dimethoxy-1-indanone in 15 commonly used solvents, including methanol, ethanol, n-propanol, isopropyl alcohol, n-butanol, isobutyl alcohol, sec-butanol, n-amyl alc...

Solubility Measurement and Data Correlation of 2,3-Dihydroxybenzoic Acid in 12 Monosolvents at Temperatures from 278.15 to 318.15 K

Abstract: The solubility of 2,3-dihydroxybenzoic acid in 12 organic solvents (ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, isoamyl alcohol, ethyl formate, methyl acetate, ethyl acetate, n-propyl ...

The Catalytic Performance of Ultrasonically Prepared AlPO4 Nanocatalysts for the Selective Production of Dimethyl Ether from Methanol

Abstract: Conversion of methanol to dimethyl ether (MTD) has known to be one of the main routes for the production of a clean bio-fuel, i.e., dimethyl ether (DME). However, efficient, selective, and stable catalyst is highly required for production of DME especially at relatively low temperature. Herein, aluminum phosphate nanocatalysts were fabricated by a co-precipitation method in the presence of triethylamine (TEA) as a surfactant. Thermal, structural, spectroscopic, morphological and texture properties of the catalysts were characterized by thermal analyses (TG–DTA), X-Ray diffraction (XRD), Fourier transform infrared (FTIR), high resolution transmission electron microscopy (HR-TEM) and N2-sorption analyses. In addition, the acidity of these catalysts was evaluated by isopropyl alcohol dehydration and chemisorption of basic probes. Results of acidity and pyridine-TPD indicated that these catalysts possessed Brϕnsted acidic sites of weak and intermediate strengths. The results of catalytic activity demonstrated that aluminum phosphate nanocatalyst (AP1T1) calcined at 400 °C exhibited the best catalytic performance for methanol dehydration into DME with a conversion of 100% and a 100% selectivity at 250 °C. In addition, this catalyst (AP1T1) exhibits a unique behavior where its catalytic performance only decreases by 10% upon increasing the % of methanol in the reacting feed to 35%. Moreover, it possessed excellent long-term stability with almost the same efficiency after a period of 120 h. The observable catalytic activity of these catalysts was well linked to the catalyst acidity and the activation energy.

Regeneration of transformer oil using a microemulsion with Triton X-100

Abstract: One way to regenerate insulation oil is to use a microemulsion, enabling improvement of the physicochemical characteristics of the oil and providing a high level of extraction of oxidized contaminants. The reclamation of insulation oil was performed using emulsions formed by mixtures of several proportions of water, Triton X-100 (surfactant), and isopropyl alcohol (cosurfactant), with subsequent washing of the oil 3 times and vacuum filtering. The oil quality was improved by adding 0.3% of 2,6-di-tert-butyl-p-cresol (DBPC) after regeneration. The efficiency of the reclamation process was evaluated in terms of the acid number, moisture, interfacial tension, dielectric strength, and dissipation factor of the recovered oil. The oxidized compounds present in the aged oil and the reclaimed oil were identified by gas chromatography coupled to mass spectrometry. The degraded oil contained nine main substances formed during oxidation of the oil, belonging to chemical groups including ketones, alcohols, ethers, hydrocarbons, and thio compounds. The reclamations performed with higher proportions of 50, 87.5, and 100% surfactant in the microemulsion resulted in the acid number values decreasing below 0.03 mg KOH/g. The washing process applied after regeneration using the microemulsion led to improvements of the interfacial tension, dielectric strength, and dissipation factor. There was a decrease of between 36 and 98% of oxidized compounds, compared to the non-reclaimed oil. These treatments can be applied to aged and degraded insulation oils.

Solvent Optimization of Transferred Graphene with Rosin Layer Based on DOE

Abstract: The method of transferring graphene to semiconductor substrates based on rosin gradually becomes common in practice Unlike the previous method (use of polymethacrylate) this procedure does not lead to significant contamination at the end of the transfer The disadvantage, however, is the need to use two solvents: acetone and banana oil instead of one The purpose of this article is to investigate, by means of a planned experiment, the influence of rosin solvents conventionally used on the resulting graphene layer contamination The solvents used were isopropyl alcohol (IPA), ethanol and xylene It was shown by the measured data using atomic force microscopy (AFM), that the lowest contamination can be achieved using isopropyl alcohol

Algorithm for Calculating the Protolytic Equilibrium Constants of Organic Acids in Isopropyl Alcohol

Abstract: An algorithm is developed for calculating the dissociation constants of weak organic acids in isopropyl alcohol. The procedure is based on spectrophotometric data in the UV and visible regions without measuring the pH of the medium or using buffer solutions. A new way of determining analytical wavelengths in spectrophotometry is proposed. The original algorithm is tested experimentally for seven organic acids of different strengths, and the relative error in determining the dissociation constants does not exceed 1%.

Designing an ideal alcohol-based hand sanitizer: in vitro antibacterial responses of ethanol and isopropyl alcohol solutions to changing composition.

Abstract: This study aimed to achieve an in vitro quantification of the effects of composition and formulation factors on the killing rates of alcohol-based hand sanitizers. The killing rates of 85% ethyl alcohol (ET) and isopropyl alcohol (IPA) were studied under different conditions such as pH, electrolyte concentration, or inclusion of herbal extracts (cucumber, carrot, and aloe vera), a quaternary ammonium compound, or thickener over different time intervals. Changes in the activities were retested after 3 months as an indication of stability. From two-way ANOVA, both the time of exposure and the sanitizer type affected the activity against Staphylococcus aureus (P = 0.001 for both alcohols), whereas for Escherichia coli, time of exposure was significant (P = 0.027), while sanitizer type was less significant (P = 0.063). Extreme pHs, the presence of ions, and the inclusion of additives such as benzalkonium chloride (BAC), plant extracts, or carbomer impacted the 3-month activity of the samples differently. Important differences existing in the activities of ET and IPA, as a function of formulation factors or use conditions have been quantified using in vitro methods. Formulations should best be tailored for particular purposes and the all-purpose hand sanitizer may not exist.

Cation-exchange resins as heterogeneous catalysts for the synthesis of 1,3-butadiene from propylene and formaldehyde

Abstract: The possibility of using the cation-exchange resin Lewatit K2420 as a catalyst for the synthesis of 1,3-butadiene from isopropyl alcohol and formaldehyde solution in one technological stage has been shown. The regularities of the process have been established and the influence of the formaldehyde form (a cyclic trimer 1,3,5-trioxane and a 37% solution in water) on the composition of the reaction mass and the yield of the main and by-products has been assessed. It has been shown that the Lewatit K2420 heterogeneous catalyst showed catalytic activity in all reactions occurring in the synthesis of 1,3-butadiene, including the decomposition of 1,3,5-trioxane, dehydration of isopropyl alcohol into propylene, condensation of propylene and formaldehyde, dehydration of 3-butene-1-ol, decomposition of 4-methyl-1,3-dioxane, etc.

Solubility Determination and Thermodynamic Correlation of 3-Amino-2-methylbenzoic Acid in 12 Monosolvents from 288.15 to 328.15 K

Abstract: A gravimetric method is adopted to measure the solid–liquid equilibrium of 3-amino-2-methylbenzoic acid in different solvents, including methanol, ethanol, 1-propanol, isopropyl alcohol, 1-butanol,...

Eco-Friendly Natural Clay: Montmorillonite Modified with Nickel or Ruthenium as an Effective Catalyst in Gamma-Valerolactone Synthesis

Abstract: Ni/Ru metals supported on cheap and available support montmorillonite K10 were used for the selective hydrogenation of levulinic acid to γ-valerolactone. Different loadings of the metals were applied by the impregnation method, and detailed characterization was performed (UV–VIS, XRD, TPR, TPD, particle size distribution, SEM, XRF). Metals’ homogeneous distribution on the surface was confirmed. The selectivity to the desired product was almost independent on the used material. A detailed study of the influence of solvents on the studied reaction was also performed—protic alcohol-based solvents caused the formation of levulinic and valeric acid esters in the reaction mixture. The selectivity was influenced mainly by the alcohol structure (the highest selectivity obtained using isopropyl alcohol and sec-butanol). Mainly the solvent’s donor number (except ethanol) influenced the reaction rate. The prepared catalysts are promising, available, and cheap materials for the studied reaction. Solvent may significantly influence the yield of γ-valerolactone.

Features and Consequences of Isopropanol Burning off PTFE-rGO Aerogels.

Abstract: An improved procedure for the preparation of aerogel granules of polytetrafluoroethylene-graphene oxide (PTFE-GO) with a composition of 50:50 (in wt %) and a specific density of 35 ± 2 mg/cm3 is described. The technique practically excludes the granule cracking. The specific density of the pellets after reduction using hydrazine vapor and annealing at 370 °C decreased to 29 ± 2 mg/cm3. The PTFE-reduced GO (rGO) pellets obtained were tested as a recyclable sorbent for isopropyl alcohol (IPA) in sorption/combustion cycles. It has been shown that the aerogel sorption capacity for IPA increases from 35.6 to 39.3 g/g as a result of alcohol burning off. During the combustion of IPA, the temperature of an individual pellet can exceed 300 °C. When several contingent pellets are burned, the temperature of their heating increases. The fine-pored structure of the near-surface layer of the granule is destroyed during the alcohol burning, the internal structure with larger pores is exposed, and the relative proportion of PTFE on the surface of the granules decreases. It was also shown that the specific surface area of PTFE-rGO increases from 26 to 49 m2/g during cycling.

Catalytic Reduction of Graphene Oxide Membranes and Water Selective Channel Formation in Water-Alcohol Separations.

Abstract: Graphene oxide (GO) is a promising membrane system for chemical separation applications due to its 2-D nanofluidics properties and an ability to control interplanar spacing for selectivity. The permeance of water, methanol (MeOH) and isopropyl alcohol (IPA) through 5 µm thick membranes was found to be 0.38 ± 0.15, 0.33 ± 0.16 and 0.42 ± 0.31 LMH/bar (liter/m2·h·bar), respectively. Interestingly, the permeance of a water–alcohol mixture was found to be dramatically lower (~0.01 LMH/bar) than any of its components. Upon removing the solvent mixture, the transmembrane flux of the pure solvent was recovered to near the original permeance. The interlayer space of a dried GO membrane was found to be 8.52 A, which increased to 12.19 A. 13.26 A and 16.20 A upon addition of water, MeOH and IPA. A decrease in d-space, about 2 A, was consistently observed when adding alcohol to water wetted GO membrane and an optical color change and reduction in permeance. A newly proposed mechanism of a partial reduction of GO through a catalytic reaction with the water–alcohol mixture is consistent with experimental observations.

Pool Boiling Heat Transfer Using Isopropyl Alcohol and Ammonium Chloride Surfactant

Abstract: This research article mainly focuses on the enhancement of pool boiling heat transfer using isopropyl alcohol and its solution with the surfactant ammonium chloride on a heating surface, which can be used in heat transfer device. A review on the effect surfactant (ammonium chloride) with different solvent on the heat transfer process also given. The solution is used as the working fluid to measure the heat transfer performance. After conducting the experiment, the result shows that in case of 200 PPM concentration, heat transfer coefficient is more than in case of 400 and 600 PPM, and it is due to the high viscosity and critical micelle concentration (CMC). The experimental data are modeled through the radial basis neural network (RBN) for the prediction of wall superheat, and heat transfer coefficient was given. The RBN model is able to predict the experimental data with a good accuracy level in comparison with the empirical and semiempirical correlations.