Solvents 2-propanol Research Articles

Laminated mordenite/ZSM-5 hybrid membranes by one-step synthesis: Preparation, membrane microstructure and pervaporation performance

Laminated mordenite/ZSM-5 hybrid zeolite membranes were fabricated on seeded porous α-alumina tubes with ZSM-5 crystals by one-step hydrothermal treatment for dehydration of industrial solutions. The microstructure was clarified with observations by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffractometer (XRD) analysis on the membranes synthesized as a function of crystallization time. The synthesized hybrid membranes were composed by two layers. The upper mordenite layer overgrew with 2μm thick above the ZSM-5 lower layer with 3μm thick. The formation sequence was estimated to be that (1) the ZSM-5 layer crystallized in the early stage of 4h; (2) then the mordenite crystals nucleated and grew on the lower ZSM-5 layer; (3) elongated mordenite grains crystallized for 4–8h to form the tightly packed layer.The potential pervaporation (PV) performance of dehydration was investigated for industrial solvents of 2-propanol (IPA) and acetic acid (AAc). In the results of PV at 75°C for a mixture of water (50wt.%)/IPA (50wt.%), the membrane exhibited higher permeation flux up to 6.4kgm−2h−1 and separation factors (α) with 1800. In the results of PV at 80°C for a mixture of water (50wt.%)/AAc (50wt.%), a higher permeation flux with 5.6kgm−2h−1 and a small amount of leakage of AAc with 0.68wt.% into the permeates or the separation factor α=150 were observed. These higher separating features in the laminated mordenite/ZSM-5 hybrid membrane could be caused by tightly assemblage of mordenite crystals that were formed uppermost layer of the membrane.

Effect of mixed solvent on structural, morphological, and optoelectrical properties of spin-coated TiO2 thin films

Nanocrystalline TiO2 anatase thin films have been synthesized from alkoxide solution via sol–gel spin coating method. The effects of different solvents of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and tert-butanol as well as those of mixed solvents on crystal structure, thermal behavior, morphology, and optoelectrical properties were investigated. It was found that not only the occurrence of rutile with anatase phase was solvent dependent, but also the morphology and optoelectrical properties of the films were strongly affected by solvent type. However, using two different types of alcohols as a single solvent brings the advantages of both solvents. Also, some unique properties in mixed solvent samples could be achieved. The viscosity, gel time, boiling point, possible complexes, dipole moment, and chain length of the solvent affect the packing density, lattice distortion, interfaces, thickness, optical band gap, refractive index, and extinction coefficient.

Kinetic analysis of 4-isopropylphenol hydrogenation over activated carbon-supported rhodium catalysts in supercritical carbon dioxide solvent

Hydrogenation behavior of 4-isopropylphenol to 4-isopropylcyclohexanol over activated carbon-supported rhodium catalysts in supercritical carbon dioxide (scCO2) at 313 K was studied in a batch reactor and the results were compared with those in 2-propanol. Higher yields of cis-4-isopropylcyclohexanol were obtained in scCO2 than in 2-propanol, and the formation of a byproduct, isopropylcyclohexane, was suppressed in scCO2. The catalyst modification with hydrochloric or phosphoric acid enhanced the yield of cis-4-isopropylcyclohexanol in both scCO2 and 2-propanol solvents. Kinetic analyses of the reaction profiles revealed higher reaction rates in scCO2 than those in 2-propanol for the 4-isopropylcyclohexanol formation both by the direct hydrogenation of 4-isopropylphenol and by the consecutive hydrogenation of 4-isopropylcyclohexanone, and also revealed that the addition of hydrochloric acid increased the consecutive hydrogenation rate of 4-isopropylcyclohexanone to cis-4-isopropylcyclohexanol, which reduced the total reaction time needed for the complete hydrogenation of 4-isopropylphenol to 4-isopropylcyclohexanol.

Medium Dependent Size and Shape Tuning of Indium Oxide Nanoparticles and Their Gas Sensing Properties

Using three primary alcohols (methanol, ethanol and propanaol) as solvent Indium oxide nanoparticles were prepared. Interestingly, the nanoparticles prepared using the three alcoholic solvents showed different morphologies. Even though the formed particles showed a cube-like structure, different sizes in the morphology have been observed in room temperature synthesis. The prepared particles showed visible light emission when excited with UV light due to oxygen vacancies. The prepared nanoparticles were made as a composite film with polyvinyl alcohol and the gas sensing behaviour of the composite film has been tested with ethanol vapours. Nanoparticles prepared using the three solvent showed good responses to the test gas ethanol. In particular, the nanoparticles prepared using methanol and ethanol solvents showed good response to ethanol when compared with the particles prepared using propanol solvent.

Application of the simplex method for optimization of chromatographic analysis of biogenic amines in fish

The aim of this study was to optimize the separation of biogenic amines with ion-exchange high-performance liquid chromatography, using the modified simplex method. A modified chromatographic response function was used, and two methodological parameters were selected as simplex variables: the proportion of the organic solvent 2-propanol in the mobile phases, added as a new mobile phase, and the variation of the gradient curve at one specific step in the elution program. In optimum conditions the correct resolution and separation of the biogenic amines (tyramine, β-phenylethylamine, histamine, tryptamine, putrescine, cadaverine, agmatine, spermidine and spermine) were completed in 16 min, reducing the analysis time by 9 min compared with the original method. The regression coefficients were higher than 0.99 in all the amines, except for spermine (0.989). The detection limits varied between 0.06 mg/L, for histamine and agmatine, and 0.22 mg/L, for tryptamine, while retention time repeatability, determined as a relative standard deviation, was between 4.64% for histamine and 11.95% for tryptamine. The repeatability variation for the amine concentrates was found between 0.71% in cadaverine and 3.23% for tryptamine. Applying the optimized method to samples of refrigerated sardine and sea bream demonstrated the effectiveness of the method in these fish species.

Bupropion hydrobromide propanol hemisolvate

The title compound {systematic name: N-[1-(3-chloro­phen­yl)-1-oxopropan-2-yl]-tert-butanaminium bromide propanol hemisolvate}, C13H19ClNO+·Br−·0.5C3H8O, crystallizes with two independent bupropion hydro­bromide ion pairs and a solvent 1-propanol mol­ecule in the asymmetric unit. In both mol­ecules, the expected proton transfer from HBr to the amino group of the bupropion mol­ecule is observed, and intra- and inter­molecular N—H⋯Br hydrogen-bond inter­actions are formed. These inter­actions link the mol­ecules into hydrogen-bond dimers. The side chains of the two cations have slightly different orientations. The 1-propanol solvent mol­ecule is linked to a bromide ion by an O—H⋯Br hydrogen bond.

Inactivation of tesA Reduces Cell Wall Lipid Production and Increases Drug Susceptibility in Mycobacteria

Phthiocerol dimycocerosates (PDIMs) and phenolic glycolipids (PGLs) are structurally related lipids noncovalently bound to the outer cell wall layer of Mycobacterium tuberculosis, Mycobacterium leprae, and several opportunistic mycobacterial human pathogens. PDIMs and PGLs are important effectors of virulence. Elucidation of the biosynthesis of these complex lipids will not only expand our understanding of mycobacterial cell wall biosynthesis, but it may also illuminate potential routes to novel therapeutics against mycobacterial infections. We report the construction of an in-frame deletion mutant of tesA (encoding a type II thioesterase) in the opportunistic human pathogen Mycobacterium marinum and the characterization of this mutant and its corresponding complemented strain control in terms of PDIM and PGL production. The growth and antibiotic susceptibility of these strains were also probed and compared with the parental wild-type strain. We show that deletion of tesA leads to a mutant that produces only traces of PDIMs and PGLs, has a slight growth yield increase and displays a substantial hypersusceptibility to several antibiotics. We also provide a robust model for the three-dimensional structure of M. marinum TesA (TesAmm) and demonstrate that a Ser-to-Ala substitution in the predicted catalytic Ser of TesAmm renders a mutant that recapitulates the phenotype of the tesA deletion mutant. Overall, our studies demonstrate a critical role for tesA in mycobacterial biology, advance our understanding of the biosynthesis of an important group of polyketide synthase-derived mycobacterial lipids, and suggest that drugs aimed at blocking PDIM and/or PGL production might synergize with antibiotic therapy in the control of mycobacterial infections.

Measurement and Correlation of Solubilities of Cefpirome Sulfate in Aqueous Alcohol Solution between (278.15 and 308.15) K

The solubilities of cefpirome sulfate in water + (methanol, ethanol, 1-propanol, or 2-propanol) solvent mixtures have been measured using a dynamic method at temperature ranging from (278.15 to 318.15) K at atmospheric pressure. A solubility equation was proposed and verified by experimental results. The dissolution enthalpy and dissolution entropy have been calculated from the solubility data. The interactions between solute and solvent were discussed.

SINTESIS BAHAN MEMBRAN SEL BAHAN BAKAR: KOPOLIMERISASI STIRENA PADA FILM ETFE DENGAN TEKNIK IRADIASI AWAL

: Preirradiation Grafting styrene monomer on ETFE film has been prepared. Research has been performed by γ-ray radiation at various total dose from 2.5 - 12.5 kGy and various dose rate from 1.3 - 1.9 kGy/hour. Irradiated copolymer is then grafted by styrene monomer in various solvent: ethanol, 2-propanol, and toluene, various concentration from 20 - 70% volume, various temperature from 50 - 90oC, and various grafting time from 2 - 12 hours. The results showed that percent of grafting is increase with increase of total dose and decrease of rate dose. The optimum experiment conditions are obtained at total dose 10 kGy, dose rate 1,9 kGy/hour, 2-propanol solvent, 40% volume styrene, 4 hours grafting time, and 70oC grafting temperature.

Preparation of Silver Nanocolloids Using Silver Alkylcarbamate Complex in Organic Medium with PVP Stabilizer

We present a method for chemically reducing silver alkylcarbamate complex with hydrazine to synthesize silver nanocolloids in an organic solvent using polyvinylpyrrolidone (PVP) as the stabilizer. To determine the optimal conditions for preparing stable silver colloids of controlled size and shape, the silver 2-ethylhexylcarbamate (Ag-EHCB) complex, PVP, hydrazine, and 2-propanol solvent concentrations in the reaction mixture were varied. The initial colloid has a mean particle diameter of 5-80 nm, and it exhibits an absorption band with various shapes in the UV region with a maximum near 420 nm. UV-vis spectroscopy, TEM, and X-ray diffraction techniques were used to investigate the formation and growth process of the metallic silver nanocolloids.

ChemInform Abstract: Time-Resolved EPR Study on the Photochemical Reactions of Benzil

A time-resolved EPR (TREPR) study on the photochemical reactions of benzil in 2-propanol and benzene-triethylamine (TEA) mixed solvents is reported. The emissive signals observed in 2-propanol are assigned to the benzoyl and benzil ketyl radicals, and the absorptive one observed in benzene-TEA is assigned to the benzil anion radical. The reactions are considered to occur from higher excited triplet (T n ) states through two-photon processes in 2-propanol but from the lowest excited triplet state through a one-photon process in benzene-TEA

RADIATION GRAFTING OF STYRENE ONTO PTFE FILM

Radiation grafting of styrene monomer onto poly(tetrafluoroethylene) (PTFE) film has been investigated. This research is emphasized on the conditioning of PTFE film. It was irradiated by -ray radiation at various irradiation dose from 2.5 - 12.5 kGy with dose rate 1.9 kGy/hour. Irradiated copolymer was then grafted by styrene monomer under various conditions. The results showed that degree of grafting increased by increasing irradiation dose, solvent concentration, temperature and time of grafting. The optimum condition of radiation grafting relatively was obtained at irradiation dose of 10 kGy, 2-propanol solvent, styrene concentration of 40 volume%, temperature and time of grafting of 70 oC and 6 hours each. Keywords: Radiation grafting, PTFE, Fuel cell

Spectroscopic characterization studies of 1-methyl indole with benzene derivatives

The NMR and fluorescence quenching of benzene, chlorobenzene and methoxybenzene in acetonitril and 2-propanol solvents have been carried out with a view to understand the quenching mechanisms. The quenching is found to be appreciable and shows positive derivation in the stern-volmer plots. UV absorbance is used to measure the excitation wavelength. Lifetime measurements are carried out and the quenching rate constant k q is also calculated. Molar extinction co-efficient, stoke's shift are also calculated. The NMR study is used to conform if there is any complex formation between 1-methylindole with the benzene derivatives.

Microwave specific effects in organic synthesis: A proposed model from the solvent-free synthesis of monoglycerylcetyldimethylammonium chloride

Microwave specific effect in the organic synthesis was examined under homogeneous and heterogeneous conditions. Monoglycerylcetyldimethylammonium chloride was synthesized from 3-chloro-1,2-propanediol (CP) and N , N -dimethylhexadecylamine (DMHA) in 2-propanol solvent and in solvent-free conditions to examine microwave specific effects. None were evident in homogeneous 2-propanol media under temperature conditions identical to conventional heating. In contrast, heterogeneous solvent-free conditions brought out specific microwave effects as evidenced by variant product yields (130 °C; 30 min): 62% by microwave and 47% by conventional heating. This variance is attributed to thermal conduction and localized hot spots formed under microwave irradiation. The model proposed for the solvent-free synthesis considers hydrophilic 3-chloro-1,2-propanediol molecules form H-bonded domains (size, 2–20 μm) preferentially heated by the microwaves and dispersed in a sea of hydrophobic N , N -dimethylhexadecylamine molecules.

Time-Resolved Resonance Raman Study of the Effect of pH on the Photoreactions of 3-Benzoylpyridine in Aqueous Solution

A nanosecond time-resolved resonance Raman investigation of the photoreactions of 3-benzoylpyridine (3-BPy) in different pH aqueous solutions is reported. In neutral, basic, and pH = 5 aqueous solution conditions, the photoreduction reaction from the triplet 3-BPy species is observed to produce the corresponding 3-phenyl pyridyl ketyl radical that was also observed in a 2-propanol solvent. Under moderate acidic conditions (at pH = 3 for example), most of the 3-BPy triplet state species goes through two protonation steps at the nitrogen atom and the carbonyl oxygen atom after UV laser photolysis and then forms a short-lived hydration intermediate via a hydration reaction at the ortho position in the benzene ring. This new species is tentatively assigned to the o-3[3-BPyH+.H2O] hydration species. In acidic aqueous solutions with a pH < or = 1, the protonated triplet states of 3-BPy cations at the nitrogen atom are generated from photoexcitation of the protonated ground state and are subsequently further protonated at the carbonyl oxygen atom to form a 3-BPy-dication triplet state. This dication intermediate reacts with water molecules at the ortho position of the benzene ring to produce the o-3[3-BPyH+.H2O] hydration species. The mechanisms of photoreduction observed for 3-BPy in different pH aqueous solutions were investigated using density functional theory calculations, and these results were used to help assign the intermediates observed in the experiments. The structures and properties of these species are briefly discussed, and an overall photoreaction mechanism is proposed based on the results from the time-resolved resonance Raman experiments and the density functional theory calculations.

Measurement and Correlation of Solubilities of Decanedioic Acid in C4−C6 Alcohol Solvents

The solubility data have been measured experimentally for decanedioic acid in n-butanol, 2-butanol, n-pentanol, n-hexanol, and binary solvents 2-propanol + water from (294 to 351) K. The system con...

Solubility of Deflazacort in Binary Solvent Mixtures

Experimental solubility data were measured for deflazacort dissolved in binary n-hexane + acetone, n-hexane + ethyl acetate, n-hexane + ethanol, and n-hexane + 2-propanol solvent mixtures at 303.15 K and atmospheric pressure by laser monitoring technique. Results of these measurements were used to test the predictive ability of the combined nearly ideal binary solvent (NIBS)/Redlich−Kister model. Computation showed that the model fit the data well.

Synthesis and characterization of a highly active alumina catalyst for methanol dehydration to dimethyl ether

Abstract A simple sol–gel method was adopted to synthesize boehmites with high surface area using aluminum iso-propoxide (AIP), acetic acid (AA) and 2-propanol, and the effects of surface area and methanol dehydration on activity were investigated. The hydrolysis conditions of AIP in the presence of AA in 2-propanol solvent were systematically varied to observe their effect on phase formation, crystallinity, surface area and pore size distribution of the alumina. The surface area and the number of acidic sites varied considerably with the variation in the molar ratio of AA/AIP. This study revealed that a high surface area boehmite (in the range of 628–717 m2/g) could be obtained by keeping the molar ratio of AA/AIP as 0.5 and that of H2O/AIP at ∼3. Rod shaped, porous γ-Al2O3 powder with a high surface area of 438 m2/g was obtained after calcination of the boehmite at 500 °C for 5 h in air. The temperature programmed desorption of ammonia (NH3-TPD) of the γ-Al2O3 samples demonstrated higher concentration of acidic sites when acetic acid was used during preparation than when it was not used. The vapor phase dehydration of methanol (containing 20 mol% H2O) to dimethyl ether (DME) was conducted on the prepared aluminas. With increasing surface area of γ-Al2O3, the temperature required to reach 50% conversion of methanol decreased due to the increased number of acidic sites which are favorable for methanol dehydration with low byproduct formation. The catalytic activity for methanol dehydration to DME correlated well with the total number of acidic sites of γ-Al2O3, which was controlled by changing the AA/AIP and H2O/AIP molar ratios.

Structural studies of sol–gel urea/polydimethylsiloxane barrier coatings and improvement of their corrosion inhibition by addition of various alkoxysilanes

A sol–gel organic–inorganic hybrid precursor, bis[(ureapropyl)triethoxysilane]bis(propyl)-terminated-polydimethylsiloxane 1000 (PDMSU, for short), was tested as a corrosion barrier coating for AA 2024 aluminium alloy. The PDMSU coatings were prepared in either ethanol (PDMSU/EtOH) or propanol (PDMSU/PrOH) solvents. XRD measurements of xerogels showed the diffraction peak of amorphous silica domains at 21.5° and a broad peak at approximately 12.2°, which could be associated with the presence of the polyhedral silsesquioxane structural units (T 2 and T 3) determined in our previous investigations from the 29Si NMR spectra. The structure of thin coatings on AA 2024 prepared by heat-treatment at 140 °C was studied with the surface-sensitive IR reflection–absorption (IR RA) spectroscopic technique. Results revealed that in both coatings the poly(dimethylsiloxane) (PDMS) chain segments were projecting from the metal surface, however, this effect was more pronounced for the PDMSU/PrOH than for the PDMSU/EtOH coatings. Information gathered from the structural studies (IR, IR RA, 29Si NMR and XRD) enabled some correlations to be drawn between the coatings’ structure and the effectiveness of the corrosion inhibition, which was assessed from the potentiodynamic and salt-spray measurements. Results showed the improved corrosion inhibition of PDMSU/PrOH coatings attributed to their denser and more compact sol–gel network and also to their higher hydrophobicity, i.e. lower surface energy determined from the contact angle measurements. Addition of various tetraalkoxysilanes and alkyltriethoxysilanes further improved the corrosion inhibition of PDMSU coatings due to more extensive cross-linking. The salt-spray tests showed that tetraethoxysilane and phenyltriethoxysilane were the most effective additives.

Comparison of solvent mixtures for pressurized solvent extraction of soil fatty acid biomarkers

The extraction and transesterification of soil lipids into fatty acid methyl esters (FAMEs) is a useful technique for studying soil microbial communities. The objective of this study was to find the best solvent mixture to extract soil lipids with a pressurized solvent extractor system. Four solvent mixtures were selected for testing: chloroform:methanol:phosphate buffer (1:2:0.8, v/v/v), chloroform:methanol (1:2, v/v), hexane:2-propanol (3:2, v/v) and acetone. Soils were from agricultural fields and had a wide range of clay, organic matter and microbial biomass contents. Total lipid fatty acid methyl esters (TL-FAMEs) were the extractable soil lipids identified and quantified with gas chromatography and flame ionization detection. Concentrations of TL-FAMEs ranged from 57.3 to 542.2 n mole g −1 soil (dry weight basis). The highest concentrations of TL-FAMEs were extracted with chloroform:methanol:buffer or chloroform:methanol mixtures than with the hexane:2-propanol or acetone solvents. The concentrations of TL-FAMEs in chemical groups, including saturated, branched, mono- and poly-unsaturated and hydroxy fatty acids were assessed, and biological groups (soil bacteria, mycorrhizal fungi, saprophytic fungi and higher plants) was distinguished. The extraction efficiency for the chemical and biological groups followed the general trend of: chloroform:methanol:buffer ≥ chloroform:methanol > hexane:2-propanol = acetone. Discriminant analysis revealed differences in TL-FAME profiles based on the solvent mixture and the soil type. Although solvent mixtures containing chloroform and methanol were the most efficient for extracting lipids from the agricultural soils in this study, soil properties and the lipid groups to be studied should be considered when selecting a solvent mixture. According to our knowledge, this is the first report of soil lipid extraction with hexane:2-propanol or acetone in a pressurized solvent extraction system.