Acetone System Research Articles

Drying processes for preparation of titania aerogel using supercritical carbon dioxide

Supercritical carbon dioxide drying was performed for the preparation of titania aerogels from sol–gel routes. The conditions of supercritical carbon dioxide drying were 313–323 K and 7.8–15.5 MPa. The solvents in titania wet gels obtained from the sol–gel routes were replaced by acetone. The titania aerogels obtained from supercritical carbon dioxide drying form needle-like structures. In supercritical carbon dioxide drying, the extraction rates of acetone from the wet gels were measured by using an on-line Fourier transform infrared spectroscope. It was found that the titania aerogels with lower cohesion were induced from the formations of homogenous phase for carbon dioxide + acetone system and the lower extraction rates of acetone. Furthermore, titania films were prepared by the depositions of the titania aerogels on ITO-coated PET substrates. The needle-like aerogels with lower cohesion derive the titania film with high surface area.

Production of diacylglycerols through low-temperature chemical glycerolysis

The aim of this study was to produce diacylglycerols (DAG) by chemical glycerolysis of soybean oil at low temperatures. Solvents and low-frequency ultrasonic irradiation were introduced to enhance the reaction. Three operation modes, namely mechanical stirring, magnetic stirring and ultrasonic irradiation, were compared. In the solvent-free system, DAG formation was not observed in any of the three operation systems. DAG were formed when reactions were incubated in tertiary alcohols for all of the three operation systems. Interesting observations were found in the acetone system. Although DAG formation was negligible under mechanical stirring with classical propeller, a total of 52.0 ± 2.2% DAG was obtained when ultrasonic irradiation was used. The same content of DAG can also be obtained under magnetic stirring; however, a 4-h reaction was required. Acetone dosage (solvent:oil, wt:wt) 3:1 and 40 W ultrasonic power were suitable for the reaction system under the conditions studied.

Numerical simulation of mass transfer in circulating drops

Numerical simulations of mass transfer are performed for a circulating liquid drop with applications in liquid–liquid extraction. Simulation parameters are chosen for a multi-component ternary system acetone–methanol–benzene. The drop circulation pattern is estimated via a truncated Galerkin representation of the drop streamfunction. Fickian diffusivities for multi-component mass transfer are obtained via Maxwell–Stefan theory with thermodynamic corrections. The advection–diffusion equations governing mass transfer are solved via two distinct numerical methods: a finite difference scheme (using the alternating direction implicit method) and a finite element scheme. Good agreement was obtained between both schemes. Simulation results are presented for a Reynolds number (Re=30) and for a selection of Peclet numbers (Pe=100, 1000 and 10 000, thereby giving insight into the effects of increasing Peclet number). The numerical simulations of the full advection–diffusion equations are compared against predictions of a rigid drop model (i.e. without circulation) and also against predictions of a semi-analytical boundary layer model developed by Uribe-Ramirez and Korchinsky. Results for bulk mass fractions reveal that the rigid drop model predictions evolve too slowly, while the boundary layer model predictions evolve much more quickly than the numerical simulations. Advection–diffusion simulation results for the evolution of mass fractions at selected individual locations in the drop show that points on streamlines nearest to the drop surface and/or drop axis evolve fastest, while those closest to the drop internal stagnation point evolve slowest. Corroborated by contour plots of component concentrations throughout the drop at selected times, this supports a picture whereby mass fractions become roughly uniform along individual streamlines, but mass is transferred diffusively from streamline to streamline.

Volume Reduction of Nonaqueous Media Contaminated with a Highly Halogenated Model Compound Using Superoxide

Highly halogenated organic compounds, which include polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins (PCDDs) formed during the synthesis of pentachlorophenol and chlorophenoxy herbicides, are often found as contaminants in less toxic nonaqueous media, such as waste oil, oily sludges, or biosolids. Superoxide is highly reactive with halogenated compounds when both are dissolved in nonaqueous media; however, superoxide is most economically generated in water, where it is unreactive with most organic compounds. Superoxide reactivity was investigated in organic solvent-water systems as a basis for treating halogenated contaminants in less toxic nonaqueous media. Such a process could potentially render a contaminated oil or sludge nonhazardous, providing a mechanism for waste volume reduction. Increasing amounts of water added to acetone and dimethyl sulfoxide systems decreased the activity of superoxide in the solvent, but enough activity remained for effective treatment. Superoxide was then generated in the aqueous phase of two-phase water-organic solvent systems, and significant superoxide activity was achieved in the organic media with the addition of phase transfer catalysts (PTCs) to transfer superoxide into the nonaqueous phase. The results of this research demonstrate that superoxide, which can be generated in water electrochemically or through the catalytic decomposition of peroxygens, has the potential to be transferred to oils, sludges, and other less toxic nonaqueous media to destroy highly refractory contaminants such as PCBs, PCDDs, and other halogenated contaminants.

Hydrogen Bonding Interactions in Three 2-Mercaptoethanol Systems: An Excess Infrared Spectroscopic Study

The hydrogen bonding properties of a representative molecule, 2-mercaptoethanol (ME), of which two functional groups OH and SH are believed to interact competitively or selectively with proton-accepting molecules, have been studied. Three binary systems, namely ME-CCl(4), ME-dimethyl sulfoxide (DMSO), and ME-acetone, were investigated with excess infrared absorption spectroscopy. It is found that when DMSO or acetone is added into ME, they preferentially form hydrogen bonds with OH, and the hydrogen bonds in the ME-DMSO system are stronger than those in the ME-acetone system. When CCl(4) is added into ME, the weak hydrogen bonds involving the SH group are broken preferentially with increasing CCl(4) concentration. The dissociation process of ME in the inert diluent CCl(4) over the entire concentration range has been discussed in detail. In the very low concentration range of CCl(4), the highly hydrogen bonded ME multimers mainly break into medium-sized aggregates. The amount of the trimers and dimers first increases and then, at x(CCl(4)) = 0.77, begins to decrease. These results suggest that excess infrared spectroscopy can provide detailed molecular pictures in liquid solutions containing complex hydrogen bonding interactions. It can also help to locate individual peak positions in the deconvolution of overlapped absorption bands.

Synthesis of Complementary Host- and Guest-Functionalized Polymeric Building Blocks and Their Self-Assembling Behavior

New polymers that incorporate paraquat or crown ether moieties as chain ends or central units were synthesized by stable free radical polymerization (SFRP) and atom transfer radical polymerization (ATRP). For SFRP, TEMPO derivatives that contain a functional unit were used as initiators. For ATRP, a copper−amine or copper−bipyridine complex was used as a catalyst with radical initiators from halide derivatives of paraquat and crown ethers. These end- or center-functionalized polymers formed pseudorotaxane complexes with complementary small molecules. They also formed reversible pseudorotaxane polymers: chain-extended, star-shaped homopolymers, and block copolymers. Complexation studies to determine stoichiometry and association constants with thermodynamic parameters were performed by NMR spectroscopy and isothermal microcalorimetric (ITC) titration. The association constants of crown ether derivatives and paraquat compounds in chloroform were measured for the first time: Ka = 2.97 × 103 M−1 for paraquat polystyrene and bis(m-phenylene)-32-crown-10 and Ka = 4.38 × 103 M−1 for paraquat polystyrene and crown ether polystyrene. These are 4−6-fold higher than the association constant of the analogous small molecule host−guest system in acetone.

Comments Concerning “Equilibrium Phase Diagram of the Ternary 2-Nitrobenzoic Acid + 3-Nitrobenzoic Acid + Acetone System at 283.15 and 313.15 K”

In a recent paper published in this journal Zhao et al. reported the equilibria phase diagram of the ternary 2-nitrobenzoic acid (1) + 3-nitrobenzoic acid (3) + acetone (3) system at both 283.15 and 313.15 K. Schreinemaker’s wet residue method was used to determine the concentrations of the liquid and solid phases. The experimental methodology involved filtering the wet solid residue from an equilibrated saturated solution (the authors state aqueous solution, which I believe should read acetone solution) and then analyzing the collected liquid and solid phases by high-performance liquid chromatography. The authors reported the concentrations as mass% for the ‘‘wet’’ solid phase. The purpose of the present communication is to point to errors that go undetected when experimental data is reported on the ‘‘wet’’ solid phase basis. In Tables 1 and 2, I have reproduced the authors’ experimental solubility data for the ternary 2-nitrobenzoic acid (1) + 3-nitrobenzoic acid (2) + acetone (3) system measured at 283.15 and at 313.15 K. For the third experimental data point in Table 1, the composition of the ‘‘wet’’ solid phase is reported to be 2.55 mass% of 2-nitrobenzoic acid and 70.39 mass% of 3-nitrobenzoic acid, respectively. The remaining 27.06 mass% would be acetone that would have been adsorbed onto the filtered solid residue from the saturated solution. The solid residue was analyzed ‘‘wet,’’ and the chromatographically measured concentrations would include the amounts of 2-nitrobenzoic acid and 3-nitrobenzoic acid absorbed onto the solid residue along with acetone. Through mass balance concentrations, it is possible to subtract the amount of 2-nitrobenzoic acid and 3-nitrobenzoic that would have been absorbed onto the solid residue along with the 27.06 mass% of acetone. For mathematical convenience, I have assumed 100 g total of each phase, so that the mass percentages become the mass of each chemical.

Onset of sidewise instability and cell–dendrite transition in directional solidification

The transition from cellular to dendritic microstructure in directional solidification is investigated in succinonitrile (SCN)–camphor alloys. This transition is found not to be sharp, but occurs locally over a range of velocities or thermal gradients, and the diffuseness of the transition is related to the existence of a range of primary spacing. Within the transition zone, critical cell spacing λ cd is present where a cell just develops sidewise perturbations. An expression for the critical spacing for the onset of sidewise perturbation is obtained, and it is used to establish the conditions for the start and end of the transition. The results of the present study are then synthesized with those in the SCN–acetone system to incorporate the effect of system parameters on the onset of sidewise instability.

Recovery of nickel from aqueous samples with water-soluble carboxyl methyl cellulose–acetone system

A simple and efficient method, which involves carboxyl methyl cellulose (CMC) and acetone, was developed for recovery of trace nickel from aqueous solutions. This method was based on the fact that Ni 2+ could react with CMC and form water-soluble complexes, which would solidify in excess acetone. After centrifugation, the solid mass consisting of the nickel complex and free CMC was easily dissolved with water and the nickel was determined by flame atomic absorption spectrometry (FAAS). Several factors influencing the recovery of nickel were thoroughly investigated and the optimized conditions were as follows: 5.00 mL water sample, 0.50 mL 0.5% CMC, 1.00 mL of 3.0 mg mL −1 KNO 3 and 20 mL acetone. Under the optimized conditions, the loading capacity of CMC for nickel was 20.6 mg Ni/g polymer. The linear range was 0.025–3.0 μg mL −1, the limit of detection was 0.019 μg mL −1 and the pre-concentration factor was 4. Ni(II) can be well recovered in this CMC–acetone system from binary ions mixtures containing Zn(II), Ba(II), Ca(II), Mo(VI), Co(II), Cd(II), Mg(II), Mn(II) and Cr(III). The developed method had been applied to the recovery of trace nickel in water samples with satisfactory results. A possible mechanism for the nickel precipitate was proposed. The efficient, convenient and affordable method provides an alternative method for the recovery of nickel from environmental waters.

A New Continuous Method for Performing Rapid Phase Equilibrium Measurements on Binary Mixtures Containing CO2 or H2O at High Pressures and Temperatures

Apart from paying a deserved tribute to Professor Schneider, a new synthetic dynamic method for rapid determination of phase boundaries at high pressures and temperatures is presented. This device is based on the change in the Flame Ionization Detector signal given by a small amount of sample taken by a capillary fiber from an equilibrium cell through which a mixture of known composition is continuously flowing. To validate the method, the phase boundaries for the system acetone + CO2 are measured at (0.2 and 0.7) acetone mole fraction and at (350 to 380) K. We also measured the phase boundaries for the system ethanol + H2O at compositions ranging from (0.05 to 0.4) ethanol mole fraction and temperatures up to 600 K. The results agree well with literature data, showing the feasibility of this method to measure the phase behavior of binary mixtures containing CO2 and H2O at extreme conditions.

Pre-concentration and separation of copper with water-soluble poly(vinyl alcohol) and acetone system prior to its spectrophotometric determination

A water-soluble poly(vinyl alcohol)–acetone system for the pre-concentration and separation of Cu2+in environmental water samples has been developed. First, poly(vinyl alcohol) (PVA) was able to complex with Cu2+, and the reaction product, the copper–PVA complex, was precipitated in excess acetone. Sequentially, the precipitate was separated by decantation and dissolved in a minimum amount of water. Finally, the copper ions were determined by the sodium diethyldithiocarbamate spectrophotometric method. Some related parameters that might affect the recovery of the copper were investigated in detail. Under the optimum experimental conditions, the detection limit is 0.014 µg mL−1 and the linearity range is from 0.025 to 3.00 µg mL−1. The relative standard deviation (n = 11) is 1.1%. The method was successfully applied to the analysis of copper in spring water, ground water, tap water, lake water and electroplating waste water. A possible mechanism of the method is also proposed.

Phase equilibria and interfacial tensions in the systems methyl tert-butyl ether + acetone + cyclohexane, methyl tert-butyl ether + acetone and methyl tert-butyl ether + cyclohexane

Isobaric vapor–liquid equilibrium (VLE) data have been measured for the ternary system methyl tert-butyl ether + acetone + cyclohexane, and for its methyl tert-butyl ether based binaries, at 94 kPa and in the temperature range 323–340 K. Equilibrium determinations were performed in a vapor–liquid equilibrium still with circulation of both phases. The dependence of interfacial tensions of these mixtures on concentration was also determined, at atmospheric pressure and 303.15 K, using the maximum bubble pressure technique. From the experimental results, it follows that the investigated mixtures exhibit positive deviation from ideal behavior and azeotropy is present for the methyl tert-butyl ether + acetone system at 94 kPa. The application of a model-free approach allows concluding about the reliability of the present vapor–liquid equilibrium data for all the indicated mixtures. Furthermore, the determined interfacial tensions exhibit negative deviation from linear behavior for all the analyzed mixtures. The vapor–liquid equilibrium data of the binary mixtures were well correlated using the NRTL, Wilson and UNIQUAC equations, while their interfacial tensions were smoothed using the Redlich–Kister equation. Scaling of these models to the ternary mixture allows concluding that both the VLE data and the interfacial tensions can be reasonably predicted from binary contributions.

Design and Use of Organic Nanoparticles Prepared from Star-Shaped Polymers with Reactive End Groups

Star-shaped poly(isobornyl acrylate) (PiBA) was prepared by atom transfer radical polymerization (ATRP) using multifunctional initiators. The optimal ATRP conditions were determined to minimize star-star coupling and to preserve high end group functionality (>90%). Star-shaped PiBA with a narrow polydispersity index was synthesized with 4, 6, and 12 arms and of varying molecular weight (10,000 to 100,000 g x mol(-1)) using 4 equiv of a Cu(I)Br/PMDETA catalyst system in acetone. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) analysis, NMR spectroscopy, and size exclusion chromatography (SEC) confirmed their controlled synthesis. The bromine end group of each arm was then transformed to a reactive end group by a nucleophilic substitution with methacrylic acid or cinnamic acid (conversion >90%). These reactive star polymers were used to prepare PiBA nanoparticles by intramolecular polymerization of the end groups. The successful preparation of this new type of organic nanoparticles on a multigram scale was proven by NMR spectroscopy and SEC. Subsequently, they have been used as additives for linear, rubbery poly(n-butyl acrylate). Rheology measurements indicated that the viscoelastic properties of the resulting materials can be fine-tuned by changing the amount of incorporated nanoparticles (1-20 wt %), as a result of the entanglements between the nanoparticles and the linear polymers.

Viscosity measurements on saturated gas expanded liquid systems—Acetone and carbon dioxide

The experimental viscosities of the saturated gas expanded liquid system of acetone and carbon dioxide were determined under pressure using a falling-weight viscometer. System pressures and temperatures were manipulated as independent variables to simultaneously influence system properties of liquid phase compositions, densities, volume expansions and viscosities. Liquid viscosities were measured and presented as a function of other system properties. Viscosity measurements were conducted at constant system temperatures of 25, 30, 35 and 40 °C, and at system pressures corresponding to liquid compositions between 0 and 0.90 carbon dioxide mole fractions along all four isotherms. Viscosity reduction was observed to be a function of increasing carbon dioxide concentration in the liquid phase, liquid volume expansion, liquid density and system pressure. A high degree of linear correlation was observed throughout the entire experimental envelope when viscosity reduction was presented as a function of liquid phase composition. Analysis of data obtained in this study in conjunction with results of previous research [R. Sih, F. Dehghani, N.R. Foster, Viscosity measurements on gas expanded liquid systems. Methanol and carbon dioxide, Journal of Supercritical Fluids 41 (2007) 148–157; R. Sih, M. Armenti, R. Mammucari, F. Dehghani, N.R. Foster, Viscosity measurements on saturated gas-expanded liquid systems. Ethanol and carbon dioxide, Journal of Supercritical Fluids 43 (2008) 460–468] shows that the viscosity behavior of independent gas expanded liquid systems consisting of carbon dioxide and either methanol, ethanol or acetone were universally related to system composition, organic solvent species and system temperature.

Vapor–liquid equilibria and interfacial tensions for the ternary system acetone + 2,2′-oxybis[propane] + cyclohexane and its constituent binary systems

Isobaric vapor–liquid equilibrium data have been measured for the ternary system acetone + 2,2′-oxybis[propane] + cyclohexane, and its constituent binaries at 94 kPa and in the temperature range 324–350 K in a vapor–liquid equilibrium still with circulation of both phases. The dependence of the interfacial tensions of these mixtures on concentration was also determined at atmospheric pressure and 303.15 K, using the maximum bubble pressure technique. From the experimental results, it follows that both the ternary and binary mixtures exhibit positive deviations from ideal behavior and, additionally, azeotropy is present for the binaries that contain acetone. The application of a model-free approach allows conclusions about the reliability of the present vapor–liquid equilibrium data for all the indicated mixtures. Furthermore, the determined interfacial tensions exhibit negative deviation from linear behavior for all the analyzed mixtures, and aneotropy is observed for the acetone + cyclohexane mixture. The vapor–liquid equilibrium data of the binary mixtures were well correlated using the NRTL, Wilson and UNIQUAC equations. In a similar manner, the interfacial tensions of the binary mixtures were smoothed using the Redlich–Kister equation. Scaling of these models to the ternary mixture allows concluding that both the vapor–liquid equilibrium data and the interfacial tensions can be reasonably predicted from binary contributions.

Solid–liquid phase equilibrium and phase diagram for ternary o-nitrobenzoic acid– p-nitrobenzoic acid–acetone system at 283.15 K and 313.15 K

In this investigation, the mutual solubilities and the density of equilibrium liquid phase for ternary o-nitrobenzoic acid– p-nitrobenzoic acid–acetone system were measured at 283.15 K and 313.15 K, respectively. Two isothermal phase diagrams of the system were constructed on the basis of the measured solubilitities, one at 283.15 K and the other at 313.15 K. The phase diagrams of the ternary system were similar at the different temperatures. Two solid-phases were formed and confirmed by Schreinemaker's wet residue method, and the two were identified as o-nitrobenzoic acid and p-nitrobenzoic acid. The crystallization regions of p-nitrobenzoic acid and o-nitrobenzoic acid increase as the temperature decreases. At each temperature, the crystallization of p-nitrobenzoic acid is larger than that of o-nitrobenzoic acid.

Isobaric Vapor–Liquid Equilibria for Binary Systems of Acetone + Isopropenyl Acetate, 2-Butanone + Isopropenyl Acetate, and Isopropenyl Acetate + Acetylacetone at 101.3 kPa

Isobaric vapor–liquid equilibrium (VLE) data have been determined with a circulation still at 101.3 kPa for binary systems of acetone + isopropenyl acetate, 2-butanone + isopropenyl acetate, and isopropenyl acetate + acetylacetone. No azeotropic behavior was found in any of the systems studied. Thermodynamic consistency has been tested for all VLE data. The experimental data have been correlated satisfactorily by the NRTL, UNIQUAC, and Wilson models. Predictions by using group-contribution methods, such as the original UNIFAC, UNIFAC−Dortmund, and UNIFAC−Lyngby, have been compared with the experimental results.

The epoxidation of allyl alcohol on Ti-complex/MCM-48 catalyst

The heterogeneous sharpless-type catalyst was prepared by an in situ method using MCM-48 as the support. The influence of the incorporation process on the structure of MCM-48 was studied by the XRD, FT-IR, 29Si MASNMR and N 2 adsorption–desorption. The obtained materials showed the definite catalytic activity on the epoxidation of allyl alcohol under the system of acetone (solvent) and peroxycarbamide (oxidant).

Photoconversion and photocatalytic activity of uranyl in acetone solutions

We have studied the effect of irradiation on the uranyl nitrate — acetone and uranyl perchlorate — acetone systems. We have established that when the uranyl perchlorate — acetone system is irradiated, polymerization of the acetone occurs and the catalyst for the process is excited uranyl complexes. In the polymer, uranium is found in the form of nanoclusters of pentavalent and tetravalent uranium, formed as a result of photochemical reactions. Polymerization does not occur in the uranyl nitrate — acetone system. We consider possible factors responsible for the noted differences.

Determination of valley and ridge of isobaric vapor–liquid equilibrium for ternary system

The aim of this paper is to describe a method for the determination of the valley and ridge of isobaric vapor–liquid equilibrium (VLE) for ternary systems which have a ternary azeotropic point at atmospheric and at lower pressure. The extended Redlich–Kister equation was employed as an activity coefficient for calculating the isobaric VLE, because this equation can be applied to the isobaric conditions provided by the Gibbs–Duhem equation, and to complete calculation of the ternary and binary azeotropes. It is possible by this method to determine the rigorous valley and ridge curves thermodynamically. In order to test the reliability of the proposed method, it has been applied to determine the valley and ridge for the system of acetone + chloroform + methanol, with a saddle point azeotrope at 101.3 kPa, and the details of the obtained curves are reported.