2-propanol Water Research Articles

Photocatalytic activity of visible light-responsive TiO2 thin films deposited on various anodized Ti-metal substrates by a RF magnetron sputtering method

Visible light-responsive TiO2 (Vis-TiO2) thin film has been deposited on two different kinds of anodized Ti-metal substrates, i.e., plate-type Titanystar (P-Titanystar) or non-woven fabric Titanystar (N-Titanystar) by a radio-frequency magnetron sputtering (RF-MS) method. These Vis-TiO2 thin film photocatalysts (Vis-TiO2/P-Titanystar and Vis-TiO2/N-Titanystar) showed high activity for the oxidation of 2-propanol in water under UV light irradiation while Vis-TiO2/N-Titanystar showed higher activity than Vis-TiO2/P-Titanystar. Furthermore, photocatalytic activity of Vis-TiO2/N-Titanystar was enhanced by the Pt deposition by an RF-MS deposition method. Pt loaded Vis-TiO2/N-Titanystar (Pt-Vis-TiO2/N-Titanystar) acted as an efficient photocatalyst for the oxidation of methanol vapor under UV light irradiation even in a flow system. Moreover, it was found that Pt-Vis-TiO2/N-Titanystar is an effective photocatalyst for the oxidation of various organic compounds in gas phase or ammonia gas even under visible light irradiation (λ > 420 nm) at 293 K.

Chemometric characterization of s-triazine derivatives in relation to structural parameters and biological activity

Objective: In this study 14 newly synthesized s-triazine derivatives were investigated by means of reversed-phase thin-layer chromatography (TLC) on C-18 stationary and five different mobile phases: acetone–water, acetonitrile–water, methanol–water, 2-propanol–water, and tetrahydrofuran–water. Methods: Principal component analysis (PCA) was performed to explore and visualize similarities and differences among the compounds and among the mobile phases. Observations from the PCA were supported using hierarchical cluster analysis (HCA). Results: Physicochemical parameters that are significant for activity, that is, absorption, distribution, and bonding for different receptors in target tissues were calculated. Conclusion: Highly predictive models, describing quantitative relationships between chromatographic retention and parameters that influence activity, were obtained using partial least squares (PLS) method.

Hydrogenation of 2-Butyne-1,4-diol Using Novel Bio-Palladium Catalysts

Palladium catalyst samples were prepared upon bacterial biomass supports (Gram-positive A. oxidans and Gram-negative R. capsulatus) and tested in the partial hydrogenation of 2-butyne-1,4-diol to 2-butene-1,4-diol. The objectives of the study were to assess the effects of operating conditions in the stirred autoclave upon the reaction conversion and selectivity and to compare the biologically supported palladium (BioPd) catalyst performance with that of a conventionally supported catalyst. Variables investigated included solvent, stirring speed, and catalyst metal loading. A maximum selectivity toward 2-butene-1,4-diol of 0.98 was observed in a solvent composed of 5% isopropyl alcohol (2-propanol) in water at a conversion of 75% 2-butyne-1,4-diol for the Pd/A. oxidans catalyst. The Pd/R.capsulatas catalyst showed a maximum selectivity of 1.0 at a conversion of 62.6%. Concentration profiles of the different hydrogenation products were fitted using a Langmuir−Hinshelwood expression, which showed a higher fitted adsorption constant of 2-butyne-1,4-diol in a 5% 2-propanol/water solvent, compared with pure 2-propanol, suggesting that adsorption is stronger in the mixed solvent. At a typical catalyst loading of 0.29 g/L (Pd/R. capsulatus), analysis of the mass-transfer steps in the reactor showed that ∼63% of the resistance to mass transfer lies at the catalyst (liquid−solid) particle and ∼37% lies at the gas bubble interface. BioPd was proven to be a highly selective catalyst for partial hydrogenation reactions and has the advantage that it can be prepared inexpensively from metal-waste-bearing solutions.

Synthesis of well-defined primary amine-based homopolymers and block copolymers and their Michael addition reactions with acrylates and acrylamides

A series of well-defined primary amine-based AB diblock copolymers were synthesised via atom transfer radical polymerisation (ATRP) using 2-aminoethyl methacrylate hydrochloride (AMA), with the other block comprising the following comonomers: 2-(diisopropylamino)ethyl methacrylate (DPA), 2-hydroxypropyl methacrylate (HPMA) and 2-(methacryloyloxy)ethyl phosphorylcholine (MPC). These copolymers were prepared with reasonably narrow polydispersities (Mw/Mn ≈ 1.1–1.4) in either 80 : 20 or 95 : 5 2-propanol–water mixtures at 50 °C using a 2-(N-morpholino)ethyl isobutyryl bromide initiator. The chain extension efficiency of PAMA was also investigated using a further charge of AMA. Unfortunately, such ‘self-blocking’ was problematic due to both catalyst deactivation and termination of the living chain ends. Nevertheless, low polydispersity all-methacrylic diblock copolymers were obtained in high yields via sequential monomer addition, provided that AMA was used as the second monomer in such syntheses. PAMA49 homopolymer and selected PAMA-based copolymers were reacted with various acrylates and acrylamides in aqueous solution at pH 9, with mean degrees of functionalisation being determined by 1H NMR spectroscopy. This facile Michael addition chemistry provides access to a library of novel functional water-soluble homopolymers and diblock copolymers.

Features of reaction of p-benzosemiquinone radicals with iron salts

In the present work we studied the reactions of para-benzosemiquinone radicals with Fe2(SO4)3 and Mohr’s salts at the flash-photolysis. These reactions were carried out in the aqueous-alcoholic solutions (the water–propanol ratio 9:1 by volume) with neutral and acidic (рН = 4.6) media. To avoid the influence of the changing ionic strength we used solutions containing sodium sulfate (0.1 М). To prevent the occurrence of additional dark reactions of oxidation and reduction at the use of Fe2(SO4)3 we used pbenzoquinone as a source of the semiquinone radicals, and with Mohr’s salt, hydroquinone. The pulse photoexcitation of hydroquinone or p-benzoquinone using a UFS-2 (280–350 nm) filter in the presence of the hydrogen donor (alcohol) leads to the formation of p-semiquinone radicals. At рН = 4.6 the semiquinone anion-radical Q– forms. These radicals are terminated not only as a result of the disproportionation, but they react with the bivalent iron to give hydroquinone and trivalent iron: At high concentrations of Mohr’s salt the kinetics of Q– disappearance adheres to the first order equation. The value K2 = 4.3×10 m s was calculated from the linear dependence between the effective constant and Mohr’s salt concentration. The semiquinone radicals QН are generated in the neutral medium. They disproportionate by themselves and also react with the biand trivalent iron: DOI: 10.1134/S1070363210010238

Liquid–liquid equilibrium of potassium/sodium carbonate + 2-propanol/ethanol + water aqueous two-phase systems and correlation at 298.15 K

Binodal data for 2-propanol + potassium/sodium carbonate + water systems and ethanol + sodium carbonate + water system were experimentally determined at 298.15 K, and the phase diagram was plotted. Three empirical equations were used to correlate binodal data. Base on the proposed equation with highest accuracy and lever rule, the phase equilibrium compositions for 2-propanol + potassium/sodium carbonate + water system were directly calculated by MATLAB. The Othmer–Tobias equation and the Bancroft equation were used to correlate tie-line data. The results indicate that the calculation method and corresponding tie-line data are reliable. The effect of salts on phase-separation was discussed. Salting-out coefficient and effective excluded volume of potassium carbonate and sodium carbonate in 2-propanol–water component solvent were calculated to evaluate the salting-out ability of salts. An effective excluded volume of sodium carbonate in ethanol/2-propanol–water component solvents was used to evaluate the phase-separation ability of investigated alcohols. Based on the experimental and calculated results, it can be concluded that sodium carbonate shows a higher salting-out ability than potassium carbonate and 2-propanol is easier to be excluded to the alcohol-rich phase than ethanol.

Synthesis and Color Evolution of Silica-Coated Hematite Nanoparticles

The aim of this communication is to investigate the color evolution of silica-coated hematite nanoparticles versus treating temperature. The silica-coated hematite nanoparticles were prepared by first suspending commercial hematite nanoparticles in an ammonia–water–2-propanol system, and then depositing amorphous nano-SiO2 onto the surface of hematite nanoparticles using the Stober method. The silica-coated nanoparticles were dripped onto biscuits and heat treated at various temperatures. The color changes of heat treated samples were determined by the CIE L*a*b* parameters, and the possible mechanism of color evolution was discussed.

Influence of ionic liquids on the separation factor of three standard separation problems

Vapor–liquid equilibria ( VLE) for the binary systems benzene–cyclohexane, 1-hexene– n-hexane and 2-propanol–water and the ternary systems with the ionic liquids 1-hexyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide [HMIM] +[BTI] − and 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide [BMPYR] +[BTI] − as entrainers were measured, to investigate the influence of ionic liquids on the separation factors. The experimental data were compared with the predicted results using mod. UNIFAC (Do). The predicted results are in good agreement with the experimental data.

Effect of Ag, Co and Cr deposit on the photocatalytic activity of titania-silica for the removal of 2-propanol in water

The influence of transition metals (Ag, Cr and Co) on the structural and photocatalytic properties of titania-silica prepared via both impregnation (imp) and photo-assisted deposition (PAD) methods has been investigated. The destruction of 2-propanol in the presence of UV-light was used to probe the effect of transition metals deposition on the activity of titania-silica. The PAD-Ag/TiO2-SiO2 was highly active, while, imp-Cr/TiO2-SiO2 showed a weakly tendency toward destruction of 2-propanol. By using a combination of various physicochemical techniques such as X-ray diffraction (XRD), diffuse reflectance UV-vis and transmission electron microscope (TEM) the products are characterised. XRD results revealed that titania anatase phase structure was remained after applying the PAD and imp methods. However, No peak from transition metal was observed, the data may imply that, the transition metals were well dispersed within the TiO2-SiO2 phase.

Viscosities of Binary and Ternary Mixtures of Water, Alcohol, Acetone, and Hexane

This articles studied and determined the viscosities of the binary mixtures of water–methanol, water–ethanol, water–propanol, water–acetone, acetone–ethanol, methanol–ethanol, and acetone–hexane and the ternary mixtures of water–methanol–ethanol and water–ethanol–acetone at 20°C. It is shown that the mixing of water with the alcohols and acetone resulted in a positive deviation of viscosity, which reached the maximum value at the water mole fraction x 1 ∼ 0.7 for water–methanol, x 1 ∼ 0.72 for water–ethanol, x 1 ∼ 0.74 for water–propanol, and x 1 ∼ 0.83 for water–acetone binary mixture. This viscosity deviation can be mainly attributed to the formation of micelles of alcohol or acetone molecules in water because of the hydrophobic attraction between the hydrocarbon chains. The micelle surfaces are surrounded by hydration layers, leading to the positive viscosity deviation in the liquid mixtures because the water in hydration layers has a much higher viscosity than bulk water. Also, the contrary observation was found in the binary mixtures of acetone–ethanol and acetone–hexane, having a negative viscosity deviation.

Preparation of hollow polylactide microcapsules through premix membrane emulsification—Effects of nonsolvent properties

Hollow polylactide microcapsules that can be used as ultrasound contrast agents were prepared using premix membrane emulsification. Polylactide/dichloromethane and dodecane solutions were emulsified together with a nonsolvent phase (water or a water–alcohol mixture) by repeated passage through a glass fibre membrane. The solvent, dichloromethane, diffuses out of the droplets and the polylactide solidifies around a droplet of dodecane. To investigate the effect of the nonsolvent properties on the size and span of the microcapsules, different methanol–water, ethanol–water and 2-propanol–water mixtures were used as nonsolvents. The alcohol lowers the interfacial tension and increases the viscosity of the nonsolvent, and therewith it decreases the size and the span of the microcapsules. It was remarkable that 2-propanol yields the smallest size (0.35 μm) followed by ethanol (0.8 μm) and methanol (1.4 μm). In contrast, the smallest span was obtained with methanol (0.7), whereas 2-propanol gave the largest span (1.5). The results further show that the size and the span of the microcapsules decreases with increasing number of emulsification passes and transmembrane flux. The presence of alcohol in the nonsolvent phase increases the efficiency of the emulsification process and decreases the optimum number of passes required to obtain the minimum average size of the droplets. A three-parameter correlation was defined that could quantitatively describe the effects of all the aforementioned parameters on the size of the microcapsules.

Separation of azeotropic mixtures of alcohols and water with FricDiff

FricDiff is an energy efficient separation process based on a difference in transport velocities of the components of a gas or vapor mixture when they diffuse through a sweep gas (‘enhancer’). The separation process takes place inside the pores of a non-selective macro-porous barrier. In this paper the separation of a 2-propanol–water mixture with the FricDiff-principle is studied, using CO 2 as the enhancer. A detailed numerical model is developed that describes the separation process that takes place inside a cylindrical FricDiff-unit. In this unit the vapor mixture to be separated and the sweep gas flow at opposite sides of a porous barrier in a counter current mode. Through the porous barrier selective mass transport of components of the feed mixture through the sweep gas takes place resulting in a separation. The model takes into account axial velocity profiles as a result of laminar flow of the gas and vapor mixtures through the flow channels, radial concentration gradients and radial velocities. The transport through the porous barrier is described with the Binary Friction Model. The influences of process conditions and the characteristics of the porous barrier on the separation process are studied.

4-(2,4,6-Trinitroanilino)benzoic acid

4-(2,4,6-Trinitro­anilino)benzoic acid (p-picramino­benzoic acid), C13H8N4O8, obtained by the reaction of 2,4,6-trinitro­benzene­sulfonic acid (picrylsulfonic acid) with 4-amino­benzoic acid in 2-propanol–water, forms a two-dimensional hydrogen-bonded network based on centrosymmetric cyclic R22(8) carboxylic acid dimers which are extended through lateral N—H⋯Ocarbox­yl inter­actions. The amino group also makes an intra­molecular N—H⋯Onitro hydrogen bond, while the two aromatic ring systems, are, as expected, non-coplanar, the C—C—N—C torsion angles being 152.0 (2) (picryl) and 136.1 (2)° (benzoic acid)..

Photodegradation of Perfluorooctane Sulfonate by UV Irradiation in Water and Alkaline 2-Propanol

Perfluorooctane sulfonate (PFOS) is the environmentally concerned compound because of its persistence and bioaccumulative properties. Since photodegradation of PFOS is not yet experimentally confirmed, photodegradation study of PFOS in water and alkaline 2-propanol solution was conducted. Aqueous and alkaline 2-propanol solution of PFOS (40 microM) was irradiated with a low-pressure mercury lamp (254 nm, 32 W) by internal irradiation for 10 d, and then PFOS, fluoride and sulfate ions, and the other degradation products were analyzed. Photodegradation of PFOS was confirmed in both media. PFOS was degraded by 8% after 1 day and by 68% after 10 days irradiation compared to the initial concentration in water. In alkaline 2-propanol, 76 and 92% of PFOS was degraded after 1 and 10 days irradiation, respectively. Photodegradation of PFOS in alkaline 2-propanol was much faster and effective than in water, as the photodegradation rate constants were 0.93 days(-1) in alkaline 2-propanol and 0.13 days(-1) in water, respectively. Formation of fluoride and sulfate was also confirmed by ion chromatography and X-ray diffraction analysis. From observation of the degradation products, two major degradation pathways of PFOS were considered: via C8HF17 and C8F17OH, respectively, resulting in short-chain fluorinated compounds such as C7HF15 and C7F15OH by stepwise removal of CF2. Formation of short-chain fluorocarbons such as CF4, C2F6, and C3F8 were also confirmed. This is the first study to confirm photodegradation of PFOS in water and alkaline 2-propanol.

Particle size control of a monodisperse spherical Y2O3:Eu3+ phosphor and its photoluminescence properties

A monodisperse spherical Y2O3:Eu3+ phosphor was prepared by a homogeneous precipitation method. The mean size of the phosphor particles (MSPP) was successfully controlled by changing the volume ratio of normal alcohol (RA) (propanol) in the solvents mixed between deionized water and normal propanol. When the RA was increased from 0 to 0.7, the MSPP decreased while maintaining a high yield of >95%. Although the prepared phosphor samples were fired at the same temperature, the thermal energy was delivered more efficiently into the inner side of the phosphor particles with the decrease of the MSPP. Therefore, the crystallinity and also the photoluminescence (PL) intensity of the phosphor increased with the decrease in the MSPP. In addition, because the numbers of Eu3+ ions located near the particle surfaces increased with the decrease of particle size, the ratio of PL intensity caused by the 5D0–7F2 transition to that caused by 5D0–7F1 transition increased from 10.8 to 12.7 with the decrease in MSPP.

Sub- and supercritical liquefaction of rice straw in the presence of ethanol–water and 2-propanol–water mixture

Abstract The critical liquefaction of rice straw to bio-oil with sub- and supercritical mixtures (ethanol–water and 2-propanol–water mixture) was studied in a 1000 ml autoclave at 533–623 K, 6–18 MPa, respectively. The results showed that the maximum yield of bio-oil was 39.7% for the 2-propanol:water volume ratio of 5:5 at 573 K, while the higher heating value (HHV) of bio-oil increased with the reaction temperature and solvent volume ratio. The formation of low-boiling-point materials was reduced by a mixture. Using a mixture could inhibit the formation of residue and then promote the conversion of rice straw with the ratio of 1:9–5:5. The bio-oil was analyzed by GC/MS and Elemental Analyzer, while the morphological changes of residue were observed by a scanning electron microscope (SEM).

Conductometric studies of interaction between anionic dyes and cetylpyridinium bromide in water–alcohol mixed solvents

The interactions between two anionic dyes and a cationic surfactant were studied by conductometric technique. The conductance of aqueous solutions of methyl orange (MO) and methyl red (MR) was measured in the presence of a cationic surfactant, cetylpyridinium bromide (CPB) at different temperatures in water–ethanol, water–propanol and water–butanol mixed solvents, containing different concentration of alcohols. The equilibrium constants and other thermodynamic functions for the process of dye–surfactant ion pair formation were calculated on the basis of a theoretical model. The results showed that the presence of alcohol, as well as increasing the length of the alcohol chain, decreases the tendency for ion pair formation. The results have shown that an increase in temperature lowers the tendency for ion pair formation as the equilibrium constants decrease with increasing temperature. According to the results, long range as well as short range interactions are responsible for the formation of the ion pair. The importance of long range electrical forces is basically to bring the dye anion and the surfactant cation close enough to enable the action of short range interactions whose contribution represents the major part of the standard free energy change for the formation of the anionic dye–cationic surfactant ion pair. By using the association constant ( K 1) for the first step of the association [ D − + S + → ( DS)°], the standard free energy change, standard enthalpy change, and standard entropy change of the association were calculated at low surfactant concentrations.

Simultaneous measurement of in situ bubble size and reaction rates with a heterogeneous catalytic hydrogenation reaction

The effect of solvent composition (water, 2-propanol and mixtures of the two) on the three phase, heterogeneously catalysed, two-step hydrogenation of 2-butyne-1,4-diol on Pd/alumina was investigated in a stirred reactor and for the first time, bubble sizes were measured in situ simultaneously with reaction rates. The first step forming the alkene is slow and gas–liquid mass transfer limitation is unlikely whilst the second step to alkane is much faster and may be mass transfer dominated. Overall, reaction rates displayed a complex relationship with solvent composition. The smallest bubbles where observed with 5% v/v 2-propanol in water and under gas–liquid mass transfer limited conditions (energy dissipation rates < 4 W / kg ), the overall reaction closely follows the ratio of mean bubble diameter to hydrogen solubility, both of which are a function of solvent. Overall, the solvent 5% v/v 2-propanol/water gave faster reactions combined with good selectivity compared to the others and is therefore recommended.

What is a green solvent? A comprehensive framework for the environmental assessment of solvents

Solvents define a major part of the environmental performance of processes in chemical industry and also impact on cost, safety and health issues. The idea of “green” solvents expresses the goal to minimize the environmental impact resulting from the use of solvents in chemical production. Here the question is raised of how to measure how “green” a solvent is. We propose a comprehensive framework for the environmental assessment of solvents that covers major aspects of the environmental performance of solvents in chemical production, as well as important health and safety issues. The framework combines the assessment of substance-specific hazards with the quantification of emissions and resource use over the full life-cycle of a solvent. The proposed framework is demonstrated on 26 organic solvents. Results show that simple alcohols (methanol, ethanol) or alkanes (heptane, hexane) are environmentally preferable solvents, whereas the use of dioxane, acetonitrile, acids, formaldehyde, and tetrahydrofuran is not recommendable from an environmental perspective. Additionally, a case study is presented in which the framework is applied for the assessment of various alcohol–water or pure alcohol mixtures used for solvolysis of p-methoxybenzoyl chloride. The results of this case study indicate that methanol–water or ethanol–water mixtures are environmentally favourable compared to pure alcohol or propanol–water mixtures. The two applications demonstrate that the presented framework is a useful instrument to select green solvents or environmentally sound solvent mixtures for processes in chemical industry. The same framework can also be used for a comprehensive assessment of new solvent technologies as soon as the present lack of data can be overcome.

Design of new systems for transfer hydrogenolysis of polychlorinated aromatics with 2-propanol using a Raney nickel catalyst

A multipurpose study deals with the transfer hydrogenolysis of 1,3,5-trichlorobenzene to benzene in the 2-propanol–Raney nickel system in the presence of KOH. At 70°C, no reaction occurs without KOH or with weaker bases, e.g. amines or poorly soluble inorganic bases; however saturated KOH as well as water over 1% suppress the reaction rate, presumably due to the competitive adsorption of these species on the catalyst. The catalytic activity also drops with time because of the deposition of the solid KCl on the catalyst but can be recovered at washing the catalyst with water. The deactivation by KCl can be mitigated with the addition of promoters, e.g. quaternary ammonium salts (Aliquat 336, CTAC) or trioctylamine. Aliquat 336 also promotes hydrodechlorination in the hydrothermal system using a 10% solution of 2-propanol in water, Raney nickel and potassium carbonate as base at 150–200°C and 10–20bar. Under these conditions, hexachlorobenzene was also selectively dechlorinated to benzene.