The effect of physiologically relevant additives on the rheological properties of concentrated Pluronic copolymer gels

The high concentration triblock copolymer poly(ethylene oxide)₉₉-poly(propylene oxide)₆₉-poly(ethylene oxide)₉₉ (Pluronic F127) aqueous solutions with the addition of different components commonly used in physiologically relevant applications were characterized by rheological measurements, differential scanning calorimetry (DSC) and small angle X-ray/neutron scattering. The sol-gel transition temperature, as well as the storage modulus of the F127 solution depend both on the concentration of polymer and of clay. Above the gel transition, the storage modulus of the solutions increased with clay concentration. Yield strain is independent of polymer and clay concentrations. Two different kinds of inorganic salts, sodium chloride (NaCl) and calcium chloride (CaCl₂) were added into the polymer and polymer-clay solutions. The sol-gel transition temperature decreased noticeably, but the storage modulus decreased only a small amount with increasing concentration of inorganic salts. Addition of salts to polymer-clay solutions resulted in precipitation of the clays which decreased the modulus. No effect on the mechanical properties was observed with the addition of common serum proteins. However, addition of 0.5-10% glucose decreased the transition temperature between 3° and 7°, without significantly affecting the modulus. The depression of the transition temperature by glucose was similar to that found with salts and indicated that the mechanism, namely competition for water, may be similar.     

Synthesis of Quaternary Ammonium Salts with Novel Counterions

The preparations of quaternary ammonium compounds from various tertiary amines and the (environmentally friendly) alkylation agent dimethyl carbonate were carried out. The effects of reaction temperature, reaction time, material mol ratio and solvent dosage on quaternization were examined, and the optimum reaction conditions were determined. Under the optimum conditions, the conversions of mono-alkyl tertiary amines could attain over 99%, while the conversions of di-alkyl tertiary amines reached over 95%. Moreover, a series of quaternary ammonium salts with new counterions (HCO₃, CH₃COO, CH₃CH₂COO, CH₃CH(OH)COO) were synthesized by the hydrolysis of methyl carbonate quaternary ammonium salts or by ion exchange reaction of methyl carbonate quaternary ammonium salts with corresponding acids.     

Proline‐Catalyzed Asymmetric Aldol Reaction in Guanidine‐ Derived Ionic Liquids

A remarkable improvement of both the chemical yield (from 6% to 82%) and the enantiomeric excess (up to >99%), of (S)‐proline catalyzed direct aldol reactions of a wide range of aldehydes with acetone was found when hexasubstituted or pentasubstituted guanidinium salts were added as ionic liquids. Effects of temperature, amount of proline and the type of guandidinium salts on the outcome of the reaction were investigated.     

Effects of imidazolium salts as cocatalysts on the copolymerization of CO2 with epoxides catalyzed by (salen)CrCl complex

Imidazolium salts, most of which are room temperature ionic liquids (ILs), have been introduced as effective and tunable cocatalysts in the copolymerization of CO₂ with epoxides catalyzed by (salen)Cr^IIICl complex for the first time. Effects of imidazolium salts with different alkyl chains as well as with different anions on the copolymerization were investigated. The results showed that the copolymerization was influenced obviously by the property of anion. In addition, the cation of imidazolium salts with longer alkyl chain length such as n-dodecyl (TOF, 242.5 h⁻¹, carbonate linkages > 99%) displays better activities and selectivity in the copolymerization as compared with N-MeIm (TOF, 72.5 h⁻¹, carbonate linkages 94%). These results are instructive for further design of task-specific ILs as effective cocatalysts to improve the copolymerization of CO₂ with epoxides.     

Removal of phosphate from wastewaters

Gas concrete waste was used to remove phosphate from aqueous solutions in this study. The influence of suspension pH, temperature, mixing rate, and gas concrete dosage on phosphate removal was investigated by conducting a series of batch adsorption experiments. In addition, the yield and mechanisms of phosphate removal were explained on the basis of the results of X-ray spectroscopy, measurements of zeta potential of particles, both values of BET-N₂ specific surface area, and images of scanning electron microscopy (SEM) of the particles before and after adsorption. In this study, phosphate removal in excess of 99% was obtained and it was concluded that wastes of gas concrete are an efficient adsorbent for the removal of phosphate. The removal of phosphate predominantly takes place by precipitation mechanism and the weak physical interactions between the surface of adsorbent and the metallic salts of phosphate.     

Thermal behavior of blends based on high-molecular polyoxyethylene and salts from seawater and sea lye

The purpose of this study was to increase the thermooxidative stability and flow of high-molecular polyoxyethylene (HMPOE) by introducing readily available, technologically convenient, and economical additives. Binary systems consisting of HMPOE with mean viscosity molar mass M _v = 3,2.10⁶ g.mol⁻¹ and inorganic salts from both the seawater and sea lye and, also, MgCl₂ of concentration from 1 to 10 mass % with respect to HMPOE, were prepared. The thermal behavior of these systems was studied by using dynamic thermal analysis, dynamic viscometry, and melt index determination. The presence of salts of concentrations from 3 up to 10 mass % in HMPOE was found to increase the temperatures of initial thermooxidative decomposition of the polymer. At the same time, the degree of viscosity reduction (−Δη, %) corresponding to lowering the average molar mass after the heat treatment for 20 h at 150°C decreased. Another effect of the salts was found to be the increased melt flow of HMPOE above 250°C. The best stabilizing effect was obtained in the presence of salts in sea lye and, also, MgCl₂. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 995–999, 1998     

Metathesis of Ionic Liquids: Continuous Ion Exchange by Donnan Dialysis

Ionic liquids (IL) are salts that have extraordinary low melting points below 100 °C. While only a very limited number of possible IL can be synthesized directly, the vast majority is prepared via the synthesis of a precursor IL with the desired cation and a subsequent anion exchange. This paper presents the continuous anion exchange by Donnan dialysis in aqueous solution with anion exchange membranes. The retention of the anion exchange membranes used in this work for inorganic and IL cations was found to be R > 99 %. The average integral transport coefficients were determined for the exchange of chloride/acetate, chloride/hydroxide and bromide/hydroxide for various IL and classical salts. The values of the integral average transport coefficients were found to be independent of the investigated counterions. Process modeling was applied to optimize the flow conditions to reach an anion exchange > 98 %. Ultrapure hydroxide solutions and acetates of common classes of IL cations were prepared with a conversion of the reactant anions of > 99 % and cationic impurity contents of < 1 %.     

Effect of blended inorganic salts containing negative hydration ions on hydration and properties of alkali-activated slag cement

Water glass (WG) is generally considered to be the most effective activator to prepare alkali-activated slag (AAS) cement in terms of strength and durability. However, the rapid setting and hardening of WG activated slag results in rapid loss of fluidity of AAS concrete mixture, which limits its engineering application. In the paper, the effect of blended inorganic salts containing negative hydration ions on the fluidity, setting time and mechanical strength of AAS cement was studied. The hydration process and hydration products were used to explore the action mechanism. Ba(NO₃)₂ greatly delayed the hydration of AAS cement. The four inorganic salts (KCl, KNO₃, KBr and NaCl) blended with a small amount of Ba(NO₃)₂ can improve both the initial fluidity and fluidity retention, and a wide setting time range can be obtained to meet engineering requirements. The compressive strength decreased with the increase of inorganic salts. The incorporation of inorganic salt did not change the composition of the main hydration products. Considering the fluidity required by construction, mechanical properties and the durability of structure, it is recommended to add 4%–5% KBr or KNO₃ blended with no more than 0.2% Ba(NO₃)₂ into AAS cement.     

A novel Fe(III) salt-catalyzed monoterpene aerobic oxidation in methyl alcohol

The Fe(III)-catalyzed aerobic oxidation of monoterpenes in CH₃OH has been developed, in which simple Fe(III) salts are used as catalysts in the absence of stabilizing ligands. Remarkably, Fe(NO₃)₃ catalyst efficiently promotes the oxidation of monoterpenes under air or dioxygen. The highest TON and TOF reached 476 and 162 h^− 1, respectively. In general, reactions with 1.0–9.0 mol% of catalyst reached high conversions (ca. 90–99%) and high oxidation products selectivity (ca. 80%). Notably, α-pinene and β-pinene were selectively oxidized into only allylic product, myrtenol methyl ether. The significant breakthroughs of this simple oxidative process are the use of inexpensive Fe(III) salts as catalysts and environmentally-friendly oxidants (air or dioxygen).     

Mechanical and thermal properties of 99% and 92% alumina at cryogenic temperatures

In the present paper, mechanical properties with respect to bending strength and fracture toughness of 99% and 92% Al₂O₃ at ambient and cryogenic temperatures (293 K, 195 K and 77 K) were measured with four-point bending method and SENB method respectively. It shows that the bending strength of both 99% and 92% Al₂O₃ seemed not to depend on temperature and with decreasing temperature there was a slight increase in the fracture toughness of 99% Al₂O₃ at 77 K but that of 92% Al₂O₃ remained almost unchanged with measurement uncertainties taken into account. It was also discovered that the reduction in the fracture toughness of glass phases in grain boundary had a negative effect on the improvement in that of α-Al₂O₃, thus the resultant toughness at 77 K appears not to increase as 99% Al₂O₃ does. On basis of qualitative analysis of phase compositions by XRD, the decrease in temperature down to 77 K did not result in any phase transformation of which the cryogenic mechanical properties are independent. The thermal conductivity of 99% and 92% Al₂O₃ was 4.1 W/(m K) and 1.7 W/(m K) at 20 K, respectively, much lower than that of stainless steel. Simultaneously alumina, whose thermal expansion is low between 123 K and 170 K, can be stable enough to temperature changes. Alumina ceramics, therefore, can be candidate materials for cryogenic application.     

5-硝基水杨醛分离纯化方法改良

对 5 硝基水杨醛的分离提纯方法进行了改良研究 ,发现加入一定量的稀碱使 3 和 5 硝基水杨醛均完全转变成钠盐是实验成功的关键。进而利用两种钠盐在水中溶解度的差异 ,采用水抽提方法 ,先将 3 和 5 硝基水杨醛的钠盐以溶液形式分离开 ,再分别经酸化及重结晶处理 ,即得产率为 5 8 0 %的 5 硝基水杨醛 ,纯度经HPLC测定为 99 4 % ,其结构经元素分析、红外、紫外、核磁等确证。同时还得到产率为 35 0 %的 3 硝基水杨醛。     

Microemulsions with excellent water solubilizing capacity at high hydrocarbon levels with quaternary ammonium salts as surfactants

In W/O microemulsions prepared by adding dry surfactant to a mixture of 85% heptane or toluene and 15% pentanol, then titrating with water, systems using quaternary ammonium salts have been shown to be capable of solubilizing much larger amounts of water than systems using the anionic sodium dodecyl sulfate. In homologous series in the range C₁₂ to C₁₆ it would appear that, with one exception, longer chain length quaternary salts are more effective at solubilizing water than are shorter chain length compounds. With quaternary salts of equal chain length, pyridinium salts are more effective at solubilizing water at high surfactant concentrations than are corresponding trimethyl salts.     

Partitioning Behavior of Tetracycline in Hydrophilic Ionic Liquids Two-Phase Systems

Ionic liquids-based aqueous two-phase system (ILs-ATPS) offers an alternative approach for the extraction of tetracycline (TC) through their partitioning between two phases. The procedure was composed of 1-butyl-3-methylimidazolium halide ([Bmim]X(X = Cl, Br)) and K₂HPO₄ using a liquid-liquid extraction technique. The influence factors on partition behavior of TC were optimized systematically, including the quality of salts and IL, the amount of TC, pH value, and temperature. The maximum extraction efficiency of TC could reach 99%. The interactions between the ATPS and TC have been examined by isothermal titration calorimetry. Extraction of antibiotics TC using ILs-ATPS could achieve nearly complete extractions in a single-step by way of the proper tailoring of their concentrations in the aqueous media.     

Hypercrosslinked polymers incorporated with imidazolium salts for enhancing CO2 capture

Hypercrosslinked polymers (ILHCPs) incorporated with imidazolium salts were prepared using 4‐vinylbenzyl chloride, divinylbenzene, and imidazole ionic liquid monomers with various alkyl groups and anions by free radical copolymerization and Friedel‐Crafts alkylation reaction. The structures of ILHCPs were characterized by using FT‐IR, solid state ¹³C CP/MAS NMR spectroscopy, TGA, and gas adsorption. ILHCPs exhibit excellent capability of CO₂ adsorption compared with that of nonfunctional hypercrosslinked polymers (HCPs), although both the BET surface area (447–667 m²/g) and pore volume (0.24–0.28 cm³/g) of ILHCPs are less than HCPs. The synergistic effect from mirco/mesopore structures and imidazolium salts are proved to play a key role in enhancing the CO₂ adsorption capability and selectivity over other gases for ILHCPs. It can be found that the imidazolium salts content in HCPs is more important compared with the pore texture for adsorbing CO₂. An optimal molar content of imidazolium salts groups is found to be 10.5% with the maximum CO₂ uptake capability of 7.56 wt% and best CO₂ adsorption selectivity (CO₂/N₂) of 47.9/1 (273 K, 1 bar), while those of the HCPs are only 5.93 wt% and 27.9/1. Such results strongly suggest that ILHCPs can be promising applied in selective CO₂ separation. POLYM. ENG. SCI., 56:573–582, 2016. © 2016 Society of Plastics Engineers     

Solvent effects in the oxidation of sulphur compounds. Anionic oxidation of high molecular weight thiols and disulphides to sulphonate salts

The base-catalysed oxidation of high molecular-weight aliphatic thiols and disulphides to sulphonate salts by molecular oxygen has been studied from 23.5° to 80°. The preferred solvent was hexamethylphosphoramide. Generally, yields and selectivities of the sulphonate salts varied from 95 to 99% at 80°. Potassium and sodium hydroxides were equally effective as the base catalysts. Other solvents and bases were explored and factors which control selectivity to the final product determined. The reactions are believed to involve sulphenate ions produced by attack of hydroxide ion on the disulphide linkage. Such species are unstable and may be oxidised directly by oxygen or disproportionate to sulphonate ions and disulphides.     

Reverse Osmosis Separation of Metal Ions in Acid Mine-Water

Abstract

Cellulose acetate membranes obtained from Osmonics Inc. were characterized in terms of pure water permeability constant, solute transport parameter, and mass transfer coefficient with the reference system of aqueous sodium chloride solution. Reverse osmosis separation behavior of Ca, Mg, Zn, Mn, Cu, Al, and Fe as nitrate, chloride, and sulfate salts was studied. The effect of the addition of sodium sulfate to Mg(ClO₄)₂ and Mn(NO₃)₂ solutions on solute separation was also investigated. Acid mine-water obtained from New Brunswick was subjected to reverse osmosis, and separation of metal ions in the range of 95 to 99 % was obtained along with the recovery of product water of suitable quality for use in recycle operations.     

Evaluation of a modified spray-applied interfacial polymerization method for preparation of nanofiltration membranes

Nanofiltration (NF) membranes were fabricated by using piperazine (PIP) and trimesoyl chloride (TMC) by conventional and spray-applied interfacial polymerization methods, studying the effect of the application method for both phases, the number of applied layers, and the displacement speed for the spray application. A polysulfone ultrafiltration membrane was used as support. NF membranes were characterized by different spectroscopic, microscopic, and physicochemical techniques. Rejection capacity was evaluated for sodium chloride (NaCl), sodium sulfate (Na₂SO₄), and magnesium sulfate (MgSO₄) salts; the decreasing rejection order was Na₂SO₄ > MgSO₄ > NaCl for each NF membrane. NF membrane prepared with one layer of the sprayed out TMC solution and conventional application of PIP solution exhibited the highest salt rejection (99% for 1000 ppm Na₂SO₄) and a permeated flux of 10.28 L m⁻² h⁻¹ at 0.55 MPa. The modified method is a facile-reproducible preparation methodology that reduces the consumption of time, effort, and reagents leading to a scalable manufacturing process for separation technology. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48129.     

Deactivation of Pt/wire-mesh and vanadia/monolith catalysts applied in selective catalytic reduction of NO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> in flue gas

In this study the deactivation of Pt/wire mesh and vanadia/monolith catalysts by aerosol particles of some inorganic salts (K₂SO₄, KCl and ZnCl₂) with high or low melting points has been investigated. The aerosol particles may either diffuse within the matrix of the catalysts and block the mezzo and micro pores, or deposit on the outer surface of the catalysts and form a porous layer causing a mass transfer resistance that ultimately deactivates the catalysts. It has been observed that in both Pt/wire mesh and vanadia/monolith catalysts the deactivation effect of ZnCl₂ was more pronouced compared to other salts. As an example, after 31 hours of exposure to ZnCl₂, 10% of the catalysts activities was lost. This may be related to the ZnCl₂ lower melting point in comparison with other poisons. These results are in agreement with the previous findings for deactivation of wire-mesh catalysts used for oxidation of volatile organic compounds (VOC) and CO by exposing the catalysts to the aerosols generated from inorganic salts.     

复合碱、盐多元驱各组分对油水界面张力和稠油黏度的影响

无机盐,混合碱NaOH、Na2CO3,阴离子表面活性剂十二烷基苯磺酸钠(LAS)、脂肪醇聚氧乙烯醚硫酸钠(AES),聚合物聚丙烯酰胺(PAM),经过混合组成多元驱。通过实验探讨了该多元驱中各个组分的用量对油水界面张力和稠油黏度的影响,优化了该多元驱中各个组分的含量。实验得出,无机盐的加入可以显著地降低界面张力和稠油黏度。当多元驱中无机盐、混合碱和表面活性剂的质量分数分别为51.87%,40.17%,6.99%,聚合物质量浓度为800 mg/L,配成质量分数为1%的水溶液,加热到50℃,油水质量比7∶3混合后,可使新疆克拉玛依地区红浅稠油黏度从23690 mPa.s降到84.83 mPa.s,降黏率达到99.64%,体系界面张力达到0.07499mN/m。室内评价表明,该多元驱可使新疆克拉玛依地区9#红浅稠油降黏率达到92%。多元驱中无机盐的质量分数超过50%,大大降低了成本。     

Extractable metal salts of carboxylic acids in Green River oil shale

A study of solvent-extractable metal salts of carboxylic acids from Colorado Green River oil shale is presented. Sodium was found to be the most abundant cation present in these acid metal salts. Identification of individual components is based on combined gas Chromatographic and mass spectrometric results obtained for their respective volatile methyl esters. Normal acid salts (C₁₁ to C₃₄), isoprenoid acid salts (C₁₅ to C₁₇, C₁₉ to C₂₂), nonisoprenoid branched acid salts (C₁₄ to C₁₉), terpenoid acid salts (C₃₀ to C₃₂), and α,ω-dicarboxylic acid salts (C₁₁ to C₂₉) were identified. Small concentrations of cyclohexyl acid salts and aromatic acid salts were also found. The high even-odd predominance for the distribution of normal acid salts indicates a mild thermal history for Green River oil shale. Some acid salts (45.6 wt%) were not identified because of nonvolatility of their methyl esters.