Liquid–Solid Phase Diagrams of PrOH–Water and BuOH–Water Systems from Differential Scanning Calorimetry

The freezing process in i-PrOH- and tert-BuOH-water systems were investigatedto obtain reliable liquid=nsolid phase diagrams by differential scanning calorimetry(DSC), especially focusing on formation of metastable solid phases. In addition,n-BuOH, sec-BuOH, and i-BuOH were studied within their solubility limits. Inmost systems studied, there exist metastable solid phases and, with increasingbranching of alkyl groups, the number of metstable solid phases increases. Themost complicated is i-PrOH-water where curious phenomena were found,probably because of the abnormally high viscosity of the solution at low temperatures.The relation between hydration in the liquid and formation of solid phases isdiscussed. It is suggested that the positional relation between methyl groups andalcoholic OH groups plays an important role; the increase in number ofalphamethyl group seems to strengthen hydration and stabilizes solid hydrates.     

Determination of Cotinine in Urine by Molecularly Imprinted Polymer Solid Phase and Liquid–Liquid Extraction Coupled with Gas Chromatography

A comparison between molecularly imprinted solid phase extraction (MISPE) and liquid–liquid extraction (LLE) was performed for cotinine in human urine followed by gas chromatography analysis. The molecularly imprinted polymer (MIP) was synthesized via bulk methodology employing cotinine, methacrylic acid, and ethylene glycol dimethacrylate as template, functional monomer, and cross-linker, respectively. Both methods were validated with good precision and accuracy. The LLE method (limit of quantification = 10 nanograms per milliliter) was slightly more sensitive than the MISPE (limit of quantification = 15 nanograms per milliliter) procedure, but both methods were able to determine cotinine at typical concentrations in urine. An important advantage of the molecularly imprinted polymer approach was its ability to be reused up to at least 100 times. Other advantages of the MISPE include simple manipulation, low solvent consumption, and low worker exposure.     

Magnetic Solid Phase Extraction Based on Modified Magnetite Nanoparticles Coupled with Dispersive Liquid–Liquid Microextraction as an Efficient Method for Simultaneous Extraction of Hydrophobic and Hydrophilic Drugs

In this work, surfactant-coated Fe₃O₄@decanoic acid nanoparticles was synthesized as a viable nanosorbent for coextraction of drugs with different polarities (hydrophobic, hydrophilic). To reach desirable enrichment factors, efficient clean-up and low limits of detection (LODs), the method was combined with dispersive liquid–liquid microextraction (DLLME). The coupling of these extraction methods with GC-FID detection was applied to simultaneous extraction and quantification of venlafaxine (VLF) as a hydrophilic model drug and desipramine (DESI) and clomipramine (CLO) as hydrophobic model drugs in urine samples. The effect of sample pH, nanosorbent amount, sorption time, surfactant concentration, eluent type, eluent volume, salt content, elution time in magnetic solid phase extraction step and extraction solvent and its volume along with sample pH in DLLME step were optimized. Under the selected conditions, linearity was achieved within the range of 5–5000 µg L^?1. The LOD values were obtained in the range of 1.5–3.0 µg L^?1 for DESI, 1.2–2.5 µg L^?1 for VLF and 2.0–4.0 µg L^?1 for CLO, respectively. The percent of extraction recoveries and relative standard deviations (n?=?5) were in the range of 82.4–95.9 and 6.1 for DESI, 60.5–92.8 and 6.9 for VLF and 57.2–58.0 and 5.5 for CLO, respectively. Ultimately, the applicability of the new method was successfully confirmed by the extraction and quantification of DESI, VLF and CLO from human urine samples.     

Solid–Gas Phase Synthesis of Coordination Networks by Using Redox-Active Ligands and Elucidation of Their Oxidation Reaction

Formation of coordination networks is a complex process affected by a multitude of factors. Many synthetic strategies have been developed that attempt to control these factors and direct the structure of the final product. Coordination bond formation and structural assembly processes, however, typically take place either in the solution or solid states. In comparison, gas-phase network synthesis remains largely unexplored. Herein, two new two-dimensional coordination networks are obtained from the solid–gas phase reaction between ZnX₂ (X=I, Br) and the redox-active 2,5,8-tri(4-pyridyl)1,3-diazaphenalene (HTPDAP) ligand. Their structures were solved by ab initio powder X-ray diffraction analysis and feature a novel Zn halide trimeric cluster. This strategy is contrasted with a conventional solvothermal synthesis, which led to a one-dimensional coordination polymer instead. The intrinsic electroactive properties of these materials were probed by solid-state cyclic voltammetry measurements, which revealed the presence of HTPDAP and halide-based processes. Chemical oxidation of the two-dimensional networks by using NOPF₆ agent, unexpectedly, led to the formation of a nitrated analog of HTPDAP, the PF₆⁻ salt of diprotonated 4,6,7,9-tetranitro-2,5,8-tris(4-pyridyl)diazaphenalene cation (denoted N-TPDAP), which was isolated and characterized. These results provide deeper insights into the oxidation process of HTPDAP-containing networks and uncover unique redox-induced chemical transformations.     

Determination of BTEX Compounds in Solid–Liquid Mixing Paint Using the Combination of Solid Phase Extraction,Thermal Desorption and GC-FID

A novel method was developed and validated for determination of benzene, toluene, p-xylene, m-xylene, o-xylene (BTEX) in a solid–liquid mixing matrix. It makes use of solid phase extraction and thermal desorption (SPE-TD), followed by gas chromatographic flame ionization detector analysis (GC-FID). The trapped BTEX can be measured directly after thermal desorption onto the stainless-steel packed chromatographic column. The effect of tailing area of solvent was removed with the use of SPE-TD technique, and the result shows good reproducibility with very little matrix dependency. The study also supports that the lifetime of the Tenax adsorption tube could be extended over 150 desorption operation at 200 °C, which enables performing excellent stability and reproducibility of BTEX analysis.

     

Preparation of ZnSe Nanoparticles via Low‐Temperature Solid Phase Process

ZnSe nanoparticles were prepared from ZnCl₂, Se and KBH₄ in the presence of cetyltrimethyl ammonium bromide (CTAB) through a room temperature solid phase process. The products were characterized with x‐ray diffraction (XRD), transmission electron microscope (TEM), and energy dispersive analysis of x‐ray (EDAX). The results show that the cubic zincblende phase ZnSe nanoparticles can be obtained using this simple method. The size of nanoparticles was evaluated to be from 8 to 30 nm.     

Solid Supported Liquid–Liquid Extraction of Chemical Warfare Agents and Related Chemicals from Water

Solid-supported liquid–liquid extraction was optimized to extract the chemical warfare agents and their non-toxic analogues from water. The developed method was compared to the conventionally used liquid–liquid extraction. This method yielded high recoveries (70–80%) of non-toxic analogues of chemical warfare agents and good recoveries (65–75%) of the nerve agent sarin and Lewisite-III. The limits of detection of non-toxic analogues of CWAs, and toxic sarin and Lewisite-III, in selected ion monitoring and full scan mode, varied from 0.01 to 0.5 μg mL^?1 and 0.1 to 1.0 μg mL^?1 respectively.     

Monitoring the Phosphorylation of Phenol Derivatives with Diethyl Chlorophosphate in Liquid–Liquid and Solid–Liquid Phase by In Situ Fourier Transform Infrared Spectroscopy,Part II

The reaction of 4-chlorophenol and 4-nitrophenol with diethyl chlorophosphate carried out in a liquid–liquid and solid–liquid two phase system, respectively, was monitored by in situ Fourier transform IR spectroscopy.     

Solid–Liquid Phase Alkylation of N-Heterocycles: Microwave-Assisted Synthesis as an Environmentally Friendly Alternative

The solid–liquid phase alkylation of a variety of five-membered N-heterocycles (carbazole, imidazole, benzimidazole, and indole-3-carbaldehyde) was carried out under different conditions. The use of alkali carbonate in dimethylformamide or in MeCN (in the latter case, in the presence of a phase-transfer catalyst) is a suitable method to prepare the corresponding N-alkylated products in an efficient way. In most cases, the solventless, microwave-assisted reaction is an environmentally friendly alternative to traditional methods.     

Preparation of Pt／C Catalyst with Solid Phase Reaction Method

The Pt/C catalyst was prepared with solid phase reaction method (Pt/C(S)) for the first time.Its Performances were compared with that prepared by the traditional liquid phase reaction method. The results demonstrate that the electrocatalytic activity of Pt/C catalyst with solid phase reaction method for methanol oxidation is higher than that with liquid phase reaction method. XRD and TEM measurements indicate that the Pt/C(S) possesses low crystalline extent and small particle size.     

Transient and Dissipative Host–Guest Hydrogels Regulated by Consumption of a Reactive Chemical Fuel

The transient self-assembly of molecules under the direction of a consumable fuel source is fundamental to biological processes such as cellular organization and motility. Such biomolecular assemblies exist in an out-of-equilibrium state, requiring continuous consumption of high energy molecules. At the same time, the creation of bioinspired supramolecular hydrogels has traditionally focused on associations occurring at the thermodynamic equilibrium state. Here, hydrogels are prepared from cucurbit[7]uril host–guest supramolecular interactions through transient physical crosslinking driven by the consumption of a reactive chemical fuel. Upon action from this fuel, the affinity and dynamics of CB[7]–guest recognition are altered. In this way, the lifetime of transient hydrogel formation and the dynamic modulus obtained are governed by fuel consumption, rather than being directed by equilibrium complex formation.     

Improved Protocol for Thorpe Reaction: Synthesis of 4‐Amino‐1‐arylpyrazole using Solid–Liquid Phase‐Transfer Conditions

Solid–liquid phase‐transfer conditions were employed for the first time in the Thorpe reaction to synthesize 4‐amino‐1‐aryl‐3,5‐substituted‐1H‐pyrazoles 3. Aryl amines were diazotized and coupled with various active methylene compounds such as cyano acetamide, cyanoacetophenone, malononitrile, and ethyl cyanoacetate, resulting into α‐arylhydrazononitriles 1. Cyclization of 1 using α‐bromo ketones or esters resulted in compounds 3.     

Boosting the “Solid–Liquid–Solid” Conversion Reaction via Bifunctional Carbonate-Based Electrolyte for Ultra-long-life Potassium–Sulfur Batteries

Potassium–sulfur (K−S) batteries have attracted wide attention owing to their high theoretical energy density and low cost. However, the intractable shuttle effect of K polysulfides results in poor cyclability of K−S batteries, which severely limits their practical application. Herein, a bifunctional concentrated electrolyte (3 mol L⁻¹ potassium bis(trifluoromethanesulfonyl)imide in ethylene carbonate (EC)) with high ionic conductivity and low viscosity is developed to regulate the dissolution behavior of polysulfides and induce uniform K deposition. The organic groups in the cathode electrolyte interphase layer derived from EC can effectively block the polysulfide shuttle and realize a “solid–liquid–solid” reaction mechanism. The KF-riched solid-electrolyte interphase inhibits K dendrite growth during cycling. As a result, the achieved K−S batteries display a high reversible capacity of 654 mAh g⁻¹ at 0.5 A g⁻¹ after 800 cycles and a long lifespan over 2000 cycles at 1 A g⁻¹.     

Solid — Liquid Phase — Transfer Catalytic Method for N-Alkylation of Nitroimidazole

A variety of 1 — alkyl — 2 — methyl — 4 — nitroimidazoles have been synthesized with a solid—liquid phase—transfer catalytic method in excellent yield     

Calculation of the Liquid–Solid Phase Diagram and the Thermodynamic Quantities of the Binary System of Tetradecane and Hexadecane Using the Mean Field Theory

Journal of Solution Chemistry - The T???x phase diagram of a binary system of tetradecane?+?hexadecane is calculated using the Landau phenomenological model....     

A Solid Phase Synthesis of Chalcones by Claisen-Schmidt Condensations

In previous papers1,2, we reported our recent findings that chalcone (l,3-dipheny1-2-propen-1-one) derivatives are novel potential antimalarials that are active against chloroquine-resistant strains of Plasmodium falciparum. According to our structure-activity relationships (SAR) and computer modeling data1,2, we expect the chalcone derivatives with hydroxyl functionality on one of the aromatic rings and with some other appropriate substitutions on the other ring will be even more potent as a…     

Evidence of Structure Sensitivity in the Fischer–Tropsch Reaction on Model Cobalt Nanoparticles by Time-Resolved Chemical Transient Kinetics

The Fischer–Tropsch process, or the catalytic hydrogenation of carbon monoxide (CO), produces long chain hydrocarbons and offers an alternative to the use of crude oil for chemical feedstocks. The observed size dependence of cobalt (Co) catalysts for the Fischer–Tropsch reaction was studied with colloidally prepared Co nanoparticles and a chemical transient kinetics reactor capable of measurements under non-steady-state conditions. Co nanoparticles of 4.3 nm and 9.5 nm diameters were synthesized and tested under atmospheric pressure conditions and H₂/CO=2. Large differences in carbon coverage (Θ_C) were observed for the two catalysts: the 4.3 nm Co catalyst has a Θ_C less than one while the 9.5 nm Co catalyst supports a Θ_C greater than two. The monomer units present on the surface during reaction are identified as single carbon species for both sizes of Co nanoparticles, and the major CO dissociation site is identified as the B₅-B geometry. The difference in activity of Co nanoparticles was found to be a result of the structure sensitivity caused by the loss of these specific types of sites at smaller nanoparticle sizes.     

Comparison of Modifiers for Mercury Speciation in Water by Solid Phase Extraction and High Performance Liquid Chromatography–Atomic Fluorescence Spectrometry

Diethyldithiocarbamate and 2-mercaptoethanol modifiers were compared for the preconcentration of mercury species in water by C₁₈ solid phase extraction (SPE). The recovery values of mercury species were determined by high performance liquid chromatography–atomic fluorescence spectrometry. The eluent type, pH, chloride ion concentration, humic acid concentration, and storage time were evaluated to compare the preconcentration efficiency. L-cysteine was employed to elute the mercury compounds. Less eluent was needed for 2-mercaptoethanol modified SPE than for diethyldithiocarbamate modified SPE at an L-cysteine concentration of 0.12%. Diethyldithiocarbamate modified SPE could be used over a wider pH range and higher humic acid concentrations, whereas 2-mercaptoethanol modified SPE was less affected by the chloride concentration. Both modified SPE systems stored mercury species for 5 days, but diethyldithiocarbamate modified SPE could be stored longer. Diethyldithiocarbamate SPE provided limits of detections of 3.5, 2.5, and 4 ng · L^?1 and average recoveries of 90.78 ± 3.37%, 96.79 ± 5.12%, and 84.88 ± 5.37% for mercury(II), methylmercury, and ethylmercury, respectively. The relative standard deviation was less 6.5%. For 2-mercaptoethanol modified SPE, the limits of detection were 1.4, 1, and 1.6 ng · L^?1 and the recoveries were of 87.66 ± 8.45%, 86.70 ± 2.61%, and 91.31 ± 6.98% for mercury(II), methylmercury, and ethylmercury, respectively, with a relative standard deviation below 9.7%. Water should be characterized for its physical and chemical characteristics before mercury preconcentration to choose the most suitable method.     

Thermodynamic Analysis of Alloys in Sodium–Tellurium System in Liquid and Solid States

The whole set of available data on the thermodynamic properties of liquid alloys and solid phases in the sodium–tellurium system is considered, beginning from the first study in 1970 and till the recent reports in 2015. The application of the sodium–tellurium system in chemical power cells is discussed.     

BET Modeling of Solid–Liquid Phase Diagrams of Common-Ion Binary Salt Hydrate Mixtures. II. Calculation of Liquidus Temperatures

The BET method, according to which a molten salt hydrate is considered as if the water is adsorbed on sites of the salt, was used to model the liquidus temperatures of binary mixtures of common-ion salt hydrates. The method requires as input the BET parameters r, the number of sites and , the energy of adsorption in excess of that of the condensation of water vapor, as derived in the preceding paper. Further needed input information is the melting temperature of the salt that crystallizes out and its latent heat of melting. It is possible to model the liquidus temperature of the branch of the phase diagram between the pure salt that crystallizes out and the (first) eutectic encountered in the system with this input. The method was applied successfully to binary salt hydrate systems involving magnesium nitrate with magnesium acetate and with aluminum or nickel nitrates, magnesium and nickel chlorides, and calcium chloride with its bromide and nitrate, and with magnesium nitrate.