High Boiling Point Organic Solvent Research Articles

Intensification of High Boiling Point Organic Solvents on SO2 Absorption in Deep Eutectic Solvents Formed by Hydroxypyridine and 1-Butyl-3-methylimidazolium Chloride

A series of hydrogen bond donors (HBDs) functionalized deep eutectic solvents (DESs) containing both physical and chemical action sites were synthesized by hydroxypyridine with different structures and proportions plus 1-butyl-3-methylimidazolium chloride (BmimCl). The effects of temperature, partial pressure, HBDs structure, and water content on SO2 absorption were investigated, and 4-hydroxypyridine (4-Op)/BmimCl (1:2) exhibited the highest SO2 absorption capacity. In order to decrease the viscosity of absorbent and increase the applicability of 4-Op/BmimCl (1:2), the SO2 absorption capacities in four hybrid absorbents based on 4-Op/BmimCl (1:2) and four high boiling point organic solvents [sulfone, dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), and 1-methylimidazole (NMI)] were further studied and compared. 4-Op/BmimCl (1:2)-(NMI) showed the best absorption performance; the addition of NMI significantly decreased the viscosity of the absorbent, and the absorption capacity of absorbent was also improved compared with that of pure 4-Op/BmimCl (1:2) absorbent. The SO2 absorption capacity of hybrid absorbents (mass fraction of NMI ω = 0.3) could reach 1.23 g SO2/g absorbent at 100 kPa SO2 and 293.15 K, and the viscosity of the absorbent before absorption was only 12 mPa·s at 298.15 K. The gravimetric absorption capacity and desorption performance of hybrid absorbents did not change in the continuous absorption–desorption cycle experiments. Furthermore, the results of quantum chemical calculation and spectral analysis showed that there were physicochemical mixing interactions between pure DESs and SO2.

Expanding the synthetic toolbox to access pristine and rare-earth-doped BaFBr nanocrystals.

A new synthetic route to access pristine and rare-earth-doped BaFBr nanocrystals is described. Central to this route is an organic-inorganic hybrid precursor of formula Ba5(CF2BrCOO)10(H2O)7 that serves as a dual-halogen source. Thermolysis of this precursor in a mixture of high-boiling point organic solvents yields spherical BaFBr nanocrystals (≈20 nm in diameter). Yb:Er:BaFBr nanocuboids (≈26 nm in length) are obtained following the same route. Rare-earth-doped nanocrystals display NIR-to-visible photon upconversion under 980 nm excitation. The temperature-dependence of the green emission from Er3+ may be exploited for optical temperature sensing between 150 and 450 K, achieving a sensitivity of 1.1 × 10-2 K-1 and a mean calculated temperature of 300.9 ± 1.5 K at 300 K. The synthetic route presented herein not only enables access to unexplored upconverting materials but also, and more importantly, creates the opportunity to develop solution-processable photostimulable phosphors based on BaFBr.

Layered Electrode Architectures Enabled By Holey Graphene Hosts

Battery electrodes are typically prepared using a slurry-based method, where high boiling point organic solvents are typically used with a polymer binder to disperse active electrode materials and conductive carbon additives followed by casting onto current collector sheets. In this process, the use of organic solvents are environmentally hazardous, energy intensive, and time-consuming, while polymeric binders add weight and can undergo parasitic reactions during battery cycling. Here we discuss the use of a unique conductive carbon nanomaterial, namely holey graphene, as a multifunctional host that can be processed via a facile, solvent-free, binder-free, cold pressing method to prepare electrodes with unique architectures. This approach can accommodate a broad range of battery chemistries, such as lithium oxygen/carbon dioxide (Li-O2/CO2), lithium sulfur/selenium (Li-S/Se), and various lithium ion chemistries. The successful use of dry, cold compression allows the convenient modification of electrode mass loading with unique architectures containing active materials randomly mixed or layered with single or multiple layers of one or more active materials. In the conventional slurry-based electrode fabrication method, it is difficult, if not impossible, to achieve such layered architectures. In particular, the layered electrode architectures from the dry, cold press approach are easy to fabricate without significantly sacrificing device performance, and are amenable to continuous roll-to-roll dry processing. In addition, these architectures offer unprecedented perspectives on the battery material loading vs. utilization efficiency, as well as enabling unique characterization opportunities to advance mechanistic understanding of various battery chemistries. Potential applications of this unique electrode fabrication approach for solid-state batteries will also be discussed.

Solventless synthesis of cerium oxide nanoparticles and their application in UV protective clear coatings.

Colloidal dispersions of cerium oxide nanoparticles are of importance for numerous applications including as catalysts, chemical mechanical polishing agents and additives for UV protective and anticorrosion coatings. Here, concentrated oleate-coated cerium oxide nanoparticles (CeO2 NPs) with a uniform size have been produced by solventless thermolysis of cerium-oleate powder under low pressure at 320 °C and subsequently dispersed in hexane. Unlike any previously reported colloidal synthesis process for ceria nanoparticles, this process does not involve any toxic high boiling point organic solvent that requires subsequent removal at high cost. Although the process is very simple, highly concentrated cerium oxide nanoparticles with more than 17 wt% solid content and 70% of the theoretical yield can be easily obtained. Moreover, the size, shape and crystallinity of cerium oxide nanoparticles can be tailored by changing the thermal decomposition temperature and reaction time. Moreover, the new synthesis route developed in this study allows the synthesis of clean and dispersible ceria nanoparticles at a relatively low cost in a single step. The prepared ceria nanoparticles have an excellent UV absorption property and remain transparent to visible light, thus having the potential to replace potentially hazardous organic compounds in UV absorbing clear coatings. As a proof of concept, the prepared dispersions of cerium oxide nanoparticles in hexane were formulated into a solvent borne binder base to develop clear UV protecting coatings for light sensitive substrates. The general synthesis strategy presented in this study is generally applicable for the low-cost production of a concentrated dispersion of metal oxide nanoparticles with minimal environmental impact.

Mechanical and dielectric properties of 3D printed highly porous ceramics fabricated via stable and durable gel ink

A novel, efficient, versatile strategy was carried out to fabricate highly porous ceramic parts based on the combination of strong colloidal gel ink fabricated with high boiling point organic solvents and DIW technique. The preparation and optimization of inks and the effect of heating temperature on the phase composition, microstructure, mechanical properties and dielectric properties of ceramic parts were systematically investigated. The strong colloidal ink exhibits excellent ambient stability and printability. The sintering temperatures bring about the evolution of phases, structural mechanical properties and dielectric properties of ceramic parts. Ultimately, Si2N2O single wall ceramic parts with a frame density of 1.07˜1.14 g/cm3 and an apparent porosity of 53.13 ± 1.29% were successful fabricated. The dielectric constant and dielectric loss of Si2N2O sample (1650℃) are only 4.24 and 0.0049, respectively. This strategy provides a reference for in-situ synthesis of high-performance porous ceramic components based on the DIW.

Synthesis of spherical iron-oxide nanoparticles of various sizes under different synthetic conditions

The present work describes eleven different syntheses of oleate-coated iron-oxide nanoparticles via thermolysis of Fe(III) oleate in high-boiling point organic solvents using a heating mantle with manual heating rate control. It has been shown that heating of iron oleate for 10 min in octadecane at 318 °C (average heating rate is about 7.7 °C/min) does not lead to the formation of iron-oxide nanoparticles, whereas decrease of the heating rate and further more continuous reflux (20, 30, 60 min) trigger their formation. The experimental results show that the use of heating mantle without automatic heating controller makes it harder to precisely control the size of the nanoparticles and indicate that certain variations of the heating rates may result in iron-oxide nanoparticles of slightly different sizes. It has been also exemplified that prehistory of the iron oleate namely its storage time may affect the morphology of the resulting iron-oxide nanoparticles.

Methanol synthesis in a high-pressure membrane reactor with liquid sweep

Membrane reactors (MR) are known for their ability to improve the selectivity and yield of chemical reactions. In this paper, a novel high-pressure MR employing a liquid sweep was applied to the methanol synthesis (MeS) reaction, aiming to increase the per single-pass conversion. For carrying-out the reaction, an asymmetric ceramic membrane was modified with a silylating agent in order to render its pore surface hydrophobic. A commercial MeS catalyst was used for the reaction, loaded in the MR shell-side, while the tube-side was swept with a high boiling point organic solvent with high solubility towards methanol. The membrane reactor was studied under a variety of experimental conditions (different pressures, temperatures, space times, and liquid sweep flow rates) and showed improved carbon conversion when compared to the conventional packed-bed reactor operating under the same conditions.

DFT study of optical properties of MoS2 and WS2 compared to spectroscopic results on liquid phase exfoliated nanoflakes

We calculate the dielectric function within the framework of the random-phase approximation (RPA) based on DFT ground-state calculations, starting from eigenvectors and eigenvalues. The final goal of our theoretical work is a comparison to corresponding experimental data. We compare our computational results with optical measurements on $$\hbox {MoS}_2$$ and $$\hbox {WS}_2$$ nanoflakes. $$\hbox {MoS}_2$$ and $$\hbox {WS}_2$$ were exfoliated by ultrasonic treatment in high-boiling point organic solvent and characterized using UV–VIS spectrophotometry. We find that DFT-RPA yields a good, computationally inexpensive first approximation of the imaginary part of the dielectric function, although excitonic effects require more complex code and extra computing power.

Luminescent ZnSe:Mn/ZnS@PMMA nanocomposites with improved refractive index and transparency

This paper deals with development of a novel ZnSe:Mn/ZnS@PMMA nanocomposites fabricated via simple film casting methods using commercial available PMMA resin (DEGALAN® Evonik). Hydrophobic ZnSe:Mn/ZnS nanoparticles were successfully produced by the hot-injection method using high boiling point organic solvents. ZnSe:Mn colloidal nanoparticles were protected from luminescence quenching and degradation by overcoating with a ZnS shell. The coverage of the nanoparticles with three layers of the ZnS shell effectively protected them against photooxidation and quenching in organic solvents. The crucial step in the production of highly transparent and luminescent ZnSe:Mn/ZnS@PMMA polymer nanocomposites was the purification of the ZnSe:Mn/ZnS nanoparticles from by-products and unreacted precursors. The optical properties of ZnSe:Mn/ZnS@PMMA nanocomposites were characterized by UV–Vis and spectroscopic ellipsometry measurements. All nanocomposite films demonstrated high transmittance in the visible range (70–90%), an intense orange emission originating from homogeneously dispersed ZnSe:Mn/ZnS nanoparticles. The intensity of the orange emission increased with increasing ZnSe:Mn/ZnS nanoparticle concentration in the nanocomposite up to a quantum yield (QY) of 19% ± 5 for a nanocomposite with nanoparticles content up to 7% wt. These novel polymer nanocomposites exhibited good optical properties (high refractive index of 1.59 at 450 nm) and stability under ambient conditions and can be easily deposited over large areas by printing process.

Structural, optical, dielectric and magnetic properties of CaFe2O4 nanocrystals prepared by solvothermal reflux method

Single crystalline CaFe2O4 nanospheres were synthesized by solvothermal reflux method using high boiling point organic solvents mixture. Both X-ray diffraction and electron diffraction profiles were confirmed single phase nature of the compound. The sample shown spherical morphology with average particle size of 10 nm which is same as crystallite size determined from the XRD. A thin layer of surfactant oleic acid was adsorbed on the surface of the nanoparticles. The optical excitation spectra reveals that the compound has direct allowed energy bandgap of 1.26 eV. The temperature dependent dielectric constant (εr′) and dielectric loss (εr″) measurements show low values at room temperature and were nominally changes with enhance of temperature upto 650 K. Above which both εr′ and εr″ were steeply increased with small variation of temperature which could be assigned to enhanced electrical conductivity due to surface charge conduction and, partially, to on-set of decomposition of oleic acid present on the surface of the sample. The samples show variable electron hopping conductivity in the temperature range studied and was supported by both Arrhenius plots and electric modulus studies at different frequencies. The CaFe2O4 nanoparticles show superparamagnetic nature at room temperature with high saturation magnetization (48.54 emu/g). The magnetization is much higher than ferrimagnetic bulk magnetization. Langevin function fit to magnetization data give 8 nm magnetic domain diameter and 1 nm magnetically disordered thin shell on the surface of the nanoparticles. As CaFe2O4 nanoparticles were electrically resistive and low dielectric loss materials, they may find applications in microwave engineering. In addition, the CaFe2O4 superparamagnetic nanoparticles were biocompatible and have high saturation magnetization, they could be used in biomedical applications such as magnetic hyperthermia and directed drug delivery applications.

The effects of exfoliation, organic solvents and anodic activation on the catalytic hydrogen evolution reaction of tungsten disulfide.

The rational design of transition metal dichalcogenide electrocatalysts for efficiently catalyzing the hydrogen evolution reaction (HER) is believed to lead to the generation of a renewable energy carrier. To this end, our work has made three main contributions. At first, we have demonstrated that exfoliation via ionic liquid assisted grinding combined with gradient centrifugation is an efficient method to exfoliate bulk WS2 to nanosheets with a thickness of a few atomic layers and lateral size dimensions in the range of 100 nm to 2 nm. These WS2 nanosheets decorated with scattered nanodots exhibited highly enhanced catalytic performance for HER with an onset potential of -130 mV vs. RHE, an overpotential of 337 mV at 10 mA cm-2 and a Tafel slope of 80 mV dec-1 in 0.5 M H2SO4. Secondly, we found a strong aging effect on the electrocatalytic performance of WS2 stored in high boiling point organic solvents such as dimethylformamide (DMF). Importantly, the HER ability could be recovered by removing the organic (DMF) residues, which obstructed the electron transport, with acetone. Thirdly, we established that the HER performance of WS2 nanosheets/nanodots could be significantly enhanced by activating the electrode surface at a positive voltage for a very short time (60 s), decreasing the kinetic overpotential by more than 80 mV at 10 mA cm-2. The performance enhancement was found to arise primarily from the ability of a formed proton-intercalated amorphous tungsten trioxide (a-WO3) to provide additional active sites and favourably modify the immediate chemical environment of the WS2 catalyst, rendering it more favorable for local proton delivery and/or transport to the active edge site of WS2. Our results provide new insights into the effects of organic solvents and electrochemical activation on the catalytic performance of two-dimensional WS2 for HER.

Cis-Tetrachlorido-bis(indazole)osmium(iv) and its osmium(iii) analogues: paving the way towards the cis-isomer of the ruthenium anticancer drugs KP1019 and/or NKP1339.

The relationship between cis-trans isomerism and anticancer activity has been mainly addressed for square-planar metal complexes, in particular, for platinum(ii), e.g., cis- and trans-[PtCl2(NH3)2], and a number of related compounds, of which, however, only cis-counterparts are in clinical use today. For octahedral metal complexes, this effect of geometrical isomerism on anticancer activity has not been investigated systematically, mainly because the relevant isomers are still unavailable. An example of such an octahedral complex is trans-[RuCl4(Hind)2]-, which is in clinical trials now as its indazolium (KP1019) or sodium salt (NKP1339), but the corresponding cis-isomers remain inaccessible. We report the synthesis of Na[cis-OsIIICl4(κN2-1H-ind)2]·(Na[1]) suggesting a route to the cis-isomer of NKP1339. The procedure involves heating (H2ind)[OsIVCl5(κN1-2H-ind)] in a high boiling point organic solvent resulting in an Anderson rearrangement with the formation of cis-[OsIVCl4(κN2-1H-ind)2] ([1]) in high yield. The transformation is accompanied by an indazole coordination mode switch from κN1 to κN2 and stabilization of the 1H-indazole tautomer. Fully reversible spectroelectrochemical reduction of [1] in acetonitrile at 0.46 V vs. NHE is accompanied by a change in electronic absorption bands indicating the formation of cis-[OsIIICl4(κN2-1H-ind)2]- ([1]-). Chemical reduction of [1] in methanol with NaBH4 followed by addition of nBu4NCl afforded the osmium(iii) complex nBu4N[cis-OsIIICl4(κN2-1H-ind)2] (nBu4N[1]). A metathesis reaction of nBu4N[1] with an ion exchange resin led to the isolation of the water-soluble salt Na[1]. The X-ray diffraction crystal structure of [1]·Me2CO was determined and compared with that of trans-[OsIVCl4(κN2-1H-ind)2]·2Me2SO (2·2Me2SO), also prepared in this work. EPR spectroscopy was performed on the OsIII complexes and the results were analyzed by ligand-field and quantum chemical theories. We furthermore assayed effects of [1] and Na[1] on cell viability and proliferation in comparison with trans-[OsIVCl4(κN1-2H-ind)2] [3] and cisplatin and found a strong reduction of cell viability at concentrations between 30 and 300 μM in different cancer cell lines (HT29, H446, 4T1 and HEK293). HT-29 cells are less sensitive to cisplatin than 4T1 cells, but more sensitive to [1] and Na[1], as shown by decreased proliferation and viability as well as an increased late apoptotic/necrotic cell population.

Colloidal synthesis and magnetic properties of anisotropic-shaped spinel CuCr2Se4 nanocrystals

Anisotropic-shaped CuCr2Se4 nanocrystals have been synthesized by thermal decomposition and reaction of novel mixed metal–oleate complexes with selenium in a high-boiling point organic solvent, trioctylamine.

Facile synthesis of graphene nanoplate-supported porous Pt–Cu alloys with high electrocatalytic properties for methanol oxidation

A porous Pt1Cu1 alloy nanocrystal catalyst supported on 1-aminopyrene functionalized graphene nanoplates, which is a highly active catalyst for methanol oxidation in alkaline medium, is synthesized by a one-step method without any high boiling point organic solvents, surfactants, stabilizers and templates.

Controlling the metal to semiconductor transition of MoS2 and WS2 in solution.

Lithiation-exfoliation produces single to few-layered MoS2 and WS2 sheets dispersible in water. However, the process transforms them from the pristine semiconducting 2H phase to a distorted metallic phase. Recovery of the semiconducting properties typically involves heating of the chemically exfoliated sheets at elevated temperatures. Therefore, it has been largely limited to sheets deposited on solid substrates. Here, we report the dispersion of chemically exfoliated MoS2 sheets in high boiling point organic solvents enabled by surface functionalization and the controllable recovery of their semiconducting properties directly in solution. This process connects the scalability of chemical exfoliation with the simplicity of solution processing, ultimately enabling a facile method for tuning the metal to semiconductor transitions of MoS2 and WS2 within a liquid medium.

Tailoring of crystal phase and Néel temperature of cobalt monoxides nanocrystals with synthetic approach conditions

Cobalt monoxide (CoO) nanocrystals were synthesized by thermal decomposition of cobalt oleate precursor in a high boiling point organic solvent 1-octadecene. The X-ray diffraction pattern and transmission electron microscopy studies suggest that pure face-centered-cubic (fcc) phase of CoO can be synthesized in the temperature range of 569–575 K. Thermolysis product at higher synthesis temperature 585 K is a mixture of fcc and hexagonal-closed-packed (hcp) phases. These nanocrystals are single crystals of CoO and exhibit mixture of two types of morphologies; one is nearly spherical with 5–25 nm diameter, and other one is 5–10 nm thick flake. The pure fcc-CoO nanocrystals show enhanced, and mixture of fcc- and hcp-CoO nanocrystals show reduced antiferromagnetic ordering temperature. Such results provide new opportunities for optimizing and enhancing the properties and performance of cobalt oxide nanomaterials.

Influence of Thickness on Performances of YBa$lt;inf$gt;2$lt;/inf$gt;Cu$lt;inf$gt;3$lt;/inf$gt;O$lt;inf$gt;7-δ$lt;/inf$gt; Films Prepared by Metal Organic Solution Deposition

Trifluoroacetate metal organic deposition (TFA-MOD) is one of the most promising technology routes for fabrication of YBa2Cu3O7-δ (YBCO) coated conductors. In this paper, high-boiling point organic solvent diethanolamine (DEA) was added to modulate and to improve the properties of precursor solution by suppression the defect in the final films. And the thickness of single coated film was increased by increased concentration of the metal ions in the precursor solution. It is revealed that an exponential relationship was found between the thickness of precursor film after low-temperature decomposition and the ion concentration, as well as the viscosity of precursor solution vs the ion concentration. Optimizing the ion concentration and dip-coating parameters, smooth and crack-free YBCO films after crystallization are achieved with the thickness more than 1.3 μm. The films show homogeneous microstructures while dispersive heterogeneous particles appear in the surface of the thick films. Critical current density (Jc) measurement shows a decrease of Jc due to the increase of the thickness of YBCO films prepared by high concentration precursor solution, while critical currents (Ic) are distinctly improved. For instance, the Ic value of YBCO film prepared by 2.5 mol/L precursor solution is 4.7 times of that by 1.0 mol/L precursor solution. 1168 无 机 材 料 学 报 第 29 卷

Synthesis and magnetic properties of octahedral magnetite nanoparticles in 20–110 nm range

Octahedral magnetite (Fe3O4) nanoparticles (NPs) with dimensions ranging from 20 to 110 nm are prepared via the decomposition of iron oleate complex in the presence of cetyltrimethylammonium bromide (CTAB) and various organic solvents. It is shown that the addition of an optimal amount of CTAB prompts the growth of equi-dimensional octahedral NPs with dominant {111} facets. Moreover, it is shown that the size of the octahedral NPs can be controlled by adjusting the relative amounts of oleic acid and CTAB and choosing an appropriate high-boiling point organic solvent. The X-ray diffraction analysis results reveal that the compositions of the as-synthesized NPs are solvent-dependent and contain different amounts of iron metal, wustite and magnetite phases. The as-synthesized NPs are oxidized to pure magnetite via an air treatment and the room-temperature magnetic properties of the resulting products are then characterized by means of a superconducting quantum interference device. The results indicate that the superparamagnetic limit for the current magnetite NPs is equal to approximately 33.3 nm at a temperature of 300 K.

Liquid-Phase Syntheses and Material Properties of Two-Dimensional Nanocrystals of Rare Earth–Selenium Compound Containing Planar Se Layers: RESe2 Nanosheets and RE4O4Se3 Nanoplates

Synthesis of diverse two-dimensional nanostructures with unique material properties is of current interest and multidisciplinary importance but remains a challenge for trivalent rare earth (RE)-selenium (Se) compounds because of the weak affinity between hard rare earth cations and soft selenium anions. In this article, for the first time, we report a mild solution approach toward a series of two-dimensional trivalent RE-selenium compound nanocrystals, namely RESe2 nanosheets (RE = La to Nd, for EuSe2, nanobars were obtained) and RE4O4Se3 nanoplates (RE = Nd, Sm, Gd to Ho), under a high chemical potential of selenium obtained by activating SeO2 powder with oleylamine in high boiling point organic solvents. Both kinds of nanocrystals contain Se with -1 valence in planar Se layers, allowing for a great variability in their crystal structures. Satellite diffraction peaks were observed in the electron diffraction pattern of LaSe2 nanosheets, indicating the presence of Peierls distortion in the Se layers. In the RE4O4Se3 nanoplates, the interaction between Se(2-) ions and [Se-Se](2-) dumbbells in the Se layers increases when the radii of the RE(3+) ions decrease along the lanthanide series, resulting in a narrower optical band gap (from 1.96 to 1.73 eV). The LaSe2 nanosheet films fabricated by drop-casting exhibited good electrical conductivity at room temperature (about 1 Ω·cm(-1)). Further, the RE4O4Se3 nanoplates showed very high light extinction capacity in the visible region (extinction coefficient μi: 4.4 × 10(5) cm(-1) for Nd4O4Se3, and 3.1 × 10(5) cm(-1) for Gd4O4Se3), comparable to that (5 × 10(5) cm(-1)) of CuInS2 commonly used in solar cells.

Synthesis of Tin Catalyzed Silicon and Germanium Nanowires in a Solvent–Vapor System and Optimization of the Seed/Nanowire Interface for Dual Lithium Cycling

Silicon and germanium nanowires are grown in high density directly from a tin layer evaporated on stainless steel. The nanowires are formed in low cost glassware apparatus using the vapor phase of a high boiling point organic solvent as the growth medium. HRTEM, DFSTEM, EELS, and EDX analysis show the NWs are single crystalline with predominant ⟨111⟩ growth directions. Investigation of the seed/nanowire interface shows that in the case of Si an amorphous carbon interlayer occurs that can be removed by modifying the growth conditions. Electrochemical data shows that both the tin metal catalyst and the semiconductor nanowire reversibly cycle with lithium when the interface between the crystalline phases of the metal and semiconductor is abrupt. The dually active nanowire arrays were shown to exhibit capacities greater than 1000 mAh g–1 after 50 charge/discharge cycles.