Jae-Jin Shim

Solubility in Supercritical Carbon Dioxide

Abbreviations Solubility Molecular Weight Nomenclature Other List of Solutes Introduction Supercritical Carbon Dioxide Solubility in Supercritical Carbon Dioxide Measurements of Solubility in Supercritical Carbon Dioxide Static Methods Dynamic Methods Modeling of Solubility in Supercritical Carbon Dioxide References Solubility Data Acenaphthene through Azobenzene Barium bis(hexafluoroacetylacetonate) through tert-Butyl-salen Cafestol through Cyproterone Acetate DDT through Dotriacontane Eflucimibe through Ewes Milk Fat Fenchone through Fungal Oil Gallium tris(acetylacetonate) through Griseofulvin Heneicosane through 1-Hydroxyxanthone Imipramine Hydrochloride through Iron tris(2,2,7-trimethyl-3,5-octanedionate) Jojoba Bean Oil Ketoprofen through Krytox Picolyl Amine Lactic Acid through Lithium Acetylacetonate Mandelic Acid through Myristic Acid Naphthalene through 1-Nonanol Octacosane through Orange Peel Oil Palladium bis(acetylacetonate) through Pyrocatechol Quercetin through p-Quinone Rape Seed Oil through Rosemary Oil Salen through Syringic Acid Taxol through Turmeric Oil 1-Undecanol through Uranyl Dinitrate-Tributyl Phosphate Complex Vanillic Acid through Vitamin K3 Water through Wool Wax 2,5-Xylenol through D-Xylose Yttrium tris(acetylacetonate) and Yttrium tris(hexafluoroacetylacetonate) Zinc bis(acetylacetonate) through Zopiclone Appendix A: Density of Carbon Dioxide Appendix B: List of Solutes by Molecular Formula

Turn-off fluorescence sensor for the detection of ferric ion in water using green synthesized N-doped carbon dots and its bio-imaging

This paper reports turn-off fluorescence sensor for Fe(3+) ion in water using fluorescent N-doped carbon dots as a probe. A simple and efficient hydrothermal carbonization of Prunus avium fruit extract for the synthesis of fluorescent nitrogen-doped carbon dots (N-CDs) is described. This green approach proceeds quickly and provides good quality N-CDs. The mean size of synthesized N-CDs was approximately 7nm calculated from the high-resolution transmission electron microscopic images. X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy revealed the presence of -OH, -NH2, -COOH, and -CO functional groups over the surface of CDs. The N-CDs showed excellent fluorescent properties, and emitted blue fluorescence at 411nm upon excitation at 310nm. The calculated quantum yield of the synthesized N-CDs is 13% against quinine sulfate as a reference fluorophore. The synthesized N-CDs were used as a fluorescent probe towards the selective and sensitive detection of biologically important Fe(3+) ions in water by fluorescence spectroscopy and for bio-imaging of MDA-MB-231 cells. The limit of detection (LOD) and the Stern-Volmer quenching constant for the synthesized N-CDs were 0.96μM and 2.0958×10(3)M of Fe(3+) ions. The green synthesized N-CDs are efficiently used as a promising candidate for the detection of Fe(3+) ions and bio-imaging.

Microwave assisted green synthesis of fluorescent N-doped carbon dots: Cytotoxicity and bio-imaging applications

A fast and facile microwave approach for the synthesis of fluorescent nitrogen-doped carbon dots (N-CDs) is reported. The N-CDs were hydrothermally synthesized using l-ascorbic acid (AA) and β-alanine (BA) as the carbon precursor and the nitrogen dopant, respectively. The morphology of synthesized N-CDs was characterized by high resolution transmission electron microscopy (HR-TEM) and the elemental composition was analyzed using elemental mapping method. The crystallinity and graphitation of N-CDs were examined by X-ray diffraction (XRD) and Raman spectroscopy. The doping of nitrogen over the carbon dots (CDs) was revealed by attenuated total reflection conjunction with Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photo electron spectroscopy (XPS). The optical properties of synthesized N-CDs were examined by UV-Visible (UV-Vis) and fluorescence spectroscopy. The synthesized N-CDs emit strong blue fluorescence at 401nm under excitation of 325nm. The excitation dependent emission property of synthesized N-CDs was exposed from fluorescence results. The quantum yield of synthesized N-CDs is about 14% against the reference quinine sulfate. The cytotoxicity of synthesized N-CDs on Madin-Darby Canine Kidney (MDCK) and HeLa cells were evaluated through Cell Counting Kit-8 (CCK-8) cytotoxicity assay. The results implied that the fluorescent N-CDs showed less cytotoxicity, further which was successfully applied as a staining probe for the confocal imaging of MDCK and HeLa cells.

Surface tension and viscosity of 1-butyl-3-methylimidazolium iodide and 1-butyl-3-methylimidazolium tetrafluoroborate, and solubility of lithium bromide+1-butyl-3-methylimidazolium bromide in water

The surface tension and viscosity of 1-butyl-3-methylimidazolium iodide ([bmim][I]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) were measured over a temperature range of 298. 15 to 323.15 K. It was found that both the viscosity and surface tension decrease with increasing temperature and that the surface tension and viscosity values of [bmim][I] were higher than those of [bmim][BF4]. Additionally, the solubility of lithium bromide (2)+1-butyl-3-methylimidazolium bromide ([bmim][Br]) (3) in water (1) was measured at three different mass ratios (w2/w3=4 and 7, w3=0) by using a visual polythermal method. The solubility of the suggested systems was better than that of lithium bromide in water.

Dyeing of pet textile fibers and films in supercritical carbon dioxide

Polyethylene terephthalate (PET) textile fibers were dyed with a disperse dye in the presence of supercritical carbon dioxide at three temperatures of 333.2, 363.2 and 393.2 K and at pressures between 15 and 25MPa. The PET film was also dyed at 393.2 K. It was found that the dye uptake in the fiber increased 2–5 times when a small amount of acetone was added as a cosolvent. The equilibrium dye uptake increased with increasing pressure at all temperatures. At 393.2 K the pressure effect appeared to be much larger. It was explained with the shift of the glass transition temperature of the polymers at high pressures. These results may be useful in designing and developing the pollution-free supercritical dyeing technique, a potential alternative to the conventional dyeing of polyesters that produces a lot of wastewater.

DYE SOLUBILITY IN SUPERCRITICAL CARBON DIOXIDE. EFFECT OF HYDROGEN BONDING WITH COSOLVENTS

The use of supercritical carbon dioxide is emerging as a potential method for achieving pollution-free dyeing. An important factor in supercritical fluid dyeing is the solubility of the dye in supercritical carbon dioxide. Our measurements show that the solubility of C. I. Disperse Red-60 dye in supercritical carbon dioxide is significantly enhanced upon addition of polar csolvents : ethanol and acetone. The solubility enhancement is attributed to the formation of hydrogen bonds between cosolvent and dye molecules. Observed solubility behavior is correlated using dilute-solution theory with lattice-fluid-hydrogen-bonding model. Needed physical and hydrogen-bonding molecular parameters are estimated using the experimental data.

Efficient Synthesis of Cyclic Carbonates by MgII/Phosphine‐Catalyzed Coupling Reactions of Carbon Dioxide and Epoxides

Carbon dioxide (CO2) is an abundant, cheap, and green solvent, and it is also a renewable C1 source for chemical syntheses. Nevertheless, the activation and fixation of CO2 remains a challenging task for researchers in organic and organometallic chemistry because of its thermodynamic stability and low reactivity. With regard to the depletion of petroleum reserves and the greenhouse effect from the increase in CO2 emissions, catalytic processes that employ CO2 as a feedstock have been investigated intensively over the last two decades. Promising methodology in this area is the coupling reactions of CO2 with epoxides to produce cyclic carbonates, [4] which are useful as synthetic intermediates, aprotic polar solvents, and feedstock for engineering plastics. Numerous catalysts have been developed for this reaction system. Although the advances have been significant, there are drawbacks, such as low catalytic stability and reactivity, air sensitivity, and the need for a co-solvent, high pressures, or high temperatures. Continuous efforts have been made to improve existing techniques and to discover new methods for CO2 activation, 8] which generally requires organometallic reagents, organic halides, or other preactivated/in situ generated carboxyl zwitterionic complexes, such as compound 1, obtained from phosphines, 10] compound 2, obtained from tertiary amines or tetralkylammonium salts, 8b, 11] compound 3, obtained from N-heterocyclic carbenes (NHCs), compound 4, obtained from 4-(dimethylamino)pyridine (DMAP), 13] and compound 5, obtained from 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) 14] (Scheme 1). Tetrabutylammonium bromide (TBAB), DMAP, and NHC-based catalyst systems have been studied extensively because of their ease of preparation and commercial availability. High temperatures are required in most cases, 6b] despite the heat that is released from the coupling reaction of epoxides with CO2. [15] Phosphine-based catalyst systems have attracted only a little attention. Therefore, this study evaluated phosphines as potential co-catalysts for the activation of CO2 at room temperature to reduce energy costs during the reaction. The synthesis of vinyl ethylene carbonate (VEC, 7 a), which is an effective electrolyte additive for high-performance Li ion battery applications and an important intermediate for fine chemicals, 17] was initially chosen as a model for investigating the reaction parameters (Table 1). Mg complexes are used widely because they are relatively less expensive than other complexes, and they are efficient catalysts in organic syntheses. Magnesium is the central ion of the porphyrin in the green pigment of plants, chlorophyll, which is widely distributed in natural metabolism systems, and it is essential for the photosynthesis of glucose from CO2. [19] A few studies have reported that Mg-based catalysts for the coupling of epoxides with CO2 still require further improvements. [20] Some of the studied catalysts showed good activity but were too complex, too expensive, or required high temperatures. Therefore, the aim of this study was to develop a better Mg-based catalyst for this coupling reaction. Scheme 1. Typical carboxyl zwitterionic complexes.

Chitosan-Zinc Oxide hybrid composite for enhanced dye degradation and antibacterial activity

In this report, chitosan (CS) encapsulated zinc oxide (ZnO) hybrid composite was prepared by chemical precipitation method. The CS-ZnO composite was characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis (TGA), transmission electron microscopy, and zeta potential. The composite exhibited high photocatalytic activity as evident from the degradation of methylene blue dye under UV irradiation. Approximately, 64% of the dye was degraded under UV irradiation within 3 h. In addition, the CS-ZnO composite showed excellent antibacterial activity against Escherichia coli as measured by colony forming units. Based on the data of present investigation, the composite being a biocompatible, eco-friendly, and low-cost material could find potential applications in various fields.

Chemical synthesis of 3D copper sulfide with different morphologies for high performance supercapacitors application

3D copper sulfide (Cu2S) with different morphologies for high performance supercapacitors were synthesized via a simple, cost effective successive ionic layer adsorption and reaction (SILAR) method. Further, these Cu2S nanostructure demonstrate excellent surface properties like uniform surface morphology, large surface area of Cu2S samples. X-ray diffraction (XRD) X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy of these samples confirmed the crystallinity and crystal structure of Cu2S. The electrochemical studies of Cu2S samples have been investigated by cyclic voltammetry, charge–discharge and electrochemical impedance spectroscopy techniques. The maximum specific capacitance of flower-like and integrated nanotubes samples are found 761 and 470 F g−1, respectively, at a scan rate of 5 mV s−1. The electrodes are prepared using a simple four-beaker SILAR system at ambient conditions, thus providing an easy approach to fabricate high-power and high-energy supercapacitors. Further, EIS analysis shows a lower ESR value, high power performance, excellent rate as well as frequency response to flower-like Cu2S sample. The Ragone plot shows better power and energy densities of all Cu2S nanostructured samples. The long-term cycling performance of Cu2S is examined with excellent retention of 95%. The high surface area provided by the porous and more conductive 3D nickel foam have been utilized properly to enhance the electrochemical properties of copper sulfides with charge transport and storage.

Emulsion stability of PMMA particles formed by dispersion polymerization of methyl methacrylate in supercritical carbon dioxide

Abstract Poly(methyl methacrylate) (PMMA) microparticles have been made by dispersion polymerization of methyl methacrylate (MMA) using PDMS-g-pyrrolidone carboxylic acid (Monasil PCA), a CO2-philic stabilizer, in supercritical carbon dioxide. The sizes of the resulting polymer particles were in the range of 2.6–5.0 μm. As the amount of surfactant increased, the particle size became smaller and the size distribution, more uniform. Among the three different amounts of initiator between 1 and 2% of monomer, 1% gave the best particle size, morphology as well as molar weights of polymer. These PMMA particles were stable in the aqueous buffer solution containing Pluronic L62 surfactant. By sonication the agglomerated polymer particles were disrupted to form small primary particles and the sonicated emulsion was more stable than the original one.