• Korean Chemical Engineering Research
• /
• v.49 no.6
• /
• pp.823-828
• /
• 2011

Characteristics of water separation in a FWKO(Free Water Knok Out) vessel was investigated to remove water from oil-water mixture. Decane, toluene, and asphalt were used as model oils. Preliminary experiments were carried out for decane in a prototype FWKO vessel. Based on the results of preliminary experiments, the prototype vessel was modified and its performance was evaluated by using toluene. The effects of experimental variables on the separation of oil-water mixture were evaluated in terms of separation efficiency. The experimental variables include water cut(water ratio), number of baffles, residence times, and operation temperatures. The optimum conditions of water separation were found to be 0.8 water cut, 3 baffles, 1,200 sec, and $45^{\circ}C$.

• Journal of the Korean Chemical Society
• /
• v.36 no.6
• /
• pp.802-811
• /
• 1992

The conformations of several carbene-olefin-transition metal complexes[$(CO)_4M$-(CHX)olefin] (X: $OCH_3,\;NHCH_3,\;SCH_3$, M: C, Mo, W) have been studied by means of Extend Huckel calculations. In the case of $d^6$ transition metal octahedral complexes, it is shown that the two main factors which determine the optimal conformation are metal-to-ligand back-donation and direct ligand-ligand interaction at the metal, but the ligand-ligand interaction dominates the situation for a metal that is coordinated to $\pi$ acceptor ligands and to $\pi$ donor group on the carbene. The relative amounts of both factors depend strongly on the electronic nature of the ligands at the metal. The greater electron donating ability of nitrogen stabilizes amino-substituted carbene complexes compared with their alkoxyl substituted analogues. This interaction is optimal when the $\pi$ systems of the carbene and olefin are coplanar. The introduction of the $\pi$ donor group on the carbene carbon increases also the importance of the ligand-ligand interaction.

• Journal of the Korean Chemical Society
• /
• v.36 no.6
• /
• pp.824-831
• /
• 1992

Absorption spectra were observed for several Ho(III)-ligand systems in aqueous solution under the changes of ligand concentration and temperature. The intensity change of hypersensitive band $(^5I_8\;\to\;^5G_6)$ was quite remarkable with temperature and concentration, and was interpreted as the change of coordination environments. The transition intensities observed in these spectra were analyzed in terms of the Judd-Ofelt intensity parameters, $\Omega_\lambda$ ($\lambda$ = 2, 4, 6), for 4f $\to$ 4f electric dipole transitions. The $\Omega_2$ parameter was the most sensitive to the temperature and concentration. Using the changes of $\Omega_2$, $Cl^-$ and ${NO_3}^-$ ions were found to form inner sphere complexes in aqueous solution.

• Journal of the Korean Chemical Society
• /
• v.36 no.6
• /
• pp.906-913
• /
• 1992

The polymeric compound [{$W(NO)_2Cl_2$}$_n$] were prepared by reductive nitrosylation of $WNaNO_2$ and acidified $WFeSO_4$ with $WWCl_6$ at room temperature. The reactions of [{$W(NO)_2Cl_2$}$_n$] with unidentate and bidentate ligands afforded neutral monomeric [$W(NO)_2Cl_2L_2$(or L-L)] in a relative high yields (70$\sim$90%). 3,5-lutidine, ${\gamma}$-cyanopyridine, 1,2-phenylenediamine, 1,10-phenanthroline, sym-diphenylethylenediamine, 9,10-phenanthrenequinone, 1,3-bis(diphenylphosphino)propane, 1,1'-bis(diphenylphosphino)ferrocene and 8-hydroxyquinoline were used as coordinating ligands. These dinitrosyltungsten complexes were characterized by elemental analysis, $^1H$-NMR, infrared, and UV-visible spectroscopy are reported. The spectral data indicated that geometric structures of the products were cis-dinitrosyl-trans-dichloro-cis-$L_2$ of $C_{2v}$ symmetry.

• Elastomers and Composites
• /
• v.48 no.1
• /
• pp.2-9
• /
• 2013

We synthesized polyethylene, poly(ethylene-co-1-decene), poly(ethylene-co-p-methylstyrene), and poly(ethylene-ter-1-decene-ter-p-methystyrene) using a rac-$Et(Ind)_2ZrCl_2$ metallocene catalyst and a methylaluminoxane cocatalyst system. The materials were characterized using nuclear magnetic spectroscopy and fourier transform infrared spectroscopy. To identify suitable reaction conditions for terpolymerization, we studied the effects of catalyst content, cocatalyst/catalyst molar ratio, polymerization time, and polymerization temperature. As the catalyst content increased, the catalytic activity and the molecular weight of the terpolymers increased. The catalytic activity sharply increased but little change was observed after a polymerization time of 30 min. The increase in the cocatalyst/catalyst molar ratio resulted in a decrease in the molecular weight of the terpolymers and an increase in the catalytic activity to some degree. The catalytic activity increased with increasing polymerization temperature, while the molecular weight of the terpolymers decreased.

• Polymer(Korea)
• /
• v.38 no.6
• /
• pp.801-808
• /
• 2014

Ion diffusion and chemical binding to acrylic polymer were investigated in a solid film. The composition of acrylic monomers containing amino group and carboxylic acid was adjusted for rapid ion migration in the film. p-Methylred (PMR) and phenolphthalein derivatives were optically sensitive to the concentration of proton and hydroxyl anion, respectively and verified the ion migration through the film layers. A rapid proton migration was observed in the film of a high amino content. On the other hand, $OH^-$ migration occurred rapidly in a high content of carboxylic acid group. The proton migration occurred through the internal layer as well as surface layer of a film and was reversible during 50 repetition examination. Copper(II) ion migration was examined with a Rhodamine-containing polymer film. The light absorption and emission spectra of a Rhodamine-Cu complex showed the key contribution of carboxylic acid group to the Cu(II) migration in a film.

• Korean Journal of Logic
• /
• v.19 no.1
• /
• pp.1-49
• /
• 2016

In the Tractatus, 'logical space' raises the several puzzles as follows. What are logical space, logical coordinates and logical place? What is the point of such analogies and what do they refer to exactly in the Tractatus? And what do occupy logical space? Can facts, proposition, propositional sign, situation and contradiction occupy it respectively? Or is it impossible to reconcile the remarks concerning logical place in the Tractatus? Futhermore, why did Wittgenstein need the concept of logical space? What is the problem that he tried to solve through this concept? In this paper, I will endeavor to answer to these problems. Logical space in the Tractatus is the system of propositions with senses. And it is the concept which Wittgenstein contrived by making model of Hertz's configuration space. Wittgenstein's fundamental coordinates are in some ways similar to geometrical ones. On the other hand logical coordinates are completely different from geometrical ones. Hence attempts to understand logical space by a kind of geometrical spaces cannot be right at all.

• Korean Journal of Materials Research
• /
• v.9 no.12
• /
• pp.1188-1195
• /
• 1999

The effect of aluminosilicate sol on the formation of mullite layer in zircon shell mold was investigated. Aluminosilicate sol was prepared by mixing of colloidal silica(NALCO(R) 1130) and an aqueous solution of aluminium nitrate at room temperature. The sol gelled at 50$^{\circ}C$ for 48 hrs. It was identified that the gel consists of aluminosilicate complexes and gibbsite. The coordination number of all aluminium ion bonded with silicon ion was four. Mullite phase formed by sintering above 1300$^{\circ}C$. XRD peak of mullite sharpened with increasing sintering temperature and the content of aluminium nitrate. Mullite phase displayed whisker-like 0.5~5${\mu}m $ particles. Separation between 1st and 3rd layers during sintering and the difference in thermal expansion coefficient between residual silica and mullite.

• Applied Chemistry for Engineering
• /
• v.3 no.3
• /
• pp.471-481
• /
• 1992

This study is related to the reactivity of dioxygen bridged palladium complexes having amine ligands. New dloxygen bridged palladium complexes were prepared using superoxide ion(${O_2}^-$) as an oxygen source. The reactions of dioxygen palladium complexes prepared in the study were examined in order to clarify the nature of the coordinated dioxygen. Treatments of a solution of the dioxygen bridged palladium complexes in benzene by water, methanol, acetic acid gave hydrogen peroxide($H_2O_2$) and hydroxy, methoxy, acetoxy-bridged palladium complexes, respectively. The dioxygen bridged palladium complexes reacted with substitution phenols of salicylaldehyde, 8-hydroxyquinoline and active mothylenes of acetylacetone, dimethyl malonate to afford mononuclear complexes of palladium and hydrogen peroxide. Furthermore, she dioxygen bridged palladium complexes changed to acetonyl bridged palladium complex and hydrogen peroxide reacting with acetone. The results suggest that dioxygen is coordinated as peroxo (${O_2}^{2-}$) in the complexes and behaves as a strong base.

• Applied Chemistry for Engineering
• /
• v.23 no.6
• /
• pp.577-582
• /
• 2012

In this work, vibrational circular dichroism (VCD) technique was applied for the determination of %EE of chiral compounds. It may provide an easy way to determine the %EE with a proper accuracy within 2% error ranges as well as the absolute configuration of enantiomers. We demonstrated herein a flow cell VCD (FT-VCD) technique for time-dependent %EE measurements. The simultaneous monitoring of the mole fraction and %EE for two chiral species (epichlorohydrin and glycidol mixture) in the mixture was shown to be successful without any further separation steps. Thus, we demonstrate that FT-VCD is an appropriate analytical tool to monitor the kinetics of reactions involving chiral molecules. FT-VCD also provides a convenient nondestructive approach for the time dependent determination of the optical purity of individual components in a reaction mixture containing chiral molecules.