• Title/Summary/Keyword: Iodine chemistry

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New Liquid Crystal-Embedded PVdF-co-HFP-Based Polymer Electrolytes for Dye-Sensitized Solar Cell Applications

  • Vijayakumar, G.;Lee, Meyoung-Jin;Song, Myung-Kwan;Jin, Sung-Ho;Lee, Jae-Wook;Lee, Chan-Woo;Gal, Yeong-Soon;Shim, Hyo-Jin;Kang, Yong-Ku;Lee, Gi-Won;Kim, Kyung-Kon;Park, Nam-Gyu;Kim, Suhk-Mann
    • Macromolecular Research
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    • v.17 no.12
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    • pp.963-968
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    • 2009
  • Liquid crystal (LC; E7 and/or ML-0249)-embedded, poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-co-HFP)-based, polymer electrolytes were prepared for use in dye-sensitized solar cells (DSSCs). The electrolytes contained 1-methyl-3-propylimidazolium iodide (PMII), tetrabutylammonium iodide (TBAI), and iodine ($I_2$), which participate in the $I_3^-/I^-$ redox couple. The incorporation of photochemically stable PVdF-co-HFP in the DSSCs created a stable polymer electrolyte that resisted leakage and volatilization. DSSCs, with liquid crystal(LC)-embedded PVdF-co-HFP-based polymer electrolytes between the amphiphilic ruthenium dye N719 absorbed to the nanocrystalline $TiO_2$ photoanode and the Pt counter electrode, were fabricated. These DSSCs displayed enhanced redox couple reduction and reduced charge recombination in comparison to that fabricated from the conventional PVdF-co-HFP-based polymer electrolyte. The behavior of the polymer electrolyte was improved by the addition of optimized amounts of plasticizers, such as ethylene carbonate (EC) and propylene carbonate (PC). The significantly increased short-circuit current density ($J_{sc}$, $14.60\;mA/cm^2$) and open-circuit voltage ($V_{oc}$, 0.68 V) of these DSSCs led to a high power conversion efficiency (PCE) of 6.42% and a fill factor of 0.65 under a standard light intensity of $100\;mW/cm^2$ irradiation of AM 1.5 sunlight. A DSSC fabricated by using E7-embedded PVdF-co-HFP-based polymer electrolyte exhibited a maximum incident photon-to-current conversion efficiency (IPCE) of 50%.

The Crystal Structure of Nicotine Dihydroiodide (Nicotine Dihydroiodide의 結晶構造)

  • Koo, Chung-Hoe;Kim, Hoon-Sup
    • Journal of the Korean Chemical Society
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    • v.9 no.3
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    • pp.134-141
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    • 1965
  • Crystals of nicotine dihydroiodide, are orthorhombic with space group $p2_12_12_1$.The unit cell of dimensions a=7.61, b=11.01, e=17.27${\AA}$, contains four formula units. The structure has been determined by X-ray diffraction method and has been refined to give the R-index, ${\sum}{\mid}{\mid}F_{\circ}{\mid}-{\mid}F_c{\mid}{\mid}{\div}{\sum}{\mid}F_{\circ}{\mid}$, of 0.16 and 0.14 for $F_{okl}\;and\;F_{hol}$ respectively.The mean lengths of C-C and C-N bonds in pyridine ring are 1.40 and $1.35{\AA}$ and those in pyrolidine ring 1.56 and $1.48{\AA}$ respectively, though accurate measurement of bond length has not been attempted. The six atoms in the pyridine ring are coplanar and on the other hand $C_6,\;C_7,\;C_8$ and $N_2$ atoms in pyrrolidine ring form a plane within accuracy of the analysis, and $C_9$ atom is distant $0.22{\AA}$ out of the plane consist of $C_6,\;C_7,\;C_8$ and $N_2$ aoms. The normals to the two planes form an angle of $94^{\circ}$ with each other. Iodine atom is distant $3.55{\AA}$ from nitrogen atom in pyridine ring and the other iodine atom $3.58{\AA}$ from nitrogen atom in pyrrolidine ring, so that the nitrogen and iodine atoms are firmly linked.It seems that the only forces binding nicotine dihydroiodide molecules together in the crystal are Van der Waals forces.

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The Study on Bunsen Reaction Process for Iodine-Sulfur Thermochemical Hydrogen Production (요오드-황 열화학 수소 제조를 위한 분젠 반응 공정 연구)

  • Kang, Young-Han;Ryu, Jae-Chun;Park, Chu-Sik;Hwang, Gab-Jin;Lee, Sang-Ho;Bae, Ki-Kwang;Kim, Young-Ho
    • Korean Chemical Engineering Research
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    • v.44 no.4
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    • pp.410-416
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    • 2006
  • For highly efficient operation of a Bunsen process section in an iodine-sulfur thermochemical hydrogen production cycle using nuclear heat, the process characteristics of $H_2SO_4-HI-H_2-O-I_2$ mixture system for separating into two liquid phases ($H_2SO_4$-rich phase and $HI_x$-rich phase) and the distribution of $H_2O$ to each phase were investigated.The experiments for process variables were carried out in the temperature range, from 298 to 353 K, and in the $H_2SO_4/HI/H_2O/I_2$ molar ratio of 1/2/14~20/0.5~8.0. As the results, for the $SO_2-I_2-H_2O$ Bunsen reaction system, the ranges between the starting point and the saturation point for two liquid phases separation were determined by calculation. The best result for the minimization of impurities (HI and $I_2$ in $H_2SO_4$ phase and $H_2SO_4$ in $HI_x$ phase) in each phase was obtained in an optimum condition with the highest temperature of 353 K and the highest $I_2$ molar composition. In this condition, the $HI/H_2SO_4$ molar ratio in the $H_2SO_4$-rich phase and the $H_2SO_4/HI_x$ molar ratio in the $HI_x$-rich phase were 0.024 and 0.028, respectively. For the distribution of $H_2O$ to each phase, it is appeared that the affinity between $HI_x$ and $H_2O$ was more superior to that between $H_2SO_4$ and $H_2O$. The affinity between $HI_x$ and $H_2O$ was decreased with increasing temperature but increased with increasing $I_2$ molar composition.

Effect of extracting solvents on physicochemical properties of vegetable seed oils and their suitability for industrial applications

  • Qeency Etim Essien;Michael Akomaye Akpe;Ofonime Okon Udo;Collins Irechukwu Nwobodo
    • Food Science and Preservation
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    • v.31 no.4
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    • pp.554-564
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    • 2024
  • The effects of extracting solvents on the physicochemical properties of vegetable oils extracted from four oil seed plants, namely Dennettia tripetala, Dacryodes edulis, Cola rostrata, and Persea americana, were studied. Vegetable oils were extracted using the Soxhlet method. The oils were used for determining % yield, acid value (AV), iodine value (IV), saponification value (SV), electrical conductivity (EC), and pH. The results revealed that the range of the mean % yield of oils extracted using hexane, carbon tetrachloride (CCl4), petroleum ether, acetone, and methanol, respectively, were 7.5-12.0, 9.0-22.0, 7.5-27.5 and 12.0-37.5 for the four oil Seeds respectively. Mean AVs of oils in mg KOH/g across the solvents were 3.1-3.7, 3.1-3.8, 2.5-3.9 and 2.4-2.8 for Cola rostrata, Dacryodes edulis, Dennettia tripetala and Persea americana respectively. Mean IVs of oils in gI2/100 g across the solvents were 33.25-33.97, 33.06-33.35, 32.06-33.76 and 33.00-34.00 for the four oil seeds, respectively. Mean SVs in mg KOH/g across the solvents were 191.00-197.44, 190.74-198.31, 194.11-202.52, and 182.23-199.44, respectively. Mean EC values ranged 0.31-0.32, 0.30-0.33, 0.30-0.33, and 0.31-0.32 µS/cm across the solvents, respectively. Mean pH values ranged from 6.1-6.4, 4.6-6.3, 6.2-6.4, and 6.1-6.3 across the solvents for the oils, respectively. The AVs of the oils suggest that they are edible oils, the IVs classify the oils as non-drying oils suitable for paint making, and SVs reveal that the oils are good for soap making. Hexane, petroleum ether, and CCl4 are suitable for oil extraction industrially, while D. edulis, D. tripetala, and P. Americana oils are economically viable oil resources due to their high percentage yield, SV and IV.

Purification and Characteristics of Tyrosinase Inhibitor Produced by Actinomycetes F-97 (방선균 F-97이 생산하는 Tyrosinase 저해제의 정제 및 특징)

  • Bang, Byung-Ho;Rhee, Moon-Soo;Kim, Jin-O;Yi, Dong-Heui
    • Applied Biological Chemistry
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    • v.51 no.3
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    • pp.153-158
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    • 2008
  • An actinomycetes F-97 producing tyrosinase inhibitor was isolated from soil samples. Isolation and purification of tyrosinase inhibitor produced by F-97 was performed as follows: IRC-120 ($NH_4^+$ type) column chromatography, silica gel column chromatography, $C_{18}$ column chromatography and Sephadex LH-20 column chromatography were used successively after the centrifuged supernatant was adjusted to pH 4.0. To identify the purity of the inhibitor, octadecylsilyl(ODS) HPLC was carried out with 5% methanol as a mobile phase. Finally, the purification yield of a tyrosinase inhibitor was 5.24%. The inhibitor was very soluble in water, methanol and ethanol but insoluble in acetone, butanol, ethylacetate and chloroform. The ${\lambda}_{max}$ value of this inhibitor in water was 194nm under UV light. The biochemical test of the inhibitor was positive in Molish, Benedict, cone. $H_2SO_4$, and $KMnO_4$ tests but negative in iodine, ninhydrin, Million, Sakaguchi, xanthoproteic and Emerson tests. The tyrosinase inhibitor was stable against heat treatment of $100^{\circ}C$ for 50 minutes and pH $4{\sim}9$. The $IC_{50}$ value of this inhibitor was $19.2{\mu}g/ml$ for mushroom tyrosinase. In $1,000{\mu}g/ml$ inhibitor concentration, inhibition zone was 27 mm for Streptomyces bikiniensis NRRL B-1049. The inhibition of F-97 against mushroom tyrosinase was competitive with tyrosine.

The Complexes of Iodine with Ortho-Substituted Anilines in Carbon Tetrachloride (오르토 치환 아닐린과 요오드 사이의 착물에 관한 연구)

  • Bu Yong Lee;Sang Up Choi
    • Journal of the Korean Chemical Society
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    • v.15 no.6
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    • pp.312-317
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    • 1971
  • The interactions of aniline, o-toluidine, o-ethylaniline and o-chloroaniline with iodine in carbon tetrachloride solution have been examined through spectrophotometric measurements. The results indicate that both aniline and the o-substituted anilines examined form one-to-one complexes with I2in solution. The formation constants of the complexes measured at room temperature are 12.8, 9.31, 3.15 and 0.576 l $mole^{-1}$, respectively. Comparison of these results with previous experimental results indicates that the relative stabilities of the $I_2$-amine complexes decrease in the following order: $C_6H_5N(C_2H_5)_2 >C_6H_5N(CH_3)_2 >C_6H_5NH_2 >o-CH_3C_6H_4NH_2 >o-C_2H_5C_6H_4NH_2 >o-ClC_6H_4NH_2$. This may support the conclusion that the relative stabilities of these complexes are explained by the inductive effect and steric hindrance of the substituents.

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The Effect of Solvents on the Formation of Complexes of Benzene with Iodine and with Iodine Monochloride (벤젠과 요오드 또는 일염화요오드 사이의 錯物에 대한 용매의 영향)

  • Choi, Sang-Up;Lee, Bu-Yong
    • Journal of the Korean Chemical Society
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    • v.9 no.4
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    • pp.161-168
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    • 1965
  • The effect of solvents on the stabilities of the $C_6H_6{\cdot}I_2$ complex and the $C_6H_6{\cdot}ICl$ complex has been investigated through ultraviolet spectrophotometric measurements. The equilibrium constants obtained at room temperature for the formation of $C_6H_6{\cdot}I_2$ complex are 0.090, 0.216 and 0.328$ lmole^{-1}$ in chloroform, cyclohexane and n-hexane, respectively. The corresponding equilibrium constants at room temperature for $C_6H_6{\cdot}ICl$ complex are 0.125, 0.676 and 0.689 $lmole^{-1}.$ These results indicate that the stabilities of the two complexes increase with decreasing dielectric constants of the solvents used, the increase in stability being more rapid in the $C_6H_6{\cdot}ICl$ complex than in the $C_6H_6{\cdot}I_2$ complex. This may support the conclusion that the dative ionic structures, $C_6H_6^+{\cdots}I_2^-$ and/or ($C_6H_6I)^+{\cdots}Cl^-,$ play important roles on the reasonance stabilization of both the $C_6H_6{\cdot}I_2$ complex and the $C_6H_6{\cdot}ICl$ complex, the roles being more important in the latter complex than in the former complex.

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Kinetics for the Transformation of Outer Charge Transfer Complex to Inner Complex (Outer Charge Transfer Complex가 Inner Complex로의 변환에 따른 속도론적 연구)

  • Kwon Oh-Yun;Paek U-Hyon;Kim Eung-Ryul
    • Journal of the Korean Chemical Society
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    • v.35 no.4
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    • pp.343-349
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    • 1991
  • Formation of charge transfer complex between iodine and substituted aniline [aniline, N,N-dimethylaniline(N,N-DMA), 2,6-dimethylaniline(2,6-DMA), 2,4,6-trimethylaniline(2,4,6-TMA)] in CHCl$_3$, CH$_2$Cl$_2$ : CHCl$_3$ (1 : 1), and CH$_2$Cl$_2$ have been studied kinetically by using conductivity method. In the transformation of initially formed outer charge transfer complex to inner complex, the effects of substituted aniline as electron donor and polar medium on the reaction were investigated. The rate of transformation depend on the dielectric contribution of medium and pK$_a$ value of substituted aniline. The order of rate increasing is 2,4,6-TMA, 2,6-DMA, aniline, and N,N-DMA. The activation enthalpy ${\Delta}H^{\neq}$ for 2.5 M-substituted aniline in CHCl$_3$ at 25$^{\circ}C$ is respectively N,N-DMA, 3.47 kcal/mol; aniline, 4.25 kcal/mol; 2,6-DMA, 7.79 kcal/mol and 2,4,6-TMA, 7.96 kcal/mol; and activation entropy ${\Delta}S^{\neq}$ is large and negative value of -41 ~ -55 cal/mol${\cdot}$K.

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Characteristics and Action Pattern of ${\alpha}-galactosidase$ from Scopulariopsis brevicaulis in Korean Traditional Meju (한국 재래 간장에서 분리한 Scopulariopsis brevicaulis가 생성하는 ${\alpha}-galactosidase$의 특성 및 작용양상)

  • Choi, Kwang-Soo;Lee, Seon-Ho;Hong, Seung-Pyo;Lee, Hee-Duck;Bae, Du-Kyung;Choi, Cheong
    • Applied Biological Chemistry
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    • v.41 no.7
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    • pp.489-495
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    • 1998
  • The optimum culture condition of Scopulariopsis brevicaulis for the production of ${\alpha}$-galactosidase was as follows: Tryptone 1.5%, $NH_4NO_3$ 0.2%, Raffinose 2.5%, $KH_2PO_4$ 0.5%, yeast extract 0.5%, pH 7.0, $27^{\circ}C$. The optimum pH and temperature for the enzyme activity of ${\alpha}$-galactosidase producing Scopulariopsis brevicaulis were pH 7.0 and $27^{\circ}C$, respectively. The enzyme was relatively stable at $pH\;6.0{\sim}8.0$ and at temperature below $40^{\circ}C$. The activity of the enzyme was inhibited by $Ag^{2+},\;Hg^{2+},\;Cu^{2+}$, p-chloromercuribenzoic acid and Iodine. These results would indicate the presence of -SH groups in the catalytic site of the enzyme. Km value was 1.9 mM for $p-nitrophenyl-{\alpha}-D-galactopyranoside$ and Vmax value was $9.66{\times}10^2\;{\mu}M/min$. Sugar constituents of culture broth were identified by HPLC that the enzyme liberated sucrose, glucose and fructose from raffinose and raffinose was significantly decreased.

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Synthesis and Lubricant Properties of Estolides based on Fatty Acid (지방산 기반 에스토라이드 합성 및 윤활특성)

  • Son, Jeong-Mae;Yoo, Seunghyun;Lee, Sangjun;Shin, Jihoon;Chung, Kunwo;Yang, Youngdo;Kim, Young-Wun
    • Tribology and Lubricants
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    • v.30 no.5
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    • pp.256-264
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    • 2014
  • Enhancing the value of fine chemicals based on biomass resources is an important objective for addressing environmental and other concerns such as demand for renewable or green products, as well as from the political perspective to reduce dependence on fossil feedstock associated with the use of petroleum-based products. Based on these considerations, we studied the synthesis of estolide using waste plant-based oil materials and their application as lubricants and pour point depressants. Five estolides were prepared by varying molar ratio of palmitic acid (PA) to oleic acid (OA) using a reaction time of 48 h. The estolides were characterized by size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR). The isolated yields were in the range of 57-78 % and purity was 93-97%, showing iodine values of 18.2-37.8, total acid numbers (TANs) of 75.6-94.2 mg KOH/g and estolide numbers (ENs) of 1.2-1.8. Increasing the ratio of OA to PA in the synthesis decreased the kinematic viscosity and clouding point of the estolides. Four ball wear test of the estolides as a base oil demonstrated that the wear scar diameter (WSD) of the estolides was significantly lower (0.320-0.495 mm) than the WSD of general base oils such as 150N and Yubase (0.735 and 0.810 mm, respectively), indicating better wear resistance of the estolides. However, the lubricant property was found to be independent of the amount of OA in the estolides. These new materials are prospective candidates for application as a lubricant base oil.