bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mutual Separation of Rare Earths in Monazite with Cation Exchange Elution Chromatography
Authors: Chen Ying‐Mao , Sung Nan‐Kuan Y. 
Published: June 2015

AbstractMutual separation of the individual rare earth elements (exception of cerium) in monazite from different districts was investigated by cation exchange elution method. Strong acid type cation exchange resin, Bio‐Rad AG 50 Wx8 and eluting solution of a α‐hydroxyisobutyric acid (α‐HIBA) were used. Radioactivity tagged Eu‐152, 154 or Tb‐160 were used as radio active indicator for determination of the distribution coefficients by batch method or for the study of column elution conditions. By gradiently increase of the pH values from 3 to 5 in 0.3 M α‐HIBA eluting solution, complete mutual separation of individual rare earth elements, exception of Dy and Y, were obtained. Dy and Y could not be separated by this scheme of separation and their elution zones were overlapped. Rare earth mixture samples of monazite from different districts were separated with this scheme and these results were compared. From this comparison followings were noticed; 1. Compositions of rare earth elements in monazite from different districts are evidently not alike. 2. Samples from Brazil and Southwestern Coast of Taiwan are much more alike in their compositions but not for those from Australia and Outskirt Island. 3. Sample from Outskirt Island has higher in contents of heavier rare earths and also Nd was higher than La.
Aliphatic Hydroxamic Acids as Chelating Agents; the Stability of Their Proton and Metal Complexes
Authors: Liu Chuen‐Ying , Chang Huoy‐Joung , Uang Suh‐Shiang , Sun Peng‐Joung 
Published: June 2015

AbstractThree kinds of aliphatic hydroxamic acids, i.e., acetohydroxamic acid, n‐butyrohydrozamic acid, and sorbohydroxamic acid have been prepared as free acids and potassium salts. Their acid dissociation constants and the formation constants of complexes formed by some bivalent metal ions of the first transition element (Mn, Co, Ni, Cu, Zn) with these three chelating agents in aqueous solution have been determined by using potentiometric titration technique at ionic strength of 0.1M by sodium perchlorate and at a temperature of 25°C±0.1°. The stability of the transition metal ion complexes with these aliphatic hydroxamic acids is in the order Mn<Co<Ni<Cu>Zn, which is in agreement with the Irving and William's rule. The chelating forming properties and the comparison of quality as analytical reagent of these three hydroxamic acids were discussed in terms of the proton displacement constant. Sorbohydroxamic acid is superior in its reactivity and the other respects among the three reagents.
The Polarographic Studies of Substituent Effects in Pyridine Complexes of Transition Metals
Authors: Wei Ho‐Hsiang , Tsai Chin‐Wu 
Published: June 2015

AbstractPolarographic reduction half‐wave potentials for the series of inorganic complexes M(RC5H4N)2Cl2 (M=Co(II), Ni(II), Cu(II), Zn(II), Cd(II); R=H, CH3, NH2, OH, CONH3, CHO, COCH2 COPh, Cl, Br and CH2OH) are reported to show the substituent effects in these complexes. Consequently, the E1/2 values correlated linearly with Hammett substituent parameters, the slope of the Eσ Vs σ plots evidently decreases in order of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II).
Studies on the Extractive Constituents of the Bark of Libocedrus Formosana Florin. II
Authors: Lin Y. T. , Kuo Y. H. , Chang B. H. 
Published: June 2015

AbstractFrom the acetone extractive of the bark of Libocedrus formosana Florin, sugiol (I), lignoceric acid, 6α–hydroxy–7–oxo–ferruginol (II), ferruginol (III), xanthoperol (IV), β–sitosterol, a mixture of hydrocarbons, a long chain ester and three unidentified products, A, B and C, were isolated.
Studies on the Preparation and Properties of Some Phenolic Derivatives of Biscyclopentadienyl Molybdenum (VI) and Bisindenyl Molybdenum (VI) Oxide Dichloride
Authors: Bhalla M. S. , Vij P. K. , Multani R. K. 
Published: June 2015

AbstractReactions of biscyclopentadenyl molybdenum (VI) oxide dichloride (I) and bisindenyl molybdenum (VI) oxide dichloride (II) with mono‐, di‐ and trihydroxy phenols have been studied and the phenoxide derivatives so formed have been isolated. Infrared spectra and some phenolic derivatives of these compounds have been studied.
On the Constituents of Paris Formosana
Authors: Chen Russel R. , Wang Lih‐Yang , Koo Wen‐Yah 
Published: June 2015

AbstractThe presence of catecholtannins and saponin in Paris formosana Hayata was observed. The crude saponin has been isolated. Diosgenin was found to be the sapogenin while glucose and rhamnose were found to be the components of the sugar chain. Glucose is the first sugar unit attached to diosgenin according to GLC. 25D‐Spirosta‐3, 5‐diene was formed during the hydrolysis of the saponin.
Comment on “Maximum Interaction Model of Force Constant Calculation of the MLx(CO)6‐x Type Molecule”
Authors: Lin K. C. , Dai H. L. 
Published: June 2015

AbstractSince the introduction of non‐mechanical coupling model proposed by Cotton and Kraihanzel1‐3) for the calculation of nonrigorous carbonyl force constants of metal carbonyls, several criticisms4‐3) and modifications6‐13) on this simplified CO‐factored force field has been reported. Recently, a different approach of so‐called “maximum interaction model” was proposed by Chen and Hsiang14). However, we found that basic assumptions of this model are very shaky and questionable since three serious abnormal results could be noted as a result of maximum interaction between carbonyl groups. Here we would like to make some comments on this model.
Studies on the Cotelomerization of Ethylene and Vinyl Chloride with Carbon Tetrachloride
Authors: Wu Cheng‐Ching , Hsu Kuei‐Hsien 
Published: June 2015

AbstractThe cotelomerization of ethylene and vinyl chloride with carbon tetrachloride was studied under various reaction conditions by using the amine‐metallic salt initiating system. From the GC and NMR spectra, we found that no cotelomerization occured. This is contrary to the findings determined by Rosin et al. The modified insertion mechanism proposed by Asahada and Wu was used to explain the experimental results.
Partial Optical Bleaching of Trapped Electrons in Glasses of 2‐Methyltetrahydrofuran at 4° K and 77° K
Authors: Lin D. P. 
Published: June 2015

AbstractThe microscopic view of trapped electron concentration gradient established within a few molecular diameters of 2‐methyltetrahydrofuran after partial bleaching is known to be considerably small that there will be essentially no effects on the relative distribution of electrons in the sample. A weakly bound excited state of trapped electrons in the system is deduced from the Arrhenius activation energies determined from the bleaching data.
Diagnostic Sodium Acetate Shifts in UV Spectrum of Benzofuran‐3‐Ones
Authors: Makrandi J.K. , Grover S.K. 
Published: June 2015

Abstract4‐Hydroxybenzofuran‐3‐ones show a large bathochromic shift in UV spectrum on the addition of sodium acetate. Such a large shift is not observed in 6‐hydroxycompounds.
The Effect of Temperature, Agitation and Content of Gold on the Thickness of Electroplated Gold at Various Current Densities
Authors: Sheu Fong Chang , Chen Kuang Shiung 
Published: June 2015

AbstractThe effect of temperature, agitation, and content of gold in the solution on the thickness of electroplated gold at various current densities can be easily explained by their effect on the limiting current. Diffusion coefficient of aurocyanide ion, thickness of diffusion layer, and the activity of aurocyanide ion in the bulk solution are the three major factors to affect the limiting current. It was found that the change of temperature will affect both diffusion coefficient and thickness of diffusion layer. However, the thickness of diffusion layer is mainly determined by the means of agitation.
Photolysis of Spiropentane with Xenon Resonance Line
Authors: Tang Y‐N , Yeh Chuin‐Tih 
Published: June 2015

AbstractSpiropentane was photolyzed using xenon 1470Å resonance light source at room temperature. The photolysis products were analyzed by means of FID‐gas‐chromatographic technique. Through the information about the yields of products, the major primary process of this light‐molecule interaction was assigned as C‐C bond breakage. Methylenecyclobutane, which has been an identified isomerization product of excited spiropentane molecule, was not able to be produced at present high excitation energy.
Kinetical Study of the Catalytic Hydrogenation of Catechol by Metals
Authors: Huang Mary , Chen Chau‐Yang 
Published: June 2015

AbstractIn this paper, the kinetical study of catalytic hydrogenation of catechol over platinum metal catalysts in liquid phase under room temperature and one atmospheric pressure was investigated.Simple models “straight line” model 1 together with “triangle” model 2 were used to interpret for the change of compositions of samples traced during the reaction process, and the interpretation was found to be satisfactory. These models are as following:Model 1: consecutive reaction pathcatechol→2‐hydroxycyclohexanone→cyclohexane‐1,2‐diolModel 2: catechol→cyclohexane‐1, 2‐diol directly was added to reaction path of model 1.The relative reaction rates during hydrogenation processes over ruthenium, rhodium, palladium and platinum were calculated too.It was also found that the strength of oxygen affinity with catalysts was the factor influenced the selectivity of reaction path and the stereoselectivity of cis and trans diol products.
Bromine‐Catalyzed Isomerization of Maleic Acid to Fumaric Acid
Authors: Jwo Jing‐Jer 
Published: June 2015

AbstractThe presence of small amounts of ceric and bromide ions in the aqueous sulfuric acid solution of maleic acid can catalyze the isomerization of maleic acid to fumaric acid rapidly and quantitatively at room temperature. A qualitative kinetic study was carried out to see how the rate and the yield of this reaction depend on the relative amounts of maleic acid, ceric ion, and bromide ion. In general, the rate increases asymptotically to a limiting value as the concentration of maleic acid, ceric or bromide ion increases. Sulfuric acid has both the chemical and physical effects on the rate of isomerization. If the relative amounts of the reactants is in the order of [maleic acid]≥[Br−]≥[Ce(IV)], a very high yield up to 98% can easily be obtained. Sulfuric acid does not have major effect on the yield. A mechanism was proposed to rationalize the experimental results.
Synthesis of 1‐Isonicotinoyl‐3‐Methyl‐4‐(Substituted AZO) Pyrazol‐5‐Ones
Authors: Singh C. P. , Ojha A. C. 
Published: June 2015

AbstractIsonicotinic acid hydrazide (INH) and their derivatives are generally used as antitubercular agent. We synthesised 1‐isonicotinoyl‐3‐methyl‐4‐(substituted azo) pyrazol‐5‐one and their derivatives. Their Rf values, chemical analyses and IR spectra were recorded, The compounds had shown significant central nervous system stimulant activity.
Study on Antitumor Plant Gymnosporia Trilocularis
Authors: Ling Han‐Chin , King Ming‐Lu , Su Muh‐Hwan , Chen Gan‐Lin , Wang Chin‐Tze 
Published: June 2015

AbstractThe alcoholic extract of Gymnosporia trilocularis Hay. (Celastraceae) was found to exhibit antitumor activities against P388 lymphocytic leukemia and KB cell culture systems. From this extract β‐amyrin (1), β‐sitosterol (2) and its monoglucoside (6), stigmasterol (3) and its monoglucoside (7), campesterol (4) and its monoglucoside (8), maniladiol (5), dulcitol (9) and six yet unidentified principles (10–15) were isolated. The stereochemistry of C‐16‐OH of maniladiol (5) was confirmed spectroscopically by 1H nmr to be equatorial. Of all the isolated compounds, the mixture of three steroid monoglucosides (6:7:8=28:1.1:1) exhibited cytotoxicity (ED50=2.6×100 mcg/ml) and 5 showed only marginal effect (ED50=2.1×101 mcg/ml) in KB test system.
Spectrophotometric Determination of Dissociation Constants of Thiovioluric Acid and the Stability Constant of its Fe(II) Complex
Authors: Singh B. R. , Ghosh R. 
Published: June 2015

AbstractSpectrophotometric studies of Fe(II)‐thiovioluric acid system indicates the presence of a 1:2 complex in the pH range 4.0–6.5. The apparent equilibrium constant (K′1) has been determined by general absorbance‐extinction concentration scheme. The first and second dissociation constants of the acid have been studied at an ionic strength of 0.1 M while the third dissociation constant has been determined at I = 1 M. The effects of sudden pH change and buffer compositions on the dissociations have also been investigated. The stability constant of the complex has been calculated from the apparent equilibrium constant at ionic strength of 0.1 M. The stability constant works out to be 15.67 at pH 5.5.
A Thermodynamic Study of Bromo‐Lanthanum (III) Complexes from EMF Measurements
Authors: Hsin Shu‐Ching , Huang Teh‐Shoon 
Published: June 2015

AbstractThe stability constants (for the formation) of LaBr2+ and LaBr2+ ions were obtained potentiometrically at various ionic strengths at 20°, 25°, 30°, and 35°. The molal free energy was given by ΔG°=‐2,444.04+2.67T log T+1.39T. The thermodynamic quantities for the formation of LaBr2+ were evaluated as ΔHf° = −207.9, ΔGf° = −199.1 kcal mole−1 and S° = −29.5 cal. deg−1 mole−1 at 25°.
An Internal‐Standard Method for Determination of Trace Impurities in Semiconductor Grade Silicon by Neutron Activation Analysis
Authors: Chou Chi‐Chiang , Pung Tong‐Chuin , Tsai Hui‐Tuh , Wu Shaw‐Chii 
Published: June 2015

AbstractAn internal‐standard method1–4) has been applied for the determination of La, Sb, Au, Cr and Ag in silicon single‐crystal by neutron activation analysis using cobalt as an internal‐standard element. No chemical separation is required in this case and the precision obtained with the present method is satisfactory.
Kinetic Studies of Picolinic Acid Catalyzed Chromic Acid Oxidation of Cyclohexanone
Authors: Lin Tzuen‐Yeuan 
Published: June 2015

AbstractThe chromic acid oxidation of cyclohexanone catalyzed by picolinic acid in water undergoes a change from first‐to zero‐order dependence in both cyclohexanone and acidity. The mechanism proposed indicates the formation of an intermediate C1 by picolinic acid and chromic acid. Then C1 would react with enol form of cyclohexanone to give another intermediate C2. C2 finally cleaves into products.
The Anomalous Emission Characteristics of the Cyalume Fluorescer: 9,10‐Bis (Phenylethynyl) Anthracene
Authors: Shih‐Chen S. J. , Wu S. H. , Fang T. S. 
Published: June 2015

AbstractA fancy emission behavior was found in the light carrier of the commercial Cyalume light stick, 9,10‐bis (phenylethynyl) anthracene (BPEA). The yellowish‐orange emission is noted from BPEA in methylcyclohexane matrix. Nitrogen laser time‐resolved spectroscopy and excitation luminescene studies of BPEA in methylcyclohexane showed that the different emission behavior is probably due to the different conformation of the ground state of the BPEA in solid and in solution.
Spectrophotometric Studies on the Aggregation of Some Acid Dyes
Authors: El‐Mariah Afaf A. R. , Kafafi Zakya H. , Moussa Eglal A. 
Published: June 2015

AbstractThe electronic absorption spectra of different acid dyes, mainly C. I. Acid Red 13, 18, 27, 88 and 141, have been investigated in aqueous and non‐aqueous solutions. As the concentration of the dye increases the absorption spectrum shifts to shorter wavelengths; this behaviour has been attributed to the formation of higher aggregates. The longer wavelength band, most marked in dilute solutions, is typical of the monomeric dye. The aggregation of these dyes were studied quantitatively using the Maximum Slope Method. The monosulfonic acid dyes Red 141 and 88 and the disulfonic acid dye 13 are aggregated at room temperature with an average aggregation number of 2.0, 2.2 and 1.5, respectively. The trisulfonic acid dyes Red 18 and 27 show very little aggregation at this temperature.
A Study of Chemically Activated Ethylmethylether
Authors: Young Yau‐Wen , Chao Kuei‐Jung 
Published: June 2015

AbstractThe decomposition rate of the chemically activated ethylmethylether produced from dimethyl ether‐oxygen‐diazomethane photolysis at 3660Å have been measured to be 2∼5×106 sec−1. By comparing the pressure dependent variation of rate constants with the RRKM calculation results, the strong collision behavior of dimethylether and the gaussian energy distribution of singlet methylene are determined.
Determination of Boron with Isotope Dilution Method
Authors: Luo Shen‐Kay , Ou‐Yang C. C. , Chang Fu‐Chung , Yeh Yu‐Chai 
Published: June 2015

Abstract100 ng or less amount of boron in the form of Na2B4O7 was loaded on tantalum filament of thermal ionization mass spectrometer. A serial isotope ratios of metaborate, Me=88 (Na2 11BO2) and Me=89 (Na2 11BO2) prepared with spike (10B enriched) and nature boron were determined successfully and compared with reference values.
Selective Ortho Chlorination of Phenols with n, n‐Dichloro‐t‐Butylamine in Various Solvents
Authors: Ogata Yoshiro , Takagi Katsuhiko , Kondo Yoshinori , Hsin Shu‐Ching , Woo Whei‐Ing , Chen Fa‐Ching 
Published: June 2015

AbstractChlorination of phenol with N,N‐dichlororo‐t‐butylamine (DCB) in appropriate solvents affording o‐ and p‐chlorophenols exhibits high ortho/para ratio up to >10. Solvents associate with phenolic OH group and interfere with the hydrogen bonding between phenol and DCB tend to decrease both rate of reaction and ortho/para ratio; e.g., <1.1 in acetonitrile. The reaction shows autocatalysis exerted by a product, t‐butylamine, which would accelerate the reaction by abstracting a proton from the benzene site on which C1 of DCB attacks. Anhydrous sodium phenoxide is little chlorinated. These facts imply a transition state in which phenol and DCB is hydrogen‐bonded for the ortho chlorination. This type of chlorination is applicable to the ortho chlorination of other phenols.
A Facile Preparation of Tebbe Reagent and its Subsequent Reactions
Authors: Chou Ta‐Shue , Huang Sung‐Ben , Hsu Wen‐Hu 
Published: June 2015

AbstractA facile preparation of Tebbe reagent (1) by reacting AlMe3 solution with Cp1TiCl2 is reported. After complete removal of solvent and excess of AlMe3, the crude Tebbe reagent could be used without purification to react with ketones in a Wittig‐type manner.
Atomic Absorption Spectrophotometric Investigation and Determination of Palladium
Authors: Mostafa M. A. , Kabil M. A. 
Published: June 2015

AbstractThis work aims to achieve a determinate characterization of compound formation and to find out the resolution to overcome chemical interferences in atomic absorption spectrophotometric (AAS) determination of palladium. The effect of flame composition in producing a neutral palladium atoms was investigated. A new analytical procedure has been elaborated for the determination of palladium.
A Study on Improving the Crystallization Rate of Poly (Ethylene Terephthalate)
Authors: Chen Leo‐Wang , Chiu Wen‐Yen , Yu Wei‐Ching 
Published: June 2015

AbstractIn this study, sodium benzoate was selected as the nucleating agent to improve the crystallization rate of Poly (Ethylene Terephthalate) (PET). A new polyester, PEAT, which was systhesized from Bis Hydroxy‐Ethyl Terephthalate (BHET) and adipic acid, was blended with PET to improve the (crystallization) rate of PET at lower temperatures. The crystallization rate of the PET blends was measured with a DSC and the kinetics of crystallization were studied.It was found that the range of the crystallization temperatures for the PET/sodium benzoate blends was wider than that for the PET/PEAT blends which shifted to a lower temperature region. PEAT showed a pronounced effect on the crystallization rate at lower temperatures, while sodium benzoate effected the crystallization rate within the entire range of crystallization temperatures.
Kinetics of Phase Transfer Catalytic Preparation of Benzyl Phenyl Ether
Authors: Yeh Mou‐Yung , Lin Tzong‐Bin , Shih Yen‐Ping 
Published: June 2015

AbstractBenzyl phenyl ether is prepared in a well‐stirred batch reactor from phenol and benzyl chloride using tetrabutylammonium iodide as phase transfer catalyst. Phenol with sodium hydroxide is dissolved in water as the aqueous phase, and benzyl chloride is dissolved in toluene as the organic phase. Tetrabutylammonium iodide gives high reaction rate without the formation of micelles during the reaction. The reaction mechanism is verified by infrared spectrum study and other experimental observations. The kinetics of the reaction of benzyl chloride is modelled as a first‐order chemical reaction. The cocatalytic effect of the iodide ion, and salting out effect on the overall reaction rate are discussed in detail using experimental data.
Charge Localization of Some Highly Polarizable Systems
Authors: Lee Shyi‐Long , Chu San‐Yan 
Published: June 2015

AbstractIn this work we discuss some close analogies among various intramolecular charge‐transfer systems with high polarizability. They range from sudden‐polarization systems concerning two‐electron localization to valence‐hole and core‐hole systems involving only one‐electron localization, and the combined situation of valence electron‐core hole pair localization. The high polarizability of a two‐site (a, b) system is shown to be correlated to the weakness of the electronic coupling integral <a|H|b> between the sites. The hole localization in core‐hole states and van der waals ions is compared with that of molecular ions due to solvation effect. The electron‐hole pair localization in the core‐hole state of the mixed valence system is compared with that in the Πg,a state of H2 due to electron correlation behavior.
A Computational Algorithm for the Polynomial Approximation Method of Sensitivity Analysis in Chemical Kinetics
Authors: Hwang Jenn‐Tai 
Published: June 2015

AbstractThis paper describes the logic for a program developed by the author to implement the polynomial approximation method (PAM) of sensitivity analysis for general kinetic purposes. The relevant equations and numerical details of the algorithm are outlined, a flow chart is provided, and some programming considerations are discussed in detail. A listing of the PAM code is given in the appendix. The paper also gives a few suggestions for possible improvements and extensions of the present algorithm.
A Metal‐Metal Bonded Dinuclear Ruthenium Ketene Complex
Authors: Lin Ying‐Chih 
Published: June 2015

AbstractWe report the synthesis of metal‐metal bonded dinuclear ruthenium ketene complex [CpRu(CO)]2(μ‐CH2CO)(μ‐CO), 3, (Cp=η5‐C5H5) which contains the unique structural feature, of a μ‐η2(C,C) ketene group bridging two metal centers. Complex 3 is prepared by a rare intramolecular CO insertion to the methylene group of a Ru complex [CpRu(CO)2]2(μ‐CH2), 1, in the absence of CO or any donor ligand. The cis and trans isomers of 3 originating from the arrangement of the Cp groups and the unsymmetrically bridging ketene group, are observed in the NMR spectra. Unlike a ketene complex without a metal‐metal bond [CpRu(CO)2]2(μ‐CH2CO), 2, complex 3 exhibits the chemistry of a ketene molecule and might be used as a stoichiometric ketene precusor in organic reactions.