bluuebunny/crossref_metadata_2025_split huggingface dataset:
Derivatization‐Gas Chromatographic Analysis of Nalidixic Acid in Tablets
Authors: Wu Shou‐Mei , Wu Hsin‐Lung , Chen Su‐Hwei 
Published: June 2015

AbstractA simple and improved gas chromatographic method has been developed for the quantitative analysis of nalidixic acid. The method is based on the derivatization of nalidixic acid with pentafluorobenzyl bromide in acetone, using potassium carbonate as a base‐catalyst. The derivative obtained was chromatographed on an OV‐101 column and the pentafluorobenzyl ester of cinoxacin was used as an internal standard. The method was satisfactorily applied to the analysis of nalidixic acid in tablets, and the results agree well with those obtained using the UV absorption spectrophotometric method.
Stereocontrolled Syntheses of (4S, 5R)‐ and (4S, 5S)‐Dihydroxy‐N‐Decanoic Acid‐4‐Lactones Via Biochemical Methods
Authors: Wang Yi‐Fong , Yiin Shiow‐Ling , Chen Sy‐Heng 
Published: June 2015

Abstract(4S‐5R)‐ and (4S‐5S)‐dihydroxy‐n‐decanoic acid‐4‐lactones have been synthesized in a stereocontrolled manner by a chemomicrobiological approach.
Sensitized Photooxygenation of 2,5‐Di‐Tert‐Butylfuran
Authors: Kuo Yueh‐Hsiung , Shih Kae‐Shyang 
Published: June 2015

AbstractSensitized photooxygenation of 2,5‐di‐teri‐butylfuran was carried out in methylene chloride at −75°C to give a labile ozonide 4a, which was heated in methylene chloride under reflux to afford six products after purification.
Structural and Mechanical Properties of Polybutadiene‐Urethane Elastomer
Authors: Chiu Wen‐Yen , Chen Leo‐Wang , Lee Shyh‐Hwang 
Published: June 2015

AbstractA series of polyurethanes based on hydroxyl‐terminated polybutadiene (HTPBD) and cured with Bis‐(‐hydroxy ethyl)‐terephthalate (BHET) have been synthesized. Mechanical, microscopic and kinetic studies were carried out to elucidate the structure‐property relationships from the view point of phase separation. We studied the effects of the polymerization method, varying the hard to soft segment ratio and changing the hard‐segment domain structure on the properties of the subject materials.Dynamic mechanical responses showed that the Tg of the soft‐segment at −60°C was independent of the hard‐segment content, which indicates that the copolymers were well phase separated. A higher hard‐segment content brought about a slight increase in the modulus, a moderate increase in the tensile strength and a decrease in the ultimate elongation.The size of the hard‐segment domain, as estimated from electron micrographs, ranged from 60A to 100A. It was observed that a higher content of hard‐segments causes an increase in the hard‐segment domain size. In addition, a general survey of the reaction rate indicated that BHET is less reactive with diphenyl methyl diisocyanate (MDI) than with HTPBD.
Analysis of Phenolic Priority Pollutants by High Performance Liquid Chromatography with Electrochemical Detection
Authors: Whang Chen‐Wen 
Published: June 2015

AbstractApplication of high performance liquid chromatography coupled with electrochemical detection (HPLC/EC) to the analysis of phenolic priority pollutants was studied. This method is highly sensitive and selective. Under optimum experimental conditions, the detection limits range from 0.05 ng for phenol to 1.20 ng for pentachlorophenol. The method was successfully applied to the direct determination of trace phenols in industrial wastewaters.
A Study of Degradation of a Jet Fuel
Authors: Li Norman C. , Tzou Ji R. , Chang Hua , Wang Sung M. 
Published: June 2015

AbstractDegradation of a jet fuel (JP‐5) derived from petroleum and manufactured by the Chinese Petroleum Corporation in Taiwan was determined using various methods. Fuel degradation was monitored in the presence of the following compounds: phenol, 2,6‐dimethylphenol, thiophenol, 2‐methylpyridine, copper powder and mixtures of some of these compounds both at room temperature and at 80°C. The extent of light scattering and the amount of copper drawn into JP‐5 from added copper powder are correlated with the extent of deposit formation due to degradation of the fuel. Copper promotes deterioration of JP‐5 because of Cu(II) complex formation. Electron spin resonance and cyclic voltammetric measurements confirm the presence of Cu(II).
Surface Acidity of Alumina Aluminum Phosphate
Authors: Yang Sze‐Ming , Lee Ming‐Jiq , Wu Shiaw‐Tzong 
Published: June 2015

AbstractAlumina aluminum phosphates in various aluminum to phosphor ratios were synthesized. The pore size can be easily controlled. The surface is weakly acidic. The number of acid sites per unit surface area shows a maximum at Al/P=1.9. The dehydration activity of tert‐butanol correlates with the total acid amount, whereas the dehydration activity of isopropanol is related to both the mumber of acidic and basic sites.
The Structure of 3‐Phenyl‐4‐(N‐Carbamyl‐1,4,2‐Oxathiazolimin‐3‐yl)Sydnone, C11H7N5O4S·0.8 CH2Cl2
Authors: Ueng Chuen‐Her , Wang Yu , Yeh Mou‐Yung 
Published: June 2015

AbstractThe title compound (Mr = 373) crystalizes in the othorhombic space group P bna with a = 10.410(2), b = 11.658(4), c = 23.108(3) Å, V = 2804.4 Å Z = 8. The single crystal intensity data were collected using MoK∞ radiation (λ = 0.7093Å) at room temperature. The crystal and molecular structure was solved with the final agreement index R = 0.039 for 1046 observed reflections. The bond lengths N(1)‐ C(7) and C(7)‐C(8) of the title compound are slightly longer than those of 3‐substituted sydnone derivatives. This may be attributed to the steric effect arising from the interaction of the phenyl ring and the 4‐substituent with the neighboring atoms of sydnone ring. Both the title compound and 4‐acetyl‐3‐(p‐tolyl)sydnone have smaller dihedral angles between the sydnone ring and the plane of the sp2 orbital of the double bond of the 4‐substituent and both have shorter C(7)‐C(9) bond lengths than those of other similar sydnone derivatives.
Zinc(II), Cobalt(II) and Nickel(II) Complexes of 5‐Substituted‐1,3,4‐Thiadiazoles
Authors: Adam F. A. 
Published: June 2015

AbstractZn(II), Co(II) and Ni(II) complexes with some 5‐substituted‐1,3,4‐thiadiazoles (L1‐L4) have been prepared and characterized by conductivity, microanalysis, thermal analysis, infrared and electronic spectra measurements. All complexes behave as 1:1 electrolyte and the ligands are coordinated as bidentate molecules. The stability constants and energy of formation are determined and discussed on the basis of the ligands structure.
Paired Electrolysis of Aldoses in a Divided Flow Cell
Authors: Chou Tse‐Chuan , Liaw Shyue‐Jang , Hwang Bing Joe 
Published: June 2015

AbstractSimultaneous anodic oxidation and cathodic reduction of aldoses in a divided flow cell were studied. The stream of the anolyte was an aqueous solution containing D‐glucose, sodium bromide, and sodium bicarbonate. The stream of the catholyte was also an aqueous solution containing xylose and sodium sulfite. The factors which affected both the anodic and cathodic reactions were studied. The results indicate that the flow rates and temperatures of the anolyte and the catholyte, concentrations of the aldoses, pH values and the material of electrodes significantly affect both anodic and cathodic yields. The selectivities of gluconic acid in the anode and xylitol in the cathode were very high. The power consumption of paired electrolysis in the flow system was less than paired electrolysis in a batch system.
The Electrochemical Behavior of Complexes of Cobalt and Nickel with δ‐Valerolactam at the Dropping Mercury Electrode
Authors: Katyal M. , Puri B. K. , Kumar Ashok , Lin Jenn‐Lin 
Published: June 2015

AbstractThe kinetics of the polarographic reduction of Co(II) and Ni(II) has been investigated in the presence of an increasing concentration of the complex forming agent δ‐valerolactam at pH 6.0 and at constant ionic strength (0.1 M KNO3,). In both cases the waves were found to be diffusion controlled and irreversible. The values of the kinetic para‐meters such as the forward rate constant K°f, k and the charge transfer coefficient αn have been calculated as a function of ligand concentration. The diffusion current was precisely proportional to the concentration up to a metal ion concentration of 3.5 mM. Hence, a straight line is useful as a calibration curve in the quantitative analysis of these two metal ions. The method has also been applied to the determination of these metals in certain alloys.
Isoochotensine, a New Spirobenzyusoquinoline Alkaloid from: Corydalis Ochotensis Turcz
Authors: Wu Tian‐Shung , Huang Shiow‐Chyn , Lu Sheng‐Teh , Wu Yang‐Chang 
Published: June 2015

AbstractSeparation of the phenolic fraction of Corydalis ochotensis afforded a new spirobenzylisoquinoline alkaloid, isoochotensine (1) and three known alkaloids, ochotensine (3), cheilanthifoline (7), and lienkonine (9) as their acetyl derivatives together with a known nonphenolic alkaloid, ochotensimine (5). Their structures were elucidated by the spectral data.
s‐p Separation Model Indo‐Mo Method and the Theoretical Study of 1H Hyperfine Coupling Constant
Authors: Chen Cheng , Sun Kuang‐Chung 
Published: June 2015

AbstractWe have recently developed a modification of the traditional semiempirical INDO‐MO method especially useful for open shell problems: INDO with s‐p separation (J. Chin. Chem. Soc., 32, 385(1985)). In order to show the reliability of our new method fifty seven free radicals and radical ions were selected as examples for our MO calculation.We are particularly interested in the unpaired electron distribution of hydrogen atoms. A linear correlation analysis between the spin density and the isotropic hyperfine coupling constant (aH) for 1H has been carried out for these radicals and ions. Most of our calculated aH's are better than the results reported using the conventional INDO method.
Organotransition‐Metal Complexes of Multidentates 1. Synthesis and Characterization of N, N‐Bis(Pyrazol‐1‐Ylmethyl)Aminomethane and N, N‐Bis(3, 5‐Dimethylpyrazol‐1‐Ylmethyl)‐Aminomethane Derivatives of the Group VI Metal Carbonyls
Authors: Shiu Kom‐Bei , Vong Wen‐Jong 
Published: June 2015

AbstractN, N‐bis(pyrazol‐1‐ylmethyl)aminomethane (bpam) and N, N‐bis(3, 5‐dimethylpyrazol‐1‐ylmethyl)aminomethane (bdmpam) reacted with M(CO)6 or M(CO)3(CH3CN)3 in acetonitrile to give respectively fac‐(bpam)M(CO)3 and fac‐(bdmpam)M(CO)3 in good yields (M=Cr, Mo, W). These complexes are characterized by elemental analysis, IR, and NMR and compared with the related polypyrazolylborate complexes of the group VI metal carbonyls.
Differential Pulse Polarographic Determination of Nitrate in AUT Solution
Authors: Lee Chi‐So 
Published: June 2015

AbstractA differential pulse polarographic method for the determination of nitrate ion has been developed. With 0.5 M CaCl2 as supporting electrolyte, NO−3 is reduced to give a peak with E1/2=–1.836 Volt vs. the Ag/AgCl electrode. The differential pulse polarographic peak height is proportional to the nitrate concentration from 20 to 60 ppm. The detection limit for nitrate is 2 ppm in pure aqueous solution. In the determination of 40 ppm nitrate a relative precision (relative standard deviation) of less than 2% was achieved. Nitrite interferes seriously and should be absent if accurate results are required. The method has been applied to the determination of nitrate in Ammonium Uranyl Tricarbonate (AUT) Solution, results obtained by this method are compared to those obtained by ion chromatography. The agreement between the two sets of results suggests that the DPP method can be used with a fair degree of confidence.
Deprotonation/Alkylation Reactions of Sulfolenes
Authors: Chou Ta‐Shue , Yu Chin‐Fen 
Published: June 2015

AbstractDeprotonation/methylation reactions have been carried out on a series of substituted 2‐sulfolenes and 3‐sulfolenes. For 2‐sulfolenes, both allylic and vinylic deprotonation reactions occur to give, after treatment with methyl iodide, 2‐methylated 3‐sulfolenes and 2‐methylated 2‐sulfolenes. These products are useful intermediates because substituted 3‐sulfolenes are precursors to substituted butadienes and 2‐alkylated 2‐sulfolenes are precursors to β‐functionalized trans olefins.
A Simple Method for Determining the Critical Micellar Concentration of a Surfactant
Authors: Chang C. Y. , Wang S. J. , Liu I. J. , Chiu Y. C. 
Published: June 2015

AbstractThis paper will present a simple method for critical micellar concentration (cmc) determination based on light scattering using a turbidimeter. The method does not require the optical clarification of the surfactant solution. The surfactant solutions were prepared from distilled water after boiling. Distinct cmc values were observed for polyoxyethylene mono n‐dodecylether, sodium taurodeoxycholate and sodium dodecyl sulfate. The cmc values obtained using the turbidity method were compared with cmc values obtained by the surface tension method and with data given in the literature. Values obtained by our simple method have comparable accuracy with data obtained from more elaborate experiments.
A Study of the Kinetics of the Sulfation of 2‐Octanol by Sulfamic Acid
Authors: Ho Wu‐Hsiung 
Published: June 2015

AbstractThe kinetics of the sulfation of 2‐octanol by sulfamic acid in dimetylformamide were studied. The rate of disappearance of sulfamic acid obeys the rate equation:Rate=k[SA]where [SA] is the concentration of sulfamic acid. The energy and entropy of activation are 3.1 ± 0.6 kcal/mol and 15±2euA possible mechanism is as follows: The sulfamic acid reacts with DMF to form DMF·SO3 which then reacts rapidly with 2‐octanol to form ammonium sec‐octyl sulfate.The kinetics of the sulfation of 2‐octanol by sulfamic acid in dimethyl sulfoxide were also studied. The reaction is described by a similar first‐order equation. The energy and entropy of activation are 33.7±1.0 kcal/mol and 17±3eu.
Platium Film Electrodes (1) Platium Film on Ti or TiO2‐Covered Ti
Authors: Wang Chung‐Reng , Hseu Tong‐Ming , Lin Zui‐Feng 
Published: June 2015

AbstractA platium film was formed on a Ti(Pt‐Ti) and on a TiO2(Pt‐TiO2‐Ti) substrate by the conventional electroplating method (ELP) and by the electroless plating technique (ELSP). The effective minimum film thickness was found to be 0.5 μm judging from the maximum electrocatalytic capablity in alkaline (1 M NaOH) water electrolysis. The film obtained from ELP is superior to that obtained from ELSP, being more tightly bound to the substrate, showing better coverage of the subsrate surface, and also being mechanically stronger. Comparisons with bright Pt and with Pt‐black electrodes were made and it is concluded that the electrodes newly prepared using ELP will work as well as Pt‐black electrods. The electrodes from ELSP are useful only as cathodes, and are not suitable as anodes.
A Two‐Dimensional 1H NMR Approach for Peptide Backbone Assignments: Gramicidin S
Authors: Yu Chin , Chen Chao‐Ming 
Published: June 2015

AbstractTwo‐dimensional NMR spectra of gramicidin S have been measured. With the combination of COSY (through bond interaction) and NOESY (through space interaction) spectra, it is possible to identify amino acid residues sequentially. It is found that the phase‐sensitive 2D technique is superior to the absolute value mode. A double quantum filtering technique could be combined with phase‐sensitive COSY experiments to obtain the optimum results.
An Unusual Reductive Debromination of 8‐Bromoguanosine by Tri‐n‐Butylphosphine
Authors: Chern Ji‐Wang , Lee Horng‐Yuh 
Published: June 2015

AbstractA reaction of 8‐bromoguanosine with benzyl disulfide in the presence of tri‐n‐butylphosphine in aprotic or protic solvent afforded guanosine instead of 8‐bromo‐5′‐benzylthio‐5′‐deoxyguanosine through an unexpected reductive debromination.
Studies on Binuclear Co(II) and Cu(II) Complexes of Tridentate N‐(2‐Carboxyphenyl)Salicylideneimine
Authors: Mahmoud M. R. , El‐Gyar S. A. , Ibrahim S. A. 
Published: June 2015

AbstractHomo Cu(II) and Co(II) binuclear complexes H[MLClMCl2] formed by using the donor properties of the cis two oxygen atoms of the tridentate N‐(2‐carboxyphenyl)‐salicylaldimine Schiff base derived from salicylaldehyde and anthranilic acid have been synthesized. It was found that the Cu(II) “complexed ligand” readily reacts with CoCl2 to form mononuclear Co(II) and binuclear oxygen bridged Co(II) complex [Co2‐L2](H2O)2. The structure of the so prepared complexes was investigated using microchemical analysis, molar conductance measurements as well as electronic and vibrational spectral studies. It was concluded that in the Cu(II) binuclear complex, the Cu(II) ion inside the “complexed ligand” has a planar structure while the other Cu(II) ion is distorted away from planarity. In the Co(II) binuclear complex, the Co atom of the “complexed ligand” is distorted from tetrahedral structure when it coordinates to the second Co atom.
Chelating Behaviour of Substituted 1‐Benzoyl‐4‐Phenylthiosemicarbazide
Authors: El‐Asmy A. A. 
Published: June 2015

AbstractThe preparation and characterization of a series of new coordination compounds of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) containing o‐methyl‐ or o‐chlorobenzoyl‐4‐phenyl‐3‐thiosemicarbazide (HMBPT, HCBPT=HL) are reported. The reaction products were investigated by analyses, electrolytic conductance, magnetic susceptibility, reflectance and IR spectral studies. The IR spectra show that HMBPT and HCBPT coordinate with the metal ions via different coordination sites (NS and/or NO). The spectral data support the suggestion that the ligands form his‐chelates with Ni(II) and Cu(II) of square planar stereochemistry and of general formulae ML2·H2O, where L is the uninegatively charged bidentate ligand. The Co(II) ion forms octahedral and tetrahedral structures with HMBPT and HCBPT, respectively. The ligand field parameters (D4, B and β) for the Co(II) chelates were calculated using the averaged‐ligand‐field approximation. The influence of the benzene ring substituents (o‐chloro or o‐methyl) on the stereochemistry are discussed. Also, the formation of the complexes in solution was tested by the pH‐metric method.
Thin Layer Chromatographic Detection and Separation of Metal Ion Complexes with Tridentate Schiff Base
Authors: Gupta Mala , Kansal B. D. 
Published: June 2015

AbstractThe Tridentate chelating, system present in Salicylidine o‐amino benzoic acid was used for complexation with Cu (11), Ni (11), Co (11) and Pd (11). The thin‐layer chromatographic (TLC) detection and separation of these complexes on Silica gel (G) layers was studied. The coloured spots of the complexes were quite visible without any visualizing agent. A maximum of four complexes could be resolved and identified. The coloured zones were eluted with solvent and characterise by elemental analysis and spectral studies. Colour of the complexes at λmax was measured.
Coupling and Cyclization of Sydnone Compounds
Authors: Tien Hsien‐Ju , Lee Yaw‐Kuen 
Published: June 2015

AbstractCyclization were occurred via the coupling reactions of some mercuric chloride derivatives of sydnone with LiPdCl3‐CuCl2.A unique six‐membered ring, 3,3′‐ethylene‐4,4′‐bissydnone, was obtained by the cyclization reation of 1,2‐di[3‐(4‐chloromercuric)sydnonyl]ethane. However, the seven‐membered 3,3′‐trimethylene‐4,4′‐bissydnone and 1,3‐di[3‐(4‐chloro)sydnonyl]‐propane were obtained from the corresponding mercuric chlroide of sydnone. Onyl substitution reaction took place when 4,4′‐di[3‐(4‐chloromercuric)sydnonyl]biphenyl, 4,4′‐di[3‐(4‐chloromercuric)sydnonyl]benzene, di(p‐[3‐(4‐chloromercuric)sydnonyl]‐phenyl}methane and, di(p‐[3‐(4‐chloromercuric)sydnonyl]phenyl]ether were treated using the same process.
Studies of the Factors Controlling Regioselective Nucleophilic Addition to Dienylium‐Iron Complexes
Authors: Hwang Wen‐Shu , Liao Rong‐Li , Ong Chi Wi 
Published: June 2015

AbstractTricarbonyl(4‐alkoxyl‐1‐alkylcyclohexadienylium)iron complexes (I) react with metal‐cation enolate nucleophiles to give in most cases a mixture of products (II) and (III), resulting from attack at the C‐1 and C‐5 termini of the dienylium ring. Factors that control the regioselectivity of nucleophilic addition, including the steric and electronic effects of the 4‐alkoxyl and 1‐alkyl substituents, the degree of association between the enolate nucleophiles and their counterions, and the polarity of the solvents, were investigated.
Determination of Benzidine and its Congeners by Liquid Chromatography with Electrochemical Detection
Authors: Whang Chen‐Wen , Yang Lin‐Lan 
Published: June 2015

AbstractHigh performance liquid chromatography coupled with electrochemical detection (HPLC‐EC) method has been developed for the determination of benzidine and its related congeners in wastewater at the low ng/mL level. With a µ‐Bondapak C18 column, 53% acetonitrile (pH 4.7), and electrochemical detection at +1.0 V applied potential, the detection limits range from 3 ng/mL for benzidine to 10 ng/mL for 3,3′‐dichlorobenzidine, assuming a 100 µL injection. The detection limits can be further lowered to the sub‐ng/mL level by incorporating a short precolumn into the HPLC system for on‐line sample enrichment. Recoveries are generally greater than 80% — except for benzidine and 3,3′‐diaminobenzidine which give 50–70% recoveries. Industrial wastewater samples from a coke‐plant and a plant producing 3,3′‐dichlorobenzidine based dyes were successfully studied via this method.
Synthesis of [µ‐1,2‐Phenylenebisphosphido‐P,P']Diironhexacarbonyl Complex and Its Reactivity
Authors: Liu Shiuh‐Tzung 
Published: June 2015

AbstractThe title compound was prepared from the reaction of o‐bisphosphinobenzene with nonacarbonyldiiron. The structure was determined by spectroscopic methods. The mechanism of formation of the complex and its reactivity are discussed.
Selectivity in the Phase Transfer Catalytic Hydrogenation of Nitrobenzene by Transition VIII Metals
Authors: Juang Tzouh‐Miin , Hwang Jeng‐Chai , Ho Hsiu‐O , Chen Chau‐Yang 
Published: June 2015

AbstractThe phase transfer hydrogenation of nitrobenzene to p‐aminophenol has been investigated for the catalysts Pt, Pd, Rh and Ru. The influence of factors such as surfactant concentration, sulfuric acid concentration, hydrogen pressure and temperature on the reaction was determined. It was found that the rate‐determining step for the catalytic hydrogenation of nitrobenzene is the catalytic process by which the hydrogen atom is absorbed on the metal surface. A reaction model is suggested which accounts for the observed hydrogenation selectivity and explains how these factors affect product composition and yield. It is shown that Pt favors p‐aminophenol production, while Pd favors aniline production.
A Study of Monodispersed Polydimethylsiloxanes
Authors: Yang M.H. , Liaw W.C. 
Published: June 2015

AbstractA series of monodispersed polydimenthylsiloxanes (PDMS) with molecular weights from 3K to 156K were synthesized. The intrinsic viscosity and absolute molecular weight of each monodispersed PDMS was measured and the Mark‐Houwink equation for the PDMS series in toluene at 25°C was derived: [eta;]=2.88 × 10−4 M0.613. It was proven that the accurate molecular weight determination of polysiloxanes is not possible using polystyrene (PS) standards. It can be achieved either by using a gel permeation chromatographic method with PDMS standards or by a calculation from the Mark‐Houwink equation using experimental values of intrinsic viscosity.