bluuebunny/crossref_metadata_2025_split huggingface dataset:
ChemInform Abstract: Principles and Theory of Two‐Cycle Circulation Liquid Chromatography.
Authors: CHIZHKOV V. P. , VARIVONCHIK N. E. 
Published: September 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Adsorptive Removal of Alkoxyphenols from Ketones and Esters with Activated Carbon – Experiments and Modelling
Authors: Gräf T. , Pasel C. , Bathen Dieter 
Published: September 2010

AbstractHochreine Chemikalien werden vor allem in den Bereichen Elektronik, Optik, Pharmazie und Analytik eingesetzt. Zur Feinreinigung von Flüssigkeiten wird besonders die Adsorption genutzt. Mit Hilfe der hier vorgestellten Adsorptionsmessungen am System Aktivkohle/Alkoxyphenol in Ketonen und Estern als Lösungsmittel wurden Adsorptionsmechanismen untersucht und thermodynamische Gleichgewichtsdaten zur Auslegung von Prozessen erhalten.
Production of H2 and medium heating value gas via steam gasification of lignins in fixed‐bed reactors
Authors: Ferdous Deena , Dalai Ajay K. , Bej Shyamal K. , Thring Ronald W. 
Published: September 2010

AbstractIn this work, steam gasification of Alcell and Kraft lignins were carried out in a fixed‐bed reactor in order to produce H2 and medium heating value gas. The conversion of lignins increased from a low of 64 wt% for Alceil lignin to a high of 88 wt% for Kraft lignin with increasing steam flow rate and temperature. Maximum H2 production of 60.7 mol% was obtained at 800°C and at a steam flow rate of 15 g/h/g of Kraft lignin, whereas maximum heating value of 18000 kl/m3 of the product gas was obtained at 650°C and at 5 g/h/g of Alcell lignin. Also, the performance of a Ni‐based steam reforming catalyst for the production of H2 was studied for both types of lignin in a dual fixed‐bed reaction system. A maximum H2 production of 63 mol% was obtained at a catalyst bed temperature of 750°C and at a catalyst loading of 0.3 g for Alcell lignin. The sulfur present in Kraft lignin had detrimental effect on the catalyst performance.
Photoelectrochemistry of electrochemically deposited cadmium‐rich cadmium mercury telluride films.
Authors: Tan Zheng , Li Jun , Mi Tian‐Ying 
Published: September 2010

AbstractThe potentiostatic deposition of cadmium‐rich CMT films onto Ti, Mo, Ni substrates from an aqueous bath was carried out. The photoelectrochemical properties of film electrodes were investigated when used in a solid‐liquid junction photoelectrochemical cell (PEC). A.C. capacitance was determined.
Studies on silicon‐containing fragrance raw materials I. Syntheses and structure‐odor relationship of acetals of 4‐trimethylsilyl‐3‐cyclohexenone and 4‐trimethylsilylcyclohexanone and their carbon counterparts
Authors: Tang Shi‐Xiong , Li Yue‐Ming , Cao Yu‐Rong , Wang Xiao‐Lan 
Published: September 2010

AbstractIn order to investigate the structure‐odor relationship of odoriferous compounds and search for new aroma chemicals, seven acetals of 4‐trimethylsilyl‐3‐cyclohexenone and their carbon counterparts were synthesized by Birch reduction of 4‐substituted anisoles and then acetalization. Seven acetals of 4‐trimethylsilylcyclohexanone and their carbon counterparts were synthesized similarly. Structures of all new compounds were determined by MS, IR and 1H NMR, and their characteristic odors were evaluated as well.The characteristic odors of the acetals formed by 4‐substituted‐3‐cyclohexenone and 1,2‐diols are fruity and woody. The acetals formed from 1, 3‐diols are woody, and formed with 1, 4‐diols are very faint in odor. Odors of acetals of 4‐substituted cyclohexanone are all very weak. As a whole, odors of organosilicon compounds are weaker, but somewhat more delicate than their carbon counterparts.
Langmuir‐Blodgett film formation of rare‐earth metal di‐, triphthalocyanine complexes and observation of their thin film by means of TEM and STM
Authors: Liu Yun‐Qi , Zhu Dao‐Ben , Ruan Li‐Ke , Bai Chun‐Li , Yamada Akira , Shigehara Kiyotaka 
Published: September 2010

AbstractThree different kinds of rare‐earth metal phthalocyanine complexes (Pc2LuH, Pc3Gd2, R12 Pc3Dy2) were synthesized. Their ultra‐thin films were prepared by the Langmuir‐Blodgett technique. Crystallites were observed in Langmuir film of Pc3Gd2 by means of transmission electron microscopy. The limiting molecular areas of the phthalocyanine derivatives on pure water increased in the order mono‐, di‐ and triphthalocyanine, implying that these phthalocyanine molecules are stacked with a face‐to‐face orientation and edge‐on to the water surface. By using scanning tunneling microscopy individual molecules of lutetium diphthalocyanine adsorbed on graphite surfaces were imaged for the first time.
Studies on bio‐antioxidants II. An ESR study on the antioxidant efficiency of ascorbyl palmitate in micelles
Authors: Liu Zhong‐Li , Han Zheng‐Xu , Cheng Pin , Wu Lung‐Min , Liu You‐Cheng 
Published: September 2010

AbstractThe kinetics for the reaction of ascorbyl palmitate and 4‐hydroxy‐TEMPO, 4‐methoxy‐TEMPO or 4‐hexanoyloxy‐TEMPO in CTAB and SDS micelles was studied by ESR spectroscopy. It was found that the behavior of ascorbyl palmitate is remarkably different from ascorbic acid in their antioxidant activity in micelles. The predominant factors governing the activity in micelles involve the lipophilicity of the antioxidant and the oxidant, the charge type of the substrates and the concentration of the surfactant. As high as 2 × 104 fold rate variation was observed by changing the lipophilicity of the antioxidant and the microenvironment of the reaction medium.
Studies on sulfinatodehalogenation XXI. A new and convenient syntheses of 2‐(F‐alkyl) aldehydes, alcohols, acids and ketones
Authors: Huang Wei‐Yuan , LÜ Long 
Published: September 2010

AbstractReaction of perfluoroalkyl iodides (1a–e) with the unsaturated ethers such as 1‐ethoxy‐1‐propene (2), 1‐methoxy‐1‐butene (3) under the sulfinatodehalogenation condition gave the corresponding 2‐(F‐alkyl) propanals (5a–e) and butanals (6c, d) very readily in high yield, which were converted to 2,4‐dinitrophenylhydrazones (7a–e, 8c, d) and characterized. The reaction products 5 and 6 were oxidized with Jone's reagent and reduced with NaBH4 in ethanol to give the corresponding acids (9, 10) and alcohols (11, 12) in good yield. Treatment of compounds 5 and 6 with pyridine gave the dehydrofluorination products 13 and 14. Under the same condition, perfluoroalkyl iodide reacted with 2‐ethoxy‐1‐propene (4) only to form RFSO2Na and RFH as the major products, but in aqueuous DMF (DMF: H2O = 5:1) to give the perfluoroalkylacetone (15) in good yield. Thus, the reaction provides a convenient, effective new method for syntheses of these useful organofluorine intermediates.
Behaviour of 4‐(4‐chlorophenyl)‐6‐(4‐tolyl)‐4,5‐dihydro pyrimidine‐2(1H) thione and 2‐hydrazino derivative toward carbon electrophiles
Authors: El‐Hashash M.A. , El‐Kafrawy A.F. , Shiba S.A. 
Published: September 2010

AbstractThe reaction of thiourea with p‐methyl‐β‐p‐chlorophenyl acrylophenone (1) is, in principle, an attractive [3 + 3]‐fragment approach to the synthesis of dihydropyrimidine bearing aryl groups.
ESR studies on reactions of dicyclopentadienyl dicarbonyl titanium with organic halides
Authors: Wang Ji‐Tao , Bai Ling‐Jin , Liu Feng‐Quan 
Published: September 2010

AbstractESR method was used to elucidate the mechanism of the reactions of alkyl, allyl or benzyl halides with dicyclopentadienyldicarbonyl titanium. The paramagnetic [intermediates of the reactions were identified during the course of the reactions. The reaction mechanism based on ESR findings and the products analyses is postulated to operate on radical pathways. When alkyl halides were used to react with the organometallic compound 1, the intermediate found was [Cp2Ti(CO)X] (C), and the main product was identified to be dicyclopentadienyl‐acyl‐halo titanium (3), an insertion of TiCO into R‐X, i.e. [Cp2Ti‐C(0)R] X. When allyl or benzyl halides were used, the intermediate found was [Cp2TiX] (B), and the main products were identified to be the dicyclopentadienyl titanium dihalides and the coupling products of allyl or benzyl groups.
13C NMR study ofD‐pantothenic acid complexes with heavy lanthanide ions in aqueous solution
Authors: Ren Ji‐Min , Pei Feng‐Kui , Wang Wen‐Yun 
Published: September 2010

AbstractThe13C NMR study of the interaction between the trivalent lanthanide ions (from Dy to Lu) andD‐pantothenic acid in aqueous solution was presented. The unambiguous resonance assignments were made on the basis of pH dependence and the analysis of molecular geometry.13C paramagnetic shifts were separated into the contact and dipolar components by Reilley's method. The complex stability constant is 12.0 L / mol for the 1:1 ytterbium complex. An analysis of the shift data shows that heavy lanthanide ions form isostructural complexes with the substrate and the hyperfine coupling constant is independent of the ions used in the study.D‐pantothenic acid is coordinated to the metal via the two oxygens of the carboxyl group with 2.25Å of Ln—O distances. The electron spin density distribution and the structural details of the complex were elucidated from the shift data. It is stated that contact contributions, while small for nuclei of several bonds away from the metal, should not be dismisseda priori.
Optimization of multicomponent solvent selection in high‐performance liquid chromatography using a statistical method
Authors: Wang Qin‐Sun , Gao Ru‐Yu , Wang Heng‐Yan , Yan Bing‐Wen 
Published: September 2010

AbstractA computer‐assisted method is presented for optimization of multicomponent solvent mobile phase selection for separation of O‐ethyl‐N‐isopropyl phosphoro (thioureido) thioates in reversed‐phase HPLC and four geometric isomers of pesticides Decis in normal‐phase HPLC. The method is based on Snyder's solvent selection triangle concept using a statistical method. The optimization of the separation over the experimental region is based on a special polynomial estimation from seven experimental runs, and resolution (Rs) is used as the selection criterion. Excellent agreement was obtained between predicted data and experimental results.
Separation mechanism of chiral compounds in chiral stationary phase liquid chromatography
Authors: Zou Han‐Fa , Zhang Yu‐Kui , Lu Pei‐Chang 
Published: September 2010

AbstractIn this paper, the concept of reversed‐ or normal‐phase chiral stationary phase liquid chromatography has been put forward according to the polar strength of mobile and stationary phases. The statistical model developed in HPLC has been used to investigate the separation mechanism of D‐ and L‐enantiomer in chiral stationary phase liquid chromatography. It has been observed that the variation of capacity factor of enantiomers with mobile phase composition in both reversed‐phase and normal‐phase chiral stationary phase liquid chromatography can be described by the fundamental elution equation lnk' = a + blnCb + cCb. The effect of mobile phase composition on the selectivity of enantiomers D and L in normal‐phase chiral stationary phase liquid chromatography can be described by the equation lnα = Δa + ΔblnCb, but in reversed‐phase chiral stationary phase liquid chromatography the selectivity is almost independant of the mobile phase composition.
The prediction of the peak width at half height in HPLC
Authors: Zou Han‐Fa , Zhang Yu‐Kui , Lu Pei‐Chang 
Published: September 2010

AbstractThe prediction of the peak width at half height is an important aspect in the optimization of the chromatographic operating conditions. In this paper, a linear relationship, between the peak widths at half height and the retention values with various isocratic elution is observed. In gradient elution, however, the relationship between the peak widths at half height and the so‐called invented retention values that correspond to the mobile phase composition by eluting the solute from the column end is developed. We believe that there is almost the same band width at half height inside the column (in unit of length) for different solutes. The peak width at half height in the chromatogram (in unit of time) is mainly determined by the capacity factor of the solute when it is eluted from the column end. The larger the capacity factor of a solute eluted from the column end, the more slowly will be the solute eluted from the column end and the wider will be the peak width at half height. It is possible to predict the peak width at half height in various isocratic and gradient elutions by using this linear relationship.
C‐Alkylation of α‐acylamino ketones. A versatile synthesis of α‐alkyl α‐amino ketones
Authors: Han Ying‐Lin , Hu Hong‐Wen 
Published: September 2010

AbstractC‐Alkylation of some α‐acylamino ketones were achieved with alkyl halides by means of sodium ethoxide in ethanol. The present paper deals with the C‐alkylation of N,N‐diformylamino ketones and the difference in stability of the amide group.
Studies on sulfinatodehalogenation XXIII. A new sulfinatodehalogenation reagent: thihurea dioxide1
Authors: Huang Wei‐Yuan , Zhuang Jin‐Lian 
Published: September 2010

AbstractHSO2− generated from thiourea dioxide and sodium bicarbonate in aqueous CH3CN at 35–45°C reacted with perfluoroalkyl iodides, polyfluoroalkyl bromide, 1,1,1‐trichloro‐2,2,2‐tri‐fluoroethane and carbon tetrachloride to give the corresponding sulfinates in good yield. Furthermore, it was shown that the reagent was able to initiate the addition of perfluoroalkyl iodide to olefins and alkynes at 30°C.
Carbonium cyclization—studies on lignans containing the dibenzocyclooctadiene system, I
Authors: Tan Rui , Zheng Qi‐Tai , He Cun‐Heng , Liang Xiao‐Tian 
Published: September 2010

AbstractThe reaction of schisandrin (1) under Ritter reaction conditions (cone, sulfuric acid / acetonitrile) was studied. Besides trace amounts of normal products (7α‐ and 7β‐acetamido derivatives 2a and 2b), the main product was a carbonium cyclization compound (3a).
Anharmonic oscillator model of overtone spectra for D3h symmetry molecules
Authors: Wang Yi‐Fei , Liang Ying‐Qiu , Tang Ao‐Qing 
Published: September 2010

AbstractThe bond stretching vibrations of XF5 molecules with D3h symmetry are treated computationally on the Morse oscillator model in which the bond oscillators are coupled harmonically. Each calculation involves four parameters for two types of Morse potential and three parameters for the kinetic‐energy, potential coupling terms. The eigenvalue formula for overtone and combination states up to three are presented and can be used to predict all the vibrational energy levels from local mode molecules through normal mode molecules. For PF5, AsF5 and VF5, the coupled Morse oscillator model gives a prediction in good agreement with the experimental data.
Photophysics studies of organic compounds VIII. Interaction between excited singlet state of pyrene and aromatic amines
Authors: Chen Feng‐Qi , Yu Qun , Meng Xian‐Juan , Shou Han‐Shen , Fan Mei‐Gong 
Published: September 2010

AbstractThe quenching processes of the excited singlet state of pyrene by triphenylamine, diphenylamine and N,N‐dibenzylaniline in various solvents at room and lower temperature have been studied with both static state fluorescence spectroscopy and fluorescence lifetime techniques. On the basis of experimental data, a preliminary quenching mechanism has been discussed. The geometrical configuration models of the exciplexes formed between the excited pyrene and aromatic amines in nonpolar solvents were proposed.
The crystal structure and conformation of N‐[2,2‐dimethyl‐3‐(2‐methylpropenyl)‐ cyclopropylcarbonyl]‐5‐methylisoxazolin‐3‐one
Authors: Xue Jie‐You , Shao Rui‐Lian , Zhu You‐Quan , Yao Xin‐Kan , Wang Hong‐Gen 
Published: September 2010

AbstractThe title compound has been synthesized and its crystal structure was determined by X‐ray crystallographic method. The crystal is triclinic, space group P‐1, with unit cell dimensions a = 6.146 (5), b = 8.473(6), c = 14.383(5) Å; α = 77.47 (4), β = 82.84 (4), γ = 69.00 (8)° and Z = 2. The results obtained reveal that the molecule of the title compound keeps a long conjugative system involving CC double bond, cyclopropane ring, carbonyl group and isoxazolinone ring and adopts a low energy conformation including s‐trans of CC double bond, s‐cis of carbonyl group with respect to the three‐membered ring and like‐s‐trans of carbonyl group with the carbonyl group within the heterocyclic moiety.
Cumulative potential‐derived atomic multipoles
Authors: Kong Jing , Yan Ji‐Min 
Published: September 2010

AbstractA method to derive the atomic multipole moments cumulatively up to quadrupole moments was developed. The multipole moments are obtained by least‐square simulating the molecular electrostatic potentials. Only the components of the term of highest order in the atomic multipole expansion are optimized while the lower terms remain fixed. The calculations on HF, H2O and NH3 show that the cumulative method can give reasonable qualitative and fairly good quantitative results.
A crosslinked chiral stationary phase for the separation of enantiomers by gas and supercritical fluid chromatography
Authors: Zhou Liang‐Mo , Lou Xian‐Wen , Sheng Yu‐Fong , Wang Qing‐Hai , Zhu Dao‐Qian 
Published: September 2010

AbstractCrosslinking experiments for the chiral stationary phase OV‐225‐L‐Val‐t‐butylamide within both fused silica and glass capillary columns have been carried out. Amino acid enantiomers were separated on crosslinked columns by both GC and SFC methods. In SFC, the a values of amino acid enantiomers are independent of the density of the mobile phase, and they are hig her than those obtained by GC for the tested enantiomers with the same column due to the lower column temperature used in SFC.
The structure correction of “8‐hydroxysubspinosin” and synthesis of 5‐hydroxydamnacanthol‐ω‐ethyl ether
Authors: Yu Ju‐Rong , Cal Jun‐Chao , Gao Yi‐Sheng 
Published: September 2010

Abstract8‐Hyaroxysubspinosin was elucidated as 2,8‐dihydroxy‐3‐ethoxymethyl‐1‐methoxyanthraquinone (2) in the literature. Here, the structure revision and synthesis of 8‐hydroxysubspinosin were presented. It should be revised to 3,5‐dihydroxy‐2‐ethoxymethyl‐1‐methoxyanthraquinone (5), i.e. 5‐hydroxydamnacanthol‐ω‐ethyl ether by comparison with the synthetic sample. 5 was synthesized by alkylation of 3‐bromo‐7‐methoxyphthalide (10) with 2,6‐dimethoxytoluene in the presence of stannic chloride, followed by reductive cleavage, cyclization, oxidation, demethylation, selective acetylation, methylation, bromination and condensation with sodium ethoxide. The isomer 1,3‐dihydroxy‐2‐ethoxymethyl‐5‐methoxyanthraquinone (5b) was also obtained.
A formal synthesis of (—)‐patchouli alcohol from (—)‐carvone
Authors: Zhao Rong‐Bao , Wu Yu‐Lin 
Published: September 2010

AbstractEnantiomerically pure 6‐acetyl‐1,3,3‐trimethyl bicyclo[2.2.2]octan‐2‐one, a key intermediate for synthesis of (‐)‐patchouli alcohol, was facilely synthesized from the adduct of a monomethylated (‐)‐carvone 2 and methyl acrylate.
A comparative study of the aromaticity in some typical conjugated six‐membered rings by the method of localized molecular orbital
Authors: Chen Zhi‐Da , Lu Jia‐Xi , Li Jun , Liu Chun‐Wan , Zhang Qian‐Er 
Published: September 2010

AbstractThe localized molecular orbitals and energy levels for four typical conjugated six‐membered ring systems C6H6, C3N3H3, B2N8H4, and (B2O4)3‐ as well as a non‐aromatic reference molecule Pa‐N3Cl6 have been calculated by using Edmiston‐ Ruedenberg energy localization technique under the CNDO / 2 approximation in order to investigate the nature of aromaticity or quasi‐aromaticity of the six‐membered ring systems studied. The contour maps for x‐type localized MO's (LMO) have been plotted to illustrate the bonding characteristics of the five ring systems studied. These LMO calculations show that for all the conjugated six‐membered ring systems considered there exists local delocalization of x‐bonds or three‐centered and occasionally four‐centered two‐electron x‐bonds in our terminology, and the cooperative effect among these x‐bonds leading to the formation of a closed continuous x‐conjugation system around the ring, which is necessary for the creation of aromaticity in the systems studied. We have been able to discuss the properties of these three‐centered x‐bonds in terms of the constituent atoms and electrons and the relevant orbitals involved.
Determination of HMO parameters with MS‐Xα‐SCF method
Authors: Wang Yi , Li Le‐Min 
Published: September 2010

AbstractA technique for determining the HMO parameters with MS‐Xα‐SCF method has been developed. The ionization potentials of even polyenes and condensed benzene compounds have been calculated. The average deviation from the existent experimental values is 0.34 eV.
Thermodynamical study on the formation of some mixed ligand complexes of non‐transition metal ions in solution I. The formation and the stability of some Pb(II) mixed ligand complexes
Authors: Liu Qi‐Tao , Zhang Feng , Song Xi‐Ming , Gao En‐Jun 
Published: September 2010

AbstractThe stability constants of the binary complexes of type PbB, PbB2, and the mixed ligand complexes of type PbAB have been studied by potentiometric pH titration technique at ionic strength I = 0.10 (KNO3) and at temperature 15, 25, 35 and 45°C respectively, where A = 2,2′‐bipyridyl (bipy) or 1,10‐phenanthroline (phen); B = malonate (mal), succinate (suc), or anthranilate (anth). The equalibrium constants ΔlogK,1 ΔΔG, ΔΔH, and ΔΔS of the reaction PbA + PbB = PbAB + Pb2+ have been calculated. The results show that the discriminating effects2 between the primary ligand (bipy or phen) and the secondary ligand (mal, suc or anth) in those non‐transition metal mixed ligand complexes are also evident, and as a measurement of this effect, ΔΔH is more appropriate than ΔlogK. The possible reasons which lead to these results have been discussed.
Fluorometric determination of trace selenium in β‐CD/SDS aqueous solution
Authors: Lu Dan‐Hong , Zheng Yong‐Xi 
Published: September 2010

AbstractA proper mixture of β‐cyclodextrin and sodium dodecylsulfate in aqueous solution was found to show a synergistic enhancement of the fluorescence intensity of 4,5‐benzopiaselenol. The determination of trace selenium can be carried out directly in aqueous solution.
Expert systems for HPLC in biochemistry—The knowledge base for selection of HPLC column system in the separation of amino acids, peptides and proteins
Authors: Zhang Yu‐Kui , Zou Han‐Fa , Lu Pei‐Zhang , Yao Zhi‐Jian 
Published: September 2010

AbstractThe strategy of expert system for high performance liquid chromatography was discussed, the attentions are mainly placed on the knowledge base for selection of column system, separation modes and detection modes in the analysis of amino acids, peptides and proteins.
Structural effects of multiple‐bonds on aggregating tendencies of long‐chain esters
Authors: Jiang Xi‐Kui , Ji Guo‐Zhen , Luo Guang‐Lin 
Published: September 2010

AbstractThe kinetics of the hydrolysis of p‐nitrophenyl esters of three types of single‐chain carboxylic acids, namely, saturated, olefinic and acetylenic, was investigated in two aquiorgano binary solvent systems, DMSO‐H2O and dioxane (DX)‐H2O. The ester probes used are: octanoic (C8), dodecanoic (C12), stearic (C18), oleic (C18‐ol), elaidic (C18‐el) and stearolic (C18‐st). The order of measured CAgC values is: C18‐ol>C18‐el>C18>C18‐st, whereas the order of decreasing magnitude of the observed hydrolytic rate constants of the monomeric species (km) is: C18>C18‐el>C18‐ol> C18‐st. These rather unanticipated results are discussed.