Table of Content

24 January 2000, Volume 16 Issue 1

Previous Issue    Next Issue

Articles

Preparation and Spectroscopic Properties of Tris (2, 2'-bipyridine)ruthenium(Ⅱ)Loaded in Siliceous Mesoporous MCM-41

CAO Xi-chuan, WANG Yue, LI Shou-gui, FANG Ming, CHEN Jie-sheng, XU Ru-ren

2000, 16(1):  1-4. 

Abstract ( )   PDF (148KB) ( )  

Related Articles | Metrics

[Ru(bpy)₃]²⁺/MCM-41 composite material obtained by loading tris(2, 2' - bipyridine)ruthenium(Ⅱ) ([Ru(bpy)₃]²⁺) in siliceous mesoporous MCM-41 was characterized by X-ray powder diffraction, UV-Vis absorption and emission spectroscopies.The absorption spectrum of [Ru(bpy)₃]²⁺ /MCM-41 is similar to that of [Ru (bpy)₃]²⁺ aqueous solution, whereas its emission spectrum exhibits hypsochromic shift compared to the solution spectrum.On the other hand, the peak position of the emission spectrum of [Ru(bpy)₃]²⁺/MCM-41 shifts towards longer wavelength when the loading amount increases.

A New Extraction Spectrophotometric Method for the Determination of Phenol in Water

KANG Chun-li, WANG Ying, DU Yao-guo, LI Run-bo, LI Jun, ZHOU Li-ming, JIN Xiang-jun, MIAO Fei

2000, 16(1):  5-9. 

Abstract ( )   PDF (261KB) ( )  

Related Articles | Metrics

The product of the reaction among phenol, sodium nitroprusside and hydroxylamine hydrochloride in an alkaline solution can be extracted by chloroform in the presence of cetylpyridinium bromide(CPB), on the basis of which a new extraction spectrophotometric method for the determination of phenol in water is developed.The optimum determination wavelength is 720 nm.The molar absorptivity is 1.05 × 10⁵ mol^-1· L· cm^-1 and the detection limit is 4.0 μg/L.For 30.0 and 60.0 μg/L standard solutions, the relative standard deviations are 4.5% and 2.2 %, respectively(n=6).F values of the statistical analysis show that there is no notable difference between the proposed method and 4-AAP method.The results of the standard addition method for the natural water samples are satisfactory.

Studies on Determining Method of Trehalose

LIU Tie-min, LIU Ying

2000, 16(1):  10-14. 

Abstract ( )   PDF (404KB) ( )  

Related Articles | Metrics

Trehalose can be determined by thin layer chromatography and high performance liquid chromatography.But it's difficult to distinguish trehalose from the similar bisaccharides.If the reaction of the reduced bisaccharides with phenyl hydrazine to form osazone is used, then the disturbance of the similar reduced bisaccharides can be rapidly and conveniently excluded, or via the ammoniated-reduced reaction, aliline can be specially bounded to the reduced hydroxyl of the bisaccharides.In that way trehalose can be accurately determined.

Characterization and Catalytic Properties of a Rapidly Quenched Ni-RE-P-Al Catalyst

MA Ai-zeng, LU Wan-zhen, ZONG Bao-ning, MIN En-ze

2000, 16(1):  15-20. 

Abstract ( )   PDF (400KB) ( )  

Related Articles | Metrics

A Ni-RE-P-Al catalyst prepared by alkaline extraction of a rapidly quenched Ni-RE-P-Al alloy was characterized by means of ICP, BET, XRD, XPS and TEM.The results show that the rapidly quenched Ni-RE-P-Al alloy contained less crystalline Al₃Ni than Al-Ni alloy.After alkaline extraction, most of Al in the Ni-RE-P-Al alloy was leached out and the resulted Ni-RE-P-Al catalyst presented a sponge structure similar to Raney Ni.Although crystalline Ni is the major phase in the Ni-RE-P-Al catalyst and Raney Ni, amorphous Ni-P phase has been detected in the Ni-RE-P-Al catalyst.Studies on catalytic hydrogenation of toluene, phenyl ethylene, acetylene benzene, nitrobenzene, cyclohexanone and adiponitrile in liquid phase showed that the activity and selectivity of this Ni-RE-P-Al catalyst are superior to those of Raney Ni, especially at low temperatures.The amorphous phase is considered to be responsible for its superior catalytic properties.

A Theoretical Study on Pyrolysis and Sensitivity of Energetic Compounds(Ⅴ) ──Nitro Derivatives of Methylbenzene

GU Zhi-ming, FAN Jian-fen, XIAO He-ming, DONG Hai-shan

2000, 16(1):  21-30. 

Abstract ( )   PDF (315KB) ( )  

Related Articles | Metrics

UHF-SCF-AM1 MO calculations were performed for two kinds of pyrolysis reactions of seven nitro derivatives of methylbenzene(homolysis reactions by the rupture of bond C-NO₂ into radicals and isomerization reactions in the way of methyl H transferring to the ortho nitro O atom).The molecular geometries of the reactants, the transition states and the products of the fourteen reactions were fully optimized.The activation energies for these two kinds of reactions have been obtained.The results indicate that this category of compounds is more easily pyrolyzed by being initiated via isomerization reactions.A parallel relationship exists between the activation energy of the isomerization reactions and the impact sensitivity of the seven titled compounds.

Ab Initio MO Studies on the Reaction Mechanism for Carbonyl Insertion Catalyzed by Carbonyl Cobalt Complex

LEI Ming, FENG Wen-lin, XU Zhen-feng

2000, 16(1):  31-35. 

Abstract ( )   PDF (338KB) ( )  

Related Articles | Metrics

Ab initio method, under the effective core potential(ECP) approximation at HF/LANL2DZ level, has been employed to study the reaction mechanism of the carbonyl insertion of olefin hydroformylation catalyzed by a carbonyl cobalt HCo(CO)₃.The two reaction paths have been discussed.The calculated potential energy barriers for the carbonyl migration and the ethyl group migration are 105.0 kJ/mol and 39.17 kJ/mol, respectively.The results indicate that the reaction path via ethyl migration is more energetically favorable than that via carbonyl insertion.

Effect of CO₂ on Atmospheric Corrosion of UNS G10190 Steel under Thin Electrolyte Film

WANG Feng-ping, ZHANG Xue-yuan, DU Yuan-long

2000, 16(1):  36-41. 

Abstract ( )   PDF (468KB) ( )  

Related Articles | Metrics

The atmospheric corrosion of UNS G10190 steel under a thin electrolyte film in the atmosphere polluted by CO₂, has been studied in the lab using an atmospheric corrosion monitor (ACM) in combination with XRD and SEM observations of the surface of steel.The ACM study indicated that the corrosion rate of the steel increased with increasing carbon dioxide concentration.The XRD and SEM observations showed that no carbonate was found in the corrosion product on the steel surface.The corrosion product consisted of two layers, i.e., inner and outer layer.From the experimental results, it was concluded that CO₂ played an enhancing role in the atmospheric corrosion of UNS G10190 steel.The film of the corrosion product showed slight protection.

Studies on the Electrochemistry of Dopamine at a Pyrocatechol Sulfonephthalein Modified Glassy Carbon Electrode

CAI Chen-xin, XUE Kuan-hong

2000, 16(1):  42-48. 

Abstract ( )   PDF (465KB) ( )  

Related Articles | Metrics

The electrochemical response of dopamine(DA) at a pyrocatechol sulfonephthalein modified glassy carbon(PS/GC) electrode is reported.The electrode can be used as a detector for the determination of dopamine with a high stability and a good sensitivity.The cyclic voltammetric results indicated that there was a couple of well-defined redox peaks for dopamine at the PS/GC electrode with E_pa= 220 mV, E_pc=95 mV and the formal potential E^o'= 157.5 mV(vs.SCE) at 100 mV/s in the buffer solution of pH 7.0.The PS/GC electrode can also be used to separate the electrochemical responses of ascorbic acid and DA by 54 mV with the differential pulse voltammetry.Under the selected conditions, the oxidation peak currents are linear with DA concetration in the range of 5.0 × 10^-6 to 5.0 × 10^-4 mol/L, and the detection limit is 1.0 ×10^-6 mol/L at S/N=3.Normalized with concentration, the relative sensitivity of dopamine to ascorbic acid reaches ca.30.8: 1.

Derivation of Martin-Hou Equation of State from Hard-particle Perturbation Theory

ZHANG Bing-jian, HOU Yu-chun

2000, 16(1):  49-56. 

Abstract ( )   PDF (504KB) ( )  

Related Articles | Metrics

In this paper, the Martin-Hou equation of state is derived by using a power series representation of radial distribution function and an analytic representation of multi-section potential based on the Barker-Henderson hard-particle perturbation theory including high-order terms.In the derivation, a theoretical form of Martin-Hou equation was obtained.It had a similar form and the same capability to predict P-V-T properties as the Martin-Hou equation and no additional data were required for evaluating the constants.The characteristic constants of the theoretical expression have certain relationships with the molecular parameters.

C-V Characterization of α-Fe₂O₃/Block-Copolymer Composite Particulate Films

QIAN Xin-ming, AI Xin, TANG Jun, WANG Da-yang, ZHANG Xin-tong, SONG Qing, BAI Yu-bai, LI Tie-jin, TANG Xin-yi

2000, 16(1):  57-60. 

Abstract ( )   PDF (259KB) ( )  

Related Articles | Metrics

α-Fe₂O₃ nanocrystal was encapsulated by a block-copolymer, hydroxylated poly (styrene-b- butadiene-styrene) (HO-SBS) to fabricate composite microspheres with α-Fe₂O₃ cores and HOSBS shell.Its film fabricated on n-Si wafer acts as the insulator layer in the metal-insulator- semiconductor(MIS) structure.The capacitance-voltage (C-V) properties were measured to characterize the composite particulate films.

Kinetics and Mechanism of the Polymerization of Methyl Methacrylate in a Y(acac)₃/n-BuMgCl System

PAN Zhi-da, SUN Jun-quan, YANG Shi-lin

2000, 16(1):  61-66. 

Abstract ( )   PDF (363KB) ( )  

Related Articles | Metrics

Based on the kinetics equation proposed by T.Kagiya, the kinetic study on the polymerization of methyl methacrylate(MMA) by Y(acac)₃/n-BuMgCl was carried out with a dilatometer.It was found that the rate of propagation is the first order with respect to the concentration of both active center and monomer.Thus, the equation of propagation rate can be described as R_p=K_p[c^*][M].In addition, the instantaneous chain initiation and single molecular termination were concluded for the present system.The activation energy is close to 32 kJ/mol.In the polymerization, n-BuMgCl acts not only as the cocatalyst, but also as chain transfer agent with c_I=3.6 × 10^-4.

Effect of Polymerization Condition on Particle Size Distribution in St/BA/MAA Emulsion Polymerization Process

TAN Bi-en, ZHANG Hong-tao, LI Jian-zong, HU Fang

2000, 16(1):  67-71. 

Abstract ( )   PDF (304KB) ( )  

Related Articles | Metrics

A series of St/BA/MAA emulsion polymerizations was carried out.By using PCS (photon correlation spectroscopy), the particle size distribution (PSD) of the whole St/BA/MAA emulsion polymerization process was gotten easily and quickly.The effect of polymerization condition on PSD in St/BA/MAA emulsion process was discussed.

Synthesis of α-Bromine-Terminated Polystyrene Macroinitiator and Its Initiation of MMA Polymerization by ATRP

LIU Feng, LIU Bing, LUO Ning, YING Shengkang, LIU Qing

2000, 16(1):  72-77. 

Abstract ( )   PDF (398KB) ( )  

Related Articles | Metrics

In the present paper the synthesis of block copolymers via the transformation from living anionic polymerization (LAP) to atom transfer radical polymerization (ATRP) was described.α-Bromine-terminated polystyrenes(PStBr) in the LAP step was prepared by using n-BuLi as initiator, tetrahydrofuran (THF) as the activator, α-methylstyrene (α-MeSt) as the capping group and liquid bromine (Br₂) as the bromating agent.The effects of reaction conditions such as the amounts of α-MeSt, THF, and Br₂ as well as molecular weight of polystyrene on the bromating efficiency (BE) and coupling extent (CE) were examined.The present results show that the yield of PStBr obtained was more than 93.8% and the coupling reaction was substantially absent.PStBr was further used as the macroinitiator in the polymerization of methyl-methacrylate (MMA) in the presence of copper (I) halogen and 2, 2' -bipyridine (bpy) complexes.It was found that the molecular weight of the resulted PSt-b-PMMA increased linearly with the increase of the conversion of MMA and the polydispersity was 1.2-1.6.The structures of PStBr and P(St-b-MMA) were characterized by ¹H NMR spectra.

Synthesis and Characterization of Poly(ether amide)s Containing Phthalazinone Moieties

JIAN Xi-gao, CHEN Lian-zhou, GUO Xiao-yuan, SUN Wen-xun

2000, 16(1):  78-82. 

Abstract ( )   PDF (301KB) ( )  

Related Articles | Metrics

Soluble aromatic polyamides containing phthalazinone moieties were prepared.Those polymers were obtained from the solution polymerization of a new diacid containing phthalazinone moieties with various diamines.The new monomer, 2-(4-carboxyphenyl)-4-(4- carboxyphenoxy) phenyl-1 (2H) phthalazinone (Ⅳ) was synthesized in a two-step reaction sequence.2- (4-Cyanophenyl)-4-(4-cyanophenoxy)phenyl-1 (2H)phthalazinone (Ⅲ) was prepared via the condensation reaction of 4-(4-hydroxyphenyl)-1 (2H) phthalazinone (I) with p-chlorobenzonitrile (Ⅱ).After (Ⅲ) was hydrolyzed, (Ⅳ) was acquired.The synthesized polyamides were characterized by means of viscosimetry, DSC, FT-IR, ¹H NMR and EA.The polyamides have a high glass transition temperature which can be as high as 316 C.The polyamides also have good solubilities in some organic solvents.

Synthesis of Syndiotactic Polystyrene/Atactic Polypropene Block Copolymer in the presnece of Half-sandwich Titanocene Catalysts

ZHU Fang-ming, WU Qing, FANG YU-tang, HUANG Qun-fang, LIN Shang-an

2000, 16(1):  83-89. 

Abstract ( )   PDF (496KB) ( )  

Related Articles | Metrics

Some highly active η⁵-pentamethylcyclopentadienyltribenzyloxy titanium complexes [Cp Ti(OBz)₃] activated by modified methylaluminoxane (mMAO) were prepared and used as the catalyst for styrene syndiospecific polymerization and propene atactic polymerization.Styrene could be copolymerized with propene when the propene was prepolymerized for a period, to which styrene and tri-isobutylaluminum (TIBA) were then added.The titled block copolymer together with the related homopolymers was obtained.The copolymerization porducts can be divided into the homopolymers and the copolymer by successive solvent extraction with boiling butanone, heptane and tetrahydrofuran (THF), and each fraction was characterized by ¹³C NMR, DSC and WAXD.It was found that aPS and aPP were soluble in boiling butanone and heptane respectively.The block copolymer (sPS-b-aPP) composed of syndiottactic polystyrene segment was soluble in boiling THF and the residue was chiefly sPS.

Letters

Synthesis and Spectroscopic Characterization of Organophosphoryl Polyoxotungstates α-A-[RP(O)]₂PW₉O₃₄^5-

SUN Zhen-gang, LIU Ju-tao, LIU Jing-fu, LI Jing

2000, 16(1):  90-92. 

Abstract ( )   PDF (187KB) ( )  

Related Articles | Metrics

Research Notes

A Study on the Fluorescence System of Sc-BPMPHD-CTMAB and Its Analytical Application

WU Xia, GE Hong-mei, HUANG Fang, WANG Min, YANG Jing-he, CAI Shao-song

2000, 16(1):  93-95. 

Abstract ( )   PDF (212KB) ( )  

Related Articles | Metrics