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1985 Volume 2 Issue 4
1985, 2(4): 1-8
Abstract:
The application of Mossbauer spectroscopy, especcially in situ Mössbauer study to heterogeneous catalysis has received more attention in recent years.Some information have been got on several important topics in catalysis,such as metal-support interaction,cluster formation on solid surface,characterization and identification of the active phase,promotive and poisoning effects, adsorption centers in zeolites etc.In this paper works concerning the above mentioned topics, mostly presented during the last decade were briefly reviewed.
The application of Mossbauer spectroscopy, especcially in situ Mössbauer study to heterogeneous catalysis has received more attention in recent years.Some information have been got on several important topics in catalysis,such as metal-support interaction,cluster formation on solid surface,characterization and identification of the active phase,promotive and poisoning effects, adsorption centers in zeolites etc.In this paper works concerning the above mentioned topics, mostly presented during the last decade were briefly reviewed.
1985, 2(4): 9-15
Abstract:
A brief review is given for the mechanism in preparing yellow tungstic oxide hydrate through homogeneous precipitation from concentrated hydrochloric acid solution,as represented by scheme 2 given in this paper. It is in contrast to the conventional method of acidification. White powdery tungstic oxide. hydrate, an active species, is prepared according to scheme4, i.e., by dropping Na2WO4 solution with stirring into 1M HNO3 until pH reaches around 1,-a reversed way of acidification. The micro-crystalline white tungstic oxide hydrate thus obtained is highly active, as represented in scheme 3. Besides preparing low valent tungsten clusters, superfine WC, light sensitive WO3·xH3O, and WO3 aggregate pyridine compounds, that white tungsten oxide hydrate can also lead to the preparation of a host of metatungstates, heteropolytungstates including organoarsenic polytungstates, as revealed in scheme 3 of the above text.
A brief review is given for the mechanism in preparing yellow tungstic oxide hydrate through homogeneous precipitation from concentrated hydrochloric acid solution,as represented by scheme 2 given in this paper. It is in contrast to the conventional method of acidification. White powdery tungstic oxide. hydrate, an active species, is prepared according to scheme4, i.e., by dropping Na2WO4 solution with stirring into 1M HNO3 until pH reaches around 1,-a reversed way of acidification. The micro-crystalline white tungstic oxide hydrate thus obtained is highly active, as represented in scheme 3. Besides preparing low valent tungsten clusters, superfine WC, light sensitive WO3·xH3O, and WO3 aggregate pyridine compounds, that white tungsten oxide hydrate can also lead to the preparation of a host of metatungstates, heteropolytungstates including organoarsenic polytungstates, as revealed in scheme 3 of the above text.
1985, 2(4): 16-19
Abstract:
Chain transfer reactions exist in the polymerization of butadiene initiated with rare earth coordination catalyst.The effect of various factors on chain transfer reactions in the polymerization of butadiene in the presence of NdCl3·3i-PrOH-AlEt3 system at various temperatures was examined in detail.
Chain transfer reactions exist in the polymerization of butadiene initiated with rare earth coordination catalyst.The effect of various factors on chain transfer reactions in the polymerization of butadiene in the presence of NdCl3·3i-PrOH-AlEt3 system at various temperatures was examined in detail.
1985, 2(4): 20-25
Abstract:
Using the electrode reaction of the ligand THAQ in Zr(Ⅳ)-THAQ complex, as we have reported previously, zirconium(Ⅳ) could be determined quantitatively by oscillop-olarography in THAQ (when pretreated with NaNO2)-borate buffer solution. In this paper a detail description of the properties of peak current of THAQ, the effect of NaNO2 and other factors are presented. The number of electrons and hydrogen ions involved in the electrode reaction of THAQ were estimated. The third and fourth order of dissociation constants of THAQ were calculated to be ka3=3.2×10-10 and ka4=2.0×10-13, respectively. The electrode reaction mechanism of THAQ and Zr(Ⅳ)-THAQ complex for the given system has been proposed.
Using the electrode reaction of the ligand THAQ in Zr(Ⅳ)-THAQ complex, as we have reported previously, zirconium(Ⅳ) could be determined quantitatively by oscillop-olarography in THAQ (when pretreated with NaNO2)-borate buffer solution. In this paper a detail description of the properties of peak current of THAQ, the effect of NaNO2 and other factors are presented. The number of electrons and hydrogen ions involved in the electrode reaction of THAQ were estimated. The third and fourth order of dissociation constants of THAQ were calculated to be ka3=3.2×10-10 and ka4=2.0×10-13, respectively. The electrode reaction mechanism of THAQ and Zr(Ⅳ)-THAQ complex for the given system has been proposed.
1985, 2(4): 26-30
Abstract:
In this paper the solid reaction of phthalonitrile and rare earth acetates was studied by DTA method. Contrary to the earlier data from other laboratories. the authors have found that the formation of rare earth phthalocyanines is independent of the heating rate. Two kinds of rare earth coordination compound, i. e. mono-and diphthalocyanine were found in the reaction products, and the ratio of these two compounds varies with the heating rate and the kinds of rare earth used. Higher heating rate such as 20°/min is in favor of the formation of lutetium diphthalocyanine.
In this paper the solid reaction of phthalonitrile and rare earth acetates was studied by DTA method. Contrary to the earlier data from other laboratories. the authors have found that the formation of rare earth phthalocyanines is independent of the heating rate. Two kinds of rare earth coordination compound, i. e. mono-and diphthalocyanine were found in the reaction products, and the ratio of these two compounds varies with the heating rate and the kinds of rare earth used. Higher heating rate such as 20°/min is in favor of the formation of lutetium diphthalocyanine.
1985, 2(4): 31-35
Abstract:
Synthesized H4Ru4(CO)12 and H4Ru4(CO)10(PPh3)2 in this laboratory were anchored on the modified polymer supports:P-Ph-CH2PPh2, SiO2Ph-CH2PPh2, P-Ph-CH2N(Et)P(NEt2)2. They were used as catalysts for the hydrogenation and isomerization of 1-hexene. The effects of the reaction conditions, i.e.variety of solvents, reaction time,crosslinking density of the organic supports,the polymer ligands used and the ligand/metal ratio of the catalysts on the catalytic properties of the cluster were investigated.
Synthesized H4Ru4(CO)12 and H4Ru4(CO)10(PPh3)2 in this laboratory were anchored on the modified polymer supports:P-Ph-CH2PPh2, SiO2Ph-CH2PPh2, P-Ph-CH2N(Et)P(NEt2)2. They were used as catalysts for the hydrogenation and isomerization of 1-hexene. The effects of the reaction conditions, i.e.variety of solvents, reaction time,crosslinking density of the organic supports,the polymer ligands used and the ligand/metal ratio of the catalysts on the catalytic properties of the cluster were investigated.
1985, 2(4): 36-41
Abstract:
The relationship of the morphology and mechanical property with the geometry structure of a set of star shaped SIS thermoplastic elastomers have been examined by means of Electron Microscopy, Tensile Tester and Rheovi-bron Viscoelastometer. The SIS thermoplastic elastomers were prepared by anionic polymerization using polyfunctional chlorosilane as linking agent and had the same arm length but different degree of branching. The results obtained show that the domain size of polystyrene, the tensile strength and Young's moduli of the polymers increase with increase of the degree of branching. Based on the crosslinked rubber equation and Kerner equation, the moduli expression as a function of branching degree has been derived.
The relationship of the morphology and mechanical property with the geometry structure of a set of star shaped SIS thermoplastic elastomers have been examined by means of Electron Microscopy, Tensile Tester and Rheovi-bron Viscoelastometer. The SIS thermoplastic elastomers were prepared by anionic polymerization using polyfunctional chlorosilane as linking agent and had the same arm length but different degree of branching. The results obtained show that the domain size of polystyrene, the tensile strength and Young's moduli of the polymers increase with increase of the degree of branching. Based on the crosslinked rubber equation and Kerner equation, the moduli expression as a function of branching degree has been derived.
1985, 2(4): 42-46
Abstract:
Single crystals of La6NiSi2S14 and La6CoSi2S14 were obtained by flux growth method at 1100℃.They belong to the hexagonal system, P63,a=10.293(1)[10.290(2)]; c=5.774(1)[5.763(2)Å,Z=1 and R=0.036[0.0959] for 627[629] reflections (I ≥ 2.5σ(Ⅰ)).La is 8-coordinated in a distorted dicapped triangular prism with an average La-S distance 2.990[2.992]Å.Ni[Co](B site) is in a trigonal antiprism of 6S (three Ni[Co]-S have distance of 2.559[2.529] Å and the other three have distance of 2.650[2.679]Å with 1/6 occupancy.Si(C site) is in a tetrahedron and coordinated with S2 at distance of 2.130[2.146]Å and coordinated with S3 at 2.098[2.093]Å.
Single crystals of La6NiSi2S14 and La6CoSi2S14 were obtained by flux growth method at 1100℃.They belong to the hexagonal system, P63,a=10.293(1)[10.290(2)]; c=5.774(1)[5.763(2)Å,Z=1 and R=0.036[0.0959] for 627[629] reflections (I ≥ 2.5σ(Ⅰ)).La is 8-coordinated in a distorted dicapped triangular prism with an average La-S distance 2.990[2.992]Å.Ni[Co](B site) is in a trigonal antiprism of 6S (three Ni[Co]-S have distance of 2.559[2.529] Å and the other three have distance of 2.650[2.679]Å with 1/6 occupancy.Si(C site) is in a tetrahedron and coordinated with S2 at distance of 2.130[2.146]Å and coordinated with S3 at 2.098[2.093]Å.
1985, 2(4): 47-52
Abstract:
In this paper,the effects of the bound rubber in NR compounds prepared with five different carbon black on stress-strain,rheological properties etc. have been studied.The results showed that the bound rubber contents were increased with increase of structure and surface area of the carbon black filled,which led to the elevation in bulk viscosity, stiffness and green strength, but to the reduction of plasticity and tackyness at low shear rates, and the poorer flow properties and the less shrinkage of extrudates at higher shear rates.In addition,the crosslink density of NR vulcanizates increased with increasing bound rubber content,hence,the modulus,hardness and abrasion resistance of vulcanizates with simultaneous decrease in their tensile strength and elongation.
In this paper,the effects of the bound rubber in NR compounds prepared with five different carbon black on stress-strain,rheological properties etc. have been studied.The results showed that the bound rubber contents were increased with increase of structure and surface area of the carbon black filled,which led to the elevation in bulk viscosity, stiffness and green strength, but to the reduction of plasticity and tackyness at low shear rates, and the poorer flow properties and the less shrinkage of extrudates at higher shear rates.In addition,the crosslink density of NR vulcanizates increased with increasing bound rubber content,hence,the modulus,hardness and abrasion resistance of vulcanizates with simultaneous decrease in their tensile strength and elongation.
1985, 2(4): 53-58
Abstract:
The catalytic behaviour of some solid acids on the polyesterification reaction was investigated. The effect of surface acidity, conditions of catalyst preparation and molecule structure of reactants on the polyesterification of alkyd resins was discussed. It was found that in conditions near to that for Industrial preparation the kinetics of the heterogeneous catalytic polyesterification of alkyd resins appeared the same as in the case of homogeneous reaction.
The catalytic behaviour of some solid acids on the polyesterification reaction was investigated. The effect of surface acidity, conditions of catalyst preparation and molecule structure of reactants on the polyesterification of alkyd resins was discussed. It was found that in conditions near to that for Industrial preparation the kinetics of the heterogeneous catalytic polyesterification of alkyd resins appeared the same as in the case of homogeneous reaction.
1985, 2(4): 59-65
Abstract:
The effects of the chain length of POE prepared from monodispersed polyoxyethylenated n-dodecyl alcohols on the thermodynamic properties,surface adsorption and micelle formation of mixed surfactants were studied.Experimental results indicate that the assumption of ideal mixing for the homologous mixtures appears reasonable.The surface adsorption Γ∞ and surface pressure πCMC of mixed solution are increased with the increase of distribution coefficient resulting in a close molecular orientation at interface.The molecules of the adducts with short POE chain are dominated both in mixed adsorbed layers and in micelles. The amounts of micelle solubilization of in ethylbenzene may be expressed in linear relation.Detergency performence of mixed solutions of C12En with wide distribution in POE chain length is surperior to that of monodispersed or narrow distributed C12En,but the effect is not noticeable beyond a certain range of distribution.
The effects of the chain length of POE prepared from monodispersed polyoxyethylenated n-dodecyl alcohols on the thermodynamic properties,surface adsorption and micelle formation of mixed surfactants were studied.Experimental results indicate that the assumption of ideal mixing for the homologous mixtures appears reasonable.The surface adsorption Γ∞ and surface pressure πCMC of mixed solution are increased with the increase of distribution coefficient resulting in a close molecular orientation at interface.The molecules of the adducts with short POE chain are dominated both in mixed adsorbed layers and in micelles. The amounts of micelle solubilization of in ethylbenzene may be expressed in linear relation.Detergency performence of mixed solutions of C12En with wide distribution in POE chain length is surperior to that of monodispersed or narrow distributed C12En,but the effect is not noticeable beyond a certain range of distribution.
1985, 2(4): 66-70
Abstract:
From carboxyl terminated vinyltetrahydrofuran-propylene oxide liquid copolymer (TVC), which has been successfully synthesized ealier (Ⅰ), we have synthesized an epoxy terminated triblock copolymer (TVCE) by reacting the terminal carboxyl of TVC with bifunctional epoxy resin. The three-component four-arm star telechelic copolymer was then prepared through the copolymerization of TVCE with vinyl monomers, e, g.St, MMA, and BA plus MMA. The effect of some factors on the dampling properties of star copolymers has been investigated.
From carboxyl terminated vinyltetrahydrofuran-propylene oxide liquid copolymer (TVC), which has been successfully synthesized ealier (Ⅰ), we have synthesized an epoxy terminated triblock copolymer (TVCE) by reacting the terminal carboxyl of TVC with bifunctional epoxy resin. The three-component four-arm star telechelic copolymer was then prepared through the copolymerization of TVCE with vinyl monomers, e, g.St, MMA, and BA plus MMA. The effect of some factors on the dampling properties of star copolymers has been investigated.
1985, 2(4): 71-75
Abstract:
The extraction system of RE(Ⅲ) (except Pm,including Y) with thenoyltriflouroacetone (HTTA) and tributylphosphine oxide (TBPO) was studied by two-phase titration method.The results showed that:(1) There is no association between HTTA and TBPO under experimental conditions. (2) The mixed ligand complexes of types RE (TTA)3 (TBPO)2, RE(TTA)3(TBPO)3, RE (TTA)3(TBPO)4 were formed in the organic phase and their stability constants were determined. (3) The stability constants β30k of RE(TTA)3(TBPO)k increase with the atomic number of the lanthanide. logβ303 shows a clear tetrad effect.The position of logβ303 for Y is between that for Ho and Er.
The extraction system of RE(Ⅲ) (except Pm,including Y) with thenoyltriflouroacetone (HTTA) and tributylphosphine oxide (TBPO) was studied by two-phase titration method.The results showed that:(1) There is no association between HTTA and TBPO under experimental conditions. (2) The mixed ligand complexes of types RE (TTA)3 (TBPO)2, RE(TTA)3(TBPO)3, RE (TTA)3(TBPO)4 were formed in the organic phase and their stability constants were determined. (3) The stability constants β30k of RE(TTA)3(TBPO)k increase with the atomic number of the lanthanide. logβ303 shows a clear tetrad effect.The position of logβ303 for Y is between that for Ho and Er.
1985, 2(4): 76-78
Abstract:
The crystallinity and crystal size of different type polystyrene (PST)-polyoxyethy-lene (PEO) block copolymers and the same type block copolymers with different PEO contents have been determined by X-ray diffraction method.It was found that the crystallinity and crystal size increase with the increase of the PEO content and decrease in the order:BAB > AB > ABA.
The crystallinity and crystal size of different type polystyrene (PST)-polyoxyethy-lene (PEO) block copolymers and the same type block copolymers with different PEO contents have been determined by X-ray diffraction method.It was found that the crystallinity and crystal size increase with the increase of the PEO content and decrease in the order:BAB > AB > ABA.
1985, 2(4): 79-82
Abstract:
In this paper the correlation between different structure state of chlorophyll a (Chl a) in vitro and the amounts of singlet oxygen formed has been investigated, used as a photosensitizer. Chl a of different structure state in vitro showed different ability to excite triplet molecular oxygen into singlet form. 1, 3, 5-Triphenylformazan (TF) and 1, 3-diphenyl-5-p-methoxyphenyl formazan (TF-OCH3) was used as the quencher for singlet oxygen and phenol as indicator for oxidation products. Irradiation of the mixed system (Chl a+TF/TF-OCH3+solv.) was carried out with a He-Ne laser (6328Å). It was found that phenol had the highest relative yield in alcohol, medium in CCl4 and the lowest in C6H14. The results were considered to be related to the difference of structure state of Chl a in solvents of different polarity.
In this paper the correlation between different structure state of chlorophyll a (Chl a) in vitro and the amounts of singlet oxygen formed has been investigated, used as a photosensitizer. Chl a of different structure state in vitro showed different ability to excite triplet molecular oxygen into singlet form. 1, 3, 5-Triphenylformazan (TF) and 1, 3-diphenyl-5-p-methoxyphenyl formazan (TF-OCH3) was used as the quencher for singlet oxygen and phenol as indicator for oxidation products. Irradiation of the mixed system (Chl a+TF/TF-OCH3+solv.) was carried out with a He-Ne laser (6328Å). It was found that phenol had the highest relative yield in alcohol, medium in CCl4 and the lowest in C6H14. The results were considered to be related to the difference of structure state of Chl a in solvents of different polarity.
1985, 2(4): 83-85
Abstract:
A new vacuum deposition method for the preparation of SnO2 gas sensor element was describcd. Sn was first deposited directly on the surface of a hollow ceramic cylinder, the metallic tin on the cylinder was afterwards oxidized into SnO2·Pd powder, used as catalyst, was coated on the surface of SnO2 and a heater was placed in the hollow part of the cylinder. The SnO2 gas sensor element thus obtained show a good sensitivity to reducible gases such as H2, C2H5OH etc.
A new vacuum deposition method for the preparation of SnO2 gas sensor element was describcd. Sn was first deposited directly on the surface of a hollow ceramic cylinder, the metallic tin on the cylinder was afterwards oxidized into SnO2·Pd powder, used as catalyst, was coated on the surface of SnO2 and a heater was placed in the hollow part of the cylinder. The SnO2 gas sensor element thus obtained show a good sensitivity to reducible gases such as H2, C2H5OH etc.
