多相催化研究中化学动力学的作用(英文)

The paper presents shortly some of the important elements of the theory and of the practical applications of the kinetics of heterogeneous catalytic reactions. Discussed are some of the most important concepts of the kinetics of complex heterogeneous catalytic reactions,methodology of building kinetic models and mathematical treatment of experimental data,influence of heat and mass transfer,types of laboratory reactors,kinetics and nanosized catalysts and others. Examples for use of the kinetic studies for the development and application of industrial catalysts and modeling of industrial reactors are presented.     

Enthalpic Interaction for α-Amino Acid with Alkali Metal Halides in Water

The studies of the enthalpic interaction parameters, hxy, hxyy and hxxy, of alkali metal halides with glycine, α-alanine and α-aminobutyric acid were published. Synthetic considering of the results of the studies, some interesting behaviors of the interaction between alkali metal halides and the α-amino acids have been found. The values of hxy will increase with the increase of the number of carbon atoms in alkyl side chain of amino acid molecules and decrease with the increase of the radius of the ions. The increasing of the salt‘s effect on the hydrophobic hydration structure as the radii of anion is more obvious than as that of cation. The value of hxxy will regularly decrease with the increase of the number of carbon atoms in the alkyl chain of amino acids and linear increase with the increase of the radius. But the relation of hxxyWith the radius of cations is not evident. The value of hxyywill increase with the increase of the radii of the ions. As the increase of the number of carbon atoms of amino acids, hxyy is decreas for the ions which have lager size and there is a maximum value at α-alanine for the ions which have small size. The behaviors of the interaction mentioned above were further discussed in view of electrostatic and structural interactions.     

RELATIONSHIP BETWEEN Φ(z/l,X) RULE OF CHEMICAL PROCESSES IN SEAWATER AND HSAB PRINCIPLE——PRINCIPLE OF LEAST Σ AND CHEMICAL MODEL OF SEAWATER

This article reports on the application of the (z/l, X) rule of chemical processes in seawater to the study of the Principle of Hard and Soft Acids and Bases (HSAB). One result is the establishment of new scales of the hardness-softness of acids and bases which are more complete than those in the literature.Based on the principle of HSAB as well as abundant experimental data, we developed a new general principle of marine chemistry viz. the principle of least . Application of the principle of least has produced good results in the study of chemical model of the major constituents of seawater, the chemical speciation of trace elements, inorganic ion exchange reactions, the Irving-Williams aeries of transition elements, etc. Our investigations indicate that chemical models of the major constituents of seawater should take into consideration the formation of chloride ion pairs.     

POLYMER SUPPORT EFFECTS OF METAL COMPLEXES FOR CATALYSIS*

In the course of investigating the catalytic behavior of metal complexes forring opening metathesis polymerization of cycloolefins, metathesis, hydroformylation andselective hydrogenation of olefins experimental results time and again indicate the pres-ence of effects of macromolecular supports -the utilization of macromolecular supportsincreases obviously the activity, selectivity, and stability of the catalysts and so as to in-crease the conversion of substrates, yields of reactions, properties of formed polymers andso on. Discussed these effects on the basis of the authors' experiments.     

SCANNING ELECTRON MICROSCOPY STUDY OF FILLED SILICONE RUBBER

The fracture surfaces of a number of silicone vulcanizates were investigated by the use of scanning electron microscopy (SEM). It was found that the difference in the presence and absence of filler, the variation of its surface modification as well as the history of thermal aging of the vulcanizates, all of these factors made difference in surface morphology of the fractured surface. This was correlated with the strength of the vulcanizates. The reinforcing effect of filler and the process of fracture were discussed.     

EFFECT OF CROSS-LINKING ON THE EXCESS ENTHALPY RELAXATION OF EPOXY

A method of comparative DSC technique is proposed for excess enthalpy relaxation study. The essential of the comparative DSC technique consists of comparing the enthalpy relaxation behavior of an aged sample with a quenched sample as reference. The accuracy of comparison is improved because of simultaneous measuring of the sample and reference which makes noise of the apparatus subtractive. This technique has been applied to studying the influence of crosslinking on the enthalpy relaxation behavior of epoxy resins. The effect of crosslinking on the kinetics of enthalpy relaxation of epoxy resins is discussed.     

Kinetics of the Exothermic Decomposition Reaction of N-Methyl-N-nitro-2,2,2- trinitroethanamine

The thermal behavior and kinetic parameters of the exothermic decomposition reaction of N-methyl-N-nitro-2,2,2-trinitroethanamine in a temperature-programmed mode have been investigated by means of differential scanning calorimetry (DSC).The kinetic equation of the exothermic decomposition process of the compound is proposed. The values of the apparent activation energy (Ea), pre-exponential factor (A), entropy of activation (ΔS^≠ ), enthalpy of activation (ΔH^≠ ), and free energy of activation (ΔG^≠ ) of this reaction and the critical temperature of thermal explosion of the compound are reported. Information is obtained on the mechanism of the initial stage of the thermal decomposition of the compound.     

A MATHEMATICAL STUDY OF THE SEVEN GRAPTOLITE BIOZONES OF THE LOWER SILURIAN LONGMAXIAN STAGE IN CHINA

With the aid of matrix theory and computer a series of data can be obtained such as the total number of localities in which r species of graptolites appears, the common number of localities in which both i and j species of graptolites appear, the total number of species of graptolites in one locality, the common number of species of graptolites found in both i and j localities, the total number of zones in which r species of graptolites appears, the common number of zones in which both i and j species appear, the total number of species of graptolites found in one zone, the common number of species of graptolites found in both i and j zones. Based on these data a common problem in biostratigraphy may be solved, that is, in the absence of the zonal graptolite which species of graptolites can be chosen to replace the zonal graptolite, or how to detect the zonal graptolite of a graptolite biozone. The result of matrix treatment not only detects the graptolite biozone but is useful to infer the paleo-biogeo     

INFLUENCE OF THERMAL AND NON—THERMAL EFFECTS OF ULTRASOUND ON ISOTHERMS OF PHENOL ON NKAⅡ RESIN

Adsorption equilibrium experiments of phenol on the NKA II resin are separately conducted in the presence and absence of ultrasound at ambient temperature.The isotherm of phenol on the polymer adsorbent in the presence of ultrasonic field is firstly reported.Results indicated that the isotherm of phenol determined in the presence of ultrasound is lower than that in the absence of ultrasound.In addition,experiments also show that the use of ultrasound to the adsorption system of the phenol aqueous solution and NKA Ⅱ resin could cause the rising of the temperature of the system in the order of 6^-C.The effect of ultrasound on the isotherm of the phenol on the NKA Ⅱ resin mostly ascribes to the thermal effect and the non-thermal effect of ultrasonic field.and the role of the later is greater than that of the former.     

超细CaCO_3的粒子尺寸对PP结晶行为的影响

The effects of CaCO3 on the crystallization behavior of polypropylene (PP) were studied by means of DSC and WAXD.The average sizes of the CaCO3 powders used were 0.1μm (UC) and 0.5μm (GC),respectively.The PP/CaCO3 composites at compositions of 1phr and 10 phr were investigated.The results showed that the addition of CaCO3 reduced the supercooling,the rate of nucleation and the overall rate of crystallization (except for the 10phr UC/PP sample).The crystallinity of PP was increased and the size distribution of the crystallites of α-PP was broadened.On the other hand,the crystallization rate of 10phr UC/PP is 1.5 times higher than that of neat PP.It has an overall rate of crystallization 2 times as much as that of the neat PP and has the maximum crystallinity.The sizes of crystallites and the unit cell parameters of α-PP were varied by the addition of CaCO3.β-PP was formed by addition of GC and was not detected by addition of UC.The differences of crystallization behaviors of PP might be attributed to the combined effects of the content and size of CaCO3 filled.     

Studies on the Steroids of Marine Sponge

Sterols are essential components of all eukaryotic cells and were the first group of marine sponge natural products used in the taxonomic characterization of marine sponges. Thus, in the past decade there has been an increasing interest in sterols of marine sponge, which has led to the discovery of a large number of novel compounds. The use of a variety of separation techniques has demonstrated the complexity of the sterol components of marine extracts, up to 50 sterols from one species of organism. However, the quantity of each sterol     

PACKING OF IONS IN SILICATE GLASSES

Any silicate glass can be regarded as the relaxation of SiO_2 glass and the volumeis composed of two parts. One is the topological volume of O~(2-), which is equal to thevolume per oxygen of SiO_2 glass, the other is the topological volumes of cations. Thetopological volume of a monovalent cation equals the volume shared by each sphere indense haphazard packing of equal spheres of the cation's size. The charges of bivalentcations cause a decrease of volume, the decrement being the packing volume of Ca~(2+). Anequation is reached for the calculation of the volume per oxygen of silicate glasses. Alot of calculations show that the equation is accurate, so accurate that the densities canbe calculated. The study reveals some characters of the glass structure and clearly ex-presses the contributions of various cations to the volumes of glasses.     

Study on the Radius of an Electrical Spherical Micelle： Functional Theoretical Approach

For the purpose of eliminating restriction, the Poisson-Bokzmann (PB) equation, which represents the potential of the electrical double layer of spherical miceUes, can be solved analytically only under the lower potential condition, a kind of iterative method in functional analysis theory has been used. The radius of the spherical particle can be obtained from the diagram of the second iterative solution of the potential versus the distance from the center of the particle. The influences of the concentration of the ions, the charge number of ions, the aggregation number of the particle, the dielectric constant of solvent and the temperature of system on the radius also have been studied.     

Construction of interesting organic supramolecular structures with synthons cooperation in the cocrystals of 1H-benzotriazole and hydroxybenzoic acids

Multifunctional molecules are capable of assembling via different supramolecular synthons,or hydrogen bond motifs,between the same or different functional groups,leading to the possibility of cocrystal.Utilization of the interplay of dimensionality(1-D,2-D and 3-D),orientation of functional groups of the building blocks,influence of rigid/flexible linking groups,and weak interactions provides an interesting route for the creation of novel supramolecular architectures in the crystal lattice.N-unsubstituted 1H-benzotriazole and carboxylic acid,being self-complementary molecules,offer a broad scope of study of binary compounds based on the complementary combination of H-bonding/donating sites.We report here the construction of three extended molecular networks in cocrystals of the carboxylic acid group of the acid and the 1H-benzotriazole triazole moiety.We have been able to identify four major supramolecualr synthons that would be helpful in the prediction of structural motifs for these kinds of studies.Interestingly,these heterosynthons are strikingly similar,to those of the homosynthons of the individual functional groups.The nature of the aza groups helps to enhance the overall volume of the crystal lattice thus leading to the formation of various supramolecular assemblies.Thermal stability of these compounds has been investigated by thermogravimetric analysis(TGA) of mass loss.     

Ag/TiO_2/freeze-dried graphene nanocomposite as a high performance photocatalyst under visible light irradiation

Ag/TiO_2/freeze-dried graphene nanocomposites have been prepared via a facile one-step solvothermal method for the photocatalytic degradation of Rh B under visible light irradiation. During the solvothermal process, reduction of graphene oxide and loading of Ag/TiO_2 nanoparticles on graphene sheets were achieved. Investigation of chemical state of products showed that covering of Ag/TiO_2 surface with higher weight ratio of graphene resulting in that Ag metals in Ag/TiO_2 were oxidized to Ag2 O in nanocomposite structure after solvothermal process. Degree of photocatalytic activity enhancement strongly depends on the coverage of Ag/TiO_2 surface by porous graphene. The sample of 1 wt% porous graphene hybridized Ag/TiO_2 showed the highest photocatalytic activity, which is related to high migration efficiency of photoinduced of electrons and reduction of electron–hole recombination rate due to high electrical conductivity of graphene. Expanding of absorption to visible light region was ascribed to surface plasmon resonance effect of Ag metals and presence of graphene. Investigation of photocatalytic performance of formic acid as a dye-less organic pollutant showed that dye sensitization effect of Rh B molecules during evaluation of photocatalytic performance was negligible.     

STUDY ON POLYMER-RARE EARTH METAL ION COMPLEXES Ⅰ. FLUORESCENT PROPERTIES OF POLY(ACRYLIC ACID-CO-4-VINYLPYRIDINE)-RARE EARTH METAL COMPLEXES

A kind of copolymer of acrylic acid and vinylpyridine was synthesized and the fluorescent properties of the complexes of the copolymer with Eu~(3+) or Tb~(3+) were studied. It was found that the fluorescence intensity of the complexes of the eopolymer with Eu~(3+) was 20 times as high as that of the complexes of polyaerylic acid with Eu~(3+) and twice as high as that of the complexes of polyvinylpyridine with Eu~(3+). The effects of the composition of the copolymer and the content of Eu~(3+) or Tb~(3+) in the complexes were studied. The fluorescence lifetime of the complexes was measured and it was found that two or more kinds of energy transfer mechanism existed.     

PHASE PLANE ANALYSIS OF NONLINEAR ODE''''S IN REACTION ENGINEERING

The application of phase plane analysis is extended on the basis of the authors' previous paper in which this approach was suggested to analyze a set of first-order nonlinear ODE's. The main point of phase plane analysis is the temporary elimination of non-intrinsic variables e.g. t and z, involved in the ODE sets which are commonly encountered in the course of solving reaction engineering problems. Two types of nonlinear ODE's i.e. a set of firstorder ODE's and a set of second-order ODE's, which depict the phenomena of parametric sensitivity and multiplicity of reactors, respectively, are explained. The concept of iso-parameter lines of phase planes is taken advantage of, and, as a methodology, emphasis has been placed on the flexibility of phase plane analysis.     

Spectrophotometric and Voltammetric Studies on the Interaction of Heparin with Phenosafranine

The interaction of phenosafranine （PSF） with a glycosaminoglycans of heparin （Hep） in aqueous solution has been characterized by UV-Vis absorption spectrophotometry and cyclic voltammetry in pH 1.5 Britton-Robinson （B-R） buffer solution. The addition of Hep caused decrease of the absorbance of PSF at 532 nm and the redox peak current of PSF. The study showed that an supramolecular complex of PSF-Hep was formed because of the electrostatic attraction of negatively charged Hep with the positively charged PSF, which resulted in the decrease of the equilibrium concentration of PSF in solutions, and the decrease of the absorbance or the peak current of PSF. The stoichiometry of the Hep/PSF complex was further calculated by voltammetric data with the result of 1：1 complex.     

INTERANNUAL VARIATION OF EARTH ROTATION,El Nio EVENTS AND ATMOSPHERIC ANGULAR MOMENTUM

In this paper the multi-stage digit filter is used to analyse the data of Earth rotation represented by the length of day, ΔLOD. The results show that the interannual variations of Earth rotation, which are in the time scale of several years but not quasi-periodic terms, exist in the long periodic fluctuations. They induce the relative variation in the length of day of 0.3×10~(-8).Comparing the series of length of day with the data of temperature departure of the sea surface in the equatorial area of the eastern Pacific, we found that the deceleration and acceleration of the interannual rate of Earth rotation are consistent with the warming up and down of sea temperature in the equatorial area very well. This means that every El Nio event always occurs after the turning of acceleration of the interannual rate of Earth rotation to deceleration.According to the strong interannual variation in the length of day and strong warming of the sea surface temperature in the equatorial area between 1982 and 1983     

三元配合物RE [(Pdtc)3(phen)]热化学性质的规律性

Treatment of hydrate rare-earth(RE=La,Pr,Nd,Sm-Lu)chloride with ammonium pyrrolidinyldithiocarboxy-late(apdtc)and 1,10-phenanthroline(phen)gave rise to thirteen complexes with an empirical formulaRE[(pdtc)_3(phen)].The enthalpies of solution of hydrate rare-earth(RE= Sm-Ho,Tm-Lu)chloride,apdtc and phenin ethanol were measured by an RD-496 Ⅲ microcalorimeter at 298.15 K,along with the mixing enthalpy of etha-nol solution of APDC and that of phen and the enthalpies of reaction of formation of the title complexes in ethanol.The enthalpies of reaction of formation of the title complexes in solid were available through a rationally thermo-chemical cycle.Using an RD-496 Ⅲ microcalorimeter,a model was developed for calculating the specific heat ca-pacity and the responding specific heat capacity of the complexes were determined.The thermochemical properties,including the enthalpies of solution of hydrate rare earth chloride in ethanol,the enthalpies of reaction of formationof the title complexes in ethanol,the enthalpies of reaction of formation of the title complexes in solid,the specialheat capacities at room temperature,the standard molar enthalpies of combustion and the standard molar enthalpiesof formation for this series of complexes versus the atomic numbers of rare earth,presented triplet effect,which isrepresentative of certain covalent bond between RE and the ligands and the result of 4f electron not shielded fullyby 5s5p.