CARBON MONOXIDE HYDROGENATION OVER SILICA-SUPPORTED RHODIUM CARBONYL CLUSTER CATALYSTS

The CO hydrogenation over Rh_4(CO)_(12)SiO_2 catalyst promoted with man-ganese and lithium was reported.As compared with conventional RhCI_3/SiO_2 catalyst,silica-supported rhodium carbonyl cluster catalysts have higher reactive activities.Manganese increases CO conversion by more than one order of magnitude and lithiumlowers CO hydrogenation activity,whereas Rh_4(CO)_(12)-MnCl_2-LiCI/SiO_2 catalyst giveshigher CO conversion and selectivity to C_2-oxygenate.XPS and IR spectra show thatmanganese stabilizes Rh(Ⅰ)ions and facilitated CO molecule activation via its syner-gism with rhodium enhancing CO conversion obviously.ESR results preliminarily revealthe interaction of rhodium with manganese.The mechanism of CO hydrogenation is dis-cussed primarily.     

CARBON FILMS PREPARED BY PLASMA POLYMERIZATION OF NATURAL GAS(Ⅱ)MECHANICAL PROPERTIES OF CARBON FILMS

Mechanical properties of carbon films deposited by plasma polymerization on different sub-strates were studied.Film hardness was measured to be approximately 20GPa.Adhesive scratch testsfound the critical load L,at which film failure occurred,of the films on silicon,glass,hard magneticrecording disc were 28,45 and 18N,respectively.No definite value was detected for the film on bear-ing steel substrate.Tribological study suggests that the friction coefficient of the films was in the rangeof 0.1—0.3.The wear rate of the carbon film was 1-2 orders of magnitude lower than that of thesubstrates.Micrographs of the wear tracks and the magnitude of the wear coefficients indicate that thelikely wear mechanism is the threebody abrasive wear.Films with stable low friction coefficient andsuperior wear resistance were obtained on silicon and steel substrates.     

ELECTRODEPOSITION OF POLYMERS ON CARBON FIBERS

Styrene-co-maleic anhydride, vinyl acetate-co-maleic anhydride, methyl methacrylate-co-maleic anhydride copolymers were deposited on the surface of carbon fibers by an electrodcposition technique. The anion-free radical mechanism of this process and the physical adhesion to the surface were preliminarily confirmed. The adhesion at fiber-resin matrix interface in carbon fiber reinforced plastics was improved by the electrodeposited polymer interlayer and the shear failure occurred mainly in the matrix. Interlaminar shear strength of the unidirectional carbon fiber reinforced epoxy composite is increased from about 600 kg/cm~2 to 1000 kg/cm~2 by electrodeposition of polymers and the strength loss of the composite which has been immersed in boiling water for 100 hrs is decreased.     

SYNTHESIS OF ALCOHOLS FROM HYDROGENATION OF CARBON DIOXIDE(Ⅲ)

The effects of catalyst preparation and reaction conditions on thecatalytic activity and selectivity for hydrogenation of carbon dioxide to alcoholsover zeolite supported bimetal catalyst were studied.The results showed that:(1)ethanol easily formed on the zeolite with larger pores and methanol did onthat with smaller pores;(2)when pH value of the ion exchange solution was10,the activity reached the maximum;(3)the optimum Cu/Ru mole ratio was3;(4)the influence of reation conditions such as temperature,pressure andH_2/CO_2 mole ratio on the topic reaction was greater.     

PURIFICATION OF CARBON MONOXIDE BY PRESSURE-SWING ADSORPTION

The effects of valence state of copper supported on charcoal on the CO adsorption perfor-mance and CO desorption kinetics were investigated by means of XPS and TG.The results indicate thatCO may be selectively adsorbed on the Cu(I)sites and the desorption is a second order reaction with anactivation energy of 24.27kJ/mol.Using a bench-seale PSA apparatus,CO can be purified fromCO-N_2 and CO-CO_2-N_2 gas mixtures separately with CO concentration increases from 31％,25％to98％,96％,net desorption of 26ml/g,22ml/g and recovery of about 95％.     

ADSORPTION CHARACTERISTICS OF L-HISTIDINE ON ACTIVE CARBON

1. INTRODUCTION L-histidine is a kind of semi-essential amino acid in human and animal body. In the medicinal field, L-his is mainly used for amino acid transfusion and intergrated amino acid formulation. In addition, L-his is production material for medicine of peptic ulcer and heart circulation, and histidine hydrochloride is also used as food additives [1,2]. Quantity requirement of L-his is rising in recent years and the production scale of L-his is expanded step and step. So it is …     

PREPARATION OF ACTIVATED CARBON FIBER AND THEIR XENON ADSORPTION PROPERTIES (III)-ADSORPTION ON MODIFIED ACTIVATED CARBON FIBER

1. INTRODUCTION Nuclear explosion and thermal fission of U produce many kinds of nuclide. The major products consist of gaseous materials, in particular the noble gases Xe. In some types of nuclear reactor it is necessary to remove 135Xe from the cooling…     

PROGRESS ON ACTIVATED CARBON FIBERS

1. INTRODUCTION The serious environment pollution and natural resources waste is imperiling human existence and development. To counter the exhaustion and dilution of natural resources, and to prevent environment from further pollution, it is their duty …     

CARBON WIRE AMPEROMETRIC FLOW THROUGH DETECTOR

A carbon wire amperometric flow through detector is describedwhich is easily constructed at low cost for application to flow injectionanalysis,continuous stream analysis and liquid chromatography.Thetheoretical limiting current of the detector is 2.14×10~6nCD~(2/3)u_f~(1/3) with 36%actual current efficiency.By use of flow injection analysis,thedetecting limits for Ag(I)and Cr(VI)had achieved 1 ppb and 0.4 ppbrespectively with 1.2%(n=20)relative standard deviation after preliminaryexperiments.     

KINETICS OF CARBON DIOXIDE——PROPYLENE OXIDE COPOLYMERIZATION

Kinetics of the anionic coordination copolymerization of carbondioxide (M_1)and propylene oxide(M_2) was studied for the first time on thebasis of the liquid vapor equilibrium.The reactivity ratio r_2 was determined tobe 0.2 by a modified integral method,while r_1 was recognized to be zero.These values indicate that the reaction in the presence of excess carbon dioxidetends to form alternating eopolymers.The rate of polymerization was found toobey the following equation:R_p=(?)M_2~2/M_1where M_1 and M_2 (mol/L) are concentrations of the monomers.and C(g/L) isamount of the catalyst.For the polymerization,a mechanism is proposedinvolving initiation by forming M_2-catalyst complex,propagation by repeatedM_1 and M_2 insertion at the active center,and a shielding of the active centerC by M_1.This mechanism predicts the dependence of R_p on the concentrationsas observed.     

CARBON FILMS PREPARED BY PLASMA POLYMERIZATION OF NATURAL GAS(Ⅰ)DEPOSITION AND CHARACTERIZATION OF CARBON FILMS

Plasma polymerization of natural gas has been investigated in a capacitively coupled RFdischarge apparatus.Carbon film with diamond-like properties was obtained.The structure of the filmwas characterized by IR,XPS,Raman spectroscopy and elemental analysis,etc..     

CARBON FILMS PREPARED BY PLASMA POLYMERIZATION OF NATURAL GAS (Ⅲ) APPLICATION OF CARBON FILM TO MAGNETIC RECORDING MEDIA

Amorphous carbon film was deposited on thin-film magneticrecording disk and tape by RF glow discharge decpmposition of methane.Thewear and corrosion resistances of the coated media were improved withoutany deterioration of magnetic performance.     

COMPOSITION, CARBON ISOTOPE CHARACTERISTICS AND THE ORIGIN OF COAL-BED GASES IN CHINA AND THEIR IMPLICATIONS

The compositions and the carbon isotope characteristics of methanes of the coal-bed gases from 14 coal mines and 3 deep to medium boreholes are studied in this paper.It is found that the coal-bed gases from the coal mines are characterized by the drying or lightening phenomena, which are absent in coal-bed gases from the boreholes.The drying and lightening features were not observed in the coalbed gases derived from both the primary zones and the lignite pyrolysis simulation experiments.Therefore, it is considered that the drying and lightening of coal-bed gases in the coal mines result from the secondary destructive processes.The origins of dried or lightened coal-bed gases may be due to (ⅰ) desorption-diffusion, (ⅱ) the exchange equilibrium of carbon isotopes between CH_4 and CO_2, and (ⅲ) mixing of primary coal-bed gases with syncoalification or postcoalification of biogenetic gases, among which the desorption-diffusion origin is of primary importance.     

THE HYDROXYLATON OF INACTIVE HYDROCARBONS WITH ACTIVE CARBON SUPPORTED METALLOPORPHYRINS

A supported Mn-porphyrin catalyst was prepared by adsorption of Mn-porphyrin on active carbon, and found to be efficient for the hydroxylation of hexane with hydrogen peroxide.     

AN INTERMOLECULAR ~(13)C{~1H} NUCLEAR OVERHAUSER EFFECT FOR THE CARBON OF CCl_4 IN POLYMER SOLUTIONS

An intermolecular ~(13)C{~1H} NOE of CCl_4 in the solutions of polystyrene and polybutadiene and their copolymers was observed. The results show that the defined polymer-CCl_4 interaction variable has a linear relation with the polymer composition and the difference of solubility parameters and exponentially depends on the reciprocal of temperature.     

STUDY OF CARBON MONOXIDE HYDROGENATION OVER SUPPORTED IRON CLUSTER CATALYSTS

Fe_3(CO)_(12)-derived Fe/r-AL_2O_3 and Fe/zeolite catalysts have higher catalytic activity than those derived from Fe(NO_3)_3. The existence of metal-metal bond in cluster species and the congruity of the adsorption of CO and H_2 are important for increasing the catalytic activity. Carbon deposition for Fe_5C(CO)_(15)-derived Fe/r-AL_2O_3 catalyst is discussed.     

STUDY ON THE FACTORS AFFECTING REDUCTION CAPACITIES OF ACTIVATED CARBON FIBERS

1. INTRODUCTION The discharge of effluent containing precious metal ions, which comes from electroplating, mining, smelting, and other industries, not only contaminate the environment where people live, but also cause the waste of natural resources. From…     

NUCLEATION BEHAVIOURS OF SILVER ON GLASSY CARBON MICROELECTRODES

The initial stage of silver deposition has been investigated using the microelectrodetechnique A disc shaped nucleus can be obtained on glassy carbon microelectrodes and the instanta.neous nucleation model applies for the process     

INVESTIGATIONS ON THE CRYSTALLINE MORPHOLOGIES OF POLYPHENYLENE SULFIDE AND THE CARBON FIBRE SURFACE EFFECTS

By the use of polarized light microscopy, chemical etching and scanning electron micro-scopy, the erystalline morphologies of polyphenylene sulfide (PPS) have been studied. Thecrystalline morphologies of PPS are greatly affected by the curing conditions. Either gra-phite fibres and carbon fibres, or glass fibres, possess the ability of inducing the transcry-stallization of PPS at different degrees. The corrosive resistance of PPS resin is not onlyrelated with its chemical structure, but also with its aggregation structure, and furthermorewith the "interface effects" of carbon fibres in the composites.     

STUDIES ON THE PREPARATION OF ZINC-CONTAINING ACTIVATED CARBON FIBERS AND THEIR ANTIBACTERIAL ACTIVITY

1. INTRODUCTION Microbial pollution will bring about various problems in industry and other vital fields, such as causing decomposing of materials, harming people抯 health. In order to reduce these problems, new antibacterial materials have been demanded. Recently, much attention has been paid to inorganic materials including zinc oxide [1~4]. These inorganic antibacterial materials are now substituting for organic materials to avoid releasing noxious organic molecules harmful to humans;…