Adsorption of Carbon Dioxide on Activated Carbon

The adsorption of CO2 on a raw activated carbon A and three modified activated carbon samples B, C, and D at temperatures ranging from 303 to 333 K and the thermodynamics of adsorption have been investigated using a vacuum adsorption apparatus in order to obtain more information about the effect of CO2 on removal of organic sulfur-containing compounds in industrial gases. The active ingredients impregnated in the carbon samples show significant influence on the adsorption for CO2 and its volumes adsorbed on modified carbon samples B, C, and D are all larger than that on the raw carbon sample A. On the other hand, the physical parameters such as surface area, pore volume, and micropore volume of carbon samples show no influence on the adsorbed amount of CO2. The Dubinin-Radushkevich (D-R) equation was the best model for fitting the adsorption data on carbon samples A and B, while the Preundlich equation was the best fit for the adsorption on carbon samples C and D. The isosteric heats of adsorption on carbon samples A, B, C, and D derived from the adsorption isotherms using the Clapeyron equation decreased slightly increasing surface loading. The heat of adsorption lay between 10.5 and 28.4 kJ/mol, with the carbon sample D having the highest value at all surface coverages that were studied. The observed entropy change associated with the adsorption for the carbon samples A, B, and C (above the surface coverage of 7 ml/g) was lower than the theoretical value for mobile adsorption. However, it was higher than the theoretical value for mobile adsorption but lower than the theoretical value for localized adsorption for carbon sample D.     

Z→E Photoisomerization of Homoactivated Carbon Carbon Double Bonds

Z-configured 1,4-diene or β,γ-unsaturated carbonyl systems are readily available by the Wittig reaction. Isomerization required for access into the E-series can easily be accomplished by irradiation using an ordinary tungsten lamp and diphenyl disulphide sensitizer. There is very little formation of conjugated isomers (less than 1%).     

Palladium-Catalyzed Addition of Carbon Monoxide and Carbon Tetrachloride to 1-Octene in Supercritical Carbon Dioxide

The Pd-catalyzed addition of carbon monoxide and carbon tetrachloride to 1-octene gave coadduct [alkyl 2-( 2, 2, 2-trichloroethyl)octanoate] as the major product in supercritical carbon dioxide by using pyridine as the base. It was found that the selectivity and the yield of coadduct were greatly affected by the pressure of carbon dioxide, the reaction temperature and the amounts of alcohol and base used.     

Catalysis of Carbon–Gas Reactions

The characteristic features on the catalysis of carbon–gas reactions has been studied by combining various techniques such as transient kinetics, temperature-programmed desorption and others. Some of recent achievements are presented to comprehend the state of the art. Many industrial processes associated with catalytic carbon–gas reactions are then discussed in relation to the fundamental chemistry of catalysis.     

Synthesis and Application of Carbon Nanotubes

Owing to the unique structure, the superior physical and chemical properties, the super strong mechanical performances, and so on, carbon nanotubes have attracted the attention of researchers all over the world. In this article, the basic properties and the main production processes of carbon nanotubes are introduced in brief, and the progress of applied research for carbon nanotubes is reviewed.     

Activation of Carbon Dioxide and Synthesis of Propylene Carbonate

Cycloaddition of carbon dioxdie and propylene oxide to propylene carbonate catalyzed by tetra-tert-butyl metal phthalocyanine in the presence of tributylamine(TBA) shows higher yield than catalyzed by unsubstituted metal phthalocyanine.Comparing different catalysts of diverse metals,(t-Bu)4PcMg is more active than (t-Bu)PcFe ,But(t-Bu)4PcCo and (t-Bu)4PcNi only have low catalytic activities towards the reaction.Moreover,the yield will increase as the temperature increases.     

Direct Electrochemistry of Catalase on Single Wall Carbon Nanotubes Modified Glassy Carbon Electrode

Direct electrochemistry of catalase (Ct) has been studied on single wall carbon nanotubes (SWNTs) modified glassy carbon (GC) electrode. A pair of well-defined nearly reversible redox peaks is given at -0.48 V (vs. SCE) in 0.1 mol/L phosphate solution (pH 7.0).The peak current in cyclic voltammogram is proportional to the scan rate. The peak potential of catalase is shifted to more negative value when the pH increases. Catalase can adsorb on the SWNTs modified electrode.     

Diiodination of Alkynes in supercritical Carbon dioxide

A general,green and efficient method for the synthesis of transdiiodoalkenes in CO2(sc) has been developed.Trans-diiodoalkenes were obtained stereospecifically in quantitative yields via diiodination of both electron-rich and electron-deficient alkynes in the presence of KI,Ce(SO4)2 and water in supercritical carbon dioxide [CO2(sc)]at 40℃.     

Hypervalent-Iodine-Mediated Carbon–Carbon Bond Cleavage and Dearomatization of 9H-Fluoren-9-ols

A transition-metal-free synthesis of spiro compounds from 9H-fluoren-9-ols mediated by hypervalent iodine is reported. In this reaction, an unprecedented β-carbon elimination of tertiary alkoxyliodine(III) to form new diaryliodonium salts is proposed. The obtained phenol intermediates undergo oxidative dearomatization to furnish a class of oxo-spiro compounds. This domino reaction significantly increases the complexity of these molecules and shows excellent regio- and stereoselectivity.     

Microwave-Enhanced Hydrogenation of Carbon–Carbon Double Bonds in Single-Stranded Polymers by p-Tosylhydrazide

A rapid and efficient method for the hydrogenation of the backbones of various single-stranded polymers with p-tosylhydrazide is developed using microwave irradiation, through which the corresponding saturated and more flexible polymers are obtained in good to excellent yields.     

The Carbonylations of Cyclohexene with Carbon Dioxide

Carb0ndi0xide,anaturalandinexpensivesourceoffunctionalcarbonunits,showspotentialabilitiesf0rthefunctionalization0f0rganicsubstrate.ThehighstabilityofCO=,however,andthelack0freliablemeth0ds0factivation,considerablyrestrictitsappIications'.Inrecentyearstransiti0nmetalcatalyzedreacti0ns0fcarb0ndi0xideaimedattheutilizationofCO2asbuildingblockinorganicsynthesishaveattractedc0nsiderableattentions,becausecarbondi0xideisthebiggestcarbonsourceonearchandthebasisofallbiochemicalorganicsynthesispr0cesse…     

Attachment of Gold Nanoparticles to Carbon Nanotubes

Carbon nanotubes were initially chemically modified with an H2SO4-HNO3 treatment, and subsequently activated with Pd-Sn catalytic nuclei via a one-step activation approach. These activated nanotubes were used as precursors for obtaining gold nanoparticles-attached nanotubes via simple electroless plating. This approach provides an efficient method for attachment of metal nanostructures to carbon nanotubes. Such novel hybrid nanostructures are attractive for many applications.     

Direct Mechanism of the First Carbon–Carbon Bond Formation in the Methanol-to-Hydrocarbons Process

In the past two decades, the reaction mechanism of C−C bond formation from either methanol or dimethyl ether (DME) in the methanol-to-hydrocarbons (MTH) process has been a highly controversial issue. Described here is the first observation of a surface methyleneoxy analogue, originating from the surface-activated DME, by in situ solid-state NMR spectroscopy, a species crucial to the first C−C bond formation in the MTH process. New insights into the first C−C bond formation were provided, thus suggesting DME/methanol activation and direct C−C bond formation by an interesting synergetic mechanism, involving C−H bond breakage and C−C bond coupling during the initial methanol reaction within the chemical environment of the zeolite catalyst.     

FT-IR Study of Carbon Nanotube Supported Co-Mo Catalysts

In this paper, adsorption properties of dibenzothiophene (DBT) on carbon nanotube, carbonnanotube supported oxide state and sulfide state CoMo catalysts are studied by using thermal gravi-metric analysis (TGA) technique and FT-IR spectroscopy. Activated carbon support, 7-A1203 supportand supported CoMo catalysts are also subjected to studies for comparison. It was found that sulfidestate CoMoS/MWCNT, CoMoS/AC and CoMoS/γ-A12O3 catalysts adsorbed much more DBT moleculesthan their corresponding oxide state catalysts, as well as their corresponding supports. The chemicallyadsorbed DBT aromatic molecules did not undergo decomposition on the surface of supports, supportedoxide state CoMo catalysts and sulfide state CoMo catalysts when out-gassing at 373 K. FT-IR results indicated that DBT molecules mainly stand upright on the active sites (acid sites and/or transition active phases) of CoMoS/MWCNT catalyst. However, DBT aromatic molecules mainly lie flat on MWCNT and CoMoO/MWCNT.     

States of Carbon Nanotube Supported Mo-Based HDS Catalysts

The dispersion of the active phase and loading capacity of the Mo species on carbon nanotube (CNT) was studied by the XRD technique. The reducibility properties of Co-Mo catalysts in the oxide state over CNTs were investigated by TPR, while the sulfided Co-Mo/CNT catalysts were characterized by means of the XRD and LRS techniques. The activity and selectivity with respect to the hydrodesulfurization (HDS) performances on carbon nanotube supported Co-Mo catalysts were evaluated. It was found that the main active molybdenum species in the oxide state MoO3/CNT catalysts were MoO2, but not MoO3, as generally expected. The maximum loading before the formation of the bulk phase was lower than 6% (percent by mass, based on MoO3). TPR studies revealed that the active species in the oxide state Co-Mo/CNT catalysts were reduced more easily at relatively lower temperatures in comparison to those of the Co-Mo/γ-Al2O3 catalysts, indicating that the CNT support promoted or favored the reduction of the active species. The active species of a Co-Mo-0.7/CNT catalyst were more easily reduced than those of the Co-Mo/CNT catalysts with Co/Mo atomic ratios of 0.2, 0.35, and 0.5, respectively, suggesting that the Co/Mo atomic ratio has a great effect on the reducibility of the active species. It was found that the incorporation of cobalt improved the dispersion of the molybdenum species on the support, and a phenomenon of mobilization and re-dispersion had occurred during the sulfurization process, resulting in low valence state Mo3S4 and Co-MoS2.17 active phases. HDS measurements showed that the Co-Mo/CNT catalysts were more active than the Co-Mo/γ-Al2O3 ones for the desulfurization of DBT, and the hydrogenolysis/hydrogenation selectivity of the Co-Mo/CNT catalysts was also much higher than those of the Co-Mo/γ-Al2O3. The Co-Mo/CNT catalyst with a Co/Mo atomic ratio of 0.7 showed the highest activity, whereas the catalyst with a Co/Mo atomic ratio of 0.35 had the highest selectivity.     

A New Application of Carbon Nanotubes Constructing Biosensor

Carbon nanotubes used for constructing biosensor was described for the first time. Single-wall carbon nanotubes (SWNTs) functionalized with carboxylic acid groups were used to immobilize glucose oxidase forming a glucose biosensor. The biosensor response can be determined by amperometric method at a low applied potential (0.40V).     

Identification of Different Cobalt Nucleation on Glassy Carbon

The nucleation mechanisms of cobalt from sulfate solutions were studied by utilizing the electrochemical technique, chronoamperometry. It was found that the recorded current-time transients introduced from 1.0mol/L CoSO4 solution were complexes with unusual shapes. All characteristic features were identified as separate process. The instantaneous or progressive nucleation with 2D or 3D growth exists during the cobalt deposition, depending on the applied potentials.     

Synthesis of Diethyl Oxalate by a Coupling-Regeneration Reaction of Carbon Monoxide

This article describes a process for the synthesis of diethyl oxalate by a coupling reaction of carbon monoxide, catalyzed by palladium in the presence of ethyl nitrite. The kinetics and mechanism of the coupling and regeneration reaction are also discussed. This paper presents the results of a scale-up test of the catalyst and the process based on an a priori computer simulation.     

Effect of Additive Agent on the Electrochemical Capacitance of Activated Carbon

In order to compare the effect of additive agent on the electrochemical capacitance of activated carbon, three additive agents like carbon nanotubes (CNTs), activated carbon fibre (ACF) and acetylene black (AB) were added to activated carbon by ultrasonic dispersion. Two electrodes including 95wt.% activated carbon, 2wt.% additive agent and 3wt.% PTFE binder were prepared. ECs were assembled in an argon-filled glove box by sandwiching a microporous separator (Celgard 2400) between two ele…