反催化动力学光度法测定微量铜（Ⅱ）的含量

研究了在乙醇介质中过硫酸铵氧化甲基红的褪色反应被微量铜（Ⅱ）阻抑的情况及其动力学条件，建立了测定微量铜的新方法。线性范围０．０１～０．４０μｇＣｕ２＋／２５ｍｌ，相关系数ｒ＝０．９９９２。

反催化动力学光度法测定痕量铜

研究了铜阻抑过硫酸钾氧化甲基红褪色反应 ,应用动力学光度法原理测定铜。试验表明 ,在酸性介质中 ,其体系灵敏度得以提高 ,建立了反催化动力学光度法测定铜的新体系最佳测定条件。其检出限为 8 349× 1 0 - 12 g mL。方法选择性高 ,一定量的常见离子不干扰测定 ,可用于测定发样。

Photocatalytic activity of Fe-doped diopside

UV-visible light induced photocatalytic degradation of methylene blue (MB) over Fe-doped diopside was investigated. The structure, composition, morphology and absorption property of UV-visible light of as-prepared samples were characterized using XRD, SEM, FTIR and UV-vis DRS. The experimental results show that doping Fe3+ induced the formation of some new species in diopside, and promoted light adsorption property of diopside in UV-visible region. Photochemical reactivity of Fe-doped diopside obviously depended on the content of doping Fe3+. The diopside with 1.848% Fe3+ exhibited the superior photocatalytic activity with 95% degradation of MB under UV-visible light for 3 h. The photocatalytic degradation kinetics of MB over all samples showed the first-order reaction nature.

Effect of TPB on curing reaction of HTPB-TDI

Catalysis effect of triphenyl bismuth （TPB） on kinetics of hydroxyl terminated polybutadiene-toluene diisocyanate （HTPB-TDI） curing reaction was studied by non-isothermal differential scanning calorimetry （DSC）. The characteristic temperature of curing system was measured for calculating kinetic parameters and establishing curing reaction kinetic equations. The results show that activation energy （Ea） of uncatalyzed HTPB-TDI curing system is 51.29 kJmol-1, and TPB decreases Ea to 46.43 kJ＇mol-1. Catalyst lowers reaction temperature and shortens curing time through decreasing ac- tivation energy of curing reaction and accelerating reaction rate. TPB can increase the reaction rate at 27 ℃ to the value of uncatalyzed system at 80 ℃. The catalytic activity reaches the maximum when concentration is 0.5 %.

Enhanced CO oxidation over potassium-promoted Pt/Al_2O_3 catalysts:Kinetic and infrared spectroscopic study

A series of K-promoted Pt/Al2O3 catalysts were tested for CO oxidation. It was found that the addition of K significantly enhanced the activity. A detailed kinetic study showed that the activation energies of the K-containing catalysts were lower than those of the K-free ones, particularly for catalysts with high Pt contents （51.6 k）/mol for 0.42K-2.0Pt/Al2O3 and 6：3.6 kJ/mol for 2.0Pt/Al2O3 ）. The CO reaction orders were higher for the K-containing catalysts （about -0.2） than for the K-free ones （about -0.5）, with the former having much lower equilibrium constants for CO adsorption than the latter. In situ Fourier-transform infrared spectroscopy showed that surface CO desorption from the 0.42K-2.0Pt/Al2O3 catalyst was easier than from 2.0Pt/Al2O3. The promoting effect of K was therefore caused by weakening of the interactions between CO and surface Pt atoms. This decreased coverage of the catalyst with CO and facilitated competitive O2 chemisorption on the Pt surface, and significantly lowered the reaction barrier between chemisorbed CO and O2 species.

Kinetics of Non-catalyzed Decomposition of D-xylose in High Temperature Liquid Water

The kinetics of non-catalyzed decompositions of xylose and its decomposition product furfural in high temperature liquid water （HTLW） was studied for temperature from 180 to 220℃ and under pressure of 10MPa. The main products of xylose decomposition were furfural and formic acid, and furfural further degraded to formic acid under HTLW condition. With the assumption of first order kinetics e.quation, the evaluated activation energy of xylose and furfural decomposition was 123.27kJ·mol^-1 and 58.84kJ·mol^-1, respectively.

Recent progress in production and usage of hydrogen peroxide

Hydrogen peroxide has attracted increasing interest as an environmentally benign and green oxidant that can also be used as a solar fuel in fuel cells.This review focuses on recent progress in production of hydrogen peroxide by solar-light-driven oxidation of water by dioxygen and its usage as a green oxidant and fuel.The photocatalytic production of hydrogen peroxide is made possible by combining the e^(-)and 4e-oxidation of water with the e^(-)reduction of dioxygen using solar energy.The catalytic control of the selectivity of the e^(-)vs.4e-oxidation of water is discussed together with the selectivity of the e^(-)vs.4e-reduction of dioxygen.The combination of the photocatalytic e^(-)oxidation of water and the e^(-)reduction of dioxygen provides the best efficiency because both processes afford hydrogen peroxide.The solar-light-driven hydrogen peroxide production by oxidation of water and by reduction of dioxygen is combined with the catalytic oxidation of substrates with hydrogen peroxides,in which dioxygen is used as the greenest oxidant.

Kinetics of Non-catalyzed Decomposition of Glucose in High-temperature Liquid Water

The decomposition kinetics of glucose was studied in high-temperature liquid water （HTLW） from 180 to 220℃ under a pressure of 10 MPa. It was found the main products from glucose decomposition were 5-hydroxymethylfurfural （5-HMF） and levulinic acid （LA）. The decomposition kinetics of 5-HMF and stability of LA in HTLW were further investigated. A kinetic model for glucose decomposition was proposed accordingly. In the model, a series of first-order reactions with the consideration of parallel by-reactions were used to illustrate the decomposition of glucose. The decomposition activation energies of glucose, 5-HMF, and LA were evaluated as 118.85, 95.40, and 31.29 kJ·mol^-1, respectively.

Study on the Performance and Commercial Application of New Generation DMMC-1 Type Catalyst for Deep Catalytic Cracking

Over the past decades SINOPEC has been uninterruptedly engaging in the development and upgrading of deep catalytic cracking （DCC） technology for manufacturing propylene from heavy oil. Recently SINOPEC after having made a lot of progress in the area of oil refining at the molecular level has developed a new generation DMMC-1 type catalyst designed for the DCC process. The laboratory evaluation tests have shown that compared to the existing MMC-2 type catalyst that features the best comprehensive performance, the DMMC-1 type catalyst has increased the propylene yield by 2.2% with the propylene selectivity increased by 10%. The said catalyst has improved its ability for heavy oil cracking and coke selectivity along with reduction of olefin content in gasoline to achieve a better product distribution and improve the product quality. The results of application of the said catalyst in a 650-kt/a commercial DCC unit at SINOPEC Anqing Branch Company have revealed that the DMMC- 1 catalyst demonstrated an enhanced capability for heavy oil cracking and could increase the total liquid yield to 84.56 m% from 83.92 m%, the LPG yield to 38.90 m % from 34.60 m %, the propylene yield to 17.80 m% from 15.37 m% and the propylene concentration to 45.91 m% from 44.91 m%, and reduce the coke yield from 7.61 m% to 7.05 m% and the olefin content in gasoline from 42.3 v% to 37.5 v%, resulting in an incremental profit amounting to 52.19 million RMB a year. This technology has further upgraded and developed the DCC technology which has been commanding a leading position among the industry peers.

Establishment of Kinetic Model for Catalytic Pyrolysis of Daqing Atmospheric Residue

An 8-lump kinetic model was proposed to predict the yields of propylene, ethylene and gasoline in the catalytic pyrolysis process of Daqing atmospheric residue. The model contains 21 kinetic parameters and one for catalyst deactivation. A series of experiments were carded out in a riser reactor over catalyst named LTB-2. The ki- netic parameters were estimated by using sub-model method, and apparent activation energies were calculated according to the Arrhenius equation： The predicted yields coincided well with the experimental values. It shows that the kinetic parameters estimated by using the sub-model method were reliable.

Steam reforming of methane over Ni catalysts prepared from hydrotalcite-type precursors: Catalytic activity and reaction kinetics

Ni/Mg–Al catalysts derived from hydrotalcite-type precursors were prepared by a co-precipitation technique and applied to steam reforming of methane. By comparison with Ni/γ-Al2O3 and Ni/α-Al2O3 catalysts prepared by incipient wetness impregnation, the Ni/Mg–Al catalyst presented much higher activity as a result of higher specific surface area and better Ni dispersion. The Ni/Mg–Al catalyst with a Ni/Mg/Al molar ratio of 0.5:2.5:1 exhibited the highest activity for steam methane reforming and was selected for kinetic investigation. With external and internal diffusion limitations eliminated, kinetic experiments were carried out at atmospheric pressure and over a temperature range of 823–973 K. The results demonstrated that the overall conversion of CH4 and the conversion of CH4 to CO2were strongly influenced by reaction temperature, residence time of reactants as well as molar ratio of steam to methane. A classical Langmuir–Hinshelwood kinetic model proposed by Xu and Froment(1989)fitted the experimental data with excellent agreement. The estimated adsorption parameters were consistent thermodynamically.

Reaction Kinetics of Biodiesel Synthesis from Waste Oil Using a Carbon-based Solid Acid Catalyst

The kinetics of simultaneous transesterification and esterification with a carbon-based solid acid catalyst was studied.Two solid acid catalysts were prepared by the sulfonation of carbonized vegetable oil asphalt and petroleum asphalt.These catalysts were characterized on the basis of elemental analysis,acidity site concentration,the Brunauer-Emmett-Teller（BET）surface area and pore size.The kinetic parameters with the two catalysts were determined,and the reaction system can be described as a pseudo homogeneous catalyzed reaction.All the forward and reverse reactions follow second order kinetics.The calculated concentration values from the kinetic equations are in good agreement with experimental values.

Recovery of Dilute Acetic Acid by Catalytic Distillation Using NKC-9 as Catalyst

The reaction kinetics of dilute acetic acid with methanol using NKC-9 as catalyst was studied at temperatures of 308 K, 318 K, 323 K, 328 K. The kinetic model based on Langmuir-Hinshelwood rate model was derived and the activation energy was 6.13 × 10^4 kJ/kmol. The experiment of recovery of dilute acetic acid was conducted in a packed bed catalytic distillation column. The optireal process parameters and operational conditions determined to make up to 85.9% conversion of acetic acid are as follows：the height of catalyst bed is 1 100 mm, reflux ratio is 4： 1, and the ratio of methanol to acetic acid is 2： 1. The method can be used as a guide in industrial scale recovery of 15% 30% dilute acetic acid.

Kinetics of 2-Methyl-6-acetyl-naphthalene Liquid Phase Catalytic Oxidation

In this paper, a kinetics model for the liquid-phase oxidation of 2-methyl-6-acetyl-naphthalene to 2,6-naphthalene dicarboxylic acid catalyzed by cobalt-manganese-bromide is proposed. The effects of the reaction temperature, catalyst concentration and ratio of catalyst on the lime evolution of the experimental concentration for the constituents including raw material, intermediates and product are investigated. The model parameters are determined in a nonlinear optimization, minimizing the difference between the simulated and experimental time evolution of the product composition obtained in a semi-batch oxidation reactor where the gas and liquid phase were well nuxed. The kinetics data demonstrate that the model is suitable to the liquid-phase oxidation of 2-methyl-6-acetyl-naphthalene to 2,6-naphthalene dicarboxylic acid.

A Reduced Mechanism for Flame Inhibition by Phosphorus-containing Compounds Based on Level of Importance Analysis

A reduced mechanism for propane/air combustion and its flame inhibition by phosphorus-containing compounds (PCCs) is constructed with the level of importance (LOI) method. The analysis is performed on solutions of freely propagating premixed flames with detailed chemical kinetics involving 121 species and 682 reactions proposed by Jayaweera et al. For the non-homogeneous reaction-diffusion system, the chemical lifetime of each species is weighted by its diffusion timescale, and the characteristic flame timescale is used to normalize the chemical lifetime. The definition of sensitivity in LOI is extended so that multi-parameters can be used as sensitivity targets. Propane, oxygen, dimethyl methylphosphonate (DMMP), and flame speed are selected to be perturbed for sensitivity analysis, the species with low LOI index are removed, and reactions involving the redundant species are excluded from the mechanism. A skeletal mechanism is obtained, which consists of 57 species and 268 elementary reactions. Calculations for laminar flame speeds, key flame radicals and catalytic cycles using the skeletal mechanism are in good agreement with those by using the detailed mechanism over a wide range of equivalence ratio undoped and doped with DMMP.

Proton reduction in the presence of oxygen by iron porphyrin enabled with 2nd sphere redox active ferrocenes

Hydrogen evolution in the presence of atmospheric level of oxygen is a significant barrier in the quest for an alternative,sustainable and green source of energy to counter the depleting fossil fuel sources and increasing global warming due to fossil fuel burning.Oxygen reduction is thermodynamically more favourable than proton reduction and it often produces reactive oxygenated species upon partial reduction which deactivates the catalyst.Thus,catalyst development is required for efficient proton reduction in the presence of oxygen.Here,we demonstrate an iron porphyrin having triazole containing 2nd sphere hydrogen bonding residues appended with redox active ferrocene moieties(α4-Tetra-2-(3-ferrocenyl-1,2,3-triazolyl)phenylporphyrin(FeFc4))as a bifunctional catalyst for fast and selective oxygen reduction to water and thus,preventing the proton reduction by the same catalyst from oxidative stress.Fe(0)is the active species for proton reduction in these iron porphyrin class of complexes and it is observed that the kinetics of proton reduction at Fe(0)state occurs at much faster rate than O2 reduction and thus,paving the way for selective proton reduction in the presence of oxygen.

Reaction kinetics for synthesis of sec-butyl alcohol catalyzed by acid-functionalized ionic liquid

The acid-functionalized ionic liquid([HSO3Pmim]HSO4) was synthesized by a two-step method. Nuclear magnetic resonance(NMR) and Fourier transform infrared spectroscopy(FT-IR) show that the synthesis method is feasible and high purity of ionic liquid can be obtained. Using [HSO3Pmim]HSO4as the catalyst, we studied the reaction kinetics of synthesizing sec-butyl alcohol from sec-butyl acetate and methanol by transesterification in a high-pressure batch reactor. The effects of temperature, initial molar ratio of methanol to ester, and catalyst concentration on the conversion of sec-butyl acetate were studied. Based on its possible reaction mechanism, a homogeneous kinetic model was established. The results show that the reaction heat ΔH is 10.94 × 103J·mol-1, so the reaction is an endothermic reaction. The activation energies Ea+and Ea-are 60.38 × 103 and 49.44 × 103J·mol-1,respectively.

Kinetics of Ortho-nitrochlorobenzene Hydrogenation on Platinum/Carbon Catalyst

The kinetics of catalytic hydrogenation of ortho-nitrochlorobenzene to 2,2′-dichloroazoxybenzene on platinum/carbon catalyst is investigated in a slurry reactor with the temperature range of 313-343 K, and orthochloroaniline is formed as a byproduct. Models based on Rideal-Eley and Langmuir-Hinshelwood mechanism have been proposed based on the rate data and the kinetic regime. The former model can be used to fit the experimental data better. Reaction controlling steps are physical adsorption of hydrogen and adsorbed ortho-nitrochlorobenzene reacted on the surface of catalyst.

Kinetic Study on Liquid-Phase Hydrodesulfurization of FCC Diesel in Tubular Reactors

According to the characteristics of FCC diesel, a technology of liquid-phase hydrodesulfurization of the diesel in tubular reactors was proposed and lab-scale experiments were carried out. A kinetic model for the hydrodesulfurization process was developed and verified. The model was utilized to predict the sulfur content of products under different operating conditions. The effects of temperature, space velocity, pressure, and hydrogen concentration on the dcsulfurization rate were investigated.

Simulation of gas-solid fluidized bed reactor for F-T synthesis

Using the lumping method, CH_4, C_3H_8, C_10H_22, and C_22H_44 were chosen as themodel products, and CO as the key component. The mathematical model of a gas-solidfluidized bed reactor was established based on some hypotheses. The consumption kinetic model of CO was investigated, and the parameters were estimated by UniversalGlobal Optimization with the Marquardt method. Residual error distribution and a statisticaltest show that the intrinsic kinetic models are reliable and acceptable. A model of carbonchain growth probability was established in terms of experiments. Coupled with the Ander-son- Schulz-Flory (ASF) distribution, the amount of specific product could be obtained.Large- scale cold model experiments were conducted to investigate the distribution of thegas (solid) phase and determine the function of the voidage with the location of the catalytic bed. The change tendencies of the components in the catalytic bed at different temperatures were computed and figured out. The calculated value computed by the modelestablished for the Fe-based F-T synthesis catalyst fit the experimental value very wellunder the same operating conditions, and all the absolute values of the relative deviationsare less than 5%.