乙丙共聚物的过氧化氢基化反应及其与烯类单体的接枝共聚合

本文研究了乙丙共聚物在含臭氧的氧气流中的过氧化氢基化反应,考察了温度、时间、浓度以及添加剂等对过氧化氢基化物(EPHP)中过氧化氢基含量的影响;研究了EPHP与苯乙烯类单体进行接枝共聚反应以及接枝产物的共混增韧作用。

Oxidation of Benzothiophenes Using Tert-amyl Hydroperoxide

Homogeneous oxidation using an oil-soluble oxidant, tert-amyl hydroperoxide （TAHP）, for ultra-deep desulfurization was performed under mild conditions in the presence of molybdenum oxide catalysts. Dibenzothio- phene （DBT）, benzothiophene （BT） and 4, 6-dimethyl-dibenzothiophene （DMDBT）, which are the refractory sulfur compounds for hydrodesulfurization （HDS）, were employed as model substrates for a simulated diesel fuel. Activity of molybdenum oxide supported on a macroporous weak acidic resin was investigated. The mass conversion of DBT reached near 100% at 90℃ and a TAHP/DBT molar ratio of 3 with 1% of molybdenum oxide supported on Amberlite IRC-748 resin for 1 h. It was further found that the activities of the model substrates decreased in the or- der of DMDBT 〉DBT 〉BT. In the flow oxidation using TAHP as the oxidant, mass conversion of DBT increased remarkably from 61.3% to 98.5% when dropping the weight hourly space velocity （WHSV） from 40 h^-1 to 10 h^-1. A series of experiments dealt with selectivity of this oxidation using TAHP revealed that the model unsaturated compounds, i.e. 4, 6, 8-trimethyl-2-nonylene, and 2-methylnaphthalene did not affect the oxidation of DBT. Carbazole had nearly no effect on the conversion of DBT using TAHP, but had some influence on the one using tert-butyl hydroperoxide （TBHP）. The mass conversion of DBT decreased remarkably from 75.2% to 3.6% when the content of carbazole increased from 0 to 500μg·g^-1. In the flow oxidation using TAHP as the oxidant, the concentration of DBT in model fuels was reduced from 500 μg·g^-1 to 7.2 μg·g^-1 at WHSV of 10 h^-1, and then reduced to 3.8 μg·g^-1 by adsorntion of Al2O3.

Oxidation of glycerol with H_2O_2 on Pb-promoted Pd/γ-Al_2O_3 catalysts

A series of bimetallic Pd-Pb catalysts with a constant Pd content of 1 wt%and Pb/Pd atomic ratio from 0 to 1.6 supported on γ-Al2O3 were prepared and used for glycerol oxidation with H2O2 as the oxidizing agent at atmospheric pressure,45℃ and pH =11.The morphology and dispersion of the catalysts were characterized by scanning electron microscopy-energy dispersive X-ray spectroscopy（SEM-EDX） and transmission electron microscopy（TEM）.The presence of an alloy phase in the bimetallic catalyst was detected by X-ray photoelectron spectroscopy（XPS）.Glycerol conversion obtained with the monometallic Pd catalyst was 19%,which was increased to 100%with the addition of Pb.The four bimetallic PdPb catalysts were able to oxidize glycerol to dihydroxyacetone（DIHA） and the selectivity to DIHA reached 59%,58%,34%and 25%for PdPb0.25,PdPb0.50,PdPb1.00 and PdPbl.60 catalysts,respectively.

Mathematical model and reaction mechanism of molybdenum and tungsten extraction with TRPO from peroxide solution

To understand the behavior of molybdenum and tungsten extracted by tri-alkyl phosphine oxide(TRPO)from peroxide solution,the extraction mechanism was studied by slope method and Raman and FTIR spectroscopy.The empirical formulas of molybdenum and tungsten extraction distribution ratio(D_(Mo)and D_(W))as functions of equilibrium pH,TRPO concentration and temperature were obtained by establishing mathematical models.Furthermore,the reliability of the empirical formula was verified in the H^(+)-W-Mo-H_(2)O_(2) solution.The results indicate that the calculated values of D_(Mo)or D_(W)were consistent with the experimental values.The apparent extraction equilibrium constants of molybdenum and tungsten wereK_(Mo)^(app)=8.51×10^(3)(0.74≤pH_(e)≤1.7),K_(Mo)^(app)=99.89×10^(3)(1.7<pH_(e)≤4.62)andK_(W)^(app)=2.65×10^(3)(0.92<pH_(e)<2.16)at 20°C,respectively.The main extraction complex of molybdenum or tungsten was[H_(2)(Mo or W)_(2)O_(3)(O_(2))_(4)(H_(2)O)_(2)]·2TRPO.These empirical formulas can be used to analyze and estimate the extraction and separation of Mo and W from low molybdenum and tungsten concentration solutions.

Kinetics of 2-Methylbutene-2 Epoxidation with 2-Methylbutane Hydroperoxide

The kinetics of epoxidation of methylbutene with structurally identical methylbutane hydroperoxide was studied in the presence of a molybdenum catalyst. The analysis of the rate curves suggested the most probable scheme of the process. The revealed features of the process and its mathematical description make it possible to more competently design a reactor unit for the commercial production of isoprene according to the developed scheme. The main kinetic constants were calculated.

Study on Oxidative Desulfurization Performance of Mesoporous Alumina Material

This article refers to the study on the performance of mesoporous silica used as the catalyst for oxidative desulfurization reactions. The test results revealed that under mild reaction conditions using tert-butyl hydroperoxide as the oxidizing agent the content of dibenzothiophene(DBT) contained in oil samples could be reduced from 5000 ppm to less than 5 ppm. Furthermore,the mesoporous silica material can be easily regenerated and recycled.

Degradation of p-nitrotoluene by O_3/H_2O_2 process and oxidation mechanism

The degradation of p-nitrotoluene by O3/H2O2 process in a bubble contact column was investigated. Effects of the molar ratio of hydrogen peroxide to ozone,pH value and t-butanol on the oxidation process were discussed. It was found that the proper H2O2/O3 molar ratio for the degradation of p-nitrotoluene was around 0.6, different pH values and the presence of t-butanol highly influenced the removal efficiency of p-nitrotoluene. 5-methyl-2-nitrophenol, 2-methyl-5-nitrophenol, (4-nitrophenyl) methanol, 5-(hydroxymethyl)-2-nitro phenol, acetic acid, 2-methylpropane diacid and 2-(hydroxylmethyl)propane diacid were identified as degradation intermediates and products through GC-MS. Radical reaction mechanism and degradation pathway were proposed based on the results of experiments. It is deduced that the benzene ring of p-nitrotoluene can be only destroyed by hydroxyl radicals through a polyhydroxy intermediate pathway. Then unstable polyhydroxy intermediates can be oxidized to different acids with low molecular weight rapidly.

Catalytic Oxidation of Cyclohexane over ZSM-5 Catalyst in N-alkyl-N-methylimidazolium Ionic Liquids

Heterogeneous oxidation of cyclohexane by tert-butyl hydroperoxide (TBHP) was carried out over ZSM-5 catalysts with different Si/Al ratios in ionic liquids and organic molecular solvents. Higher yield and selec-tivity of the desired products were found in ionic liquids than in molecular solvents. The conversion of cyclohexane exhibits a decrease from 15.8% to 10.8% with the increase of Si/Al ratio of the HZSM-5 catalyst, and all the cata-lysts exhibit good selectivity of monofunctional oxidation products at around 97%. The activity of catalyst is found strongly dependent on the alkyl chain length of ionic liquid.

Continuous Flow Reactor for Hydroxylation of Benzene to Phenol by Hydrogen Peroxide

The direct hydroxylation of benzene to phenol catalyzed by activated carbon-supported Fe （Fe/AC） in acetonitrile using H2O2 as the oxidant was studied in a continuous flow reactor. Results showed that the continuous operation could obtain high phenol yield of 28.1%, coupled with the turnover frequency of 3 h^-1, and high selectivity of 98% under mild condition. The catalyst was characterized by N2 adsorption/desorption, Boehm titration, X-ray photoelectron spectra, and Fourier transform infrared spectroscopy. It was observed that iron may interact with the carboxyl group forming iron-carboxylate like species, which act as the active phase. The apparent activation energy obtained by fitting an Arrhenius model to the experimental data was 13.4 kJ/mol. The reaction order was calculated to be about i, 0.2 for benzene and 0.7 for H202.

Free-Radical Conjugated Oxidation of Natural Methane by Hydrogen Peroxide

There has been carried out the process of noncatalytic oxidation of natural methane in the presence of hydrogen peroxide at the temperatures 840-880 ℃ what permitted to obtain hydrogen with high yield of hydrogen （74%） with inconsiderable quantity of CO （0.4%） in converted gas. As observed in the experiment, a variation of H2O2 concentration in the aqueous solution and other basic parameters of the process may induce the synthesis of gas with given H2：CO ratio for its further application in methanol or ammonia synthesis. In the latter process low CO concentration is required. Compared with the common high-temperature conversion of natural gas and further carbon oxide conversion on a catalyst, the current process promotes process simplification： the reaction is implemented at relatively low temperature （860-900 ℃ instead of 1400-1600 ℃for existing non-catalytic processes of methane conversion） and an additional unit for catalytic conversion of carbon oxide is excluded （in NH3 production）. The mechanism of chemical conjugation in the CH4-H2O2-H2O system was elucidated and the inducing effect of H2O2 decomposition on the desired （secondary） reaction was quantitavely estimated. An adequate kinetic model was formulated on the basis of the proposed free-radical scheme.

Hydroxylation of phenol with hydrogen peroxide catalyzed by Fe- and AIFe-Bentonite

The paper described pillarisations of natural bentonite from Pacitan East Java of Indonesia by using AI and Fe. Intercalation process by using surfactant molecule has also been carried out. Natural bentonite was intercalated with HDTMA-Br （hexadecyltrimethylammonium-bromide） 1, 5% solution before pillared with AI and Fe metal to give HDTMA-bentonite forms. The ratio of bentonite and intercalating agent or pillaring agent was 1 gr/50 mL. The mixture was agitated, and then the solid phase was washed with distilled water. Then it was dried and calcined at 450℃ for 4 hours. Their catalytic activity and selectivity were studied for phenol hydroxylation using tlzOz （30%）. The reaction condition of this reaction was as follows： ratio of phenol/ H202 = 1：1 （molar ratio）, concentration of phenol = 1 M, reaction temperature was 60℃, and ratio of catalyst/phenol was 1：10. The products were hydroquinone and cathecol.

A novel strategy for immobilization of thionine based on calcium carbonate-gold nanoparticles inorganic hybrid composite and its application in hydrogen peroxide sensor

A novel strategy for efficient immobilization of electroactive Thionine(Th)on the gold(Au)electrode surface based on calcium carbonate-gold nanoparticles(CaCO3-AuNPs)inorganic hybrid composite was proposed and conducted by the strong electrostatic interaction between positively charged Th and negatively charged CaCO3-AuNPs composite.The hybrid composite was obtained by the adsorption of AuNPs onto the surface of CaCO3 microspheres through electrostatic interaction.Due to the microporous architecture,large surface area,and good biocompatibility of CaCO3-AuNPs composite,the amount and stability of the immobilized Th were highly strengthened.The application of the resulting Th modified electrode in the hydrogen peroxide(H2O2)sensor was also investigated.It exhibited rapid response to H2O2 within 3 s.The linear calibration ranged from 8.00×107to 1.06×10 -3mol/L with a detection limit of 2.00×10 -7mol/L.

Platinum nanowires catalyzed direct amidation of aldehydes and amines

Different from the conventional synthesis methods and substrates, we designed a brand new method for synthesizing amides with platinum nanowires as catalysts and tert-butylhydroperoxide(TBHP) as the oxidant. Influence of factors, such as the catalyst, solvents, and the reaction temperature, were studied to determine the optimal reaction conditions. In addition, we explored the substrate generality and observed excellent yields.