Influences of the [Co^2＋]/[Co^3＋] Ratio on the Process of Liquid-phase Oxidation of Toluene by Air

Liquid phase oxidation of toluene is an environmental benign route for the production of benzoic acid.In a φ48mm bubble column reactor,the commercial process of toluene liquid phase oxidation was conducted with Co(CH3COO)2.4H2O as catalyst.The Co2+ concentration [Co2+] was determined by extraction spectrophotometry and hereby the Co3+ concentration [Co3+] was obtained by mass balance.The results showed that [Co3+] reached the maximum at about 25-30min.[Co3+] increased with increasing Co catalyst amount at total Co concentration<150 mg.L-1 of toluene.The conversion of toluene,yield and selectivity of benzoic acid increased with the increasing [Co3+/Co2+] max.A high [Co3+] and a high [Co3+]/[Co2+] ratio are beneficial to the reaction.

Peracetic Acid Synthesis by Acetaldehyde Liquid Phase Oxidation in Trickle Bed Reactor

在这篇论文，有在喷淋床过程为的高产率的更短的停留时间(一些分钟) 每醋酸，由乙醛液相氧化的合成能在选择填充材料 SA-5118 上被认识到。为在有是的铁的离子的丙酮的乙醛催化剂，优化工艺操作条件被介绍。影响收益，选择和变换的主要因素分别地是停留时间，温度和乙醛集中。检查的温度范围从 30 ～ 65 ° C。当停留时间是 5.5min，乙醛集中是 9.85% 时，有 91.84% 罐头的高选择的 81.53% 的高产率在 55 ° C 的高温被获得(由质量) 。并且在 18% 和 19.5% 之间有一个批评乙醛集中点(Cccp )( 由质量) 。在温度不到 55 ° C，高产率到当乙醛集中在 Cccp 下面并且当乙醛集中在 Cccp 上面时，与温度减少时，每在各个的醋酸，温度位与温度增加。

Liquid Phase Catalytic Oxidation of Low-Concentration H_2S in Cerium Doped Absorption Solution

For the goal of sulfur recovery, most methods are aimed at the tail gas with high-concentration H2S, but few effective methods are used for low-concentration H2S. In this work, Low-concentration H2S could be purified well by liquid phase catalytic oxidation (LCO), and the sulfur resource could also be recovered. The absorption solution was prepared by FeCl3 and sulfosalicylic acid. Under the experimental conditions, the conversion of H2S to S could be maintained above 94% at 60 ℃. In order to enhance the economical efficiency of LCO method, the absorption solution was modified by doping Ce, and a series of experiments were designed to investigate its performance. The results showed that the conversion of H2S had no obvious improvement, but above 98% conversion could be gained at 60 ℃, and the H2S conversion rate was enhanced. The optimum addition quality of Ce(NO3)3 was 0.08 g to 50 ml Fe3+ solution.

Kinetics and Mechanism Modeling of Liquid-Phase Toluene Oxidation to Benzaldehyde Catalyzed by Mn–Mo Oxide

In this study, liquid-phase aerobic oxidation of toluene catalyzed by Mn–Mo oxide was conducted in a 1.0 L batch reactor. The macroscopic kinetics of toluene consumption and benzaldehyde generation at 413–443 K were obtained from a combination of experimental observation and hypothetical models. The results clearly showed that both the oxidation rate of toluene and generation rate of the aromatic product were proportional to the concentration of the substrate, the partial pressure of oxygen and the surface area of the catalyst. The energy barrier of toluene oxidation to benzyl alcohol was the highest(≈ 81 kJ mol^(-1)), while that of benzyl alcohol oxidation to benzaldehyde was the lowest(≈ 57 kJ mol^(-1)). Moreover, the activation energy of further oxidation of benzaldehyde in an acetic acid solvent was only slightly lower(≈ 1.9 kJ mol^(-1)) than that of toluene oxidation. Significantly, the transformation of benzyl alcohol indeed contributed to the generation of benzaldehyde and this step conformed to a first-order parallel-consecutive model. Increased reaction temperature and residence time favored the transformation of benzyl alcohol to benzaldehyde. In addition, doping with molybdenum at Mn/Mo = 3/1 enhanced the catalytic performance of the heterogeneous catalyst and was attributed to the presence of a synergetic effect between different metal cations. Regarding the microscopic kinetics, the LH-OS-ND mechanism(Langmuir–Hinshelwood adsorption of reagents on the same type of active sites and non-dissociative adsorption of oxygen) was verified as responsible for the heterogeneous oxidation of toluene. Oxygen and benzaldehyde were weakly adsorbed(Δ H_(ads,Oxy) ≈^(-1)5 kJ mol^(-1), Δ H _(ads)0,Bald) ≈-30 kJ mol^(-1)), but showed strong mobility(Δ S_(ads,Oxy) ≈-22 J mol^(-1) K^(-1)), Δ S_(ads,Bald) ≈-39 J mol^(-1) K^(-1)). The fundamental intrinsic rates were deduced based on the LH-OS-ND mechanism and showed great consistency with the macroscopic results.

Unraveling the catalytically active phase of carbon dioxide hydrogenation to methanol on Zn/Cu alloy: Single atom versus small cluster

Methanol synthesis from CO_(2)hydrogenation catalyzed by Zn/Cu alloy has been widely studied,but there is still debate on its catalytic active phase and whether the Zn can be oxidized during the reaction process.What is more,as Zn atoms could locate on Zn/Cu alloy surface in forms of both single atom and cluster,how Zn surface distribution affects catalytic activity is still not clear.In this work,we performed a systematic theoretical study to compare the mechanistic natures and catalytic pathways between Zn single atom and small cluster on catalyst surface,where the surface oxidation was shown to play the critical role.Before surface oxidation,the Zn single atom/Cu is more active than the Zn small cluster/Cu,but its surface oxidation is difficult to take place.Instead,after the easy surface oxidation by CO_(2)decomposition,the oxidized Zn small cluster/Cu becomes much more active,which even exceeds the hardlyoxidized Zn single atom/Cu to become the active phase.Further analyses show this dramatic promotion of surface oxidation can be ascribed to the following factors:i)The O from surface oxidation could preferably occupy the strongest binding sites on the center of Zn cluster.That makes the O intermediates bind at the Zn/Cu interface,preventing their too tight binding for further hydrogenation;ii)The higher positive charge and work function on the oxidized surface could also promote the hydrogenation of O intermediates.This work provided one more example that under certain condition,the metal cluster can be more active than the single atom in heterogeneous catalysis.

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

在这篇论文，为到二羟基的酸由 cobalt-manganese-bromide 催化的 2,6 萘的 2-methyl-6-acetyl-naphthalene 的液体阶段氧化的一个动力学模型被建议。反应温度，催化剂集中和为包括原料，中介和产品的成分的试验性的集中的时间进化上的催化剂的比率的效果被调查。模型参数在非线性的优化被决定，最小化之间的差别模仿，产品作文的试验性的时间进化在气体和液体分阶段执行的一个半批氧化反应堆获得了很好被混合。Thekinetics 数据证明模型对到 2,6 萘的 2-methyl-6-acetyl-naphthalene 的液体阶段氧化合适二羟基的酸。

Dynamics of liquid-phase catalytic oxidation of hydrogen sulfide removal in rural biogas

Hydrogen sulfide in rural biogas was removed with liquid-phase catalytic oxidation.By using rare earth as catalyst,and sulfosalicylic acid as stabilizer,H2S purification efficiency could increase as high as 96%,and sulfur capacity of the composite solution was about 3 g/L.The results show that purification efficiency was affected by catalyst addition,pH,experimental temperature,and sulfur capacity.The parameters effects on catalytic oxidation were studied,and the optimized conditions were that Fe3+ concentration 0.08 mg/L,reaction temperature 70°C,pH 9.0,with a absorption solution volume of 50 mL,a gas flow rate 200 mL/min,and H2S mass concentration of 1.58-2.02 mg/m3.

Separation process study of liquid phase catalytic exchange reaction based on the Pt/C/PTFE catalysts

The liquid phase catalytic exchange(LPCE) reaction is an effective process for heavy water detritiation and production of deuterium-depleted potable water. In the current study, hydrophobic carbon-supported platinum catalysts(Pt/C/PTFE) with high efficiency as reported previously for LPCE were prepared and comprehensive performance evaluation method is applied to evaluate the separation behaviors of LPCE systematically. Experimental results indicate that the optimum reaction temperature of 60–80℃ and the molar feed ratio G/L of 1.5–2.5 would lead to higher separation efficiencies. As to the packing method, a random packing mode with a packing ratio of hydrophobic catalysts 0.25 is recommended. In addition, thermodynamic analysis corresponds well with experimental results under lower temperature and G/L, while the suppression of kinetic factors should not be neglected when T > 80℃ and G/L > 1.5.

Efficiency of Iron Supported on Porous Material (Prepared from Peanut Shell) for Liquid Phase Aerobic Oxidation of Alcohols

Catalytic activity and selectivity of prepared catalysts (Fe2O3/ and Fe2O3/AC(KOH)) were investigated for liquid phase aerobic oxidation of primary and secondary alcohols, in a batch reactor, using solvent free condition and/or eco-friendly solvents. The catalysts were characterized by SEM, EDX, XRD, FTIR, TGA/DTA, and surface area and pore size analysis. Experimental data revealed that Fe2O3/AC(KOH) was an efficient catalyst for the oxidation (dehydrogenation) of alcohol while was found to show catalytic activity for both dehydration and dehydrogenation of alcohols. The catalysts were recycled by simple filtration, and used several times without any loss of catalytic activity.

The Catalysis of NAD^+, NADP^+ and Nicotinic Amide for Methanol Electrooxidation at Platinum Electrode

A group of liquid catalysts composed of nicotinic amide functioning on the anode of DMFC were investigated at a Pt eleetrode, which were nicotinic amide, nicotinamide adenine dinucleotide （ NAD^＋ ） and its phosphate （ NAD （ P ） ^＋ ）. The kinetics of methanol anode oxidation in the three reaction systems was compared by measuring poteatiodynarnic current-potential curves and AC impedances. The experimeatal results show that the dynamic behavior of methanol oxidation at a Pt electrode has been changed with adding the three substances. The influence of temperature on the catalysis of these coenzymes and nicotinic amicle was discussed by comparing the AC impedances spectra of methanol oxidation at differeat temperatures.

Deep Desulfurization of Diesel Fuels with Plasma/Air as Oxidizing Medium,Diperiodatocuprate(Ⅲ)as Catalyzer and Ionic Liquid as Extraction Solvent

In this paper, the oxidative desulfurization （ODS） system is directly applied to deal with the catalytic oxidation of sulfur compounds of sulfur-containing model oil by dielectric barrier discharge （DBD） plasma in the presence of air plus an extraction step with the oxidation-treated fuel put over ionic liquid [BMIM]FeC14 （1-butyl-3-methylimidazolium tetrachloroferrate）. This new system exhibited an excellent desulfurization effect. The sulfur content of DBT in diesel oil decreased from 200 ppm to 4.92 ppm （S removal rate up to 97.5%） under the following optimal reaction conditions： air flow rate （v） of 60 mL/min, amplitude of applied voltage （U） on DBD of 16 kV, input frequency （f） of 79 kHz, catalyst amount （w） of 1.25 wt%, reaction time （t） of 10 min. Moreover, a high desulfurization rate was obtained during oxidation of benzothiophene （BT） or 4,6-DMDBT （4,6-dimethyl-dibenzothiophene） under the aforementioned conditions. The oxidation reactivity of different S compounds was decreased in the order of DBT, 4,6-DMDBT and BT. The remarkable advantage of the novel ODS system is that the desulfurization condition applies in the presence of air at ambient conditions without peroxides, aqueous solvent or biphasic oil-aqueous solution system.

Gas Phase Selective Catalytic Oxidation of Toluene to Benzaldehyde on V_2O_5-Ag2O/η-Al_2O_3 Catalyst

Gas phase selective catalytic oxidation of toluene to benzatdehyde was studied on V_2O_5-Ag_2O/η-Al_2O_3 catalyst prepared by impregnation. The catalyst was characterized by XRD, XPS, TEM, and FT-IR. The catalytic results showed that toluene conversion and selectivity for benzaldehyde on catalyst sample No.4 (V/(V+Ag)=0.68) was higher than other catalysts with different V/Ag ratios. This was attributed to the higher surface area, larger pore volume and pore diameter of the catalyst sample No. 4 than the other catalysts. The XRD patterns recorded from the catalyst before and after the oxidation reaction revealed that the new phases were developed, and this suggested that silver had entered the vanadium lattice. XPS results showed that the vanadium on the surface of No.4 and No.5 sample was more than that in the bulk, thus forming a vanadium rich layer on the surface. It was noted that when the catalyst was doped by potassium promoter, the toluene conversion and selectivity for benzaldehyde were higher than those on the undoped catalyst. This was attributed to the disordered structure of V_2O_5 lattice of the K-doped catalyst and a better interracial contact between the particles.

Catalytic Oxidative Desulfurization of Gasoline Using Vanadium(V)-substituted Polyoxometalate/H_2O_2/Ionic Liquid Emulsion System

Aiming at deep desulfurization of gasoline,three amphiphilic catalysts [C18H37N(CH3)3]3+x [PMo12-xVxO40](x=1,2,or 3) were prepared and characterized.The amphiphilic vanadium(V)-substituted polyoxometalates were dissolved in water-immiscible ionic liquid([Bmim]PF6),forming a H2O2-in-[Bmim]PF6 emulsion desulfurization system with 30 m% H2O2 serving as the oxidant.The catalytic oxidation of sulfur-containing model oil has been studied in detail under various reaction conditions using this system.The ionic liquid emulsion system showed high catalytic oxidative activity in the treatment of commodity gasoline.Furthermore,the mechanism of catalytic oxidative desulfurization was also elaborated.

Recent Progress in Direct Partial Oxidation of Methane to Methanol

The direct conversion of methane to methanol has attracted a great deal ofattention for nearly a century since it was first found possible in 1902, and it is still achallenging task. This review article describes recent advancements in the direct partial oxidationof methane to methanol. The history of direct oxidation of methane and the difficulties encounteredin the partial oxidation of methane to methanol are briefly summarized. Recently reporteddevelopments in gas-phase homogeneous oxidation, heterogeneous catalytic oxidation and liquid phasehomogeneous catalytic oxidation of methane are reviewed.

Acid Separation, Catalytic Oxidation and Coagulation for ATC Waste Liquid Treatment

It is difficult to treat 2-amino-thiazoline-4-carboxylic acid （ATC） waste liquid effectively at present for its characteristics of high chemical oxygen demand （COD）, high salinity and low biodegradability. In order to solve this problem, this paper presents several kinds of physical-chemical treatment unit techniques, including acid separation, catalytic oxidation and coagulation. First of all, acid separation was adopted to precipitate relevant organics at isoelectric point. When the temperature and pH value of acid separation were controlled at about 5 ℃ and 2.2 respectively, the COD removal rate could reach 27.600. Secondly, oxidation was used to break chemical constitution of refractory organics. The optimal reaction parameters of catalytic oxidation should be 20 ℃, pH adjusted to 5.0 and [Fe2+] 300 mg/L. Then with 500 H2O2 added and after one-hour reaction, the COD removal rate could achieve about 5200. Finally, coagulation was adopted to remove a portion of refractory organics, and 1500 polymeric molysite flocculant was the best for the coagulation, and the COD removal rate could reach about 1500. Therefore, the proposed feasible process of physical-chemical pretreatment for ATC waste liquid could have about 7000 COD removed in total.

Property and Activity of Molybdates Dispersed on Silica Obtained from Various Synthetic Procedures

The synthesis and characterization of several dispersed molybdena catalysts on silica support (MoO3-SiO2) prepared from a variety of precursors (Mo(VI)-acetylacetonate, oxo-peroxo Mo-species, hydrated ammonium heptamolybdate) and preparation methods (deposition of the Mo-phase on finite SiO2 support by aqueous and methanol impregnations, by adsorption, by oxo-peroxo route-like, and by one-step synthesis of MoO3-SiO2 system with molecular precursors) are presented. The molybdena concentration on silica was comprised in a large interval (1.5 - 14 wt%) depending on the preparation method which governed the Mo-loading on silica. Convenient comparisons among samples at similar Mo-concentration have been made discussing the morphologic-structural (XRD, XPS, UV-vis-DRS, and N2-adsorption) and physicochemical (TG-DTG, TPR, and n-butylamine-TPD) sample properties. Polymeric octahedral polymolybdate aggregates predominated in the samples prepared by aqueous and methanol impregnations, which were at high Mo-concentration. On the contrary, isolated Mo(VI) species in distorted Td symmetry predominated in the sample prepared by adsorption which was at very low Mo-concentration. The sample acidity was composed of a weak acidy site population, associated with the silica support, and a strong acid site population associated with the Mo-dispersed phase. Oxidation tests of formaldehyde, an oxygen-containing VOC (Volatile Organic Compound), were performed to determine the prevalent redox or acidic function of the Mo-species at the surface of the catalysts.

Liquid-phase and solid-phase microwave irradiations for reduction of graphite oxide

In this paper, two microwave irradiation methods：（i） liquid-phase microwave irradiation（MWI） reduction of graphite oxide suspension dissolved in de-ionized water and N, N-dimethylformamide, respectively, and（ii） solid-phase MWI reduction of graphite oxide powder have been successfully carried out to reduce graphite oxide. The reduced graphene oxide products are thoroughly characterized by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectral analysis, Raman spectroscopy, UV-Vis absorption spectral analysis,and four-point probe conductivity measurements. The results show that both methods can efficiently remove the oxygencontaining functional groups attached to the graphite layers, though the solid-phase MWI reduction method can obtain far more efficiently a higher quality-reduced graphene oxide with fewer defects. The I（D）/I（G） ratio of the solid-phase MWI sample is as low as 0.46, which is only half of that of the liquid-phase MWI samples. The electrical conductivity of the reduced graphene oxide by the solid method reaches 747.9 S/m, which is about 25 times higher than that made by the liquid-phase method.

聚合离子液体设计及催化环己烷选择性氧化性能研究

以乙烯基咪唑为单体,添加不同量的引发剂,采用常规热聚合中自由基聚合的方式,合成了不同分子量的聚乙烯基咪唑,热重(TG)分析表明该聚合物具有良好的热稳定性。采用季铵化反应,对最优聚合物进行1-氯代十八烷、1-氯代十二烷以及1-氯代正己烷三种不同烷基链长度的取代,合成系列聚合离子液体(PIL)。通过傅里叶红外光谱(FT-IR)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、接触角等表征手段分析了聚合离子液体的化学结构及形貌特征,并考察了PIL-C_(18)、PIL-C_(12)、PIL-C_(6)催化环己烷选择性氧化为己二酸的性能,进而选取PIL-C_(12)深入研究了离子率对催化性能的影响规律。结果表明,烷基链段长度以及离子率可以有效调控亲疏水性和反应活性位点,进而提高反应性能,使得反应生成己二酸的转化率达到21.8%,选择性为41.5%。

Fe-Mn/TiO_(2)的制备及其催化臭氧氧化双酚A的性能研究

采用浸渍法制备Fe-Mn/TiO_(2)双金属催化材料,以双酚A(BPA)为目标降解物,探究了Fe-Mn/TiO_(2)对其的降解效果及降解机制。结果表明,Fe-Mn/TiO_(2)催化臭氧氧化降解BPA的去除率相较于单独TiO_(2)处理提升了83.4%;Fe、Mn成功负载且催化剂孔洞较丰富;相较于TiO_(2),Fe-Mn/TiO_(2)中锐钛矿质量分数增加能产生更多的羟基自由基。同时,Fe、Mn在TiO_(2)表面能发生价态转化,可作为活性位点促进臭氧分解为·OH等活性物质,增强催化反应活性。