Pd／SiO2存在下2—乙基蒽醌深度氢化选择性动力学

研究了在Ｐｄ／ＳｉＯ２触媒存在下深度氢化生成的产物，以及反应条件（触媒量、触媒粒度、反应温度）和反应方式（扩散控制过程或动力学控制过程）对反应进程的影响。     

2-戊基蒽醌氢化本征动力学研究

采用商品化的Pd/Al2O3催化剂,在温度为313.15～343.15 K、压力为0.1～0.2 Mpa的条件下,研究了2-戊基蒽醌加氢本征动力学.反应在体积比为3:1的三甲苯/磷酸三辛酯混合溶剂中进行.采用幂指型方程表达加氢反应速率,并用多元线性回归分析对测得的动力学数据进行处理,得到了方程中的参数.结果表明,2-戊基蒽醌加氢反应对2-戊基蒽醌浓度为零级;对氢气分压为0.48级,反应活化能为15663 J·mol-1.     

蒽醌法制过氧化氢氢化反应动力学研究述评

评述了近年发表的蒽醌法制过氧化氢氢化瓜在动力学研究结果,指出无论是使用镍催化剂或是钯催化剂,在具有工业应用价值的实验范围内,蒽醌的氢化对工作液听 有效蒽醌浓度均为0级反应,对氢气分压均为1级反应,同时对不同作者的动力学研究结果进行了评价,为正确引用实验结果提供了参考。     

2-乙基氢蒽醌氧化生产过氧化氢中的催化剂

介绍了蒽醌法生产过氧化氢在蒽醌氢化工作液氧化步骤中所用的催化剂。由2-乙基氢蒽醌的氧化反应机理看，释放出氢质子的两步可逆反应为控制步骤。向蒽醌氢化工作液体系中加入某些碱性化合物（无机碱如氢氧化钠水溶液等；有机胺类化合物中仲胺如二正辛胺、二正丁胺等，叔胺如三正辛胺、三乙胺等；多相碱性催化剂）能够很好地提高2-乙基氢蒽醌的氧化效率和氧化反应的反应速率，可以提高整个蒽醌法过氧化氢生产中的经济效益。     

双氧水工作液中蒽醌类物质的色谱测定法

生产过氧化氢是以2-乙基蒽醌(EAQ)为载体,重芳烃、磷酸三辛酯(TOP)为混合溶剂,配制成具有一定组份的溶液(以下称工作液)。若组分中2-乙基蒽醌、生成的四氢2-乙基蒽醌及降解物含量(主要是蒽酮)分析不准,将直接影响过氧化氢产量。采用气相色谱法和液相色谱法对其组分含量进行比对分析。     

双氧水生产中应用烷基蒽醌的分析

介绍了2-乙基蒽醌、2-丁基蒽醌和2-戊基蒽醌的理化特性,对比了3种烷基蒽醌在双氧水生产过程中的优劣性,分析了不同烷基蒽醌可能的应用发展方向。     

二次导数极谱法测定工作液中2-乙基蒽醌和四氢-2-乙基蒽醌含量

建立了采用二次导数极谱法测定蒽醌法生产过氧化氢用钯催化剂选择性评价工作液中2-乙基蒽醌(EAQ)和四氢-2-乙基蒽醌(H4EAQ)含量的方法。克服了常规极谱法测定EAQ和H4EAQ含量时分辨率低、误差大等局限性,可使EAQ和H4EAQ的极谱波清晰地分离;并通过加入适量的除氧剂,有效消除了氧波对波形的干扰,改善了波形,并抑制了极谱极大峰的出现,实现了对工作液中EAQ和H4EAQ含量的准确测定。该法测定EAQ和H4EAQ的相对误差分别为+4.6%和+4.3%,相对标准偏差分别为2.1%和1.7%,检出限分别为4.1 mg/L和1.7 mg/L。     

电化学氧化降解蒽醌染料动力学研究

利用形稳阳极原位电生成活性氯对蒽醌型染料活性艳蓝KN-R进行氧化脱色.以该染料的2个特征波长处吸光度为主要指标,对染料脱色及其芳环结构氧化降解的过程进行同步分析.在电流密度15A/m2、0.1mol/L Na2SO4、0.2 mol/LNaCl、0.1 mmol/L活性艳蓝KN-R、初始pH值6.4、温度30℃的实验条件下,经4h的电解,可使染料100%脱色,45%左右的染料芳环结构被破坏,处理每千克染料的能耗为0.28 kWh.实验结果表明,电流密度、氯化钠浓度、染料浓度、温度对染料的脱色及其母体结构氧化降解有较强的影响;染料脱色及其芳环结构氧化降解过程遵循准一级动力学;在整个的电氧化过程中,电解液未发生矿化.     

高效液相色谱法检测蒽醌法生产过氧化氢工作液中有效蒽醌

根据蒽醌法生产过氧化氢中控质量控制的需求,建立了一种高效液相色谱法检测蒽醌法生产过氧化氢工作液中有效蒽醌的方法。采用Acclaim TM 120 C18 (150 mm×4.6 mm, 5μm）液相色谱柱,40℃恒定柱温,流动相为75%色谱甲醇水溶液,流动相流速为1 m L/min,紫外检测器,检测波长254 nm,进样量20μL的检测条件,先根据2-乙基蒽醌（EAQ）、2-乙基四氢蒽醌（THEAQ）单标的保留时间进行定性分析,再采用标准曲线法对工作液中EAQ和THEAQ进行定量分析。结果表明：高效液相色谱法可准确测定蒽醌法生产过氧化氢工作液中2种有效蒽醌的质量浓度,EAQ和THEAQ的保留时间分别为8.275 min和11.080 min,经检测,分析2022年5月28日新配制工作液中EAQ、THEAQ分别为143.64和0.86 g/L,10月21日循环工作液中EAQ、THEAQ分别为123.94和27.74 g/L,该方法操作简单、相对标准偏差在0.02%～0.18%之间、加标回收率在98.59%～1 01.05%之间,可作为蒽醌法生产过氧化氢中间过程质量控制。     

蒽醌法生产过氧化氢中氢化反应影响因素分析

蒽醌法过氧化氢生产工艺以2-乙基蒽醌和2-乙基四氢蒽醌为载体,重芳烃和磷酸三辛酯为混合溶剂配成工作液。该工作液与氢气并流进入装有加氢催化剂（钯催化剂）的滴流床反应器（氢化塔）内,在压力0．15～0．36MPa、温度40～75℃条件下进行加氢反应,生成相应的氢蒽醌溶液（氢化液）。氢化液进入氧化塔,在0．18～0．30MPa、40～55℃条件下用空气氧化,氢化液中的氢蒽醌氧化成原来的蒽醌,同时生成过氧化氢,     

圆形微通道反应器内2-乙基四氢蒽氢醌氧化反应

以管径为900 μm的圆形微通道反应器内2-乙基四氢蒽氢醌(THEAQH2)的氧化反应为研究对象,研究了反应过程中气液两相的流动形态,考察了反应温度、反应压力、液体流速ULS、气液比rAS等因素对THEAQH2氧化反应的影响.研究表明,圆形微通道反应器内进行THEAQH2的氧化反应时可得到较高的气液两相接触比表面积;氧化反应随温度升高、压力增大和液体流速ULS的增加而显著加快;THEAQH2的氧化反应在圆形微通道反应器内进行可得到较高的过氧化氢时空收率YSTY (Space-Time Yield),在温度50℃、压力0.29 MPa、液体流速0.052 m/s时,YSTY可达1 790 kg/(m3·h),高出常规反应器1～2个数量级.     

中间相沥青高温炭的氧化动力学研究

研究了２种镁碳砖粘结剂高温炭的氧化动力学。结果表明,中间相沥青粘结剂比酚醛树脂粘结剂高温炭具有更好的抗氧化性能,脱除了原生喹啉不溶物后,可提高中间相沥青粘结剂的抗氧化性能。     

叔丁醇的复合氧化反应动力学及其降解的研究

在光谱反应器中研究了有机物叔丁醇（ＴＢＡ）在Ｈ２Ｏ２,Ｏ３和Ｏ３／Ｈ２Ｏ２及不同ｐＨ值时的氧化反应动力学及其降解过程。结果表明,ＴＢＡ几乎不被过氧化氢氧化;在酸性及中性条件下,ＴＢＡ较难在臭氧中降解,随着ｐＨ增加,ＴＢＡ的臭氧化速率加快,ＴＢＡ较容易在Ｏ３／Ｈ２Ｏ２中氧化降解。     

The Role of Mass Transfer in the Kinetics of Chemical Oxidation of Anthracine Slurry to Anthraquinone in a Batch Stirred Tank Reactor

The kinetics of chemical oxidation of anthracine powder by acidified dichromate in a batch agitated vessel stirred by a 45° four pitched blade turbine impeller was studied under different conditions. Variables studied were impeller rotation speed, solution physical properties and temperature. The rate of anthracine oxidation was found to increase with temperature according to the Arrhenius equation with an activation energy of 3.98 cal/mole. The rate of anthracine oxidation was found to increase with 0.56 power of impeller rotation speed. The value of the activation energy and the sensitivity of the rate of oxidation to stirring lend support to the diffusion‐controlled nature of the reaction. The data were correlated by the equation: Sh = 0.5 · 10^–3 Sc^0.33 · Fr^0.33 Implication of the above equation for the operation of industrial reactors was noted.     

Kinetics of Sulfite Oxidation in the Simultaneous Desulfurization and Denitrification of the Oxidation‐Absorption Process

The kinetics of sulfite oxidation in the simultaneous desulfurization and denitrification of the oxidation‐absorption process was investigated with a bubbling apparatus under the conditions of varying pH, sulfite concentration, nitrite concentration, temperature, and air flow. The results indicate that the oxidation of sulfite is promoted dramatically by mixing with nitrite, due to the decline of the apparent energy of activation and the initiation of nitric dioxide decomposition by nitrite. An increase of the nitrite concentration, the air flow, the reaction temperature, or the pH supports the decomposition of nitrite and the production of nitric dioxide, thus leading to an enhancement of the sulfite oxidation rate. A kinetic model is established according to the experimental results. A satisfactory agreement between the calculated and the experimental values is obtained.     

Kinetics of Estrone Ozone/Hydrogen Peroxide Advanced Oxidation Treatment

Ozone/hydrogen peroxide batch treatment was utilized to study the degradation of the steroidal hormone estrone (E1). The competition kinetics method was used to determine the rate constants of reaction for direct ozone and E1, and for hydroxyl radicals and E1 at three pH levels (4, 7, and 8.5), three different molar O₃/H₂O₂ ratios (1:2, 2:1, and 4:1) and a temperature about 20°C. The average second-order rate constants for direct ozone-E1 reaction were determined as 6.2?×?10³?±?3.2?×?10³ M^?1s^?1, 9.4?×?10⁵?±?2.7?×?10⁵ M^?1s^?1, and 2.1?×?10⁷?±?3.1?×?10⁶ M^?1s^?1 at pH 4, 7, and 8.5, respectively. It was found that pH had the greatest influence on the reaction rate, whereas O₃/H₂O₂ ratio was found to be slightly statistically significant. For the hydroxyl radical-E1 reaction, apparent rate constants ranged from 1.1?×?10¹⁰ M^?1s^?1 to 7.0?×?10¹⁰ M^?1s^?1 with an average value of 2.6?×?10¹⁰ M^?1s^?1. Overall, O₃/H₂O₂ is shown to be an effective treatment for E1.     

两步一釜法合成邻乙酰氨基苯酚

以邻硝基苯酚为原料,在同一釜中先后经过原还,酰化合成了邻乙酰氨基苯酚,收率８０％,纯度≥９９％,较两步法有明显提高。     

Kinetic Analysis of Hydroxide-Catalyzed,Aerobic Oxidation of 2-Mercaptoethanol

Experiments and mechanistic kinetic analyses are conducted for the hydroxide-catalyzed, aerobic oxidation of the thiol 2-mercaptoethanol (2-ME) to water and the corresponding disulfide at 22°C and 1 atm total pressure in tetrahydrofuran. The experiments are performed in an isothermal, bench-scale reactor with a maintained O₂ partial pressure. The 2-ME concentrations are measured using gas chromatograph/flame ionization detector (GC/FID). The mixture includes a small amount of aqueous NaOH required to activate the thiol (RSH) to thiolate (RS^?). The observed 2-ME conversion is first order in 2-ME concentration. A multistep mechanism is proposed consistent with the observed kinetics. The rate-determining step is the coupling of RS^? to dissolved O₂, with an estimated rate constant k = 1.93 × 10^?6 liter/mmol h.     

Kinetics of Photocatalyzed Gas Reactions Using Titanium Dioxide as the Catalyst Part II: Photocatalyzed Total Oxidation of Alkanes with Oxygen

In order to obtain a useful expression for the kinetics of the photocatalyzed total oxidation reaction of alkanes with oxygen and TiO₂ as the catalyst, the dependence of the reaction rate on the concentration of the starting material species, the absorbed irradiation intensity, the wavelength of the light and the temperature was investigated. The experiments were performed in a CSTR system. The rate law found for alkane oxidation differs from that obtained for olefin oxidation due to a different reaction mechanism. While a reversible catalyst deactivation process takes place in the latter case, there is no hint of such a process during alkane oxidation. The kinetic data lead to the conclusion that the formation of an alkane and a hydrogen‐radical at a defect site of the catalyst is the first step in the total oxidation reaction of these species followed by the formation of a stronger adsorbed hydroperoxide species. The subsequent transformation of the hydroperoxide into further oxidized species mediated by the electron‐hole pairs generated by the absorbed light on the semiconductor's surface was recognized to be the rate determining step. The reaction behavior for the investigated alkanes could be modeled using this concept with the exception of methane. Its rate law differs strongly from that found for ethane, propane as well as iso‐butane.     

Three‐Phase Nitrobenzene Hydrogenation over Supported Glass Fiber Catalysts: Reaction Kinetics Study

The catalytic properties of Pd and Pt supported on woven glass fibers (GF) were investigated in the three‐phase hydrogenation of nitrobenzene (NB). Over all catalysts, a 100 % yield of aniline was attained. The catalytic activity for the best catalysts was two times higher than the activity of commercial Pt/C catalyst traditionally used for liquid–phase hydrogenation. The intrinsic reaction kinetics were studied and a reaction scheme is suggested. The direct formation of aniline from NB was observed over Pd/GF with traces of intermediates. Four intermediate products were detected during aniline formation over Pt/GF: nitrosobenzene, phenylhydroxylamine, azoxybenzene, and azobenzene. The Eley‐Rideal kinetic model fits the experimental data well. The parameters of the model were determined as a function of initial NB concentration and hydrogen pressure. Pt and Pd supported on GF in woven fabrics are suggested as suitable materials for reactors with a structured catalytic bed in multi‐phase reactor performance.