糠醛液相加氢制糠醇骨架钴催化剂反应动力学研究

采用合金架钴催化剂在间隙高压反应釜中进行了糠醛液相加氢反应动力学及失活动力学的研究。提出了该反应的动力学及失活动力学的数学模型，并求得了该反应的反应级数、反应活化能值、反应速率常数及失活速率常数值，还测得了钴催化剂的使用寿命。     

Esterification of decanoic acid with methanol using Amberlyst 15: Reaction kinetics

Methyl decanoate is used as a surrogate fuel. The surrogate fuels are structurally similar to actual biodiesel. We synthesized methyl decanoate in a small batch reactor by esterification reaction using decanoic acid and methanol on solid acid catalyst Amberlyst 15 used in dry state. The outcome of different reaction parameters including catalyst loading, temperature, molar ratio, stirrer speed, water concentration effect, and adsorption on catalyst pellets were studied for optimization of rate of conversion. The effect of external and internal diffusion limitations on catalyst granules was calculated theoretically from the reaction kinetics data. An analysis of the reaction kinetics revealed that the esterification reaction was rate controlled by adsorption of methanol on the solid acid catalyst and the reaction can be modeled as Eley–Rideal model. Activation energy of the esterification reaction was 39.4?KJ/mol. Reaction enthalpy and entropy were found to be 29.81?kJ/mol and 87.38?J/mol. K, respectively.     

Studies on Macro-kinetics of Gas Phase Polymerization of Butadiene with Rare-earth Catalyst

The study of the kinetics of gas phase polymerization of butadiene with heterogeneous catalyst based on neodymium (Nd) was carried out. The effects of reaction temperature, reaction pressure, dispersing medium, and types of catalyst on kinetics of polymerization were investigated. A kinetic model with two kinds of active sites was proposed. The results show that the effects of the reaction temperature and the types of dispersing medium and catalyst on the kinetic performance of polymerization are significant, and that the combined model of first and second order decay of active site of catalyst can be used to describe the phenomena.     

Raney镍上松香加氢制备二氢和四氢枞酸的本征动力学

采用FYX-2G型高压搅拌釜,以Raney镍为催化剂,在温度423～453K、压力4.0～7.0MPa下进行松香催化加氢反应动力学的研究。利用改进搅拌器类型、提高搅拌速度、加入200#溶剂油和改变催化剂粒径的方法消除内外扩散,使反应处于化学动力学控制区,然后采集动力学数据,经对17种可能的反应机理模型进行筛选,结果表明,Raney镍催化枞酸加氢生成二氢和四氢枞酸是并行反应,最可几反应机理为:松香中的主要成分枞酸分子与催化剂表面上被吸附的氢原子进行反应,氢原子的吸附为控制步骤,生成二氢枞酸和四氢枞酸的活化能分别为47.18kJ.mol-1和106.35kJ.mol-1。     

TiO_2负载Pd-Fe催化间硝基三氟甲苯常压加氢反应动力学

研究了TiO2负载Pd-Fe催化间硝基三氟甲苯的常压加氢反应,考察了反应温度和催化剂质量浓度对加氢反应的影响,建立了加氢反应的动力学方程。结果表明:在间硝基三氟甲苯初始浓度0.125 mol/L,催化剂质量浓度0.32 g/L,氢气压力0.1 MPa,,323.2 K和2.5 h条件下,间硝基三氟甲苯转化率达到99.2%。通过拟合实验数据,加氢反应对间硝基三氟甲苯浓度表现为1级,对催化剂质量浓度表现为0.464级,反应活化能为22 728.0 J/mol。由动力学方程回算得到的间硝基三氟甲苯浓度与实验值能较好地吻合。     

苯基三甲氧基硅烷水解动力学研究

采用气相色谱法研究了三氟甲基磺酸催化苯基三甲氧基硅烷的水解反应动力学。考察了温度、用水量及催化剂用量对水解反应的影响。结果表明:水的用量会导致水解反应级数的变化,在过量水的情况下,水解反应可按一级反应来描述;当水的用量减少至理论用量以下时,水解初始反应表现为一级反应,随着水的消耗,反应级数转变为二级。在297~324 K范围内,温度对水解速率的影响明显,温度越高,水解速率越快,水解反应活化能为37.83 kJ/mol。催化剂的用量增加,反应速率加快。     

甲烷化梅花状催化剂CFD计算及改进

对合成气甲烷化反应体系进行CFD（计算流体动力学）计算,并对模型提出合理的改进。通过建立合理的甲烷化梅花状催化剂颗粒三维模型进行计算,并验证了模型的有效性。结果表明：甲烷化反应内扩散阻力很大,CO在催化剂表面与内部存在明显的浓度差。且H₂与CO扩散速率不同,导致催化剂内部的氢碳比很高,内部的反应条件与催化剂表面相比发生改变,使用单一的动力学方程无法准确描述实际的反应过程。因此,提出对催化剂的不同区域分别讨论,根据催化剂内CO含量的变化将两种不同的动力学方程分别应用在催化剂的不同区域。计算后发现采用两种动力学控制下催化剂内甲烷化反应的平均反应速率加快,反应进行的程度变大,更加接近实际过程,提高了计算的精确性。     

在离子交换树脂作用下甲缩醛合成反应本征动力学

将强酸性离子交换树脂作为甲缩醛合成的反应的催化剂，采用测温法测定了在其作用下甲缩醛合成反应本征动力学数据，提出了经验动力学模型，并由反应温度与反应时间的关系直接设计了模型参数。     

CO在成型催化剂上脱除NOx的反应动力学模型

采用实验和模拟相结合的方法研究了NO_x在固定床反应器中的吸附还原过程。选取商业常用的堇青石和TiO₂为主要的成型催化剂基体材料，以铜铁铈复合型金属氧化物为活性成分，制备了蜂窝成型催化剂，对蜂窝催化剂的吸附性能和脱硝还原活性进行测定。建立了固定床反应器中CO脱除NO_x的反应动力学模型，由于CO法脱硝反应的解耦分解，脱硝反应模型也由吸附模型和还原模型组成。吸附模型由固相和气相的微分质量平衡方程建立，还原模型由一组微分方程组成。通过固定床NO_x吸附曲线和不同温度下NO_x的转化率对模型中的关键参数进行了拟合，得到了CO在成型催化剂上脱除NO_x的反应动力学模型，该模型与实验数据吻合较好。在此基础上，模拟了其他条件下吸附过程的穿透曲线和还原反应的转化率。此模型能较好地揭示CO在蜂窝催化剂上还原NO_x的反应动力学，为CO法成型催化剂脱除NO_x的实验或者工程提供理论指导。     

Kinetics of selective hydrogenation of pyrolysis gasoline over an egg-shell catalyst

The kinetics of liquid-phase selective hydrogenation of pyrolysis gasoline over a commercial egg-shell catalyst was investigated in a stirred semi-batch reactor in the absence of external transport limitations. Experimental observations showed that competitive hydrogenation between monoolefins and diolefins was noticeable, and that the reaction rates of diolefins were much faster than those of monoolefins. A Langmuir–Hinshelwood-type reaction mechanism was proposed for the reaction system, and then a rigorous diffusion-reaction mathematical model was developed. For the egg-shell catalyst particle, the diffusion and reaction of species were described separately in two distinct regions, i.e., the outer active region, where both diffusion and reaction occurred, and the inner inertia region, where only diffusion happened. The kinetic and adsorption parameters were estimated from the diffusion-reaction model with the experimental data. The model was able to describe the experimental observations very well. The simulation results showed that significant concentration gradients existed inside the egg-shell catalyst, which revealed that the influence of the internal diffusion resistances on the reaction kinetics was considerable.     

硫锆催化合成三醋酸甘油酯的反应动力学

研究了甘油和乙酸以氧化锆负载硫酸为催化剂合成三醋酸甘油酯的反应动力学,建立了酯化反应动力学方程. 考察了温度、催化剂用量、反应时间以及反应原料摩尔配比对反应速率的影响. 实验结果表明,反应时间10 h,催化剂用量为甘油的5%(w),甘油/乙酸=1:8(摩尔比)的条件下,三醋酸甘油酯的收率达93.8%. 100~130℃时,反应活化能为113.245 kJ/mol.     

Anchovy oil thermal polymerization kinetics

The thermal polymerization reaction kinetics of anchovy oil was investigated with and without catalyst. In order to make a comparison, linseed oil was included in the study. Reactions were carried out 260, 270, and 280°C, and a kinetic model was determined for each case. The reactions for linseed oil with and without catalyst at all temperatures followed the first-order kinetics. In the case of anchovy oil, the best-fitted straight line is obtained by plotting viscosity values against time, and the reaction proceeds in two stages at 280°C without catalyst. The use of catalyst lowered the temperature to 270°C for the appearance of two different rates. Additionally, some mathematical equations were derived between iodine value, refractive index, viscosity, and reaction time.     

POLYMERIZATION KINETICS AND MODELING OF SLURRY ETHYLENE POLYMERIZATION PROCESS WITH METALLOCENE/MAO CATALYSTS

Polymerization methods of ethylene include the slurry, solution, and gas-phase processes. This study investigates polymerization conditions and kinetics under slurry process. Typical metallocene catalyst/cocatalyst Cp₂ZrCl₂/MAO system was used for ethylene polymerization. Two kinds of polymerization kinetics were compared in this study, multiple active-site model and transfer-effect model. The kinetic studies used metallocene-type polymerization kinetics, including catalyst activation, initiation, chain propagation, chain transfer, and termination steps. In addition, kinetic constants of polymerization reaction model were calculated. Calculation results of catalyst activity and molecular weight were compared with experimental results, indicating their good correlation. Moreover, the conventional polymerization was modified to accurately predict the molecular weight behaviors under various reaction conditions with the proposed transfer-effect model. Exactly, how reaction time, pressure, catalyst concentration, and cocatalyst ratio affect catalyst activity and molecular weight of the polymer were also discussed.     

Reaction kinetics for the heterogeneously resin-catalyzed and homogeneously self-catalyzed esterification of thioglycolic acid with 2-ethyl-1-hexanol

Producing 2-ethyl-1-hexyl thioglycolate (ETE) via esterification reaction with thioglycolic acid (TGA)aqueous solution as raw material by reactive-separation coupling technology is a promising process inten-sification method.To choose suitable reactive-separation coupling strategy,the kinetic studies of the esterification of TGA with 2-ethyl-1-hexanol (EHL) were carried out in a batch system.The commercial ion exchange resin was employed as an eco-friendly catalyst.The effects of temperature,catalyst concen-tration and molar ratio were determined.It was interesting to observe that the equilibrium conversion of TGA increased with the increase of catalyst mass fraction due to the adsorption of product water onto resin surface.The activity-based pseudo-homogeneous (PH),Eley-Rideal (ER) and Langmuir-Hinshelwood-Ho ugen-Watson (LHHW) models were used to fit the kinetics data of the resin-catalyzed reaction.The models of ER and LHHW performed better than the PH model.The kinetics of the TGA-self-catalyzed reaction was also determined.An activity-based homogeneous kinetics model could well describe this self-catalyzed reaction.These results would be meaningful to the selection and design of an appropriate reaction-separation strategy for the production of ETE,to realize the process intensification.     

相转移催化剂存在下邻甲酚醛环氧树脂的醚化动力学

根据线性缩聚原理,研究了用相转移催化剂催化邻甲酚醛树脂与过量的环氧氯丙烷的醚化动力学,讨论了配比、反应温度、催化剂用量对其醚化反应的影响,通过对大量数据的总结,回归,得到其醚化反应速率模型。     

1,1,1,3,3-五氯丙烷合成的反应动力学

以铁粉为催化剂前体,磷酸二丁酯为助催化剂,对四氯化碳与氯乙烯合成1,1,1,3,3-五氯丙烷的调聚反应动力学进行了研究。考察了铁粉用量、助催化剂用量及反应温度对反应的影响。研究结果表明：在反应物料比n（CCl₄）：n（VnCl）=1：0.25,反应温度353～388 K范围内该反应为一级反应,反应活化能为69.15 kJ·mol^-1,得到了氯乙烯消耗速率的动力学方程。动力学研究结果表明,在无催化剂条件下反应遵循纯自由基机理,而在催化剂存在条件下反应遵循非链式氧化还原机理。     

硫酸氢钠催化合成共轭亚油酸的反应动力学

常压下,以蓖麻油为原料,硫酸氢钠为催化剂,对合成共轭亚油酸的反应动力学进行了研究,分析了搅拌速度、反应时间、催化剂的用量对反应转化率的影响。结果表明,蓖麻油酸异构化反应为一级反应,反应活化能为18.060 kJ/mol,动力学方程为r C=35.943 e-18.060/RT C A。     

Curing kinetics of a rigid polyurethane foam formulation

The curing kinetics of a typical commercial formulation used in the manufacture of rigid polyurethane foams has been studied. The adiabatic temperature rise method was used, taking into account corrections for heat losses. A polymeric isocyanate was reacted with a stoichiometric amount of a polyether polyol, using dibutyltin dilaurate (DBTDL) as catalyst. For DBTDL < 2.6 mol m^?3, a strong inhibition of the catalyst took place, and the uncatalysed reaction played a major role. Second order kinetics gave a good fit for the whole conversion range. For DBTDL > 2.6 mol m^?3, the catalysed reaction took place. Second order kinetics were applicable up to the gel point, but then the rate slowed down severely. A first order dependence on the initial catalyst concentration was observed in the pre-gel region. The kinetics are discussed in terms of a modified version of the Van der Weij's mechanism. The heat of reaction was 17.6 kcal/NCO equivalent.     

Study of the effect of BDMA catalyst in the epoxy novolac curing process by isothermal DSC

Epoxy novolac/anhydride cure kinetics has been studied by differential scanning calorimetry under isothermal conditions. The system used in this study was an epoxy novolac resin (DEN431), with nadic methyl anhydride as hardener and benzyldimethylamine as accelerator. Kinetic parameters including the reaction order, activation energy and kinetic rate constants, were investigated. The cure reaction was described with the catalyst concentration, and a normalized kinetic model developed for it. It is shown that the cure reaction is dependent on the cure temperature and catalyst concentration, and that it proceeds through an autocatalytic kinetic mechanism. The curing kinetic constants and the cure activation energies were obtained using the Arrhenius kinetic model. A suggested kinetic model with a diffusion term was successfully used to describe and predict the cure kinetics of epoxy novolac resin compositions as a function of the catalyst content and temperature. Copyright © 2003 Society of Chemical Industry     

双季铵碱催化HDI三聚反应动力学研究

以双季铵碱为催化剂,采用溶液聚合工艺对HDI进行三聚反应,气相色谱测定三聚反应体系中游离HDI的含量,研究了HDI三聚反应的动力学规律。结果表明,HDI三聚反应过程的前期反应阶段为三级反应,动力学方程为γ1=kc3,k=1.71×10-5h-1。