Reaction-Kinetics Theories of Reaction Rates 简单碰撞理论的基本假设
Chapter 16 Kinetics The Rate of Reaction
Chapter 11 Kinetics: The Rate of ReactionStudy Guide/Test ReviewThe Factors that Influence Reaction Rate•Concentration of reactants•Process by which the reaction takes place•The temperature•The presence of a catalyst•The reaction mechanismFor a chemical reaction to be feasible it must occur at a reasonable rate. Therefore it is important to be able to control the rate of reaction.•Examples:o Speeding up a reaction:▪Synthesizing a new drug▪School chemistry labso Slowing down a reaction:▪The aging process ( a biological oxidation involving free radicals)Section 11: 1 Meaning of Reaction RateThe rate of reaction is a positive quantity that expresses how the concentration of a reactant or product changes over time.Example:N2O5(g) → 2NO2(g) + ½ O2(g)As the concentration of the N2O5 decrease over time the concentration of the NO2 and O2 increases over time. Since the coefficients in the equation are not all the same, the concentrations do not change at the same rate. As 1 mole of N2O5 decomposes, 2 moles of NO2 and ½ moles of O2 are formed. Mathematically this is represented by:-∆[ N2O5] = ∆[ NO2] = ∆[ O2]2 ½Remember:∆ = change in[ ] = concentrationThe negative sign (-) in front of the equation takes into account that the concentration of N2O5 is decreasing as the reaction takes place. The above equation can be rewritten to incorporate change in time, (∆t):Rate = -∆[ N2O5] = ∆[ NO2] = ∆[ O2]∆t 2∆t ½ ∆tExample:N2(g) + 3H2(g) → 2NH3(g)The N2 is disappearing at a rate of 0.10 mol/L per minute;∆[N2]/ ∆t = - 0.10 mol/L⋅minFrom the coefficients in the equation we can see that the concentration of the H2 must be decreasing three (3) times as fast as the N2 and the NH3 must be forming at a rate two (2) times as fast as the N2. Mathematically:Rate = -∆[ N2] = ∆[ H2] = ∆[ NH3] = [ 0.10 mol]∆t 3∆t 2 ∆t L⋅minThe concentration will be represented as mol/L, time may be expressed as seconds, minutes, hours, days, etc. Measurement of RateExample:N2O5(g) → 2NO2(g) + ½ O2(g)The rate could be measured by:•Absorption of visible light by the NO2 formed; since NO2 is reddish brown and the N2O5 and the O2 are colorless.•The change in pressure that results from the increase in the number of moles of gas (1 mole gas –reactant → 2 ½ moles gas – products)Section 11: 2 Reaction Rate & ConcentrationReaction rate is directly related to the reactant concentration. The higher the concentration of starting materials, the more rapidly a reaction takes place.Example:H2O2(l) → H2O(g) + ½ O2(g)Pure H2O2(l) at 40 M (40 mol/L) decomposes explosively so fast the rate can’t be meas ured;but the hydrogen peroxide you but in the store is ~1 M (1mol/L) decomposes so slowly that it is stable for several months.•The dependence of reaction rate on concentration is easily explained: reactions occur as the result of collisions between reactant molecules. The higher the concentration of molecules, the greater thenumber of collisions in time, and hence the faster the reaction.•Also, as the reaction proceeds the concentration of the reactants decreases as products are formed.Therefore, there will be fewer collisions and the rate of reaction drops off with time. Eventually the reaction rate drops to zero (0) when the limiting reactant is consumed.Rate Expression & Rate ConstantSince rate is directly proportional to the concentration (when rate vs. concentration is plotted a straight line through the origin is created) it can be expressed mathematically:Example:N2O5(g) → 2NO2(g) + ½ O2(g)Rate = k[N2O5]This equation is called the rate expression for the decomposition of N2O5. It tells how the rate or reaction depends on the concentration of the reactant. The proportionality constant k is called the rate constant. It is independent of the other quantities in the equation.The rate expression can have various forms depending on the reaction.Order of Reaction Involving a Single ReactantMany rate expressions have been determined experimentally.For reactions involving only one reactant:A → products the rate expression has the general form rate = k[A]mNote:•[A] is the concentration of A in mol/L•The power to which the concentration of reactant A is raised in the rate expression is called the order of the reaction (m).•The order of the reaction (m) can be 0, 1, 2, 3… even 3/2 is possibleo The order of the reaction (m) can not be determined from the coefficient in the equation it must be determined experimentally.How can we find the order of the reaction (m) for A → products?▪Measure the initial rate (rate at t = 0) for 2 different concentrations of reactants for the same reaction ▪This gives us 2 initial rates (rate1, rate2) corresponding to 2 different concentrations of A•Rate1 = [A]1•Rate2 = [A]2▪Using the rate expression:•Rate1 = k[A]2m•Rate2 = k[A]1m▪Divide the Rate2 by Rate1: Array•Rate2 = [A]2mRate1 [A]1mSince all the quantities are known except for m, the order can be calculated.Order of Reaction with More Than One ReactantMost reactions involve more than one reactant. Represented by the following equation:aB + bB → productsThe rate is expressed as:Rate = k[A]m x [B]nm = the order of the reaction with respect to An = the order of reaction with respect to BThe overall order of reaction = m + nExample:If m = 1 and n = 2Then the reaction is first order in A, second order in B and third order overall.The order of the reaction with respect to the reactant can be determined by holding the concentration of the reactant in question constant and varying the concentration of the other reactants.Rate1 = k[A]1m x [B]n Rate2 = k[A]2m x [B]nDivide the second equation by the first.Rate1 = k[A]1m x [B]n = [A]2m = [A]Rate1 = k[A]1m x [B]n [A]1mSince all the quantities are known except for m, the order can be calculated.Section 11.3 Reactant Concentration & TimeVocabularyFirst Order Reaction- A reaction whose rate depends upon reactant concentration raised to the first power.Half Life- The time required for one half of a reactant to decompose via a first order reaction has a fixed value, independent of concentration.Zero Order Reaction- a reaction whose rate is independent of reactant concentration. Second Order reaction- a reaction whose rate depends on second power of reactant concentration.All right, the first thing we need to understand is the association of time and concentration for a first order reaction. This can be expressed by an equation.Ln initial concentration = (reaction rate) (time)Concentration after timeLn [A]0 = kt or ln[A]0-ln[A] = kt [A] The next important relationship is the half-life of the reactant which canbe written as…(first order)t1/2 = ln2kThese relationships are different for second and zero order reactions due to the change in the influence of the concentration of the reactant.For Zero Order (rate = k ) For Second Order ( rate = [A]^2)[A] = [A]0 – kt 1 – 1 = kt[A] [A]0The Half-lives are different as well also due to the change in the influence of the concentration of the reactant. For Zero Order (rate = k ) For Second Order ( rate = [A]^2) t1/2 = [A]0 t1/2= 1 .2k k[A]0Chapter 11 Kinetics: The Rate of ReactionSection 5 Outline: Reaction Rate and TemperatureLaura Batson•The rates of most reactions increase as the temperature rises.•The effect temperature has on reaction rate can be explained in terms of the kinetic theory.- Raising the temperature increases the number of molecules having high kinetic energies.- These molecules with the high kinetic energy are most likely to react when they collide.- The higher the temperature, the larger the number of molecules with this high kinetic energy that are able to provide the activation energy required for the reaction.*Note: Activation energy is the minimum energy that must be possessed by a pair of molecules if collision is to result in the reaction.•The fraction of molecules having a kinetic energy equal to or greater than the activation energy increases with increasing temperature. Therefore, the fraction of effective collisions increases, causing the reaction rate to increase with temperature.The Arrhenius Equation•Recall from Section 11.4 that the collision model yields the following expression for the rate constant: k = p x Z x e^-Ea/RT, where the steric factor, p, is temperature-independent and the collision number, Z, is insensitive to temperature.•To a degree of approximation, therefore, we can write, when talking of temperature dependency that: k = Ae^-Ea/RT•This equation was first proven to be valid by Svante Arrheniu in 1889, and it is referred to as the Arrhenius equation.This is used when you are looking for concentration ( [A] or [A]0 )•When comparing the Arrhenius equation with the general equation for a line, y = mx + b, a plot of ln k (“y”) ver sus 1/T (“x”) should be linear. The slope of the line is equal to -Ea/R.- From the slope of this line, the activation energy can be determined with eh equation:Ea = -R x slopeTwo-Point Equation Relating k and T•The Arrhenius equation can be expressed in a different form by the following procedure using the Clausius-Clapeyron equation from Chapter 9. At two different temperatures, T2 and T1,ln k2 = ln A – (Ea/RT2)ln k1 = ln A – (Ea/RT1)Subtracting the second equation from the first eliminates ln A, and we obtainln k2 – ln k1 = -Ea/R[(1/T2) – (1/T1)] orln (k2/k1) = Ea/R[(1/T2) – (1/T1)]•Example: Using the two point Arrhenius equation, what temperature would a reaction go twice as fast given the following:activation energy: 48.2 kj/mol, temperature:20 degrees Celciusrate constant: 0.0130 s-1?Solution: k1 = k2 · { (Ea/R) · (1/T2 - 1/T1) }ln(k1/k2) = (Ea/R) · (1/T2 - 1/T1)T1 = 1 / [ 1/T2 - (R/Ea)·ln(k1/k2) ]= 1 / [ 1/293.15K - (8.31472J/molK / 48200J)·ln(2) ]= 303.75K= 30.6°C11.6 CATALYSISCaroline WashnockCatalyst: a substance that increases the rate of a reaction without being consumed by it✦ A substance does this by changing the reaction path to one with a lower activation energyHeterogeneous Catalysis✦ A heterogeneous catalyst is one that is in a different phase from the reaction mixture✦Most commonly, that catalyst is a solid that increases the rate of a gas-phase or liquid-phase reactionExample: N20 (g) →N2 (g)+ ½ O2 (g) (Au acts as a catalyst)✦In the catalyzed decomposition, N2O is chemically absorbed on the surface of the solid✦ A chemical bond is formed between the oxygen atom of an N2O molecule and a gold atom on the surface✦This WEAKENS the bond joining the nitrogen to oxygen, making it easier for the N2O molecule to break apartHomogeneous Catalysis✦ A homogeneous catalyst is one that is present in the same phase as the reactants✦It speeds up the reaction by forming a reactive intermediate that decomposes to give products; provides an alternative process of lower activation energy✦By adding a certain compound to a reaction, it can greatly increase the speed of reaction Enzymes✦Many reactions that take place slowly under ordinary conditions occur readily in living organisms in the presence of catalysts called enzymes✦In blood or tissues, the decomposition of hydrogen peroxide is catalyzed by an enzyme called catalase; catalase prevents the build-up of hydrogen peroxide, a powerfuloxidizing agent✦Enzymes, like all other catalysts, lower the activation energy for reaction.Mary Elsa Tomlin11.7 Reaction Mechanismsmechanism- the step by step pathway by which a rxn occurso elementary steps- individual steps that constitute a rxn mechanismo slowest step - the rate determining step(think –“a chain is only as strong as its weakest link”)Up above, & Y are intermediates b/c they appear in the mechanism but they cancel out of the balanced equation(the steps of a rxn mechanism must add up to = the balanced eq. with all the intermediates canceled out)A + A + X +B + Y + B X +C + Y + DThe underlined intermediates cancel out leaving you with2A + 2B C + D (which is what you are given)To find the rate expression for the above mechanism:▪Use the slow step: rate = K2[X][B]NOTE: the slow step contains an intermediate (X) -- remember rate equations should not have intermediates▪To eliminate the intermediate use the fast equilibrium in the 1st step to develop an equation for [X] (your intermediate)▪The forward rate must = the reverse rate for this to be an equilibrium, so rate1= rate-1 and then so k1[A]² = k-1[X]▪Now solve for [X] (your intermediate) --- [X] = (k1/k-1)[A]²▪Substitute this into the rate = K2[X][B] equationrate = K2(k1/k-1)[A]² [B]rate = K2[A]² [B] (k is the combined rate constant)the answer。
Kinetics_Homogenous_reactions 传递理论与反应工程英文版课件
1
During a chemical reaction
aA + bB rR + sS
Overall Mass is conserved
Is mass with respect to a species conserved?
The mass of a reactant depletes / disappears when a reaction is in progress.
If i is a reactant, moles of reactant get consumed
and hence the rate is -ve
3
To avoid dealing with both +ve and –ve rates
If i is a product, the rate is defined in terms of rate of appearance (ri)
Solution: 1. Write the rate law for the desired compound
rS = k3[A*] 2. Write the rate for the intermediate compounds
rA* = k1 [A]2 – k2[A*][A] – k3[A*] 3. Use PSSH:
1 V
dN R dt
It may be noted that: rate of disappearance = - (rate of appearance)
4
For the Reaction: aA + bB rR + sS
反应动力学 英文
反应动力学英文Reaction kinetics is the study of the rates at which chemical reactions occur and the factors that influence these rates. It involves the investigation of how the concentrations of reactants and products change over time, as well as the determination of the rate law for a reaction. The field of reaction kinetics is crucial in understanding and predicting the behavior of chemical systems and is widely applied in various industries, including pharmaceuticals, environmental sciences, and materials synthesis.One of the key concepts in reaction kinetics is the reaction rate, which is defined as the change in concentration of a reactant or a product per unit of time. It can be determined experimentally by measuring the change in concentration over a specific time period. The rate law for a reaction describes the relationship between the rate of the reaction and the concentrations of the reactants. It can be expressed mathematically as:Rate = k[A]^m[B]^nWhere k is the rate constant and m and n are the reaction orders with respect to reactants A and B, respectively. The overall reaction order is the sum of the individual reaction orders.The rate constant is a proportionality constant that depends on the temperature and the nature of the reactants. It represents the rate at which reactant molecules collide and undergo the necessary chemical transformations for the reaction to proceed. The units of the rate constant depend on the reaction order.Factors that influence reaction rates include temperature, concentration, catalysts, and surface area. According to the collision theory, an increase in temperature leads to higher molecular kinetic energy, resulting in increased molecular collisions and, therefore, an increased reaction rate. Similarly, an increase in reactant concentration increases the frequency of molecular collisions and, consequently, the reaction rate.Catalysts are substances that increase the rate of a chemical reaction without being consumed during the process. They provide an alternative reaction pathway with lower activation energy, allowing for more successful molecular collisions and a higher reaction rate. Surface area is another important factor, especially in heterogeneous reactions, where reactants are initially present in different phases. Increasing the surface area of a solid reactant increases the number of accessible reactive sites, enhancing the frequency of molecular collisions and, hence, the reaction rate.Reaction kinetics can be described using different mathematical models, such as the integrated rate laws and the Arrhenius equation. Integrated rate laws represent the relationship between concentration and time for a reaction of a specific order. The Arrhenius equation relates the rate constant with temperature and activation energy. It can be expressed as:k = A * exp(-Ea/RT)Where k is the rate constant, A is the pre-exponential factor, Ea is the activation energy, R is the ideal gas constant, and T is the temperature in Kelvin.In conclusion, reaction kinetics is a fundamental field in chemistry that studies the rates at which chemical reactions occur. It involves the determination of rate laws, rate constants, and the factors that affect reaction rates. Understanding reaction kinetics is essential for predicting and controlling the behavior of chemical systems and is widely applicable in numerous scientific and industrial settings.。
Chemical kinetics
Chemical kineticsChemical kinetics contains three principal concepts, reaction rate, reaction equilibrium, and reaction mechanism.1.The reaction as a process that occurs in time, its rate, a change in the rate with the development of the process, the interrelation of the reaction rate and concentration of reactants-all this is characterized by kinetic parameters.2.The influence of the reaction conditions, such as the temperature, phase state of reactants, pressure, medium (solvent), presence of neutral ions, etc., on the rate and other kinetic parameters of the reaction. The final result of these studies is the quantitative empirical correlations between the kinetic characteristics and reaction conditions.3. The kinetics studies the methods for controlling the chemical process using catalysts, initiators, promoters, and inhibitors.Evgeniĭ Timofeevich Denisov,Oleg M. Sarkisov,Gert︠s︡ Ilʹich Likhtenshteĭn Reaction rateReaction rate is the change in the concentration of a reactant or a product with time. 反应速率是化学反应快慢程度的量度，广义地讲是参与反应的物质的量随时间的变化量的绝对值，分为平均速率与瞬时速率两种Reaction rate, the measurement of the degree of chemical reaction speed, is divided by mean speed and momentary speed.影响因素：浓度、压强、温度~~~~~~~~~~~~Reaction equilibriumFor any reversible reaction, when reaching equilibrium state to a significant extent, the molecule of reactants and resultants must be stable, the entropy is defined as a precise value. The symbol of reaction equilibrium is that the densities of each substance in the system stay constant.对于任一可逆的化学反应，在一定条件下达到化学平衡状态(chemistry equilibrium state)时，体系中各反应物和生成物的物质的量不再发生变化，其活度熵为一定值。
本征动力学的英语
本征动力学的英语Intrinsic KineticsThe study of intrinsic kinetics is a fundamental aspect of chemical engineering and chemistry, providing insights into the underlying mechanisms and rate-controlling steps of chemical reactions. Intrinsic kinetics refers to the inherent rate of a reaction, unaffected by external factors such as mass transfer limitations or heat transfer effects. Understanding intrinsic kinetics is crucial for the design, optimization, and scale-up of chemical processes, as well as for the development of new materials and catalysts.One of the key concepts in intrinsic kinetics is the rate equation, which describes the relationship between the reaction rate and the concentrations of the reactants and products. The rate equation is typically expressed as a function of the reactant concentrations raised to various powers, known as the reaction order. Determining the reaction order is a crucial step in understanding the underlying mechanism of a reaction, as it provides information about the molecularity of the rate-determining step.Another important aspect of intrinsic kinetics is the activation energy,which represents the energy barrier that must be overcome for the reaction to occur. The activation energy is related to the temperature dependence of the reaction rate, as described by the Arrhenius equation. By studying the temperature dependence of the reaction rate, researchers can determine the activation energy and gain insights into the energy requirements of the reaction.The study of intrinsic kinetics also involves the investigation of reaction mechanisms, which describe the sequence of elementary steps that occur during a chemical reaction. Understanding the reaction mechanism is essential for the rational design of catalysts and the optimization of reaction conditions. Various experimental and computational techniques, such as kinetic studies, spectroscopic methods, and quantum chemical calculations, are used to elucidate reaction mechanisms.One of the key applications of intrinsic kinetics is in the field of heterogeneous catalysis, where the rate-determining step often involves the adsorption, surface reaction, and desorption of reactants and products on the catalyst surface. By studying the intrinsic kinetics of these surface processes, researchers can develop more efficient catalysts and optimize reaction conditions to improve the overall performance of the catalytic system.Another important application of intrinsic kinetics is in the designand optimization of chemical reactors. The intrinsic kinetics of a reaction, combined with information about the reactor geometry and operating conditions, can be used to predict the performance of the reactor and optimize its design. This knowledge is crucial for the scale-up of chemical processes from the laboratory to industrial scale.In recent years, the study of intrinsic kinetics has also become increasingly important in the field of renewable energy and sustainable chemistry. As the world transitions towards more environmentally friendly energy sources and chemical processes, understanding the intrinsic kinetics of reactions involved in these technologies, such as biofuel production, CO2 conversion, and water splitting, is essential for improving their efficiency and viability.In conclusion, the study of intrinsic kinetics is a fundamental and multifaceted field of chemical engineering and chemistry, providing valuable insights into the underlying mechanisms and rate-controlling steps of chemical reactions. By understanding intrinsic kinetics, researchers and engineers can develop more efficient and sustainable chemical processes, design better catalysts, and optimize the performance of chemical reactors. As the world continues to face complex challenges in areas such as energy, materials, and the environment, the importance of intrinsic kinetics will only continue to grow.。
化工专业英语词汇
化工专业英语词汇reaction kinetics 反应动力学reactant 反应物purify 精制提纯recycle 循环回收unconverted reactant未转化的反应物chemical reactortransfer of heat,evaporation,crystallization结晶drying干燥screening筛选，浮选chemical reaction化学反应cracking of petroleum石油裂解catalyst催化剂，reaction zone反应区conservation of mass and energy能量与质量守衡定律technical advance 技术进步efficiency improvement 效率提高reaction 反应separation 分离heat exchange 热交换reactive distillation 反应精馏capital expenditure 基建投资setup 装置capital outlay 费用，成本，基建投资yield 产率，收率reaction byproduct 反应副产物equilibrium constant 平衡常数waste 废物feedstock 进料，原料product 产物，产品percent conversion百分比转化率ether 乙醚gasoline汽油oxygenate content 氧含量catalyst 催化剂reactant 反应物inert 惰性物，不参加反应的物质reactive distillation 反应精馏-energy saving 节约能量energy efficiency 能量效率heat-sensitive material 热敏性物质pharmaceutical 制药foodstuff 食品gas diffusivity气体扩散性，气体扩散系数gas adsorption 吸收；absorption：吸附specialty chemical特殊化学品，特种化学品batch间歇的；continuous：连续的micro-reactor 微型反应器hydrogen and methane oxidation 氢气和甲烷氧化反应ethylene epoxidation 乙烯环氧化反应phosgene synthesis 光气合成.commercial proportions 商业规模replication 复制sensor 传感器，探头separation of solids 固体分离suspension 悬浮液porous medium 多孔介质filtration 过滤medium 介质filter 过滤器trap 收集，捕集Buchner funnel 布氏漏斗Vacuum 真空conical funnel 锥形漏斗filter paper 滤纸area 面积filter cake 滤饼factor 因数，因子，系数，比例viscosity 黏度density 密度corrosive property 腐蚀性particle size 颗粒尺寸shape 形状size distribution 粒度分布packing characteristics填充性质concentration 浓度filtrate 滤液feed liquor 进料液pretreatment 预处理latent heat 潜热resistance 阻力surface layer 表面层-filtering medium 过滤介质drop in pressure 压降filtering surface 过滤表面filter cake 滤饼cake filtration 饼层过滤deep bed filtration 深层过滤depth 深度law 定律net flow 净流量conduction 传导convection 对流radiation 辐射temperature gradient 温度梯度metallic solid 金属固体thermal conduction 热传导motion of unbound electrons 自由电子的运动electrical conductivity 导电性thermal conductivity 导热性poor conductor of electricity 不良导电体transport of momentum 动量传递the random motion of molecules 分子无规则运动brick wall 墙壁furnace 火炉，燃烧器metal wall of a tube 金属管壁macroscopic particle 宏观的粒子control volume 控制体enthalpy 焓macroscopic phenomenon 宏观现象forces of friction 摩擦力fluid mechanics 流体力学flux（通量，流通量）of enthalpy 焓通量eddy 尾流，涡流turbulent flow 湍流natural and forced convection 自然对流和强制对流buoyancy force 浮力temperature gradient 温度梯度electromagnetic wave 电磁波fused quartz 熔化的石英reflect 反射，inflection:折射matte无光泽的，无光的temperature level 温度高低inter-phase mass transfer界相际间质量传递-rate of diffusion扩散速率acetone 丙酮dissolve 溶解ammonia 氨ammonia-air mixture 氨气-水混合物physical process 物理过程oxides of nitrogen 氮氧化物nitric acid 硝酸carbon dioxide 二氧化碳sodium hydroxide 氢氧化钠actualrate of absorption 实际吸收速率two-film theory 双膜理论concentration difference 浓度差in the vicinity of 在…附近，靠近..,大约…，在…左右molecular diffusion 分子扩散laminar sub-layer 层流底层resistance 阻力，阻止boundary layer 边界层Fick’s Law费克定律is proportional to 与…成比例concentration gradient 浓度梯度plate tower 板式塔installation 装置feed 进料bottom 底部，塔底solvent 溶剂top 顶部，塔顶partial vaporization 部分汽化boiling point 沸点equimolecular counter-diffusion 等分子反向扩散ideal system 理想系统ratio of A to B A与B的比值with the result that：由于的缘故，鉴于的结果tray 塔板packed tower 填料塔bubble-cap tower 泡罩塔spray chamber 喷淋室maintenance expense 维修费foundation 基础tower shell 塔体packing material 填料pump 泵blower 风机accessory heater 附属加热器-cooler 冷却器heat exchanger 换热器solvent-recovery system 溶剂回收系统operating cost 操作费用power 动力circulating gas 循环气labor 劳动力steam蒸汽regenerate再生cooling water 冷却水solvent make-up 补充溶剂optimum 最优的unabsorbed component未吸收组分purity纯度volatility挥发性vapor pressure蒸汽压liquid mixture 液体混合物condense凝缩，冷凝binary distillation双组分精馏multi-component distillation多组分精馏stage-type distillation column级板式精馏塔mount 安装，固定conduit导流管）,downcomer 降液管gravity重力weir溢流堰vapor-liquid contacting device汽液接触装置valve tray浮阀塔板reboiler再沸器vaporization汽化condensate冷凝液，凝缩液overhead vapor塔顶汽体condenser冷凝器ifeed tray进料板base塔底，基础bottoms product塔底产品condensation冷凝stripping section汽提段,提馏段distillate section精馏段total condense全凝器distillate product塔顶馏出产品reflux回流thermodynamic equilibrium 热力学平衡solution溶液-fractional crystallization分步结晶solubility，溶解度，溶解性soluble可溶解的solvent溶剂employ采纳，利用miscible可混合的，可溶的，可搅拌的mechanical separation 机械分离）liquid-liquid extraction 液液萃取aromatic 芳香烃的paraffin石蜡，链烷烃lubricating oil润滑油decompose分解，离解，还原，腐烂penicillin青霉素streptomycin（链霉素）precipitation沉淀，沉析ethyl alcohol乙醇)extract萃取液heat requirement热负荷solute溶质extract phase萃取相baffle-plate折流挡板，缓冲挡板settling tank沉降槽centrifuge离心.离心机，离心分离emulsifying agent乳化剂density difference密度差raffinate萃余液extract 萃取液drying of Solids 固体干燥process material过程物料(相对最终产品而言的）organic有机的，有机物的benzene苯humidity湿度moisture content湿含量drying rate干燥速率critical moisture content临界湿湿含量falling-rate降速concave （凸的，凸面）or convex（凹的，凹面）approximate to：接近，趋近straight line：直线constant-rate drying period恒速干燥阶段convection drying对流干燥drying gas干燥气体falling-rate period降速干燥阶段mean value平均值-vacuum drying真空干燥discolor变色，脱色sublime升华freeze drying冷冻干燥adiabatic绝热的，不传热的pressure gradientperpendicular to：与----垂直counter-current逆流per unit area单位面积water-cooling tower水冷塔sensible heat（sensible heat：显热）water droplet水珠，水滴quantitative relation定量关系thermal diffusion热扩散at right angles to 与…成直角，与…垂直by virtue of 由于，根据，凭借于molecular transfer分子传递balance 抵消，平衡drag forces曳力a function of …的函数of the same order具有同一数量级eddy diffusion涡流扩散is almost inversely proportional to 几乎与…成反比Reynolds number雷诺准数fully developed turbulent flow充分发展湍流coefficient系数In principle从原理而言exothermic（放热的，endothermic吸热的,adiabatic绝热的）triple bond三健，三价nitrogen oxides氮氧化物compound化合物conversion转化，转化率protein蛋白质compress压缩reaction yield反应产率reaction speed反应速度one-pass（单程） reactorenergy input能量输入maximum最大的near toequilibrium接近平衡output产出，输出，产量fertilizer化肥urea尿素ammonium nitrate硝酸铵-ammonium phosphate磷酸铵ammonium sulfate硫酸铵diammonium hydrogen phosphate磷酸二氢铵ash纯碱pyridine砒啶polymers聚合物nylon尼龙acrylics丙烯酸树脂via经，由，通过，借助于hydrogen cyanide氰化氢nitric acid硝酸bulk explosive集装炸药crude oil原油natural gas天然气bitumen沥青fossil fuel化石燃料seepage渗出物asphalt沥青oil drilling采油gasoline汽油paint涂料plastic塑料synthetic rubber合成橡胶fiber纤维soap肥皂cleansing agent清洗剂wax石蜡explosive炸药oil shale油页岩deposit沉积物aquatic plant 水生植物sedimentary rock沉积岩sandstone砂岩siltstone泥岩tar sand沥青石chain-shaped链状的methane甲烷paraffin石蜡，烷烃ring-shaped（环状的）hydrocarbonnaphthene环烷烃naphtha石脑油tarry柏油的，焦油的，焦油状的asphaltene沥青油impurity杂质-pollutant 污染物combustion燃烧capillarity毛细现象，毛细管力viscous resistance粘性阻力barrel桶(国际原油计量单位)tanker油轮kerosene煤油heavy gas oil重瓦斯油reforming重整cracking裂化octane number of gasoline汽油辛烷值branched-chain（带支链的）materials science材料科学mechanical, thermal, chemical, electric, magnetic, and optical behavior. （机械性能、热学性能、化学性能、电学性能、磁性能、光学性能）Amalgam 汞齐，水银；混合物，交叉solid state physics固体物理学metallurgy 冶金学，冶金术magnet 磁铁，有吸引力的人或物insulation 绝缘catalytic cracking 催化裂化structural steels 结构钢computer microchip 计算机芯片Aerospace 航空Telecommunication 电信information processing 信息处理nuclear power 核能energy conversion 能量转化internal structure 内部结构defect structure 结构缺陷crystal flaw 晶体瑕疵vacant atomic site 原子空位dislocation 错位precipitate 沉淀物semiconductor 半导体mechanical disturbance 机械扰动ductility 延展性brittleness 脆性spinning electrons 旋转电子amorphous 非定型的，非晶型的，非结晶的，玻璃状的；无一定目的的，乱七八糟chemical process safety 化工过程安全exotic chemistry 奇异化学-hydrodynamic model水力学模型two-phase flow两相流dispersion model分散模型toxic有毒的release释放，排放probability of failure失效概率accident prevention事故预防hard hat 安全帽safety shoe防护鞋rules and regulations 规章制度loss prevention损失预防hazard identification 危害辩识，technical evaluation技术评估safety management support安全管理基础知识safety experience安全经验technical competence技术能力safety knowledge安全知识design engineer设计师cost engineer造价师process engineering过程工程plant layout工厂布局general service facilities公用工程plant location工厂选址close teamwork紧密的团队协作specialized group专业组storage仓库waste disposal废物处理terminology术语，词汇accountant会计师，会计，出纳final-proposal决议tangible return有形回报Empirical model 经验模型process control（过程控制）first-principles基本原理，基本规则regression model回归模型.operating condition操作条件nonlinear-equation-solving technique非线性方程求解技术process-simulation software packages过程模拟软件包least-squares-regression最小二乘法statistical technique 统计技术intensity强度，程度phenomenological model 现象模型model identification模式识别-neural network神经网络a priori：先验的，既定的，不根据经验的，由原因推出结果的，演绎的，直觉的process data historian：过程数据历史编撰师qualitative定性的quantitative precision定量的精确high-fidelity高保真的computationally intensive计算量大的mathematical expressionsteady-state model稳态模型bioengineering生物工程artificial人工的hearing aid助听器artificial limb假肢supportive or substitute organ辅助或替代器官biosynthesis生物合成life scientist生命科学家agricultural engineer农艺师fermentation发酵civil engineer土木工程师sanitation卫生physiologists生理学criteria 指标human medicine人体医学medical electronics医疗电子medical instrumentation医疗器械blood-flow dynamics血液流动动力学prosthetics假肢器官学biomechanics生物力学surgeon外科医生replacement organ器官移植physiologist生理学家counterpart对应物，配对物psychology心理学self-taught自学barrier障碍物medical engineering医学工程，医疗工程health care保健diagnostic application of computers计算机诊断agricultural engineering农业工程biological production生物制品生产bionics（仿生学）human-factors engineering人类与环境工程environmental health engineering环境健康工程environmentally benign processing环境友好加工commodity or specialty通用商品或特殊化学品styrene苯乙烯ibuprofen异丁苯丙酸the Chemical Manufacturers Association化工生产协会as a whole整体而言emission释放物，排放物voluntary自愿的，无偿的，义务的；有意的，随意的；民办的in the absence of无---存在deactivate失活bulk chemical 大宗化工产品Fine chemical 精细化工Pharmaceutical制药segment段，片，区间，部门，部分；弓形，圆缺；分割，切断tonnage吨位，吨数，吨产量inorganic salt无机盐hydroquinone 对苯二酚demonstrate论证，证明，证实；说明，表明，显示forefront最前线，最前沿Lewis acid不可再生的路易斯酸anhydrous无水的phaseout消除HF alkylation氰氟酸烷基化catalytic oxidation催化氧化governmental regulation政府规定pharmaceutical intermediate药物中间体stereoselective立体选择性的ketone酮functional group官能团detrimental有害的chlorofluorocarbon二氯二氟化碳，氟里昂carbon tetrachloride四氯化碳straightforward简单明了的coordinating ligand配合体，向心配合体kilogram千克thermal stability热稳定性devastate破坏，蹂躏outline描绘，勾勒membrane technology膜技术production line生产线dairy牛奶water purification水净化lifetime寿命membrane module膜组件durability 耐久性，寿命，使用期限，强度chemical additive添加剂end-of-pipe solution 最终方案closed system封闭系统substitute取代，替代technical challenge技术挑战，技术困难wastewater treatment污水处理fouling污垢，发泡surface treatment表面处理applied Chemistry应用化学nomenclature of chemical compound化学化合物的命名法descriptive 描述性的prefix前缀alkane烷烃family族carbon skeleton碳骨架chain链Latin or Greek stem 拉丁或者希腊词根suffix后缀constitute取代物，取代基homologous series同系物branched chain支链烷烃parent母链，主链derivative衍生物substituent取代基locant位次，位标replicating prefix重复前缀词Gas and Liquid Chromatography气相色谱与液相色谱analytical chemistry分析化学moving gas stream移动的气流heats of solution and vaporization溶解热和汽化热activity coefficient活度系数counteract抵消milliliter毫升essential oil香精油test mixture测试混合物sample样品helium氦argon氩carrier载体injection注射stationary nonvolatile phase静止的不挥发相detector检测器fraction collector馏分收集器columnar liquid chromatography柱状液相色谱仪retention volume保留体积retention times保留时间high-performance高性能mobile phase移动相high-efficiency高效的analyte分析物plane chromatography薄层色谱capillary action毛细管作用assay分析化验fluorescence 荧光色，荧光retardation factor保留因子，延迟因子。
反应动力学英语
反应动力学英语Reaction Kinetics: The Fundamental Principles of Chemical TransformationsChemical reactions are the heart of the natural world, driving the processes that sustain life and shape our environment. At the core of these transformations lies the field of reaction kinetics, a branch of chemistry that delves into the intricate details of how and why chemical reactions occur. Understanding the principles of reaction kinetics is crucial for a wide range of applications, from the development of new pharmaceuticals to the optimization of industrial processes.At its most fundamental level, reaction kinetics explores the rates at which chemical reactions take place. This involves the study of the factors that influence the speed of a reaction, such as temperature, pressure, and the concentrations of the reactants. By understanding these factors, scientists and engineers can manipulate the conditions of a reaction to achieve desired outcomes, whether it's maximizing the yield of a valuable product or minimizing the formation of unwanted byproducts.One of the key concepts in reaction kinetics is the rate law, which describes the relationship between the concentrations of the reactants and the rate of the reaction. The rate law is typically expressed as a mathematical equation, with the rate constant and the reaction order as the primary variables. The rate constant reflects the inherent reactivity of the substances involved, while the reaction order indicates how the rate of the reaction changes as the concentrations of the reactants are altered.Another important aspect of reaction kinetics is the concept of the activation energy, which is the minimum amount of energy required for a reaction to occur. Reactions with higher activation energies tend to be slower and less favorable, while those with lower activation energies are more likely to occur spontaneously. Understanding the factors that influence activation energy, such as the molecular structure of the reactants and the presence of catalysts, is crucial for designing efficient and cost-effective chemical processes.The study of reaction kinetics also encompasses the mechanisms by which chemical reactions take place. These mechanisms can be quite complex, involving a series of elementary steps that collectively result in the overall transformation. By elucidating the mechanism of a reaction, scientists can gain valuable insights into the fundamental nature of the chemical process, which can then be used to developmore effective strategies for controlling and optimizing the reaction.One of the key applications of reaction kinetics is in the field of chemical engineering, where it plays a crucial role in the design and optimization of chemical processes. By understanding the kinetics of a reaction, engineers can determine the optimal operating conditions, such as temperature, pressure, and residence time, to maximize the yield and efficiency of the process. This knowledge is particularly important in the production of fuels, pharmaceuticals, and other high-value chemicals, where even small improvements in reaction kinetics can have a significant impact on the bottom line.Another important application of reaction kinetics is in the field of environmental chemistry, where it is used to understand and predict the fate of pollutants in the environment. By studying the kinetics of reactions involving environmental contaminants, scientists can develop strategies for their removal or remediation, as well as predict the long-term impacts of these substances on ecosystems and human health.In the realm of biological chemistry, reaction kinetics plays a crucial role in understanding the complex biochemical processes that sustain life. From the enzymatic reactions that drive metabolic pathways to the signaling cascades that regulate cellular function, the principles of reaction kinetics are essential for unraveling theintricate mechanisms that underlie the living world.As the scientific community continues to push the boundaries of our understanding of the natural world, the field of reaction kinetics will undoubtedly play an increasingly important role. By unlocking the secrets of how and why chemical reactions occur, we can unlock the keys to a more sustainable, efficient, and innovative future, one that harnesses the power of chemistry to address the pressing challenges of our time.。
包晶共晶反应的英语
Peritectic and Eutectic Reactions inMetallurgy: A Comparative AnalysisIn the field of metallurgy, peritectic and eutectic reactions play crucial roles in the formation of alloys and microstructures. These reactions occur duringsolidification processes, influencing the mechanical properties, phase composition, and microstructural evolution of metals and alloys.Peritectic reactions involve the formation of a solid phase from two liquid phases. This reaction occurs when a liquid phase with a higher melting point reacts with another liquid phase with a lower melting point to produce a solid phase with an intermediate melting point. The driving force for this reaction is the reduction in Gibbs free energy associated with the formation of the more stable solid phase.On the other hand, eutectic reactions occur when two or more liquid phases react to form a single solid phase. These reactions are characterized by a distinctive eutectic microstructure, which consists of fine lamellar ordendritic structures. The eutectic reaction occurs at aconstant temperature, known as the eutectic temperature, which is lower than the melting points of the constituent liquid phases.A key difference between peritectic and eutectic reactions lies in the number of liquid phases involved. Peritectic reactions involve two liquid phases, while eutectic reactions involve two or more liquid phases. Additionally, the solid phase formed in peritectic reactions has an intermediate melting point, whereas the solid phase formed in eutectic reactions has a lower melting point than the constituent liquid phases.In terms of applications, peritectic reactions are commonly observed in alloys such as steel, where carbon and iron react to form cementite, a hard and brittle phase. On the other hand, eutectic reactions are commonly found in alloys like aluminum-silicon, where the eutectic microstructure enhances the mechanical properties of the alloy by providing a combination of strength and ductility. In conclusion, peritectic and eutectic reactions are fundamental processes in metallurgy that govern the formation of alloys and microstructures. Understandingthese reactions and their underlying mechanisms is crucial for developing advanced materials with optimized properties for specific applications.**包晶共晶反应在冶金学中的比较分析**在冶金学领域，包晶反应和共晶反应对于合金和微观结构的形成起着至关重要的作用。
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supermolecule
Only exists during collision
9
Physical Chemistry
Reaction Kinetics
Morse potential Energy
Potential-Energy Surfaces
Ep (r) De [exp{2a(r r0 )} 2exp{a(r r0 )}]
e 1 / 2
for B C
(23.6)
The hard-sphere threshold energy is nearly the same as the activation energy. The simple collision theory gives only the pre-exponential factor A (but not for the calculation of Ethr)
Reaction Kinetics
Hard-Sphere Collision Theory of Gas-Phase Reactions
8RT 1 1 k N A (rB rC ) 2 M M C B
8RT 2 k N Ad B M 1/ 2 2 B 1
r 1 d [ B] k[ B]2 2 dt
Ethr / RT NA
The rate of disappearance of B
1 d [ B] / dt Z BBe Ethr / RT k 2 [ B]2 N A[ B]2
d [ B] 2Z BCe dt
r k[ B]2
(1) all supermolecules that cross the critical dividing surface from the reactant side become products. Once a supermolecule crosses the critical surface it is a downhill journey to products. (2) during the reaction the Boltzmann distribution of energy is maintained for the reactant molecules. (3) the supermolecules crossing the critical surface from the reactant side have a Boltzmann distribution of energy corresponding to the temperature of the reacting system.
1/ 2
e Ethr / RT
for B C for B = C
(23.3) (23.4)
e Ethr / RT
Ethr 1 ln k const ln T 2 RT
E 1 Ea RT 2 T thr RT 2 2
Ea Ethr 1 RT 2 Ea RT 2 d ln k dT
1/ 2
e Ethr / RT
for B C
(23.3)
(23.5)
1/2RT is small
1 Ea RT 2
Ea Ethr
Ea A ke RT
1 RT 2
Ea Ethr
(17.69)
1/ 2
8RT 1 1 A N A (rB rC ) 2 M B MC
3
Physical Chemistry
Reaction Kinetics
Hard-Sphere Collision Theory of Gas-Phase Reactions
The number of B reacting in a bimolecular reaction B + C Products Ethr NA thr Z BCe Ethr / RT
7
Physical Chemistry Reaction Kinetics A comparison of theoretic calculation and experimental measurement
Reaction T K E kJ·mol-1
k0 1011dm3 ·mol-1 ·s-1 measured cal. k0 (theo) k0 (cal)
(17.68) (23.5)
6
Physical Chemistry
Reaction Kinetics
Theories of Reaction Rates
Hard-Sphere Collision Theory of Gas-Phase Reactions
1 1 2 8RT k N A (rB rC ) M M C B
图中R点是反应物BC分子的基态,随着A原子的靠近,势能 沿着RT线升高，到达T点形成活化络合物。
随着C原子的离去，势能沿 着TP线下降，到P点是生成 物AB分子的稳态。
A-----B-----C
D点是完全离解为A,B,C原子 时的势能；OEP一侧,是原子 间的相斥能,也很高。
A-------B---C
K + Br2 CH3 + CH3
KBr + Br C2H6 CHO
600 300
0 0
10 0.24
2.1 1.1
4.8 0.22
2NOCl
2NO + Cl2 470
CHO 500
102
0.094
0.59
0.16
+ H2 + C2H4
83
1.5×10 -5
3.0
5×10- 6
C2H6 800
180
In chemical reactions, bonds are being formed and broken. Intramolecular forces Forces acting on atoms in the molecules
Intermolecular forces
Consider two molecules to form a single quantum-mechanical entity
1.24×10 -5 7.3
1.7×10- 6
8
Physical Chemistry
Potential-Energy Surfaces
Reaction Kinetics
The hard-sphere collision theory does not give accurate rate constants.
当r>r0时,有引力,即化学键力。
当r<r0时，有斥力。
=0时的能级为振动基态能级， E0为零点能。 D0为把基态分子离解为孤立 原子所需的能量，它的值可
从光谱数据得到。
10
Physical Chemistry For a reaction
A BC A B C AB C
The use of (15.63) for ZBB
8RT 2 k N Ad B M 21 / 2 B 1
1/ 2
e Ethr / RT
for B = C
(23.4)
5
Physical Chemistry
Theories of Reaction Rates
1/ 2
Reaction Kinetics
Potential-Energy Surfaces
A
Rab
B
Rbc C
If < 180o Potential is a function of Rab and Rbc only.
11
Physical Chemistry
Reaction Kinetics
Potential-Energy Surfaces
A---B-------C
12
Physical Chemistry
Reaction Kinetics
Transition-State Theory
Transition-State Theory (TST) Activation-Complex Theory (ACT)
The potential-energy surface for a reaction has a reaction region and a product region that are separated by a barrier. TST chooses a boundary surface located between the reactant and product regions and assumes that all supermolecules that cross this boundary surface (critical dividing surface) become products. The critical dividing surface (Fig. 23.7) is taken to pass through the saddle point of the potential-energy surface.
Physical Chemistry
Reaction Kinetics (6)
Xuan Cheng Xiamen University
1
Physical Chemistry
Theories of Reaction Rates
Reaction Kinetics