What Is Chemical Kinetics?

Chemical kinetics, also known as reaction kinetics and chemical reaction kinetics, is a branch of physical chemistry and a branch of physical chemistry that studies the rate and reaction mechanism of chemical processes. Its research object is an unbalanced dynamic system whose properties change with time. Its main research areas include: molecular reaction kinetics, catalytic kinetics, elementary reaction kinetics, macro-dynamics, micro-dynamics, etc. It can also be classified into organic reaction kinetics and inorganic reaction kinetics according to different chemical branches. Chemical kinetics is often the decisive factor in chemical production processes.

In the first half of the 20th century, a lot of research work was on the determination of these parameters, theoretical analysis and the use of parameters to study the reaction mechanism. However, confirmation of the reaction mechanism mainly depends on the ability to detect and analyze reaction intermediates. Late 20th century, free radicals

Chemical kinetics is a branch of chemistry that studies the rate of reaction and mechanism of reaction. The main contents of chemical kinetics include the following:

1) Determine the rate of chemical reaction and the influence of external factors such as temperature, pressure, catalyst, solvent and light on the reaction rate;

2) Study the chemical reaction mechanism and reveal the nature of the chemical reaction rate;

3) Explore the relationship and laws between material structure and reaction ability.

Through the study of chemical kinetics, you can know how to control the reaction conditions, increase the rate of the main reaction, increase product yield, suppress the rate of side reactions, reduce raw material consumption, reduce by-products, improve purity, and improve product quality. Chemical kinetics also studies how to avoid the explosion of dangerous goods, the corrosion of materials, the deterioration and aging of products. Therefore, the study of chemical kinetics has great theoretical and practical significance. ^[1]

The research methods of chemical kinetics are:

Phenomenological dynamics

Chemical kinetics is a branch of physical chemistry that studies the rate and reaction mechanism of chemical processes.

Chemical kinetics is different from chemical thermodynamics. Instead of calculating the degree or conversion of the reaction when the reaction equilibrium is reached, it is to observe the chemical reaction from a dynamic point of view, study the time required for the transformation of the reaction system, and the microcosms involved. process. The basis of chemical kinetics and thermodynamics is statistical mechanics,

Using chemical kinetics principles:

(1) Study the mechanism of drug degradation;

(2) Study the factors that affect drug degradation and stabilization measures;

(3) Forecast

Chemical kinetic reaction rate

The reaction rate is a measure of the speed of a chemical reaction. In a broad sense, it is the absolute value of the amount of the substance involved in the reaction over time, divided into two types: average rate and instantaneous rate. The average rate is the change of the amount of substances involved in the reaction within a certain time interval (t) in the reaction process, which can be expressed by the decrease of the reactant or the increase of the product per unit time; the instantaneous rate is the rate of change of concentration with time , The tangent slope of the function on a concentration-time image at a specific time. ^[2]

Chemical kinetic reaction equilibrium

Reaction Equilibrium: Thermodynamics studies the state of a reaction when it reaches reaction equilibrium. In a reversible reaction, the reactants and products reach a dynamic equilibrium, the rates of the forward reaction and the reverse reaction are equal, and the concentrations of the reactants and products no longer change. It can be demonstrated through multi-component reaction processes such as the Hubble synthesis of ammonia, chemical oscillation reactions such as the Belousov-Zhabotinsky reaction (BZ reaction), and the iodine clock reaction. ^[2]

Chemical kinetic reaction mechanism

Reaction mechanism: Although the metering ratio of each substance in the chemical equation seems simple, microscopically, a chemical reaction is usually completed through several steps. The chemical kinetic branch that describes the microscopic process of a chemical reaction is called the reaction mechanism. In the reaction mechanism, each step of the reaction is called a primitive reaction, and the total number of molecules of a reactant in a primitive reaction is called a reaction molecular number. The reactor is composed of one or more elementary reactions, and the net reaction of these elementary reactions is the apparent chemical reaction. ^[2]