In chemistry, reactions are very important to test, identify and analyse a wide range of materials. There are many types of reactions based on reactants and products. The chemical reaction will depend on many factors like temperature, pressure, surface area and so on. These are the factors that affect the reaction to occur at a specific rate. In addition, there are some agitators or agents which speed up the reaction. They are called enzymes.
The substances that speed up the reaction that lower the activation energy of a specific reaction by providing an alternate reaction pathway without undergoing any chemical reaction is known as catalysts. It participates in a reaction but is not permanently changed in the process, as they are regenerated to their original state.
Characteristic features of the catalyst
Catalysis is the term used for the reaction that is involved by the catalyst. Catalysis is considered the central process in the industrial area, which uses chemical reactions to turn raw materials into valuable products. Some characteristics are listed below.
- A catalytic agent remains unchanged in mass and chemical composition at the end of the reaction.
- A specific amount of the agent catalyses almost all unlimited reactions.
- It cannot initiate the reaction: The function of the catalytic agent is to alter the speed of the reaction rather than to start it.
- A substance, which acts as a catalyst for a particular reaction, fails to catalyse the other reaction. Different agents for the same reactant may provide the additional product.
- It catalyses both forward and backward reactions to the same extent in a reversible reaction and has no effect on the equilibrium constant.
Types of catalysts
According to the need or requirement for a chemical reaction to occur, these agents are divided into many types. They are
They usually perform to increase the rate of a chemical reaction by lowering the activation energy barriers. As a result, numerous reaction molecules are converted into products by increasing the yield of the product.
They decrease the reaction rate by increasing the activation energy barrier, which reduces the number of reactant molecules to transform into products.
Accelerators or promoters
The activity of catalytic agents is increased with the help of promoters or accelerators. For instance, in Haber’s process, promoters are molybdenum or a mixture of potassium and Aluminium oxides.
Inhibitors decrease the activity of catalytic agents. For example, In the hydrogenation of alkyne to an alkene, catalyst palladium is poisoned with barium sulphate in a quinolone solution, and the reaction is stopped at the alkene level.
Significance of catalyst
The catalytic agents are vital in Industries as well as in the human body also. Many proteins in your body are catalysts called enzymes, which do everything from creating signals that move your limbs to help digest your food. Natural proteins (enzymes) or nucleic acids (RNA or ribozymes and DNAs) used to catalyse specific chemical reactions outside the living cells is called biocatalysis.
In organic chemistry, the catalyst has many uses. One example of the reaction involving stimulus is Friedel-crafts alkylation.
The Friedel-Crafts alkylation of benzene
Alkylation is when a hydrogen atom is replaced on a benzene ring with an alkyl group like methyl or ethyl. The aluminium chloride is a catalyst. Benzene is treated with chloroalkane (for example, chloromethane or chloroethane) in the presence of aluminium chloride as a catalyst.
C6H6 + CH3Cl → C6H5CH3 + HCl
- The substance that increases the reaction rate without undergoing any chemical reaction is called a catalyst.
- Catalysis is the term used for the reaction that is involved by the catalyst.
- The function of the catalytic agent is to alter the speed of the reaction rather than to start it.
- Positive catalyst, negative catalyst, promoters or accelerator, inhibitors are the types of catalytic agents.