Catalyst

1.0What is Catalyst in Chemistry? 

A catalyst in Chemistry is a substance that accelerates a chemical reaction by offering an alternative pathway with lower activation energy. This action enhances the reaction rate without being consumed or undergoing permanent alteration.

2.0Catalyst Definition

In a chemical reaction, bonds between atoms in molecules are broken, rearranged, and recombined to form new molecules. Catalysts enhance this process by lowering the activation energy, making it more efficient.

Catalysts significantly improve chemical processes by lowering the activation energy, which is the minimum energy required for reactants to transition into products. This reduction in the energy barrier enhances the efficiency of the chemical reaction. As a result, catalysts make it easier for atoms to break and form chemical bonds to produce new combinations and new substances.

Catalyst Meaning refers to a substance that speeds up chemical reactions by providing an alternative pathway with lower energy requirements, allowing reactions to occur faster or at lower temperatures without being consumed itself.

3.0Features of Catalysts

Here are some important features of Catalysts- 

• They speed up Reactions: Catalysts facilitate reactions by providing an alternate mechanism that requires less energy for the reactants to transform into products.
• They do not participate in the reaction: Catalysts themselves are not consumed or altered during the reaction. At the end of the reaction, they can be recovered unchanged.
• Specificity: Some catalysts are highly specific to certain reactions or types of reactions, while others are more versatile.
• Reaction Rate: Catalysts enhance reaction rates but do not change the equilibrium position or alter the thermodynamics of the reaction.

4.0Types of Catalysts with Examples

Here are some important catalyst types and examples of catalyst in chemistry discussed below-

1. Positive Catalysts: These substances increase the rate of a reaction by lowering the activation energy required for the reaction to occur. For example, iron oxide in the Haber process facilitates the synthesis of ammonia, enhancing the yield of the desired product.

2. Negative Catalysts: These decrease the rate of a reaction by increasing the activation energy required for the reaction. An example of catalyst is acetanilide retarding the decomposition of hydrogen peroxide is accurate. Negative catalysts impede the formation of the desired product.

3. Promoters or Accelerators: These substances enhance the activity of a catalyst without being catalysts themselves. An example of catalyst is molybdenum or a mixture of potassium and aluminum oxides acting as promoters in the Haber process is correct. They boost the efficiency of the primary catalyst.

4. Catalyst Poisons or Inhibitors: These substances reduce or deactivate the catalyst's activity. For example, Barium sulfate poisoning palladium in Lindler's catalyst during alkyne hydrogenation is accurate. Catalyst positions hinder or halt the catalyst's function.

5. Homogeneous Catalysts: These are in the same phase as the reactants.Catalyst Examples include : 

• Transition metal complexes: Such as Wilkinson's catalyst (RhCl(PPh₃)₃) used in hydrogenation reactions.
• Acids and bases: Like sulfuric acid or hydrochloric acid used in esterification reactions.
• Enzymes : Biological catalysts like catalase, amylase, or lipase.

6. Heterogeneous Catalysts: These exist in a different phase from the reactants. Examples are:

• Metal catalysts : Such as platinum, palladium, or nickel used in catalytic converters for automobile exhaust.
• Zeolites : Porous materials used in the petrochemical industry for cracking hydrocarbons.

7. Supported catalysts: Like Raney nickel or supported metal oxides.

Enzyme Catalysts: Biological catalysts found in living organisms. They are highly specific and efficient in their actions. Examples include:

• DNA polymerase: Catalyzes the formation of DNA molecules during DNA replication.
• Pepsin: An enzyme found in the stomach, responsible for breaking down proteins into smaller peptides during digestion.

8. Photocatalysts: These catalysts use light to activate a chemical reaction. Examples of Catalyst are:

• Titanium dioxide: Utilized in the photodegradation of organic pollutants in wastewater treatment.
• Ruthenium complexes: Employed in artificial photosynthesis for hydrogen production.

9. Industrial Catalysts: Catalysts used on a large scale in industrial processes. Examples include:

• Fischer-Tropsch catalysts: Used for converting syngas (mixture of hydrogen and carbon monoxide) into hydrocarbons.
• Ziegler-Natta catalysts: Employed in the production of polyethylene and polypropylene plastics.

10. Organic Catalysts: These are carbon-based catalysts used in organic chemistry. Examples include:

• Proline: Used in asymmetric synthesis.
• Grubbs' catalyst: Utilized in olefin metathesis reactions.

5.0Unit of Catalyst 

Catalytic activity measures how speedy this helper is and is measured in "katal" (like a speedometer for reactions) in units of moles per second. Productivity is like counting how many times this helper does its job, called "turnover number (TON)."Turnover frequency (TOF) is how many times this helper can do its job in a certain time, like per second or minute.

Note- For enzymes in biology, they have their own way of measuring activity called "enzyme units," showing how many reactions they speed up in a second.