What is Catalysis?
Catalysis is a process in which the rate of a chemical reaction is increased by a substance known as a
catalyst. The catalyst itself is not consumed during the reaction and can act repeatedly to facilitate multiple transformations.
What is a Catalyst?
A
catalyst is a substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change. Catalysts work by providing an alternative reaction pathway with a lower
activation energy.
Types of Catalysis
Catalysis is broadly classified into two types: Homogeneous Catalysis: The catalyst is in the same phase as the reactants, typically in a solution.
Heterogeneous Catalysis: The catalyst is in a different phase than the reactants, often involving a solid catalyst and gaseous or liquid reactants.
How Do Catalysts Work?
Catalysts provide a different pathway for the reaction with a lower
activation energy. This allows more molecules to have the energy required to reach the transition state, thereby increasing the reaction rate. Catalysts may also work by stabilizing the
transition state or by bringing reactants into close proximity in an optimal orientation.
What is Enzyme Catalysis?
Enzyme catalysis is a form of catalysis that occurs in biological systems. Enzymes are proteins that act as highly specific catalysts for biochemical reactions. They operate under mild conditions and offer a high degree of specificity for their substrates.
What are Catalytic Cycles?
A
catalytic cycle describes the sequence of steps that a catalyst goes through in facilitating a chemical reaction. The cycle starts with the catalyst in its original state, involves several intermediate states, and ends with the catalyst being regenerated in its original form.
What is Turnover Number?
The
turnover number (TON) refers to the number of times a single catalyst molecule can facilitate the reaction of reactant molecules before becoming inactive. It is a measure of the efficiency and durability of a catalyst.
What is Turnover Frequency?
Turnover frequency (TOF) is the number of catalytic cycles that each active site of the catalyst undergoes per unit time. It is typically expressed in terms of reactions per second or per minute and provides a measure of the catalyst's activity.
What are Catalytic Promoters and Inhibitors?
Promoters are substances that increase the activity or selectivity of a catalyst without themselves being catalysts.
Inhibitors, on the other hand, decrease the activity of a catalyst. Both promoters and inhibitors can significantly impact the efficiency of a catalytic process.
What is Catalytic Selectivity?
Catalytic selectivity refers to the ability of a catalyst to direct a reaction toward a specific product, even when multiple products are possible. High selectivity is especially important in industrial processes where the desired product must be obtained in high yield and purity.
What is a Catalyst Poison?
A
catalyst poison is a substance that deactivates a catalyst by binding to its active sites, thereby preventing it from facilitating the desired reaction. Poisoning can be reversible or irreversible depending on the nature of the interactions involved.
