The phenomenon of increasing the rate of a chemical reaction by a chemical present in the reaction medium (hogeneous catalysis), or by a solid surface on which the reaction can occur (heterogeneous catalysis)
acceleration of a chemical reaction induced the presence of material that is chemically unchanged at the end of the reaction; "of the top 50 commodity chemicals, 30 are created directly by catalysis and another 6 are made from raw materials that are catalytically produced"
The speeding up or, sometimes, slowing down of a chemical reaction by adding a substance which itself is not changed or consumed in the process: therefore, the catalyst is returned, unchanged from the reaction; note that the liberation of the catalyst may not be apparent, as it may evaporate during the reaction (e g , curing or kicking) process Factors such as temperature, pressure, and humidity will affect the reaction time
The chemical or biological process whereby the presence of an external compound, a catalyst, serves as an agent to cause a chemical reaction to occur or to improve reaction performance without altering the external compound
A reaction taking place due to the presence of an enabling agent, one that is not changed in the process An essential part of autocatalytic processes
It is now believed that such reactions are attended with the formation of an intermediate compound or compounds, so that by alternate composition and decomposition the agent is apparenty left unchanged; as, the catalysis of making ether from alcohol by means of sulphuric acid; or catalysis in the action of soluble ferments (as diastase, or ptyalin) on starch
{i} acceleration of a chemical reaction caused by a substance that remains unchanged by the process; changes brought about by an agent that is unaffected by those same changes
is a phenomena in which a relatively small amount of material augments the rate of reaction without itself being consumed
Catalysis is the speeding up of a chemical reaction by adding a catalyst to it. the process of making a chemical reaction quicker by adding a catalyst (katalysis, from katalyein , from kata- ( CATACLYSM) + lyein ). Modification (usually acceleration) of a chemical reaction rate by addition of a catalyst, which combines with the reactants but is ultimately regenerated so that its amount remains unchanged and the chemical equilibrium of the conditions of the reaction is not altered. Catalysts reduce the activation energy barrier between reactants and products. When more than one reaction is possible, a catalyst that accelerates only one reaction pathway selectively enhances the creation of its product. Catalysis is inhibited if the reactant or the catalyst is removed or altered by any of several types of agents (inhibitors). Catalysis in a single phase (e.g., the catalyst is dispersed in a liquid solution or gaseous mixture with the reactants) is homogeneous; that in more than one phase (e.g., the reactants are liquids and the catalyst a solid) is heterogeneous. Chemisorption, a type of heterogeneous catalysis, often involves bonding between the catalyst's solid surface and the reactant, changing the nature of the chemisorbed molecules. To make the accessible surface area as large as possible, such catalysts are finely powdered or highly porous solids. Catalysis is essential to the modern chemical industry. See also enzyme
Catalysis in which the catalyst is present in a separate phase; normally the catalyst is a solid and the reactants are gas or liquid; it proceeds by the reaction of chemisorbed complexes
a process in which the rate of a reaction in a heterogeneous two-phase system is enhanced by the addition of a substance that transfers one of the reactants across the interface between the two phases