initiatorkatalysator

Inititatorkatalysator is a term used in chemistry to describe a chemical species that can both initiate a reaction and catalyze the subsequent steps within the same catalytic cycle. The concept is especially relevant in polymer chemistry, where initiation creates reactive centers (such as radicals, cations, or anions) that start polymer chains, and the same species can facilitate propagation or other steps that follow initiation.

In practice, initiation and catalysis are often carried out by separate molecules, but some systems employ a single compound that serves as both initiator and catalyst. This dual functionality can streamline reaction design and, in certain cases, enable living or controlled polymerization, where active centers are generated and continuously regenerated throughout the process.

Mechanisms of initiation-coupled catalysis vary. They may be thermal or photochemical, generating reactive species that begin the reaction, after which the catalyst supports chain growth by stabilizing intermediates, lowering activation barriers, or re-generating reactive centers. In metal-catalyzed polymerizations, a metal complex might decompose to form an active species and then persist in the catalytic cycle, while in organocatalytic systems, organic molecules can perform both initiation and subsequent catalytic roles.

The term is not uniformly standardized across literature. In many contexts, initiation and catalysis are treated as separate concepts; the designation “initiator catalyst” emphasizes a single reagent capable of fulfilling both roles. Applications include radical polymerization, ring-opening polymerization, and certain organometallic or photo- and redox-catalyzed processes. See also initiator, catalyst, polymerization, and related catalytic strategies.