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In chemistry, chain propagation (sometimes just referred to as propagation) is a process in which a reactive intermediate is continuously regenerated during the course of a chemical chain reaction. For example, in the chlorination of methane , there is a two-step propagation cycle involving as chain carriers a chlorine atom and a methyl radical ...
chain branching (a propagation step where one active particle enters the step and two or more are formed); chain transfer (a propagation step in which the active particle is a growing polymer chain which reacts to form an inactive polymer whose growth is terminated and an active small particle (such as a radical), which may then react to form a ...
Propagation can refer to: Chain propagation in a chemical reaction mechanism; Crack propagation, the growth of a crack during the fracture of materials; Propaganda, non-objective information used to further an agenda; Reproduction, and other forms of multiplication or increase Plant propagation, the production of more plants
Propagation proceeds by addition of monomer to the active species, i.e. the carbenium ion. The monomer is added to the growing chain in a head-to-tail fashion; in the process, the cationic end group is regenerated to allow for the next round of monomer addition. [6] General propagation pathway
In chemistry, initiation is a chemical reaction that triggers one or more secondary reactions. Initiation creates a reactive centre on a molecule which produces a chain reaction . [ 1 ] The reactive centre generated by initiation is usually a radical , but can also be cations or anions . [ 2 ]
Chain-growth includes both initiation and propagation steps (at least), and the propagation of chain-growth polymers proceeds by the addition of monomers to a growing polymer with an active centre. In contrast step-growth polymerization involves only one type of step, and macromolecules can grow by reaction steps between any two molecular ...
“Old vine” is a commonly used term in the world of high-end wine. It seems to imply something regal about a wine, a greater sense of depth, concentration or profundity of character.
Wavenumber, as used in spectroscopy and most chemistry fields, is defined as the number of wavelengths per unit distance, typically centimeters (cm −1): ~ =, where λ is the wavelength. It is sometimes called the "spectroscopic wavenumber". [1] It equals the spatial frequency.