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A single chemical reaction is said to have undergone autocatalysis, or be autocatalytic, if the reaction product is itself the catalyst for that reaction. A chemical reaction is a process that results in the interconversion of chemical substances [1]. The substance or substances initially involved in a chemical reaction are called reactants. ...
A catalyst (Greek: καταλÏτης, catalytÄ“s) is a substance that accelerates the rate (speed) of a chemical reaction (see also catalysis). ...
A set of chemical reactions can be said to be "collectively autocatalytic" if a number of those reactions produce, as reaction products, catalysts for enough of the other reactions that the entire set of chemical reactions is self sustaining given an input of energy and food molecules (see autocatalytic set). An autocatalytic set is a collection of entities, each of which is able to catalyze the creation of others within the set, such that as a whole, the set was able to catalyze its own replication. ...
Rate law in autocatalytic reactions
 Sigmoid variation of product concentration in autocatalytical reactions The rate law for the first order autocatalytical reaction  is ![v = k[A][B]](http://upload.wikimedia.org/math/d/e/1/de10acc5c8a835e03ff527ffd5d6a61c.png) . Image File history File links Sigmoid_curve_for_an_autocatalytical_reaction. ...
Image File history File links Sigmoid_curve_for_an_autocatalytical_reaction. ...
A rate law is an equation that relates concentrations of reactants to the reaction rate. ...
The concentrations of A and B vary in time according to ![[A]=frac{[A]_0+[B]_0}{1+frac{[B]_0}{[A]_0}e^{([A]_0+[B]_0)kt}}](http://upload.wikimedia.org/math/7/0/2/702f04dd65537d65853d6785c376928d.png) and ![[B]=frac{[A]_0+[B]_0}{1+frac{[A]_0}{[B]_0}e^{-([A]_0+[B]_0)kt}}](http://upload.wikimedia.org/math/a/2/e/a2e8f292ed1676b68823e5e5bdcff432.png) .
The graph for these equations is a sigmoid curve, which is typical for autocatalytical reactions: these chemical reactions proceed slowly at the start because there is little catalyst present, the rate of reaction increases progressively as the reaction proceeds a the amount of catalyst increases and then it again slows down as the reactant concentration decreases. If the concentration of a reactant or product in an experiment follows a sigmoid curve, the reaction is likely to be autocatalytic The logistic curve A sigmoid function is a mathematical function that produces a sigmoid curve — a curve having an S shape. ...
Examples of autocatalytic reactions Tin pest is an allotropic transformation of the element tin, which causes deterioration of tin objects at low temperatures. ...
Layers of Atmosphere (NOAA) Earths atmosphere is layer of gases surrounding the planet Earth and retained by the Earths gravity. ...
For the Moldavian pop group see O-Zone Ozone (O3) is an allotrope of oxygen, the molecule consisting of three oxygen atoms instead of the more stable diatomic O2. ...
Vinegar syndrome [= VS] is a problem with cellulose triacetate film, in which it degrades and releases a smell resembling that of vinegar. ...
External links - http://www.eeng.dcu.ie/~alife/bmcm9901/html-multi/
- http://arxiv.org/pdf/adap-org/9809003
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