Talk:Autocatalysis

Read the sentence at the bottom carefully I think it's wrong molecule-x-1 -> molecule-x-2 (molecule-x-2 is the catalyst*) in my mind molecule-x-1 is the catalyst otherwise its not an autocatalyst but a mutating enzyme with high inertance and after getting the first activation energy the reaction-speed multiplies or the reaction is self-preserving until resources are depleted like a diesel motor. An autocatalyst must always be an enzyme with a trigger otherwise it would be a radical.

If the statement at the bottom is true the description auto meaning self is wrong and a new word needs to be invented for this kind of reaction and the old (autocatalyst) needs to be reasigned to enzymes or chemicals with triggering mechanisms.

please explain.

• extracted from the logically wrong statement below.

A single chemical reaction is said to have undergone autocatalysis, or be autocatalytic, if the reaction product is itself the catalyst for that reaction.

mfg

Jan Girke 19:36, 21 April 2006 (UTC) (After reading only the first sentence. Now I know the If is true. 19:45[UTC])

Role in origin of life

The idea is clearly exposed in a 1974's article of Nobel Prize Melvin Calvin. — Preceding unsigned comment added by 178.139.95.46 (talk) 14:55, 6 January 2018 (UTC)

It's right

I don't understand your reasoning but I am sure that the definition is correct, the product is increasing the reaction rate, this happens usually with Mn(II) which catalyses many reactions involving other Manganese ions. In biochemical reactions the process is usually the opposite and the product acts as an inhibitor.Knights who say ni 01:36, 22 April 2006 (UTC)

Plain English

I'm hoping I can ask for a short, plain english (reading lvl 8th grade or less?) for this.

Ice 9

Would the fictional Ice-nine phase change qualify as a notable fictional example, or would the process described not be an autocatalytic reaction? --Random832 (contribs) 23:06, 8 May 2008 (UTC)

I don't think it has to do with autocatalysis. NikolaiHo^☎️ 19:55, 14 October 2017 (UTC)

The Kurt Vonnegut's fictional Ice 9 is an example of metastability and front triggering. The idea is that there are multiple configurational stable states of $H_{2}O$ at room temperature, being water the most common, but not the most stable one. A state with lower free energy than water would be Ice 9, which will trigger a front from the less stable water to most stable Ice 9. It is not autocatalytic reaction but a front.User:SpinodalCactus, 15 May 2019.

Biochemichal Example

What about the self catalysis of healthy into diseased protein that happens in Mad Cow Diseas? —Preceding unsigned comment added by Dauto (talk • contribs) 23:16, 25 February 2009 (UTC)

Merger proposal

There doesn't seem to be a good reason to have different articles here. Some of the autocatalytic reaction material could go to chemical clock (which I would call an oscillating reaction) instead, which seems to be the point of this section. Olin (talk) 18:49, 26 July 2011 (UTC)

I am surprised that no one has replied to this in almost 4 years. Yes, we now have two articles (this and Autocatalytic reaction) which are more or less on the same subject and something should be done. I see two possible solutions: (1) merge the two and try to organize the combined material more logically, or (2) divide the material between the two on a more logical basis.

For one article, a logical organizing theme would be to consider systems in order of increasing complexity. First the definition and the simplest case A + B → 2B and its time integration, then systems of several coupled reactions (Lotka-Volterra etc.) and real examples with oscillation (BZ etc.), and finally implications for very complex systems such as the origin of life.

For two articles, we could put specific systems and details in Autocatalytic reaction, and reserve this article (Autocatalysis) for a more qualitative overview. This would make it easier for readers to get to the implications for origin of life etc. without going through all the details.

Other opinions? Dirac66 (talk) 19:02, 26 April 2015 (UTC)

@Dirac66: Given that autocatalysis is just what happens during an autocatalytic reaction, I can't see any way of separating them that is likely to be supported by sources. So I support a merge. Given the lack of reaction on this page, I'll wait a week and then do it if no one objects. RockMagnetist(talk) 17:15, 2 October 2015 (UTC)

I've been performing some merges on other articles but held off on this one in case it wasn't as obvious a merger candidate as it appeared to a layman like me. I would agree with RockMagnetist that there isn't an obvious way to separate the articles so a merge is the best option. Richard3120 (talk) 05:14, 15 October 2015 (UTC)

Done. Now a lot of cleanup will be needed! RockMagnetist(talk) 22:47, 15 October 2015 (UTC)

Lotka-Volterra diagram

"The Lotka-Volterra equation is isomorphic with the predator prey model and the two reaction autocatalytic model. In this example baboons and cheetahs are equivalent to two different chemical species in autocatalytic reactions."

WHAT...THE...FUCK? Maybe try NOT explaining that "isomorphic" equivalence in the CAPTION of a diagram. Equations with chemical species of A, X, Y, and E we've managed to illustrate with axes of cute fluffy animals and a UNITLESS key plotting not points but curves of GOD...KNOWS...WHAT! Very sorry for cynically flinging my excrement like a baboon, if you will, but this deserves it. DAVilla (talk) 04:40, 19 January 2016 (UTC)

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Major edit

I removed most of the contents today. I searched in vain within that removed content for "autocatalysis" or similar terms. Nothing. Admittedly I am not talented mathematically, but most of the material seemed to be off topic. It was far from garbage and possibly applicable to other articles, I couldn't figure out where though. At least for chemists, autocatalysis is an important topic, so I tried to make the article useful for that audience. I did keep the mathematics for rate expressions. Also removed were the repeated references to various luminaries in the biogenesis area. That topic is sufficiently thorny that readers dont need to be distracted by "big names", which are cited anyway. Some topics that might be mentioned: self-replication, autoxidation, photography. --Smokefoot (talk) 15:43, 10 June 2023 (UTC)

Mathematical Inaccuracies

with the rate equations (for an elementary reaction)

${d \over dt}[A]=-k_{+}[A][B]+k_{-}[B]^{2}\,$

${d \over dt}[B]=+k_{+}[A][B]-k_{-}[B]^{2}\,$.

This reaction is one in which a molecule of species A interacts with a molecule of species B. The A molecule is converted into a B molecule. The final product consists of the original B molecule plus the B molecule created in the reaction.

The key feature of these rate equations is that they are nonlinear; the second term on the right varies as the square of the concentration of B. This feature can lead to multiple fixed points of the system, much like a quadratic equation can have two roots. Multiple fixed points allow for multiple states of the system. A system existing in multiple macroscopic states is more orderly (has lower entropy) than a system in a single state.

The concentrations of A and B vary in time according to

$[A]={\frac {[A]_{0}+[B]_{0}}{1+{\frac {[B]_{0}}{[A]_{0}}}e^{([A]_{0}+[B]_{0})kt}}}$

and

$[B]={\frac {[A]_{0}+[B]_{0}}{1+{\frac {[A]_{0}}{[B]_{0}}}e^{-([A]_{0}+[B]_{0})kt}}}$.

Bluntly put, the solutions are INACCURATE. Yes they are the solutions to the differential equations of the following:

${d \over dt}[A]=-k_{+}[A][B]\,$

${d \over dt}[B]=+k_{+}[A][B]\,$

Just because the following source uses $[A],[B]$ as their reactants and products respectively, the differential equations are different (see the one I uploaded above) because it assumes the reaction is irreversible. In fact, a simple look at the source material will reveal the different differential equations used and reveal the grossly overlooked error.

Regarding the incorrect equations, basic calculus with limits would tell you that as $n\to \infty$, $[B]\to [A]_{0}+[B]_{0}$ and $[A]\to 0$. Which is by the way, not the definition of a reversible reaction.

As for the solutions, the original differential equations can be solved by WolframAlpha, or even a 18 year old taking A-Level Mathematics and using integration by partial fractions.

$[B]={\frac {[A]_{0}+[B]_{0}}{({\frac {[A]_{0}}{[B]_{0}}}-{\frac {k_{-}}{k_{+}}})e^{-k_{+}([A]_{0}+[B]_{0})t}+1+{\frac {k_{-}}{k_{+}}}}}$

$[A]={\frac {([A]_{0}+[B]_{0})(({\frac {[A]_{0}}{[B]_{0}}}-{\frac {k_{-}}{k_{+}}})e^{-k_{+}([A]_{0}+[B]_{0})t}+{\frac {k_{-}}{k_{+}}})}{({\frac {[A]_{0}}{[B]_{0}}}-{\frac {k_{-}}{k_{+}}})e^{-k_{+}([A]_{0}+[B]_{0})t}+1+{\frac {k_{-}}{k_{+}}}}}$

I will edit the section to ensure it includes the proper solution, as well as the original solution, carefully stipulating the conditions where it applies. View my user page for the procedure I used. Matthionine (talk) 07:33, 27 August 2023 (UTC)

References