Chemical Forums
Specialty Chemistry Forums => Other Sciences Question Forum => Topic started by: ayslam on January 09, 2007, 12:23:08 AM
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It may be a silly question. But I really thank for your help.
Are there a set of elementary (fundamental) chemical reactions which are components of all possible chemical reactions in the world? In other words, I wonder if there are a set of elementary reactions, with different orders or compositions, can compose all chemical reactions.
Thanks a lot!
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I doubt it, but there are some common reaction mechanisms (e.g. SN1, SN2, E1, E2, etc.) which compose many chemical reactions (at least in organic chemistry).
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In the end all chemical reactions are re-organization of electron orbitals. Together with atomic nuclei, electrons make up atoms; their interaction with adjacent nuclei is the main cause of chemical bonding.
So basically all possible chemical reactions could be included in the set of all possible electron wavefunctions. The Dirac equation (http://en.wikipedia.org/wiki/Dirac_Equation) explains the singe electron, but in chemical reactions you'll need to consider the interactions and it gets a bit tricky. All I can do is point towards quantum mechanics and say the truth is out there. Good luck trying to figure it out...
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I read somewhere that it works to classify reactions as either
1. acid base reactions (Lewis) or
2. redox reactions
for example electrophile-nuleophile reactions are just acid-base where the nucleophile is the base and the electrophile the acid
complex formations are acid-base reactions
the only problem I know is when you talk about isomerisations of systems with pi-bonds
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a more general concept according to someone who's name I don't know is that those two concepts can be combined to electron transfer reactions. that means some kind of electron transfer is the basis for all kinds of chemical reactions.
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So basically all possible chemical reactions could be included in the set of all possible electron wavefunctions.
I think it is to simple to say that everything depends on the quantum physics. I will say there is no answer for your (ayslam's) question. There is no perfect model that unite every reaction, but bits of the truth in every model. Put together correctly (that is what chemistry is all about) they form what we can understand of the reality. The human brain is not hardwired for understanding molecules. Only to understand other chemists.
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Some reaction mechanisms simply are not fully understood. An example is the second step of an oxymercuration reaction. This step involves sodium borohydride, NaBH4, which reduces the alcohol.
We simply do not udnerstand how this works.
Another example is epoxidation of alkenes. We know of a mechanism, but we do not know if this is the way the reaction occurs with 100% confidence.
Simply put, a lot of the reactions out there, the majority of them organic, we have to propose mechanisms for using raw data and kinetics. Sometimes it's just about what works: what has to happen in order for the observable products of the reaction to exist, and how this happens in accordance with what we already know.