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Topic: superacid  (Read 8096 times)

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Offline abcc

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« on: December 01, 2006, 08:30:25 AM »
What are the applications of superacid  ???
thx ;)

Offline AWK

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Re: superacid
« Reply #1 on: December 01, 2006, 08:47:38 AM »
Google: superacid application

Offline mdlhvn

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Re: superacid
« Reply #2 on: December 01, 2006, 12:22:51 PM »
Thank you very much for your questioni. Actually, I have never heard superacid before. Now I think this link will help you a lot

Offline Alberto_Kravina

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Re: superacid
« Reply #3 on: December 01, 2006, 03:50:03 PM »
Check me on this, but I think that I've heard that superacids are used to create oxonium ions by protonating alcohols

Something like this: R-OH + H+ ? R-OH2+

Offline orpheus

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Re: superacid
« Reply #4 on: December 12, 2006, 08:42:01 PM »
A reasonable working definition of  superacid, is an acid that is stronger than 100% H2SO4 (Sulphuric Acid). A classical example of a superacid is hydrofluoric acid, or HF. This is a very interesting inorganic acid to study and is one of the best organic and inorganic solvents available other than water.

HF can be used in heterogeneous catalysis, for example, you can functionalise a binary metal-oxide catalyst such as amorphous chromia or gamma-alumina (Al2O3) to produce a catalytically active substance. Evidence suggests that sub-surface insertion of the fluoride anion occurs and facilitates a through-lattice inductive effect that in turn alters the reactivity of Bronsted and Lewis acid sites on the surface of the catalyst.

The F-Al2O3 functionalised heterogeneous catalyst can then be used for a variety of industrial transformations, for example it can be used to produce the current drop-in replacement for CFC-12 (dichlorodifluromethane, that was banned under the Montreal protocol), that is,  1,1,1,2-tetrafluoroethane (HFC-134a) from 2-chloro-1,1,1-trifluoroethane (HCFC-133a) via a Cl for F halogen exchange mechanism.

This is an example of the use of a superacid (HF) in industrial heterogeneous catalysis.

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