Superacid

You don't need to be Editor-In-Chief to add or edit content to WikiDoc. You can begin to add to or edit text on this WikiDoc page by clicking on the edit button at the top of this page. Next enter or edit the information that you would like to appear here. Once you are done editing, scroll down and click the Save page button at the bottom of the page.

Please Take Over This Page and Apply to be Editor-In-Chief for this topic: There can be one or more than one Editor-In-Chief. You may also apply to be an Associate Editor-In-Chief of one of the subtopics below. Please mail us [1] to indicate your interest in serving either as an Editor-In-Chief of the entire topic or as an Associate Editor-In-Chief for a subtopic. Please be sure to attach your CV and or biographical sketch.

A superacid is an acid with an acidity greater than that of 100% sulfuric acid, which has a Hammett acidity function of -12. Commercially available superacids include trifluoromethanesulfonic acid (CF₃SO₃H), also known as triflic acid, and fluorosulfuric acid (FSO₃H), both of which are about a thousand times stronger (i.e. have more negative H₀ values) than sulfuric acid. The strongest superacids are prepared by the combination of two components, a strong Lewis acid and a strong Brønsted acid.

The term superacid was originally coined by James Bryant Conant in 1927 to describe acids that were stronger than conventional mineral acids.^[1] George A. Olah was awarded the 1994 Nobel prize in chemistry for his investigations of superacids and their use in the direct observation of carbocations. Olah's "magic acid", so-named for its ability to attack hydrocarbons, is prepared by mixing antimony pentafluoride (SbF₅) and fluorosulfuric acid. The name was coined after one of Professor Olah's post-doctoral associates placed a candle in a sample of magic acid. The candle was dissolved, showing the ability of the acid to protonate hydrocarbons (which are not basic).

The strongest super acid system, the so-called fluoroantimonic acid, is a combination of hydrogen fluoride and SbF₅. In this system, HF releases its proton (H⁺) concomitant with the binding of F⁻ by the antimony pentafluoride. The resulting anion (SbF₆⁻) is both a weak nucleophile and a weak base. The proton effectively becomes "naked", which accounts for the system's extreme acidity. Fluoroantimonic acid is 2×10¹⁹ times stronger than 100% sulfuric acid,^[1] and can produce solutions with a pH down to –25.^[1]

Olah showed that at 140 °C (284 °F), FSO₃H-SbF₅ will convert methane into the tertiary-butyl carbocation, a reaction that begins with the protonation of methane:^[1]

CH₄ + H⁺ → CH₅⁺

CH₅⁺ → CH₃⁺ + H₂

CH₃⁺ + 3 CH₄ → (CH₃)₃C⁺ + 3/2 H₂

Applications

Common uses of superacids include providing an environment to create and maintain organic cations which are useful as intermediate molecules in numerous reactions, such as involving plastics and high-octane gasoline production and study.^[1]

See also

• Superbase

References

WikiDoc Help Menu Quick Start.. Get Started Here! How to Login How to Search Pages How to Start a New Page How to Edit a Page Cheat Sheet Editing basics Learning Basic Formatting How to make Links in WikiDoc & to External Sites How to Make Lists How to Ignoring Formatting Adding References or Footnotes to Articles Tracking Changes You Have Made How to Put an Article Into a Category When Multiple Topics Should Go To The Same Page (MI, Acute MI, AMI) Using Redirection Advanced editing How to Make Tables How to Insert Images and Other Media How to Add Video Help:How to Make Columns Web Colors How To Make Templates How to Move Pages Inserting Dynamic Dates and Times Inserting WikiDoc Statistics Editing the Table of Contents Communicating your edits Let others know what you changed: The importance of Edit Summaries Minor Edits Edit Conflicts Help Videos You Can Watch Getting Started Video

de:Supersäurenfr:Superacide it:Superacido he:סופרחומצה ja:超酸fi:Superhappo sv:Supersyror vi:Siêu axít