| 翻訳と辞書 |
Superbase
In chemistry, a superbase is an extremely basic compound or substance that has a high affinity for protons. The hydroxide ion is the strongest base possible in aqueous solutions, but bases exist with much greater strengths than can exist in water. Such bases are valuable in organic synthesis and are fundamental to physical organic chemistry. Superbases have been described and used since the 1850s.〔(【引用サイトリンク】url=http://www.bbc.co.uk/dna/h2g2/alabaster/A708257 )〕 Reactions involving superbases often require special techniques since they are destroyed by water and atmospheric carbon dioxide as well as oxygen. Inert atmosphere techniques and low temperatures minimize these side reactions. Superbases also have a corrosive effect.
==Definitions==
IUPAC defines superbases simply as a "compound having a very high basicity, such as lithium diisopropylamide." Caubère defines superbases qualitatively but more precisely:
"The term ''superbases'' should only be applied to bases resulting from a mixing of two (or more) bases leading to new basic species possessing inherent new properties. The term ''superbase'' does not mean a base is thermodynamically and/or kinetically stronger than another, instead it means that a basic reagent is created by combining the characteristics of several different bases."
Superbases have also been defined semi-quantitatively as any species with a higher absolute proton affinity (APA = 245.3 kcal/mol) and intrinsic gas phase basicity (GB = 239 kcal/mol) than Alder's canonical proton sponge (1,8-bis-(dimethylamino)-naphthalene).
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「Superbase」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|