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2,6-Di-tert-butylpyridine, a weak non-nucleophilic base [2] pK a = 3.58; Phosphazene bases, such as t-Bu-P 4 [3] Non-nucleophilic bases of high strength are usually anions. For these species, the pK a s of the conjugate acids are around 35–40. Lithium diisopropylamide (LDA), pK a = 36
An organic base is an organic compound which acts as a base. Organic bases are usually, but not always, proton acceptors. They usually contain nitrogen atoms, which can easily be protonated. For example, amines or nitrogen-containing heterocyclic compounds have a lone pair of electrons on the nitrogen atom and can thus act as proton acceptors. [1]
Amine. In chemistry, amines (/ ə ˈ m iː n, ˈ æ m iː n /, [1] [2] UK also / ˈ eɪ m iː n / [3]) are compounds and functional groups that contain a basic nitrogen atom with a lone pair.Formally, amines are derivatives of ammonia (NH 3 (in which the bond angle between the nitrogen and hydrogen is 170°), wherein one or more hydrogen atoms have been replaced by a substituent such as an ...
An example of a weak base is ammonia. It does not contain hydroxide ions, but it reacts with water to produce ammonium ions and hydroxide ions. [4] The position of equilibrium varies from base to base when a weak base reacts with water. The further to the left it is, the weaker the base. [5]
Bases of carbon, nitrogen and oxygen without resonance stabilization are usually very strong, or superbases, which cannot exist in a water solution due to the acidity of water. Resonance stabilization, however, enables weaker bases such as carboxylates; for example, sodium acetate is a weak base.
In the Mannich reaction, primary or secondary amines or ammonia react with formaldehyde to form a Schiff base. Tertiary amines lack an N–H proton and so do not react. The Schiff base can react with α-CH-acidic compounds (nucleophiles) that include carbonyl compounds, nitriles, acetylenes, aliphatic nitro compounds, α-alkyl-pyridines or imines.
Like other simple aliphatic amines, ethylamine is a weak base: the pK a of [CH 3 CH 2 NH 3] + has been determined to be 10.8 [8] [9] Ethylamine undergoes the reactions anticipated for a primary alkyl amine, such as acylation and protonation. Reaction with sulfuryl chloride followed by oxidation of the sulfonamide give diethyldiazene, EtN=NEt. [10]
Aniline is a weak base. Aromatic amines such as aniline are, in general, much weaker bases than aliphatic amines. Aniline reacts with strong acids to form the anilinium (or phenylammonium) ion (C 6 H 5 −NH + 3). [20]