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Organic base

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] Examples include:

Factors affecting alkalinity edit

Most organic bases are considered to be weak. Many factors can affect the strength of the compounds. One such factor is the inductive effect. A simple explanation of the term would state that electropositive atoms (such as carbon groups) attached in close proximity to the potential proton acceptor have an "electron-releasing" effect, such that the positive charge acquired by the proton acceptor is distributed over other adjacent atoms in the chain. The converse is also possible as alleviation of alkalinity: electronegative atoms or species (such as fluorine or the nitro group) will have an "electron-withdrawal" effect and thereby reduce the basicity. To this end, trimethylamine is a more potent base than merely ammonia, due to the inductive effect of the methyl groups allowing the nitrogen atom to more readily accept a proton and become a cation being much greater than that of the hydrogen atoms.[citation needed] In guanidines, the protonated form (guanidinium) has three resonance structures, giving it increased stability and making guanidines stronger bases.

Phosphazene bases also contain phosphorus and are, in general, more alkaline than standard amines and nitrogen-based heterocyclics. Protonation takes place at the nitrogen atom, not the phosphorus atom to which the nitrogen is double-bonded.

Hydroxide donors edit

Some organic bases, such as tetramethylammonium hydroxide, tetrabutylammonium hydroxide, or choline hydroxide are hydroxide donors rather than proton acceptors like the above compounds. However, they are not always stable. Choline hydroxide, for example, is metastable and slowly breaks down to release trimethylamine.

References edit

  1. ^ "Organic Acids and Bases and Some of Their Derivatives" (PDF).

organic, base, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, jstor, june, 2020, . This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Organic base news newspapers books scholar JSTOR June 2020 Learn how and when to remove this template message 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 Examples include pyridine alkylamines such as methylamine imidazole benzimidazole histidine guanidine phosphazene bases hydroxides of quaternary ammonium cations or some other organic cationsFactors affecting alkalinity editMost organic bases are considered to be weak Many factors can affect the strength of the compounds One such factor is the inductive effect A simple explanation of the term would state that electropositive atoms such as carbon groups attached in close proximity to the potential proton acceptor have an electron releasing effect such that the positive charge acquired by the proton acceptor is distributed over other adjacent atoms in the chain The converse is also possible as alleviation of alkalinity electronegative atoms or species such as fluorine or the nitro group will have an electron withdrawal effect and thereby reduce the basicity To this end trimethylamine is a more potent base than merely ammonia due to the inductive effect of the methyl groups allowing the nitrogen atom to more readily accept a proton and become a cation being much greater than that of the hydrogen atoms citation needed In guanidines the protonated form guanidinium has three resonance structures giving it increased stability and making guanidines stronger bases Phosphazene bases also contain phosphorus and are in general more alkaline than standard amines and nitrogen based heterocyclics Protonation takes place at the nitrogen atom not the phosphorus atom to which the nitrogen is double bonded Hydroxide donors editSome organic bases such as tetramethylammonium hydroxide tetrabutylammonium hydroxide or choline hydroxide are hydroxide donors rather than proton acceptors like the above compounds However they are not always stable Choline hydroxide for example is metastable and slowly breaks down to release trimethylamine References edit Organic Acids and Bases and Some of Their Derivatives PDF Retrieved from https en wikipedia org w index php title Organic base amp oldid 1163179587, wikipedia, wiki, book, books, library,

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