Hinsberg separation

The following experimental details will illustrate how the Hinsberg separation of amines may be carried out in practice. 

Hinsberg separation. To this solution, which should be cold (5-8°), is now added 23 g. of benzenesulfonyl chloride,4 and the mixture is stirred vigorously for 30 minutes. The separatory funnel is replaced by a stopper bearing a thermometer, and the... 

Sulfonamides of type RS02NH2 or RS02NHR containing the S02NH moiety are weakly acidic and form water soluble sodium salts (see the Hinsberg separation of amines, p. 105). In such cases, removal of the acidic proton allows alkylation or acylation at nitrogen (Scheme 49). 

In the preparation of 1-n-butyIpyrrolidine (3) from di-n-butylamine (1) by the Hofmann-LofHer reaction, benzenesulfonyl chloride is used for Hinsberg separation of the product (3) from starting material (1). The /-amine (3) is separated by steam... 

The three classes of amines also react differently with organic sulfonyl chlorides this is exploited in the Hinsberg separation of primary, secondary and tertiary amines. ... 

Separation of a Mixture of Aniline, Monomethyianiline, and Dimethylaniline.f Hinsberg s Method. 

Special methods are available for particular classes of compounds, Hinsberg s method of separating primary, secondary and tertiary amines (p. 249)-... 

Hinsberg procedure for the separation of primary, secondary and tertiary amines is given under (viii) above, and this method may be used. The following experimental details may, however, be found useful for the preparation of derivatives of primary and secondary amines. 

Benzenesulphonyl chloride reacts with primary and secondary, but not with tertiary, amines to yield substituted sulphonamides (for full discussion, see Section IV,100,3). The substituted sulphonamide formed from a primary amine dissolves in the alkaline medium, whilst that produced from a secondary amine is insoluble in alkali tertiary amines do not react. Upon acidifying the solution produced with a primary amine, the substituted sulphonamide is precipitated. The reactions form the basis of the Hinsberg procedure for the separation of amines see Section IV,100,(viii) for details. Feebly basic amines, such as o-nitroaniline, react slowly in the presence of allcali in such cases it is best to carry out the reaction in pyridine solution see Section IV,100,3. ... 

The separation of a mixture of amines by means of benzenesulphonyl chloride or p-toluenesulphonyl chloride (Hinsberg s procedure) is described in Section IV,100,(viii). 

For the separation of mixtures of primary, secondary and tertiary amines using benzenesulphonyl or toluene-p-sulphonyl chloride (Hinsberg s method), see p. 1288. 

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