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Separation of acidic, basic & neutral substances in solution

Draw a flow sheet to show how you would separate the components of a mixture containing and acid substance, toluic acid, a basic substance, p-bromo-aniline, and a neutral substance, anthracene.

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When separating mixtures of organic compounds that have acidic or basic
functional groups, such as carboxylic acids, phenols (acidic) and amines (basic), one can exploit the different solubility properties of their protonated and non-protonated forms.

Many of the carboxylic acids are strong enough that they can be deprotonated by a saturated solution of sodium bicarbonate, a relatively weak base. Hydrochloric acid is generally used to protonate amines. The ionic forms of the acidic and basic organic compounds can be recovered from the aqueous solution using the same solubility switch principles.

When acid is added to an aqueous solution that contains the salt of a deprotonated organic acid, the organic acid is reprotonated. In this form, it is now water insoluble and precipitates from the aqueous solution as a solid, which can be collected by vacuum filtration.

Similarly, the salt of a protonated amine can be deprotonated by ...

Solution Summary

This solution provides method for the separation of an acidic, basic and neutral substance from the aqueous solution. The acidic substance present is toluic acid, basic is p-bromo-aniline and the neutral substance is anthracene.