Benzene sulfonyl chloride test

The complete solubility of the product in chloroform 1 shows the trimethylamine hydrochloride to be free from ammonium chloride and methylamine hydrochloride and the fact that no precipitate is obtained when tested with sodium hydroxide and benzene sulfonyl chloride in aqueous solution shows that dimethylamine hydrochloride is absent. 

The Hinsberg test, which can distinguish primary, secondary, and tertiary amines, is based upon sulfonamide formation. In the Hinsberg test, an amine is reacted with benzene sulfonyl chloride. If a product forms, the amine is either a primary or secondary amine, because tertiary amines do not form stable sulfonamides. If the sulfonamide that forms dissolves in aqueous sodium hydroxide solution, it is a primary amine. If the sulfonamide is insoluble in aqueous sodium hydroxide, it is a secondary amine. The sulfonamide of a primary amine is soluble in an aqueous base because it still possesses an acidic hydrogen on the nitrogen, which can be lost to form a sodium salt. 

The importance of MP can be related to the physical state of the substance under the conditions of Draize test. In this study, it was assumed that chemicals with a MP less than or equal to 37°C would exist as liquids in the test procedure and that, in general, liquids would be more likely than solids to cause corrosion and irritation. The results confirm that there is indeed a relationship between physical state and the potential for acute skin toxicity. The fact that some solids are corrosive or irritant may relate to the fact that their MPs are not much higher than 37°C and that they exist as wax-like substances, which are more capable of penetrating into the skin than are solids with higher MPs. For example, carvacrol, and thymol, which are both irritant and corrosive, have predicted MPs of 38°C and 38.1°C, respectively. In the case of other solids, such as benzene sulfonyl chloride (MP = 61°C), the corrosive response may be due to a more toxic derivative (e.g., benzene sulfonic acid). 

It does not react with benzene-sulfonyl chloride/ therefore it is a tertiary amine. This analysis is known as the Hinsberg test ... 

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