Dianisidine chlorosulfonate

Germany s use of chemical weapons on the battlefield began on October 27, 1914 when they fired shells loaded with dianisidine chlorosulfonate, a tear gas, at the British near Neuve Chapelle. This tear gas normally produces violent sneezing. In this case, however, the chemical dispersed so rapidly in the air that the British never knew they were attacked by gas (Charles, 2005). Following this experiment, the Germans continued to test other potential chemical weapons. 

Reaction of chlorosulfonic acid with mono- [141] or disazo dyes [142] yields sulfonyl chlorides, which can then be transformed into cationically substituted sulfonamides by reaction with dialkylaminoalkylamines. The coupling product of diazotized 2-anisidine with 2-hydroxynaphthoic acid arylide upon such treatment dyes paper red, and the azo dye from tetrazotized dianisidine and l-phenyl-3-methyl-5 -pyrazolone gives yellowish orange shades. 

A solution of 0.5 ml anisaldehyde and 1 ml concentrated sulfuric acid in either 25-50 ml glacial acetic acid or methanol will give colored reaction products with many phenols after 1 to a few minutes at 100° C. Aromatic aldehydes are most conveniently detected by spraying the plates with a very dilute (0.01-2%) ethanolic solution of p-phenylenediamine oro-dianisidine. Triethylamine, used in neat form, will produce intense colors with quinonoid compounds. A saturated solution of antimony pentachloride in chloroform or a 10% solution of chlorosulfonic acid in glacial acetic acid will, forex-ample, reveal terpenes after heating the plates to 100°-120°C. 

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