Naphthalene-1 ,5-disulfonyl chloride

After sufficient chloroform has been evaporated to give a solution volume approximating 250 ml., the solution is cooled in an ice bath and the crystalline product collected on a filter. By further concentration of the mother liquor, an additional quantity of naphthalene-1,5-disulfonyl chloride is obtained. A total yield of 85-115 g. (65-88%) of recrystallized material results m.p. 181-183°. 

Naphthalene-1,5-disulfonyl chloride has been prepared by the reaction of naphthalene with chlorosulfonic acid.2 3 5 However, the yields are generally poor and the conditions difficult to reproduce. 

Naphthalene-1,5-disulfonyl chloride by treatment with a very large excess of chlorosulfonic acid afforded the 1,3,5-trisulfonyl chloride. The powerful conditions required for this reaction are indicative of the strongly deactivating influence of the two sulfonyl groups on the substrate. 

In the disulfonation of naphthalene 40, the two sulfonic acid groups are never 0-, p- or /7eri-(l,8)- with respect to each other. Naphthalene, by treatment with chlorosulfonic acid (two equivalents) at 15-45 °C, yields a mixture of the 1,5-disulfonic acid and the 1,5-disulfonyl chloride. ... 

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