Tetrafluoro-m-phenylenediamine dihydrochloride → 4,6-Diaminoresorcinol Dihydrochloride

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Reaction Conditions

Reaction Steps

The crude dihydrochloride salt of 4,6-diaminoresorcinol (57.0 g) containing 10% Pd/C catalyst is dissolved in 400 g of 6% (by weight) aqueous HCl at 80° C. The catalyst present is removed by filtration. An additional 50.0 g of concentrated HCl containing 1.5 g of stannous chloride dihydrate is added to the product mixture along with 5.0 g of activated carbon. The solution is heated at reflux for 15 minutes and the carbon is then removed by filtration. The filtrate is cooled to 0° C. to allow crystallization of the monomer. The resulting precipitate is isolated by filtration under a purge of dry nitrogen. This filter cake is then dried in vacuo at 40° C. to a constant weight to yield 48.7 g of essentially pure (99.8%) 4,6-diaminoresorcinol dihydrochloride having an m.p. of >300° C. with decomposition. Elemental Anal. calc'd for C6H10Cl2N2O2 (213.0642): C, 33.82; H, 4.73; Cl, 33.28; N, 13.15; O, 15.02, found: C, 33.6; H, 4.64; N, 13.20.

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