Potassium Salt of 7-Hydroxy-4,6-dinitrobenzofuroxan

The potassium salt of 7-hydroxy-4,6-dinitrobenzofuroxan (KDNP) has a very similar chemical structure to KDNBF. However, as opposed to KDNBF which forms Meisenheimer adducts, this compound is aromatic. The aromaticity of KDNP has been confirmed by X-ray analysis [46]. 

The potassium salt (KDNP) exists in two forms. The first is a monohydrate which is prepared in aqueous solution. The second form is an anhydrous salt resulting from using a nonaqueous reaction medium [46]. 

The density of the anhydrous salt is 1.94-2.13 g cm. The monohydrate forms brown crystals with density depending on crystal morphology. The potassium salt is only slightly hygroscopic compared with its more hygroscopic sodium analog [46]. KDNP is moderately soluble in water [49]. 

Sensitivity to impact and friction of the various forms of KDNP is summarized in Table 7.4. The sensitivity of crystalline KDNP to impact is equivalent to milled LS while the needles and amorphous compound are half as sensitive. The sensitivity of KDNP to friction is much lower than that of LS of similar crystal size the needle crystals are significantly more sensitive than either the crystalline or amorphous form [46]. 

KDNP is more thermally stable than KDNBF it remains stable at 120 °C for 90 days. The higher thermal stability compared with KDNBF is probably due to loss of aromaticity of the KDNBF molecule. The DSC data indicate that KDNP is roughly equivalent to LS in terms of onset and peak temperatures [46]. 

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