| 摘要 |
PURPOSE:To provide the titled compd. which is stable even at a high temp. and useful as a dye which dyes polyester fibers to navy blue at a uniform density with excellent fastness to light, having a crystal modification (B modification) exhibiting a specified X-ray diffraction pattern. CONSTITUTION:A thiophene dis-azo compd. of the formula has a crystal modification (beta modification) characterized by X-ray diffraction pattern (CuKalpha) with five intermediate-intensity peaks at diffraction angles (2theta) of 13.4 deg., 15.4 deg., 18.0 deg., 22.2 deg. and 27.2 deg.. This compd. exists in the form of three kinds of crystal modifications, and alpha modification is unstable against heat, while said beta modification and gamma modification are stable against heat. The beta modification can be obtd. by treating the alpha modification obtd. by the method described in literature in an aq. medium or in an org. solvent such as ethanol or ethylene glycol at 15-60 deg.C for 30min-3hr.
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