New crystal polymorphs of a yellow disazo colorant, and their preparation

摘要

The invention relates to six new crystal polymorphs, (alpha), (beta), (gamma), (delta), (zeta), and (eta), of the disazo colorant of the formula I, chemistry chemdraw filechemistry mol file;having characteristic reflections in the X-ray diffraction spectrum. The novel crystal polymorphs are prepared by treatment in organic solvents.