Crystal transformations of the acid pasted crystals consisting of unsubstituted quinacridone (Q. A.) and 1, 2, 4, 8, 9, 11-hexachloroquinacridon (H. C. Q. A.) in organic solvents were studied.
As organic solvents, dimethylformamide, dimethylsulfoxide and N-methyl-2-pyrrolidone were used. The effects of the ratio of two components, the solvent, the time and the temperature on crystal transformation were studied.
It was found that the crystal phase during the boiling treatment in such solvents was controlled as a function of the ratio of two components.
The following table shows a range of the ratio of two components and the crystal phase of product.
Group. Ratio of H. C. Q. A (wt%) Crystal Phase of Product
I II III IV V 0 H.C.Q.A<2.5 2.5≤.H.C.Q.A<80 H.C.Q.A≥80 100γ-phase of Q. A. r-phase+β-phase of Q. A.β-phase of Q.A.+Solid Solution Solid Solution γ-phase of H. C. Q. A
The β-crystal phase of Q. A. obtained in the group III were mainly studied. The speed and activation evergy of the crystal transformation in N-methyl-2-pyrrolidone were affected with the ratio of H. C. Q. A., and its mechanism was considered.
Color of the produced crystal changed remarkably with the ratio of two components.
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