&bgr; modified monoazo dye resistant to dyeing, its...

Organic compounds -- part of the class 532-570 series – Organic compounds – Azo

Reexamination Certificate

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C534S575000, C534S597000

Reexamination Certificate

active

06673906

ABSTRACT:

The present invention relates to a novel crystal modification (“&bgr; modification”) resistant to dyeing of the dye of the formula I
which in the X-ray diffraction pattern (Cu K
&agr;
radiation) exhibits lines at the following diffraction angles 2&thgr; (°):
high-intensity lines: 7.15, 10.25, 25.9,
medium-intensity lines: 16.9, 19.5, 20.1, 21.85, 22.65, 23.4, 25.2, 28.5, 32.45.
The X-ray diffraction pattern of the &bgr; modification resistant to dyeing, which was recorded using Cu K
&agr;
radiation, is shown in FIG.
1
. It was recorded using a computer-controlled Siemens D 500 powder diffractometer.
The dye of the formula I is known, its preparation is described, for example, in Japanese Patent Specification 74/37,931. It involves diazotizing 2-cyano-4,6-dinitroaniline and coupling the resulting diazonium salt onto 3-[bis(2-methoxyethyl)amino]acetanilide. This results in the formation of a dye in a slightly crystalline, unstable modification (“&agr;
1
modification”) whose X-ray diffraction pattern (Cu K
&agr;
radiation) is shown in FIG.
2
.
An alternative synthesis is described in EP-A-545,161. It involves preparing the dye of the formula I by the so-called cyano exchange method by reacting, for example, 2-acetylamino-4-[bis(2-methoxyethyl)amino]-2′-bromo-4′,6′-dinitroazobenzene with cyanide. In this reaction, it is obtained in a crystal modification (“&agr;
2
modification”) whose X-ray diffraction pattern (Cu K
&agr;
radiation) is reproduced in FIG.
3
and which is characterized by lines at the following diffraction angles 2&thgr;
high-intensity lines: 6.1, 18.0, 22.0, 24.3, 25.6, 26.3,
medium-intensity lines: 9.9, 12.5, 13.2, 16.
This crystal modification is also unstable.
However, powder and liquid preparations prepared from these unstable crystal modifications of the dye exhibit substantial technical defects, in particular during handling, but also already during preparation and also during dyeing of textile polyester materials. Technical defects during handling are observed, for example, when these preparations are redispersed, i.e., when they are incorporated in dyeing liquors and printing pastes. However, problems arise especially when these preparations are used in redispersed form in modern dyehouses.
The dye can be used without problems if it is present in the &bgr; modification according to the invention. This &bgr; modification allows higher space-time yields to be achieved when preparing powder preparations and dyeings are produced on piece goods and wound packages which are speckle-free and free of dye deposits, that is, are homogeneous.
The &bgr; modification according to the invention can be obtained by heating the a modifications in aqueous phase to temperatures of 70 to 150° C., preferably 80 to 130° C. This heating usually takes place in aqueous suspension, advantageously with stirring. If the temperatures to be applied are above the boiling point of the aqueous phase, the conversion into the &bgr; modification is carried out in sealed vessels, for example autoclaves. Heating is carried out for a time sufficient for converting the a modification completely into the &bgr; modification.


REFERENCES:
patent: 2007382 (1935-07-01), Ockman et al.
patent: 3956270 (1976-05-01), Rambach et al.
patent: 4327999 (1982-05-01), Koller et al.
patent: 4329144 (1982-05-01), Eugster et al.
patent: 4460375 (1984-07-01), Sommer et al.
patent: 4536569 (1985-08-01), Hashimoto et al.
patent: 4937325 (1990-06-01), Buhler, I et al.
patent: 5160495 (1992-11-01), Buhler, II et al.
patent: 5389109 (1995-02-01), Buhler
patent: 2525505 (1976-12-01), None
patent: 2921210 (1980-12-01), None
patent: 0217231 (1985-01-01), None
patent: 0217232 (1985-01-01), None
Chemical Abstracts, vol. 81, No. 20, Nov. 18, 1974, Columbus, Ohio, US; abstract No. 122767, p. 131; JP-A-49 037 931 (Mitsubishi Chemical Industries Co.) (Apr. 9, 1974).
Chemical Abstracts, vol. 99, No. 22, Nov. 28, 1983, Columbus, Ohio, US; abstract No. 177482d, NI, JUABO et al.: “New Blue Monoazo Disperse Dyes”; Huadong Huagong Xueyuan Xuebao, Nr. 4, 1982, pp. 437-448.

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