Compositions: coating or plastic – Materials or ingredients – Pigment – filler – or aggregate compositions – e.g. – stone,...
Reexamination Certificate
2001-07-02
2003-08-05
Green, Anthony J. (Department: 1755)
Compositions: coating or plastic
Materials or ingredients
Pigment, filler, or aggregate compositions, e.g., stone,...
C106S493000, C106S494000, C534S781000
Reexamination Certificate
active
06602342
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to four novel crystal polymorphs (beta, gamma, delta and epsilon) of C.I. Pigment Yellow 191 of the formula (1), to their preparation and to their use as pigments.
C.I. Pigment Yellow 191 (from now on: P.Y. 191) is the name for the compound of the formula (1) which forms by coupling diazotized 2-amino-4-chloro-5-methylbenzenesulfonic acid with 1-(3′-sulfophenyl)-3-methyl-5-pyrazolone and then reacting the resulting disulfo acid with a calcium salt.
In the solid state the compound (1) may also be present in another tautomeric and/or cis/trans-isomeric form, and may also contain Na
+
ions, Cl
−
ions, and water molecules, usually in each case up to 10% by weight. Pigment Yellow 191 is described in EP-A-0 361 431.
The majority of organic pigments exist in a plurality of different crystal forms, also called polymorphs. Crystal polymorphs have the same chemical composition but a different arrangement of the building blocks (molecules or ions) in the crystal. The crystal structure determines the chemical and physical properties; consequently the individual polymorphs frequently differ in rheology, color, and other coloristic properties. The different polymorphs may be identified by means of X-ray powder diffractometry.
To date only one crystal polymorph of P.Y. 191 has been disclosed. It is referred to below as the &agr; polymorph and has the following characteristic lines in the X-ray powder diagram (Cu—K
&agr;
radiation, double the Bragg angle to 2&THgr; in degrees, interplanar spacings d in Å
−1
):
&agr; (alpha) polymorph:
&agr; (alpha) polymorph:
2&THgr;
d
rel. intensity
4.96
17.78
51
8.98
9.84
32
10.04
8.80
16
11.33
7.80
24
11.53
7.66
20
15.00
5.90
17
16.03
5.52
20
17.21
5.14
26
18.17
4.87
39
18.56
4.77
31
19.26
4.60
18
20.12
4.40
34
21.04
4.21
47
21.29
4.17
30
22.82
3.89
19
23.10
3.84
39
24.31
3.65
15
26.29
3.38
100
26.58
3.35
62
27.25
3.26
21
28.69
3.10
11
29.12
3.06
10
29.89
2.98
20
31.47
2.84
9
All of the line positions are given to an accuracy of ±0.2°.
The alpa phase is form in the synthesis of P.Y.191 if the coupling of the disulfo acid with the sulfonated pyrazolone is conducted in accordance with the details given in EP-A-0 361 431.
SUMMARY OF THE INVENTION
It has now surprisingly been found that, by treating P.Y. 191 with certain solvents, four new crystal polymorphs are formed. The new polymorphs are called &bgr; (beta),
&ggr; (gamma), &dgr; (delta) and, &egr; (epsilon) forms.
They feature the following characteristic lines (Cu—K
60
radiation, 2&THgr; in degrees, d in Å
−1
):
&bgr; (beta) polymorph:
&bgr; (beta) polymorph:
2&THgr;
d
rel. intensity
4.90
18.03
100
8.44
10.47
9
9.49
9.31
10
10.04
8.80
19
12.53
7.05
8
14.73
6.01
12
15.21
5.81
20
15.79
5.60
12
16.93
5.23
9
17.74
4.99
17
18.50
4.79
13
19.79
4.48
13
20.11
4.41
17
21.77
4.07
7
23.01
3.86
8
25.44
3.49
32
25.85
3.44
19
26.89
3.31
10
29.11
3.06
7
29.71
3.00
5
30.40
2.93
7
&ggr; (gamma) polymorph
2&THgr;
d
rel. intensity
4.77
18.49
100
10.08
8.76
27
11.79
7.50
29
13.39
6.60
20
14.34
6.17
21
16.71
5.30
22
18.23
4.86
30
21.22
4.18
29
22.67
3.91
21
23.10
3.84
20
25.79
3.45
36
&dgr; (delta) polymorph
2&THgr;
d
rel. intensity
4.69
18.82
46.6
8.14
10.85
28.1
8.67
10.19
23.8
10.09
8.76
24.7
11.37
7.78
25.1
13.50
6.55
18.8
15.83
5.60
19.9
16.27
5.44
22.9
17.03
5.20
29.2
17.70
5.01
20.7
19.13
4.63
20.4
19.39
4.57
26.1
20.27
4.38
22.0
21.41
4.15
39.6
22.96
3.87
32.4
24.16
3.68
100.0
24.79
3.59
26.1
26.30
3.39
21.2
27.14
3.28
11.3
27.67
3.22
12.8
30.99
2.88
10.5
31.59
2.83
10.6
33.13
2.70
10.6
&egr; (epsilon) polymorph:
2l
d
rel. intensity
5.34
16.54
66
7.81
11.31
100
12.20
7.25
35
18.49
4.79
45
23.22
3.83
63
25.04
3.55
57
29.58
3.01
29
The line positions are recorded to an accuracy of ±0.2° in the case of the beta, gamma and delta polymorphs and to an accuracy of 0.5° in the case of the epsilon polymorph.
The polymorphs of the invention may contain not only Ca
2+
ions but also Na
+
ions and Cl
−
ions and also water molecules in the crystal lattice, normally in amounts of up to 10% by weight based on the overall weight.
All four new polymorphs are of low solubility and are notable for good fastness properties and yellow colorations.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention provides a process for phase conversion of P.Y. 191, which comprises causing a solvent selected from the group consisting of diethylene glycol dimethyl ether, N-methylpyrrolidone, dimethyl sulfoxide, ethylene glycol, dimethylacetamide and dimethylformamide to act on the compound of the formula (1)
or on a tautomer, cis/trans isomer or tautomeric cis/trans isomer of the compound of the formula (1) at a temperature of preferably from 20 to 250° C., in particular from 80 to 200° C.
Judiciously the P.Y. 191 used, in the alpha phase, for example, is dissolved in the solvent and subsequently precipitated by reducing the temperature, adding water and/or evaporating the solvent, giving one or more of the phases of the invention.
The beta polymorph is obtained, for example, when C.I. Pigment Yellow 191 is recrystallized from N-methylpyrrolidone, dimethylacetamide or dimethyl sulfoxide. In this case C.I. Pigment Yellow 191, in the alpha polymorph for example, is dissolved in one of the stated solvents, preferably at a temperature of between 150 and 210° C., and then precipitated by a reduction in temperature and/or the addition of water.
The gamma polymorph is obtained, for example, by heating C.I. Pigment Yellow 191 in diethylene glycol dimethyl ether to a temperature between 150 and 170° C. and cooling it again.
The delta polymorph is obtained, for example, by heating C.I. Pigment Yellow 191 in ethylene glycol to from 170 to 200° C. and cooling it again.
The epsilon polymorph is obtained, for example, when C.I. Pigment Yellow 191 is dissolved in dimethylformamide and the solvent is evaporated under reduced pressure at from 80 to 120° C.
The starting product for preparing the new crystal phases is preferably P.Y. 191 in the alpha polymorph, although it is also possible to convert in each case one or more of the new crystal polymorphs into one of the other new crystal polymorphs by means of the measures described.
The duration of the solvent treatment may judiciously be from 10 minutes to 10 hours, preferably from 30 minutes to 5 hours.
Depending on the purity of the starting materials, the concentrations, the applied temperatures and temperature programs, any aftertreatment, the pressure, the presence of impurities or additives, and the presence of seed crystals, the new crystal polymorphs may be obtained in pure form or as a mixture of alpha and/or beta and/or gamma and/or delta and/or epsilon phases.
A pure or predominantly pure crystal polymorph is formed preferably by starting from a solution or suspension already containing seed crystals of said polymorph and if the precipitation is carried out with sufficient slowness that the supersaturation is held within a range in which the rate of crystal growth is relatively high while the rate of crystal seed formation is relatively low, so that the existing crystal seeds grow while retaining the polymorph. The use of a mechanical stirrer may be of advantage, since it breaks down existing crystals of the desired polymorph into a large number of smaller fragments which may then serve in turn as crystal seeds for this polymorph (in a process known as secondary nucleation). If the supersaturation is higher, for example, because the solution is cooled more rapidly, the rate of crystal seed formation is much higher, with the result that many crystal seeds of this polymorph and other polymorphs may form spontaneously. In this case, polymorph mixtures are obtained preferentially which consist only in part of the desired polymorph.
The preparation of a mixture of two or more of the polymorphs of the invention, or of one or more of the polymorphs of the invention with the alpha polymorph, may be of interest if certain coloristic and rheol
Acs Arpad
Jung Rüdiger
Schmidt Martin U.
Schui Franz
Bisulca Anthony A.
Clariant GmbH
Green Anthony J.
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