Organic compounds -- part of the class 532-570 series – Organic compounds – Azo
Reexamination Certificate
2001-06-20
2002-04-02
Powers, Fiona T. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Azo
C540S130000, C560S025000
Reexamination Certificate
active
06365720
ABSTRACT:
Thermally cleavable, soluble pigment derivatives (sometimes also called latent pigments) have recently gained importance. It has become known that they can be used advantageously not only in expensive state-of-the-art technologies, for example colour filters, but also, for example, in wood. As a result, the demands made of production processes for their production in high purity are also increasing.
The production of soluble pigment derivatives is known from EP 648 817 and WO 98/32802. In those processes, pigments are reacted inter alia with dicarbonates in a solvent, optionally in the presence of a catalyst A number of solvents are disclosed, including also aromatic solvents such as benzene, toluene, xylene, anisole, chlorobenzene and pyridine. Preference is given to the highly polar solvents N,N-dimethylformamide, N-methyl-pyrrolidone or tetrahydrofuran. In the Examples, only N,N-dimethylformamide, N,N-dimethyl-acetamide or tetrahydrofuran are used.
It has been found, however, that that method does not always yield satisfactory results to the desired extent. Some pigments produce inexplicably low yields or can be reacted only partially, with hydroxy or amide groups that are retained impairing the desired solubilisation (high solubility) of the product. Other pigments react better, but the crude soluble pigment derivatives obtained therefrom exhibit unsatisfactory purity or inadequate storage stability, so that complex purification steps are necessary. Still further pigments give rise to unexpected problems on a pilot scale or production scale.
It has now been found that certain pigments can be solubilised with surprisingly better results if the reaction is carried out with a pyrocarbonic acid diester in an aromatic solvent. Both the yield and the purity are markedly higher, and more solubilising groups can be incorporated into the pigment. The method according to the invention is also excellently suitable especially for the production of latent pigments in relatively large amounts (≧1 mol).
It is in itself very surprising that a more complete reaction is obtained in, of all things, relatively non-polar solvents in which the pigments and soluble pigment derivatives obtained therefrom are less soluble than in solvents used hitherto.
Accordingly, the invention relates to a method for preparing a compound of the formula A(D)
x
(E)
y
(I) by reaction of a compound of the formula A(H)
x
(H)
y
with a pyrocarbonic acid diester of the formula
wherein
x and y are each independently of the other an integer from 0 to 6, but x and y are not simultaneously the number 0,
A is the radical of a chromophore of the quinacridone, anthraquinone, perylene, indigo, quinophthalone, indanthrone, isoindolinone, isoindoline, dioxazine, azo, phthalocyanine or diketopyrrolopyrrole series, which radical is bonded via one or more nitrogen atoms to x groups D and via one or more oxygen atoms to y groups E, the nitrogen atoms and oxygen atoms forming part of the radical A,
each group D or E independently of any other(s) is hydrogen or a group of the formula
wherein at least one group D or E is not hydrogen, and L is any desired group suitable for solubilisation,
in the presence of a base as catalyst, in which method the reaction takes place in an aromatic or heteroaromatic solvent selected from diphenyl, pyridine, quinoline, pyrrole and benzene unsubstituted or mono- to tri-substituted by C
1
-C
6
alkyl, phenyl, benzyl, C
1
-C
6
-alkoxy, phenoxy, C
1
-C
24
alkylthio, halogen and/or by nitro, and any desired mixtures thereof.
Aromatic solvents are preferred. Special preference is given to benzene that is unsubstituted or mono- to tri-substituted by C
1
-C
24
alkyl, C
1
-C
24
alkoxy or by halogen, for example toluene, o-xylene, mesitylene or isopropylbenzene. Aromatic mixtures, for example Dowtherm® A, may also be used.
A is preferably the radical of a chromophore of the monoazo, disazo or phthalocyanine series. A preferably has at least one immediately adjacent or conjugated carbonyl group at each nitrogen atom bonded to x groups D.
Preference is given to the production of soluble pigment derivatives of the formula A(D)
x
(E)
y
(I) wherein at least one group D that is other than hydrogen is bonded to the nitrogen atom of a hydrazone or sulfonamide group, or wherein at least one group E that is other than hydrogen is bonded to the oxygen atom of an enol, phenol or naphthol. It is also possible, however, for a plurality, or even all, of the groups D and/or E to be bonded to such nitrogen or oxygen atoms.
In the case of the above-mentioned preferred pigment classes, the complete reaction of all substitutable hydrogen atoms, which is desirable for use in state-of-the-art technologies, has, according to processes used hitherto, surprisingly proved to be impossible when there are more than three substitutable hydrogen atoms. Accordingly, special preference is given to the production of pigment derivatives of the formula A(D)
x
(E)
y
(I) containing from 4 to 8, especially from 5 to 8, groups D and E that are not hydrogen. Very special preference is given to the production of pigment derivatives of the formula A(D)
x
(E)
y
(I) wherein all of the groups D and E are each a group of the formula
State-of-the-art technologies are, in addition to colour filters, also applications on anodised aluminium or synthetic ceramics, which are the subject of parallel patent applications.
Soluble pigment derivatives having the following partial structures may be mentioned as examples of a group D that is other than hydrogen and is bonded to the nitrogen atom of a hydrazone or sulfonamide group, or of a group E that is other than hydrogen and is bonded to the oxygen atom of an enol, phenol or naphthol:
Very special preference is given to the production of soluble pigment derivatives from Colour Index Pigment Yellow 13, Pigment Yellow 93, Pigment Yellow 94, Pigment Yellow 95, Pigment Yellow 128, Pigment Yellow 154, Pigment Red 185 and Pigment Red 222.
Groups suitable for the solubilisation of pigments are known, for example, from the publications mentioned above or from EP 761 772.
L may be any desired group known for the solubilisation of pigments.
L is preferably a group of the formula
wherein R
1
, R
3
and R
2
are each independently of the others C
1
-C
6
alkyl,
R
4
and R
5
are each independently of the other C
1
-C
6
alkyl, C
1
-C
6
alkyl interrupted by O, S or by N(R
12
)
2
, unsubstituted or C
1
-C
6
alkyl-, C
1
-C
6
alkoxy-, halo-, cyano- or nitro-substituted phenyl or biphenyl,
R
6
, R
7
and R
8
are each independently of the others hydrogen or C
1
-C
6
alkyl,
R
9
is hydrogen, C
1
-C
6
alkyl or a group of the formula
R
10
and R
11
are each independently of the other hydrogen, C
1
-C
6
alkyl, C
1
-C
6
alkoxy, halogen, cyano, nitro, N(R
12
)
2
, unsubstituted or halo-, cyano-, nitro-, C
1
-C
6
alkyl- or C
1
-C
6
alkoxy-substituted phenyl,
R
12
and R
13
are C
1
-C
6
alkyl, R
14
is hydrogen or C
1
-C
6
alkyl and R
15
is hydrogen, C
1
-C
6
alkyl, unsubstituted or C
1
-C
6
alkyl-substituted phenyl,
Q is p,q-C
2
-C
6
alkylene that is unsubstituted or mono- or poly-substituted by C
1
-C
6
alkoxy, C
1
-C
6
alkylthio or by C
2
-C
12
dialkylamino, wherein p and q are different position numbers,
X is a hetero atom selected from the group consisting of N, O and S, m being the number 0 when X is O or S and the number 1 when X is N, and
L
1
and L
2
are each independently of the other [-(p′,q′-C
2
-C
6
alkylene)—Z—]
n
—C
1
-C
6
alkyl or C
1
-C
6
alkyl unsubstituted or mono- or poly-substituted by C
1
-C
12
alkoxy, C
1
-C
12
alkylthio, C
2
-C
24
dialkylamino, C
6
-C
12
aryloxy, C
6
-C
12
arylthio, C
7
-C
24
alkylarylamino or by C
12
-C
24
diarylamino, wherein n is a number from 1 to 1000, p′ and q′ are different position numbers, each Z independently of the other(s) is a hetero atom O, S or C
1
-C
12
alkyl-substituted N, and C
2
--C
6
alkylene in the repeating units [—C
2
-C
6
alkylene—Z—] may be the same or different,
and L
1
and L
2
may be saturated or unsaturated from
Chandrasekhar Mudaliar Dayal
Moegle Gilbert
Monnier Charles Edward
Schacht Hans-Thomas
Sreenivasan Ramaswami
Ciba Specialty Chemicals Corporation
Crichton David R.
Powers Fiona T.
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