Note: Descriptions are shown in the official language in which they were submitted.
~os~66
It has been found that new, valuable disa~o pigments
of the formula
Xl Xl
N ~ ~ N
N
Cl Cl
~ CONH ~ NHOC ~ ~
wherein Xl denotes a chlorine atom or a methyl group, X denotes
a chlorine atom or a methyl, methoxy, nitro or nitrile group,
Y denotes a H or chlorine atom or a methyl group, Y denoting
a methyl group if Xl and X represent chlorine atoms, and Y
denoting a H atom if X represents a methoxy, nitro or nitrile
group, and Y denoting a H atom or a methyl group if Xl repre-
sents a methyl group, of the formula
Xl Xl
N ~ ~ N
N N.
Cl Cl
OH X HO
~ ~ CONH ~ NHOC ~ ~
wherein Xl denotes a chlorine atom or a methyl group, X denotesa chlorine atom or a methoxy, nitro or cyano group, are obtained
if a) a carboxylic acid halide of the formula
X
N ~
Cl
OH
COHal
-- 2
~05816fà
particularly a carboxylic acid halide of the formula
N ~
N
Cl
~ COCl
is condensed, in a molar ratio of 2:1, with a diamine of the
formula
2 ~ NH2
y
particularly a diamine of the formula
or b) the dla~o compound of an amine of the formula
X
H2N~
Cl
is coupled, in a molar ratio of 2:1, with a bis-naphthol of the
formula
~ CONH ~ NUOC ~
Disazo pigments of particular interest are those of the
formula Xl Xl
N ~ ~ N
Cl Cl
3 ~
1(~S8~G6
Cl Cl
,N, ~ 1 ~ NN
CON ~ NHOC
Cl Cl
'NN ~ 1 ~ NN
CONH ~ NHOC
CH3 ~CH3
N ~ ~ N
N Cl Cl
~ CONH ~ NHOC ~
wherein Xl denotes a chlorine atom or a methyl group and X
denotes a chlorine atom or a methoxy, nitro or cyano group.
The azo colorant carboxylic acids on which the acid
halide used as the starting material is based, are obtained
by coupling diazotised 2,5-dichloroaniline or 2-methyl-5-
chloroaniline with 2,3-hydroxynaphthoic acid.
The azo colorant carboxylic acids obtained are treated
with agents which are capable of con~erting carboxylic acids
into their halides, for example the chlorides or bromides, that
is to say, in particular, with phosphorus halides, such as
phosphorus pentachloride or phosphorus trichloride or penta-
bromide or phosphorus oxyhalides, and, preferably, with thionyl
chloride.
~ - 4 -
105~166
The treatment with agents of this kind which produce
acid halides is appropriately carried out in inert organic
solvents, such as dimethylformamide, chlorobenzenes, for
example mono- or di-chlorobenzene, toluene, xylene or nitro-
benzene, with the optional addition of dimethylformamide in
the case of the last 5 mentioned. When preparing the carboxylic
acid halides, it is appropriate, first of all to dry the azo
compound, which has been prepared in an aqueous medium or to
free it azeotropically from water by boiling in an organic
solvent. This azeotropic drying can, if desired, be carried
out directly before the treatment with the agents which produce
acid halides.
The following examples of diamines may be mentioned:
- 4a -
iO5~ 6
2-chloro-1,4-phenylenediamine, 2-methyl-1,4-phenylenediamine,
2-methoxy-1,4-phenylenediamine, 2-nitro-1,4-phenylenediamine,
2-cyano-1,4-phenylenediamine, 2,5-dimethyl-1,4-phenylene-
diamine and 2-chloro-5-methyl-1~4-phenylenediamine.
The condensation between the carboxylic acid halides,
particularly the carboxylic acid chlorides, and the diamines
is appropriately carried out in an anhydrous medium. It is
carried out at temperatures which are within the boiling range
of normal organic solvents, such as toluene, monochlorobenzene 9
dichlorobenzene, trichlorobenzene, nitrobenzene and the like.
In order to accelerate the reaction, it is advisable to use an
acid-binding agent, such as anhydrous sodium acetate or pyri-
dine. The colorants obtained are in some cases crystalline
and in some cases amorphous and are generally obtained in a
very good yield and in a pure state. It is appropriate,
first of all,to separate the acid chlorides which are obtained
from the carboxylic acids. In some cases~ however, it is pos-
sible, without loss, to dispense with separating the acid
chlorides and to carry ou-t the condensation directly subse-
quently to the preparation of the carboxylic acid chlorides.
The coupling according to embodlment b) of the process
according to the invention is appropriately carried out by
gradually adding the aqueous alkaline solution of the coupling
component to the acid solution of the diazonium salt. The
quantity of alkali metal hydroxide to be used for dissolving
the coupling component is appropriately regulated in such a
way that it is adequate to neutralise the mineral acid which is
liberated from the diazonium salt during the coupling. The
-- 5 --
~. .
. .
~05~
coupling is advantageously carried out at a pH-value of 4 to
6. The pH-value is advantageously regulated by the addition
of a buffer. Examples of possible buffers are the salts,
particularly alkali metal salts, of formic acid, phosphoric
acid or, in particular, acetic acid. The alkaline solution
of the coupling componen-t appropriately contains a wetting
agent, dispersing agent or emulsifier, for example an aralkyl-
sulphonate, such as dodecylbenzenesulphonate, or the sodium
salt of l,l'-naphthylmethanesulphonic acid~ polyconder.sation
products of alkylene oxides, such as the reaction product of
ethylene oxide and p-tert.-octylphenyl, and also alkyl esters
of sulphoricinoleates, for example n-butyl sulphoricinoleate.
The dispersion of the coupling component can also advantage-
ously contain protective colloids, for example methylcellulose
or minor quantities of inert organic solvents which are spar-
ingly soluble or insoluble in water, for e~ample optionally
halogenated or nitrated aromatic hydrocarbons, such as benzene,
toluene, xylene, chlorobenzene, dichlorobenzenes or nitroben-
zene, and aliphatic halogenohydrocarbons, such as, for
example, carbon tetrachloride or trichloroethylene, and also
organic solvents which are miscible wi-th water, such as ace-
tone, ethylene glycol mono~methyl ether, methyl ethyl ketone~
methanol, ethanol or isopropanol.
It is advantageous to carry out the coupling by con-
tinuously combining, in a mixing jet, an acid solution of the
diazonium salt with an alkaline solution of the coupling com-
ponent, whereupon an immediate coupling of the components
takes place. Care should be taken that the diazo component
lOS8~66
and the coupling component are present in equimolecular
amounts in the mixin~ jet, a slight excess of the coupling
component being found advantageous. This is most easily
effected by controlling the pH-value of the liquid in the
mixing jet. A vigorous turbulence of the two solutions in
the mixing jet should also be ensured. The resulting col-
orant dispersion is continuously withdrawn from the mixing
jet and the colorant is removed by filtration.
Finally, the coupling can also be carried out by sus-
pending the amine to be diazotised together with the coupling
component in a molar ratio of 2:1 in an organic solvent and
treating the mixture with a diazotising agent, particularly
an ester of nitrous acid, such as methyl, ethyl, butyl, amyl
or eth~l nitrite.
By virtue of their insolubility, the resulting pig-
ments can be isolated from the reaction mixtures by filtration.
Since the by-products remain in solution, the pigments formed
are produced in a state of ex~ellent purity. An after-
treatment us~ng organic solvents is advisable for pigments
which are obtained by the aqueous coupling route. A further
advantage of the process according to the invention is the
high yield, the advantage,ous form in terms of pigment techno-
logy and the constancy of the properties of the resulting
pigments.
The new colorants represent valuable, red pigments
which can be used in a finely divided form for pigmenting high
molecular organic material, for example cellulose ethers and
esters, such as ethylcellulose, nitrocellulose, cellulose
-- 7 --
- ~ 0 58 ~ ~ ~
acetate or cellulose butyrate, po~yamides or polyurethanes or
polyesters, natural resins or synthetic resins, such as poly-
merisation resins or condensation resins, for example amino-
plasts, particularly urea-~ormaldehyde and melamine-~ormal-
dehyde resins, alkyd resins, phenoplasts, polycarbonates, poly-
olefines, such as polystyrene, polyvinyl chlorlde, polyethylene
or polypropylene, polyacrylonitrile, polyacrylic acid esters,
rubber, casein, silicone and silicone resins, on their own or
as mixtures.
In this it is immaterial whether thehigh molecular
compounds mentioned are present as pla~tic compasitions ar
melts or in the form of spinning solutions, lacquers, paints
or printing inks. Depending on the application, it is found
advantageous to use the new pigments as t~ners or in the form
o~ preparations.
~ he dyeings obtained using the pigments according to
the inventi~n are distinguished by great depth of colour and
brilliance and ou-tstanding fastness properties to light and
migration and good heat-stability.
Compared with the most nearly comparable colorants,
which are described in German Patent Specification 921,223,
the colorants according to the invention are distinguished by
better fastness to migration and light and by a purer colour
shade .
~ n the examples which follow, unless otherwise speci-
fied, the parts denote parts by weight and the percentages
denote percentages by weight.
Exam~le 1
72.2 parts of the azo colorant obtained by coupling
-- 8 --
0~ 6
diazotised l-amino-2,5-dichlorobenzene with 2,3-hydroxynapn-
thoic acid are heated to 85C with stirring9 as a fine dis-
pérsion, mixed with 520 parts of o-dichlorobenzene. Subse-
quently, at ~O-90C, 32.7 parts of thionyl chloride are added
dropwise over the course of 10 minutes. The reaction rnixture
is heated further and is kept at 115-120C for 60 minutes.
kfter cooling to 20C, the azo colorant carboxylic acid chlo-
ride, which has precipitated in the crystalline state,
is isolated by filtration, rinsed with a li-ttle o-dichloroben-
zene and then with benzene, and dried at 70C in vacuo.
~ 7.95 parts of the carboxylic acid chloride thus
obtained are heated in 650 parts of o-dichlorobenzene to
100-110C, with stirring. A solution, heated to 120C,
containing 6.65 parts of 2-cyano-1,4-phenylenediamine in 195
parts of o-dichlorobenzene is now added over the course of
3 - 5 minutes. The mixture is stirred for 16 hours at 140-
145C. The condensation product formed is filtered off at
100C, rinsed ~irst with o-dicnlorobenzene heated to 100C and
then with methanol heated to 20C, and dried in vacuo at 100C.
The resulting produc-t has the following formula:
C1 ~ 1
N~
~ ONI~ HO~ ~
The organic pigment is a red powder which is very
sparingly soluble in organic solvents and ~hich is made into
_ 9 _
105~1~6
a fine dispersion which dyes poly~inyl chloride ~ilm in bril-
liant red shades o~ very good fastness to overlacquering,
migration and light.
Exam~es 2 - 10
The table which follows describes ~urther acid amide
derlvatives of azo colorants which are obtained when 2 mols
of the acid chloride of the monoazo colorant carboxylic acidJ
which is obtained by coupling 2 mols of the diazo compound of
~he amine indicated in column I to 2,3-hydroxynaphthoic acidj
is condensed with the phenylenediamine indicated in column II.
Column III indicates the colour shade of the polyvinyl chloride
films dyed using the colorants. The resulting pigments can
also be prepared without isolating the acid chloride mentioned
in Exarnple 1, it being advantageous to distil off any excess
of thionyl chloride which may be present.
Ex- I II III
ample Diazo component Phenylenediamine Colorant
.
2 1-Amino-2,5- 2-Methyl-1,4-phenylene- Bluish-tinged
dichlorobenzene diamine tinged red
_ _
3 ditto 2-Me-thoxy-1,4- Bluish-
phenylenediamine tinged red
. .
4 ditto 2-Nitro-1,4-phenylene- Red-brown
diamine
5 ditto 2-Methyl-5-chloro-1,4- Red
phenylenediamine
.
6 1-Amino-2-methyl- 2-Chloro-1,4-phenylene- Red
5-chlorobenzene diamine
_
7 ditto 2,5-Dimethyl-1,4- Claret
phenylenediamine
8 ditto 2-Methyl-5-chloro-1,4- Claret
phenylenediamine
-- 10 --
.. . . . . .. .
105~
Example 11
o.6 g of the pigment prepared according to Example 1
are mixed with 67 g of polyvinyl chloride, ~3 g of dioctyl
phthalate, 2 g of dibutyl-tin dilaurate and 2 g of titanium
dioxide and the mixture is processed on a roll mill for 15 min-
utes at 160C to give a thin film. The red dyeing -thus pro-
duced has a deep colour and is ~ast to migration, heat and
light.
Exam~le 12
10 g of titanium dioxide and 2 g o`f~ the pigment pre-
pared according to Example 1 are ground for 48 hours in a ball
mill together with 88 g of a mixture of 26.4 g of coconut alkyd
resin, 24.0 g of melamine-formaldehyde resin (50% solids con-
tent), 8.8 g of ethylene glycol monomethyl ether and 28.8 g
of xylene.
If this lacquer is sprayed onto an aluminium foil, pre-
dried at room temperature for 30 minutes and then stoved at
120C for 30 minutes, a red lacquering is obtained which is
distinguished by very good fastness to overlacquering, light
and weathering and has a good depth of colour.
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