Note: Descriptions are shown in the official language in which they were submitted.
~ ~3'~
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The invention provides azo compounds of the formula I
N02 N ~ CH3
ROOC~
X Y
in which R is an alkyl radical having from 1 to 4 carbon
atoms; X is hydrogen a chlorine or bromine atom, a methyl,
ethyl, methoxy or ethoxy group; and Y is hydrogen, a
methyl or ethyl group.
The invention provides furthermore a process for the
preparation of the cited azo compounds, which comprises
diazotizing compounds of the formula II
N02
ROOC ~ NH2 (II)
in which R is as defined above, and coupling the diazonium
compound obtained with a compound of the formula III
; H
~ N~ O (III)
X Y
in which X and Y are as defined sub formula I. ~-
. .
3'7
- 3
'rhe invention rela-tes furthermore to the use of the
azo compounds of the invention as coloring agents, especial-
ly as pigments.
As amines of -the formula II, there may be used for
example:
3-Nitro-4-aminoben%oic acid methyl ester,
3-Nitro-4-aminobenzoic acid ethyl ester,
3-Nitro-4-aminobenæoic acid-n-propyl-ester,
3-Nitro-4-aminobenzoic acid-isopropyl ester,
3-Nitro-4-aminobenzoic acid-n-butyl ester,
3-Nitro-4-aminobenzoic acid-isobutyl ester and
3-Nitro-4-aminobenzoic acid-1-methylpropyl ester.
lhe amine of the formula II can be diazotized for
example with alkali metal nitrites or lower alkyl nitrites
and sufficiently strong acids, especially a mineral acid,
but also nitrosulfuric acid. ~y "lower" in connection
with alkyl radicals, there are to be understood here and
hereinafter groups having from 1 to 6, especially 1 to 4
carbon atoms. It may prove to be advantageous to add
surfactants such as nonionic, anion-active or cation-active
dispersing agents in this process step as well as in the
subsequent coupling operation.
Examples of coupling components to be used are the
following:
5-Acetoacetylaminobenzimidazolone-(2),
5-Acetoacetylamino-6-chlorobenzimidazolone-(2)
5-Acetoacetylamino-7-chlorobenzimidazolone-(2)
5-Acetoacetylamino-6-bromobenzimidazolone-(2)
5-Acetoacetylamino-7-bromobenzimidazolone-(2)
5-Acetoacetylamino-6-methylbenzimidazolone-(2)
5-Acetoacetylamino-7-methylbenzimidazolone-(2)
5-Acetoacetylamino-6-methoxybenzimidazolone-(2)
5-Acetoacetylamino-7-methoxybenzimidazolone-(2)
5-Acetoacetylamino-6-ethoxybenzimidazolone-(2)
5-Acetoacetylamino-7-ethoxybenzimidazolone-(2)
5-Acetoacetylamino-1-methylbenzimidazolone-(2)
5-Acetoacetylamino-1-ethylbenzimidazolone-(2) and
5-Acetoacetylamino-1-methyl-6-chlorobenzimidazolone-(2).
7'~
4 --
Diazotization and coupling may alternatively be
carried out in the presence of suitable organic solvents,
for example glacial acetic acid, lower alkanols, dioxan,
formamide, dimethyl formamide, dimethyl sulfoxide, pyridine
or N-methylpyrrolidone.
In order to attain full tinctorial strength and an
especially favorable crystal structure, it is advantageous
in many cases to heat the coupling mixture for a certain
time, for example to boil it or to maintain it at a
temperature above 100C by applying pressure, optionally
in the presence of` organic solvents such as lower a]kanols,
for example ethanol, halogenated aromatic compounds such
as chlorobenzene, or dichlorobenzenes such as o-dichloro-
benzene, dimethyl formamide, or in the presence of resin
soap. ~specially pure pigments of high tinctorial strength
are obtained from the products of the invention when after
coupling the moist press cakes or the dried powders are
subjected to a thermal after-treatment with organic solv-
vents such as alcohols, especially lower alkanols, pyridine,
glacial acetic acid, dimethyl formamide, N-methylpyrroli
done, dimethyl sulfoxide, halogenated aromatic compounds such
as chlorobenzene, or dichlorobenzenes such as o-dichloroben-
zene or nitrobenzene, or when the pigments are subsequently
ground with addition of grinding auxiliaries.
The pigments may alternatively be prepared in the
presence of a carrier material, for example barium sulfate.
The novel compounds are water-insoluble and insoluble
in the usual organic solvents and they are suitable for
pigmenting printing inks, color varnishes and dispersion
paints, and for dyeing rubber, plastics and natural or
synthetic resins. They are especially suitable for those
varnishes and plastics which have to meet severe fastness
requirements. They are furthermore suitable for pigment
printing of substrates, especially textile fiber materials
or other flat structures such as paper. The pigments can
be applied also in other fields, for example, in a finely
disperse form, for -the dyeing of the spinning mass for
rayon made from viscose or cellulose ethers or esters,
5 _
polyamides, polyurethanes, polyglycol terephthala-tes or
polyacrylonitri]es; or for the dyeing of paper.
The pi~ments can be easily processed in the cited
media. The dyeings have a very good fastness to light and
weathering, and they are stable to influences of chemicals,
especially solven-ts. In varnishes, the pigments of -the
invention are furthermore fast to overvarnishin~, and in
plastics, they are fast to bleeding.
The following examples illustrate the invention; per-
centages being by weight.
~ X A M P L ~ 1:
_ _ _
10.5 g of 3-nitro-4-aminobenzoic acid ethyl ester are
suspended in 80 ml of glacial acetic acid, and stirred for
1 hour with 15 ml of 31 ~ hydrochloric acid. The bath is
then cooled to 8-10C, 10 ml of a 5 N sodium nitrite
solution are added dropwise, and stirring is continued for
a further 30 minutes.
12 g of 5-acetoacetylaminobenzimidazolone-(2) are
dissolved in 150 ml of water and 9 ml of 33 % sodium
hydroxide solution, and filtered after addition of 5 g of
kieselguhr. 1 g of a condensation product of stearyl
alcohol with 25 equivalents of ethylene oxide is added to
the filtered solution, and the coupling component is
precipitated by adding 6 ml of glacial acid in 50 ml of
water all at once. Subseqquently, 25 ml of a 4 N sodium
acetate solution are added.
The diazonium salt solution so prepared is added
dropwise at 25C within 1 hour to the suspension of the
coupling component. After coupling, the batch is heated
for 30 mintes to 95C, the product is suction-filtered,
washed with water until it is free from salt, and dried at
60-70C. The dry crude pigment is heated to 115C in
250 ml of glacial acetic acid, and maintained at this
temperature for 15 minutes. The orange colored pigment is
then filtered off, washed with methanol and water, and
dried. Yield: 20.2 g of pigment having the formula
3~7
- 6 -
N2 ~ CH~
C2H500C ~ ~ ~H> o
lI
X A M P IJ ~ 2
___ _
31.8 g of 40 % nitrosylsulfuric acid are added within
45 minutes to 19.6 g of 3-nitro-4-aminobenzoic acid methyl
ester dissolved in 200 ml of glacial acetic acid. 23.3 g
` of 5-acetoacetylaminobenzimidazolone-(2) are dissolved in
200 ml of water and 18 ml of 33 % sodium hydroxide solu-
tion. This solution and the diazonium salt solution are
added dropwise and simultaneously to a solution of 200 ml
of water, 12 ml of glacial acetic acid, 20 ml of a 10 %
aqueous solution of the condensation product of stearyl
alcohol with 25 equivalents of ethylene oxide, and 25 ml
of a 4 N sodium acetate solution. Coupling is complete
after 45 minutes. The mixture os heated to 95C,
maintained at this temperature for 30 minutes, and cooled
to 70C. The product is suction-filtered, washed free
from salt; the moist pressure cake is stirred with 600 ml
of 50 % isobutanol, and heated for 1 hour to 120C.
After having distilled off the isobutanol by means of
steam, the product os filtered and dried. Yield: 42.3 g
of a reddish-yellow pigment having the formula
~_ O~
H3COOC O N
H
-- 7 --
X A It~ P ~
10.5 g of 3-nitro-4-aminobenzoic acld ethyl es-ter are
stirred for 1 hour in 160 ml of glacial acetic acid and 30 ml
of 30 7~ hydrochloric acid. The batch is cooled to 10C,
and 10 ml of a 5 N sodium nitrite solution is added below
the surface. The diazonillm salt solution is stirred for a
further 30 mintes, and clarified by adding a small amount
of kieselguhr and filtering.
14 g of 5-ace-toacetylamino-7-chlorobenzimidazolone-(2)
are dissolved in 150 ml of water and 10 ml of 33 ~ sodium
hydroxide solution. The two solutions so prepared are
added dropwise and simultaneously at 10C to a solution
prepared frorn -the following components: 200 ml of ice-
water, 6 ml of glacial acetic acid, 10 ml of a 10
aqueous solution of the addition product of stearyl
alcohol with 25 equivalents of ethylene oxide, and 25 ml
of a 4 N sodium acetate solution. Dropwise addition takes
1 hour. After coupling, stirring is continued for 1 hour
at room temperature, the product os suction-filtered,
washed with water until it is free from salt, and dried.
The crude pigment is heated to 120C in 250 ml of
chlorobenzene, and maintained for 15 minutes at this
temperature. Subsequently, it is suction-filtered, washed
with chlorobenzene, methanol and water, and dried. Yield:
21 g of a reddish-yellow pigment having the formula
N2 N CH3
C2H500C ~ ~ N
Cl H
In the following table, there are listed further
examples of azo compounds obtained by coupling the diazoti-
zed aromatic amines (diazo components) of the formula II
with the coupling components of the formula III:
3'7~
-- 8 --
_ ._
~ . No. formula Il formula III Sh~de
X Y
, _ _ _ ____
4 CH3 6-Cl H yellowish oran~e
CH3 7-Cl .H yel:lowish orange
6 CH3 6-~Br H yellow
7 CH3 7-:E3r H reddish yellow
8 CH3 6-CH ~ II brown
9 CH3 7-CH3 H reddish yellow
CH3 6-OCH3 H yellowish brown
11 CH3 7-OCH3 H orange
12 CE-I3 6-OC2H5 H yellowish brown
13 CH3 7-OC2H5 H orange
14 CH3 H CH3 yellowish brown
C2H5 6-Cl H reddish yellow
16 C2H5 6-Br H orange
17 C2H5 7-33r H yellowish brown
18 C2H5 6-CH3 H brown
19 C2H5 7-CH3 H orange
C2H5 6-OCH3 H brown
21 C2H5 7-OCH3 H orange
22 C2H5 6-OC2H5 H brown
23 C2H5 H CH3 orange
24 C2H5 6-Cl CH3 brown
n-C3H7 H H reddish yellow
26 iso-C3H7 H H yellow
27 n-C4Hg H H reddish yellow
28 iso-C4Hg H H reddish yellow
29 ,CEI CH2 CH3 H H yellow
C~I3
n~C3~I7 7-Cl H reddish yellow
31 . _ rCl H reddish yellow
