Note: Descriptions are shown in the official language in which they were submitted.
The i~vention relates to stilbene dyestuffs and light-
polarizing films or sheets, containing stilbene dye-
stuffs.
Films based on polyvinyl alcohol (PVA) containing iodine
or dichroic dyestuffs as polarizing agents are known.
Un~il now, it has been v ry predomi~antly the iodine-
containing polarizers which have found industrial appli-
cations, for example in passive li~iid cry tal displays
for the visualization of information. In the ab~ence of
moisture, these polarizer are charactsrized by excellent
light fa~tness and outstanding dichroic properties in the
long-wave region of the vi~ible spectrum. The active
- agent of these films is the iodine/PVA complex (M.M.
Zwick. J. Appl. Polym. Sci. 9, 2393-2424 (1965)~, which
admittedly absorbs a wide band of the daylight spectr~m,
but not all of it. In the short-wave region, a "hole",
i.e. a region of diminished extinction, is present, which
is the rea~on tha the sh~ets have a characteristic blue
colour
~hi3 has disadvanta~eous con~equences, if it is desired
to produce white light. The light tran~mitted in unpolar-
ized form dimini~hes the dichroism and thus the polariæa-
tion psrfv~mance in this region. To increase it again, it
is nec~ssary to incr~ase the concentration of iodine
Z5 complex. HoweYer, ~his correction in ~he short-wave
region re~ult~ in sxaessive extinction in the long-wave
region. Thi3 leads to a si~nificant decrease of the
transmi ted light in the transmi~sion ~etting in combina-
tion with a decrease in the brigh~nes~ of ~he display
w~ich is equippsd with this sheet. To achieve acceptable
degxeeæ of brigh~ne~, compromiseR must be made.
Le A 26 ?60 - 1 -
~0~
An important critical parameter of a display is its
readability under various illumination conditions; it i5
usually stated as "perceived contras~ ratio (PCR =
Tl/T¦¦~; this ratio should be as large as possible. From
this follows that the transmission on the one hand has
to made as small as possible in the blocked setting (T¦¦)
(readability in the dark) and, on the other hand as large
as possible in the transmission setting (Tl) (readability
in the light). This reguires a very uniform polarizing
performance of the filter over the entire spectral range,
which can usually not be achieved by maans of the iodine
sheet.
There has not been a lack of attempts to replace iodine
by dyestuff triples of dichroic dyestuffs ~o produce a
neutral grey colour having a uniform dichroism.
However, this requires a range of high-performance
dyestuffs. In addition ~o good light and weather fast-
ness, they must have a high extinction and a high
dichxoism in ~he matrixt in addition, they must not have
secondary densities which have lower dichroism. Thus,
preferably polyazo dyestuffs have been proposed
(~A 59/145,255, JA 60/156,759, JA 60/168,7433. However,
althouqh dichroism i~ a wide-spread property with dye-
stuffs (cf. W. ~anle, H. Scherex, %eitschr. Naturforsch.
6a, 437-439 (1951)), it haæ sofax not been possible to
achieve or surpass the ~pectral properties sf the iodine
~heet. This can be attributed, on the one hand, to the
lack of good blue shades, and, on the other hand, to he
requirement of high dichroism o~ the system dyestuff/
matrix.
Surpri~ingly, it ha~ now been found that certain novel
stilbene dye3tuff~ have excellent dichroic proper~ies and
ars highly suitable for the production of
Le A_26 260 - 2 -
ligh~-polarizing films or sheets.
(In what follows, a definition of a radical or index once
given is maintained in the further text).
The invention accordingly relates, in one aspect, to
S dyestuffs which, in the form of their free acid, conform
to the formula
x ~ H-CH ~ ~ Y
503H
in which
X, Y signify -N=N-R, -C~3, -CONH2, -CONHRl, -CONRlR2,
-COOH, -COOR1, -CN, -NO2, -NHz, -NHRl, -NRlR2, -OH,
-ORl, -R1CONH-, -O-CO-R1
halogen or a substituted or unsubstituted hetero-
cyclic radical, with the proviso that at least
one of the radicals X~ Y represents -N=N-R, in
which
R represents an aryl or a heterocyclic radical and
Rl, R2 represent alkyl, cycloalkyl, aryl or aralkyl,
which may be interrupted by O and/or S,
and in which furthermore the radicals mentioned for R, R1
and R2 can be substituted, the dyestuff which, in the form
of its free acid, conforms to the formula I where
H2N OH
= Ho35~3N-N~N=N-
H03s
Le A 26 260 - 3 ~
H2N CH
and Y = H035~N=N~-N-
HO35
being excepted and the azo dyestuffs containing a maximumof eight azobridges.
In particular, R signifies an aromatic radical from the
benzene or naphthalene series, ~rcS2rably of the formula~
R4 R7 R8
RS ~ ~6
in which
R3 si~nifies H, OH, -ORl, -NH2, -NHRl, -N~lR2,
-NH-CO~1, -O-CORl~ -N=N=Rll, a heterocyclic radi-
- cal~ :
R4, Rs, R7, R8, R9, Rl signify H, halogen, -OH, -ORl, -NH2,
-NHRl, -NRlR2, Rl, -SO3H, -SO2-NH2, -SO2-NHRl,
-SO2-NRlR2, -O-CO-Rl, -NH-CO-Rl,
R6 signifies H, -N=N=Rll, a substituted or unsub-
stituted heterocyclic radical and
Rll signifies a substituted or unsubstituted aryl
radical, preferably a substituted or unsubstitut-
ed phenyl or naphthyl radical or a substituted or
unsubstituted heterocyclic radical
or a nitrogen-containing heterocyclic radical.
,:
Preferred radicals R and R11 of the benzene series are as
follows:
.,
Le A 26 260 - 4 -
,
, . .
4~
R4 R3
~ R3 , ~
In particular, suitable radicals are those which are
derived from phenol and its substitution products, if
appropriate subsequently alkylated or acylated, and from
aniline and its substitution product also, if appropri-
ate, subseqllently alkylated or acylated. Examples are:
H, ~ CH~, ~ C2H5,
-CH2-CH2-OH, ~ H , ~ H ,
S03H SO3H
: ~ NH2~ ~ ~CH3 ~ ~CH3
CH3 CH2-CH2-OH
\CH2-CHz-OCH3 ~N~CH3
~N~ ' ~3N _ N _ R l 1 ~N = N _ R l 1
.
CH~ OCH3 CH3
=N_Rl 1 ~N-N-Rl 1 , ~N=N-Rl 1, -
CH~ CH3 OCH3
OCH3 OH
~N=N Rl 1 , ~N=N_Rl 1, ~
OCH3 HN~ 503H
COCH3
.
Le A 26 260 - 5 -
,. . . .......................
Preferred radicals R and R11 of the naphthalene series are
listed below:
R 1 2
Y~
Rl2 = -OH, -NH2
~ 1 0
~8 ~ 9
R13 is H, if R14 = -N=N-R11 or H, and is -N=N-R11, if
R14 = -OH, -NH2,
R14 is -OH, -NH2, -N=N-R11,
R17
1S ~ ~14
~R6 ~<
~ R6 ~ 16 R15 ~ R16
Rl5, Rl6 are H, -OH, -OR1, -3-CORl, -NH2, -NH-Rl, -NHRlR2,
-NH-CO-R1, -SO3H,
R17 is H, -SO3H.
In particu}ar, the ~ollowing radicals R and R11 of the
naphthalene seriss are preferred:
OH OH R15
B
~lB i5 H, OH, N~2, -NH-CO-R~, -NH-R1, -N=N-R~l, -S03H,
h~ ZE~ - 6 -
R20 R2 1 R20
~=19,~, 50 .H
503H SO ~H H035 ~ 21 Rl9
R
Rl9 is H, -N=N-Rll,
R20, R21 are OH, NH2, -O~CO-Rl, -NH-CO-R1,
OH OH ~20 CH Rl 7
, ~,~ = Rl ' `~
S03H 53~ 503H
Preferably, R ~nd R1l are derived from the (substituted)
S I acid:
: OH
R22 is -NH-Rl, -NH CO-R1, -N=N-R
~03S R22
: PrefPrred radicals X, Y, R3 and R5 of the heterocyclic
~: series have the formula
~: Rl9
-X Z
: in which
~ is a C or an N atom, where the free valence of
carbon has been saturated by a double bound, and
Z represents the remaining members of a preferably
~: 5- or 6-membered monocyclic or bicyclic or
tricyclic ring
15 which can contain 1 to 3 hetersatoms from the series con-
sisting of ~, O, S and i5 subatituted or unsubs~ituted.
Le A 26 260 - 7 -
~ ~ '
~o~
In particular, they are derived from the following
heterocyclic systems:
triazole, pyrazole, ben~otriazole, naphthotriazole,
oxazole, imidazole, thiazole, oxadiazole.
Preferred radicals R and R11 of the heterocyclic series
have the formula R19
-C Z
in whicn
Z represents the remaining members of a preferably
5- or 6-membered monocyclic or bicyclic or
tricyclic ring,
which can contain 1 to 3 heteroatoms from the series con-
sisting of N, O, S and is substituted or unsubstituted,
the free valence of carbon being saturated by a double
bond.
In particular, R and R11 are derived from the following
heterocyclic systems (coupling components):
thiophene, triazole, pyrazole, pyridine, benzotriazols,
pyridone, naphthotriazole.
In addition, Rll is derived from the following hetero-
cyclic systems (diazo components)-
thiadiazole, thiazole, benzothiazole.
Suitable het~rocyclic radicals R and R~l are in particular
a ~ubstituted 5-amino- or 5-hydroxypyrazole radical.
Further preferred radicals R ~nd Rll are those of the
formula:
-~-A-N=N-)p-L
k~ h_~Q - B -
in which
A is a substituted or unsubstituted phenylene or
naphthalene radical,
L is a substituted or unsubstituted phenyl or
naphthyl radical and
p is 1, 2, 3.
In particular, A represents
R4 R7 R8
R5
and L represents
R5 R7 R8
Examples of radicals R and Rll are:
SO3H OH
HO ~ , CH30 ~ , ~ J H3C ~ CH~ !-
OH CH3-CO-NH OH
~ONH~- ~O~'i, ~503H, `-
S03H
_'H3-CO-NH OH OH
~503H, CH3-CO-NH ~ 503H ,
~e A 26 260 - 9 - ?
, :.
O-,~H OH Cl ~ ~ O-,~jlY. OH
~ ~ 503H, ~ 503H~
C03H
OH OH
;G -
S03H
S03H
.~03f OH H03S OH
~2'~ ~ ~ ' . ., ~J
¦ ~ ~ O-.~H
503H ~ _ ~ S03H
-CO-NH OH CH3-CO-NH OH
H03s- ~503H, Ho3s~3~\503U,
. OH OH
3 h'~ " ~ 503H O-NH ~ 503H
OH NH2 OH
r H 3 - C O - !`1 H ~ ,~,~
503H
S03H
NH2 OH
~ 1 9H
'~35~-'~ ~ O-NH ~ 503H
S03
~4 o~
.o~
~ 21
L~ A 26_26~ - 10 -
R20, R21 are H, C1-C4-alkyl (methyl), C1-C4-alkylcarbonyl,
in which alkyl can be substi uted by -OH, OAlk,
CN or are (2-hydroxyethyl, 2-cyanoethyl), phenyl,
benzyl, benzoyl which can be substituted by -NO2,
S-OH, Cl-C4-alkyl (methyl), halogen, -SO3H, -COOH,
_ ~ r. ~ I
R~N-~. I ~ ~R21
~7 o~y
N=~ `~'~
,yo35J~N~
~ S O 3H ) n
n is 0, 1 or 2
R7 OH
~$ N= ~ ~ N
H03S
50~H)n
.Y N H 2
\~=-N-RI I
HO~S
503H
OH NH2 OH
.~03S X ~ ~ ;N-R11 ~ ~ ~S03H
NH2
OH NH2
S~3H ~ 03H
.~03S N_N~ 03s i N
e A 26 260 ~
41~
'H _C~H OH
!~ ~X~,
03H N=,~ Rl 1 HO3S N-N_Rl 1
OH
~,C.Y ~ 10CH3
~N = ,~ ' 1 ~0~ N = N - R ! 1
OCH
CH
~ 3
CH3~N=N-R1 1 ' ~N=N-Rl 1
CH ~
OCH3 ICH3
=N_RI ~ `$N=N_Rl I
CH 3 OCH
:~
Le A 26 260 - 12 -
. , ' ' ' '' " ' .
2 ~
J~l R 2 4
R ~ 2
R23 is H, Cl-C4-alkyl (methyl), -COOH,
R24 is a substituted or unsubstituted aryl radical,
preferably
~ So~H, - ~ j ~ S3
-~ ~ N=N-~ ~ 503H
The radical R pxeferably contains 0, 1, 2 or 3 azo
groups.
Preferred are compounds of the formula I in which
X=Y=-N=N-R.
Halogen (X, Y~ preferably repr~sen s F, Cl, Br, I.
He~erocyclic radicals (X, Y) are preferably derived from
a 5- or 6-membered heterocycle which contains 1 to 3
heteroatoms from the series Consisting of N, 0, S, for
example triazole, pyrazole, oxazoler imidazole, thiazole,
oxdiazole, thiadiazole,;benzothiazole.
Alkyl (Rl, R2) preferably represents C1_CB_a1kY1 ~methyl,
ethyl), cycloalkyl (Rl, R2) preferably represents C3-C7-
cycloalkyl (cyclopentyLI cyclohexylj.
Aryl (Rl, R2~ praferably represents phenyl and naphthyl.
Aral~yl (Rl, R2) preferably repxesents phenyl-Cl-C4-alkyl
~benzyl, phenethyl).
Suitable substituents for the alkyl and cycloalkyl
radicals (Rl, R2) are, for example, halogen ~Cl, Br, F),
-0~, -CN, C1-C4-alkoxy and the like.
Suitable subs~ituants for the aryl and aral~yl radicals
I.e A 26 2~0 - 13 ~
,
' :
(R1, R2) are, for example, haloyen (Cl, Br, F), -OH, C,-C4-
alkoxy (methoxy), C,-C4-alkyl (methyl), CF3, NO2, CN.
Compounds I can be prepared in analogy to processes known
from the literature. Compounds II to V, th~ preparation
of which is illustrated below, can serve as starting
material.
CH3-C0-NH ~ H-0 ~ H3C ~ ~ N02
503H
C.~! 3 - C C - ~IH~H - C H~}No 2
/ 503H
HCl ~ (II)
H2~ ~ H=CH ~ No2 NaHS
S03~ ~
~III) CH3-C0-~H ~ ~ H=CH ~ NH2
\ NaHS HCl 503H
( I V )
H2N ~ } CH=CH ~ 3 ~H2
SO~H
( v )
- ~urther possible syntheses of these and similar suitable
intermediates for the synthesis of dyestuff can be found
in DOS (German Patent Specification~ 3,805,513; see in
p~rt~ular Example 2 and Example 2ter.
~he ~yn~hesis of the dye~tuff from these compounds is
carried out in the usual manner by diazotization and
coupling onto sui~able coupling components.
- Compound III i~ diazotized, and the product is
Le A 26 260 - 14 -
.
.
,
L4
coupled onto components such as phenols, aniline~,
(aminohydroquinone dLmethyl ether~, benzoyl I acid,
acetyl gamma-acid, N-(4-sulphophenyl~-5-pyrazolone
etc. The phenolic OH groups of th~ products from the
phenol couplings can then be sealed ~y alkylation.
The free amino groups of the product from the
aniline couplings can again be diazotized, and the
product again be coupled onto phenol~, anilines,
benzoyl I acid, acetyl gamma-acid etc. Finally, the
nitro group on the dyestuff can be reduced, and the
free amino group can be coupled onto the coupling
components mentioned, which makes it possible to
prepare "unsymmetrical" compounds.
The free amino groups from the aniline coupling or
the reduction of the nitro groups can also bs
acylated, for ex~mple with benzoyl chloride.
- Compound (IV) is diazotized and coupled onto
components as phenoles, anilines (aminohydroquinone
dimethyl ether), benzoyl I acid, acetyl gamma-acid,
acetyl H acid, N-(4'-~ulpho-diphenyl)-5~pyrazolone,
etc. The phenolic OH group~ of the products from the
phenol couplings can then be se~led by alkylation.
~he free amino group~ of the products from the
aniline couplings can again be diazotized, and the
product again be coupled onto phenols, anilines,
be~zoyl I acid, acetyl gamm -acid etc. Finally, the
acetylamino group on the dyestuff can be cleaved,
and the free amino group ~an be coupled onto the
coupling component~ mentioned; thus, it i8 possible
al~o to prepare the derivative~ which, with respect
to ths position of the ~ulpho group~, are isomers
to those prepared frsm ~III). The free amino gxoups
from the aniline coupling or the cleavage o the
Le A 26 260 15 -
^- 2~0~i4~4
acetylamino group can also be acylated, for example
with benzoyl chloride.
- Compound (v) can be tetrazotized, and the product
can ~e coupled onto the abovementioned coupling com-
ponents. The phenolic OH groups of the products from
the phenol couplings can then be sealed ~y alkyla-
tion. The free amino groups of the products from the
aniline couplings can again be diazotizedJ and the
product ag~in coupled onto phenols, anilines,
benzoyl I acid, acetyl gamma-acid etc., and they can
also be acylated, for example with benzoyl chloride.
- The amino groups of the monoamino compounds III
and IV can be conYerted to the corresponding halo-
gen, CN, OH compounds ~tc. according to Sandmeyer
or, for example, to various d rivatives (triazole,
pyrazole etc.). After reduction of the nitro group
or hydrolysis of the acekylamino group, the mono-
amino compound~ obtained can be coupled to giv~ azo
dyestuffs.
20 ~ - Diamino compound V can be condensed with azodye-
stuffs which contain a nitro group, preferably in a
4-po~ition with respect to an azo group, to form
azoxy bridges, which can subsequently be reduced to
azo bridges ~ treatment, for example, with glucose.
Likewi~e, 4,4'-dinitros~ilbene-2-~ulphonic acid
~Preparation see DOS ~erman Patent Specification)
3,805,513, ExampIe ~) can be Gonden~ed with azo
dye~tufs which contains an amino group, preferably
in the 4 po~ition with~respect to an azo group, to
~orm a~oxy bridges, which can likewi~e be reduced to
azo bridges.
In ~ further aspec~, the invention relates to light-
Le A 26 260 - 16 -
4~
polarizing film~ (sheet~) which contain an organic
polymer and one or more compounds of foxmula I.
The organic polymer is preferably an oriented polymer
which forms transparent films and i6 compatible with
S dyestuffs which contain~ acidic groups. Examples of such
a polymer are: liquid-cry~talline polymers, for example
based on polyesters, polyamides, cellulose aceta~e, vinyl
alcohol homopolymers and copo].ymers and vinyl acetate
homopol~mers and copolymer~, where the comonomer~ present
can b~, for example, èthylene, propylene, cro~onic acid,
(meth)acrylic acid, maleic acid. Polyvinyl alcohols which
have been prepared by complete or partial hydrolysis of
polyvinyl acetate, in particular those types which have
a viscosity of > 4 mPa.sec2, preferably 20 to 70 mPa.sec2,
at 20C in 4~ strength a~ueous solution and a hydrolysis
degree of > 8Q mole %, preferably 85 to 100 mole %, are
preferably used. The films preferably have a thickness of
10 to 150 ~. Preferably, those sheets are u~ed which ha~e
stretched at room temperature or elevated temperature,
preferably at 80 to 160C, by 200 to 1000 ~.
The films preferably have a thickness of 10 to 150 ~. The
films preferably contain 0.01 to 10 % by weight, parti-
cularly preferred 0.5 to 6 ~ by weight, relative to the
weight of the film, of the dyestuf~ or the dyes~uff
mixture. The films are coloured in the u~ual manner, fsr
example by colouring the polymer which is dissolved (in
water). It i~ recommended ~o fre0 the dye~tuff~ or dye-
stuff salta be~ore use sf foreign salt~, or ex~mple by
recry~tallization, ex~raction and/or dialysifi.
Ths dichrolsm of tha ~y~tem can be con~idar~bly enhanced
by addition of polyhydric alcohols, ~uch as glycol,
glycerol, diglycol, trimetholetha~e, trLmethylolpropane,
pentaerythritol, ~orbitol~ their ethers, ~uch as glycol
Le A 2_6 260 - 17 -
monomethyl ether, glycol monoethyl ether, glycol dLmethyl
ether, di~lycol diethyl ether, hydroxy amine~, such as
propanolamine or amides, such as DMF, N-methylpyrroli-
done, pyrrolidone, e -caprolactam, to the casting solu-
tion. The additives can be used alone or, more advantage-
ously, in mixtures, in which lower monohydric alcohols,
for example methanol, ethanol, propanol, i-propanol, can
also be pxesent as components of the mixture. The addi-
tives are added to the casting solution in amounts of 1-
50 % by weight, relative to the casting solution.
The film is produced in a manner known per se from the
solution by casting.
If desired, the dyestuff-containing ilms can also be
sub~ected to an aftertreatment, for example with aqueous
boric acid solution, in order to improv~ ~he light
permeability or the polarization coefficient. The condi-
tions under which this aftertreatment iæ carried out can
~ary, depending on the film material and dyestuff.
Preferably, a 1 15 % strength by weight, particularly
preferably a 5-10 % strength by weiqhtl boric acid
~olution i8 used at 30-80C, particularly preferably at
50-~C.
Preferablyr 6urfactants and, if desired, inorganic salts
are added to the boric acid solution. The ~urfactants can
be nonionicl cationic or anionic; preferably, they are
nonionic. Example~ of nonionic ~urfactant~ are: addition
products o~ e~h~lene oxide with higher alcohols or addi-
tion products of ethylene oxide with nonylphenol. Prefer-
ably, 0.005-0.5 % by weight, particularly preferably
0.02-0.2 % by w0ight, of surfactant i8 used, relative to
the water.
Suitable inorganic ~alts are preferably sodium sulphate
Le A 26 ?60 - 18 -
and furthermore potassium sulphate, sodium chloride,
potassium chloride, sodium nitra~e, potassium nitrate.
Relative to the water, preferably 0.1-5 % by weight,
particularly preferably 0.3-3 % by weight, of inorganic
salts are used. If desired, this can be followed by a
fixation treatment with an aqueous solution of a high-
molecular weight cationic compound.
The light-polarizing films or sheets can be compounded or
laminated with other materials in a manner known per se.
Examples of suitable protective coatings are sheets made
of a tetrafluoroethylene/hexafluoroethylene copolymer or
another fluorohydrocarbon resin, a polyester, polyolefine
or polyamide resin,a polycarbonate or cellulose ester,
preferably cellulose triacetate, cellulose tripropionate,
cellulose tributyrate.
Besides being used in light-polarizing films, the dye-
stuffs of the formula (I) can be used alone or in mix-
~ures for rendering ordered structures visible in the
analysis of polymers and in biological material.
Example 1
a) Synthesis of the dyestuff:
R-N=N ~ H-CH ~ N=N-R
503H
OH
3CONH~ 503H
29 g (0.1 M) of 4,4'-diaminostilbene-2-sulphonic acid
(prepared according to DOS (Germa~ Patent Specification)
3,805,513, Example 3) are ~u~pended in 1 1 of water.
e A 26 260 - 19 -
4~L~
83 ml of concentrated hydrochloric acid are added and
51 ml (0.22 M) of ~odium nitrite solution las an ~pproxi-
mately 30 % strength ~olution) ar~ added dropwise slowly
at room temperature. The suspension is stirred overnight.
After this time, it should be possible to detect a
nitrite excess which is destroyed by the addition of
sulphamic acid solution. This tetrazonium salt solution
i~ ~lowly added dropwise at room temperature, while
controlling the pH, to a solution of 69 g (0.2 M) of
l~hydroxy 6-ben~oylaminonaphthalene-3-sulphonic acid in
0.5 1 of water, the pH being maintained between 6.5 and
7 by dropwise addition of 10 per cent strength ~odium
hydroxide æolution. After ~tirring overnight, the preci-
pitated dyestuff i~ filtered off wi~h suction and washed
several times with small portions of water. The dyestuff
i~ then di~solved in water and subjected to dialysis, to
separate off salt~; the dye~tuff solution obt~ined is
then evaporated, and the residue is dried. Yield: 95 g.
.
b~ Manufacture of the sheet
9.9 g of ~MOWIOL 28-99 (hydrolyzed polyvinyl acetate;
degree of hydrolysis 99.4 + 0.4 mole %; vi~cosiky of the
4 % strength of aqueous solution at 2DC:28 + 2.0
mPa.sec2; from Hoechst A~) and 0.1 g of the dy0 of Example
la are di~olved in 190 ml of water by hea~ing ~he
mixture at 9~C for 2 hours with ~tirring. 5 g of methan-
ol and 2.5 g of glycerol are added to 92.5 g of the 1 ~
strength, relative to the polymer, dye~tuff solution
o~tained. By mean~ of a knife, 50Q ~ thicX lay2rs are
applled ~rom thi~ ~olutlon to a clean glassplate, and the
l~yers thu~ obtained are dried in air at room ~emperature
on a support i~ an exactly horizontal position. The
resulting dry ~heets are peeled off from the gla~splate;
~hey have a violet colour and are about 40-50 ~ ~hicX.
Le A 26 260 - 20 -
Z E30641
c) Stretching of the sheets
To produce dichroic properties, the sheets are stretched.
To this end, th~y are heated in a drying cabinet at a
constant temperature of 130C for 15 minute~ and then
stretched at a speed of about 10 cm/min to about 700 % of
their original length. The stretched sheets have a
dichroic ratio of about 43 at the absorption maximum (570
nm~, measured with polarized light; losse~ due to reflec-
tion are not taXen into account in the measurement.
d) Sheet manufacture on the casting machine
O.2 g of the dyestuff of Example la is dissolved in
100 g of hot water. 10 g of glycerol are added, and
19.8 g of ~NOWIOL 28-99 are stirred into the cooled
so'ution. After stirring at room temperature for 1 hour,
the mixture is heated to 90C, and stirring is continued
at this temperature until, after about 3 hour~, a homoge-
nous solution has been formed. At 50C, 5 g of methanol
are then stirred in. The warm solution i~ filtered
through a filt~r pre~, while injecting air, and i8 then
~0 degas~ed by evacuation. The casting solution i~ pourable
and stable at 30~C.
To produce a sheet, the casting solution is applied
continuou~ly by means of 250 ~ knife to the casting wheel
~wheel diameter 25 cm, rotating speed about 7.5 min per
revolution) which has been preheated to about 50~C. The
la~er i~ dried by pa~ing heated air over it, and the
solidified sheet i~ continuou31y peeled off ~he wheel and
additionally dried. The sheet obtained i~ about 40 ~
~hick. It i~ ~retched as described above in c), leading
to similar result~.
e) Rxactly analogou~ly as in Example la, analogous
Le A 26 260 - 21 -
dyestuffs are obtained by using the coupling components
mentioned (the lina -- denotes in each case the coupling
site), which are incorporated into sheets according to
lb. Stretching according to lc gives dichroic sheets.
OH
rH~-CO-NH SO~H
011
,~J
S03H
OH
HO~S
OH
HO ~S S 03H
N~2 OH
.
HO~S~
503H
Le A 26 260 -- 22 -
Further dyestuffs are prepared analogously to Example la
from the following coupling componentsO
OH OH
H035 ~ ~ ~ ~ NH ~
503H S03H
`H3C-CO-NH OH
.~O~
/ H03S 503H
503H
Cl ~ O-NH OH
0.'1 1 1 ,
H03S S03H
CO-NH S03H
OH H~C CO-NH OH
NH SO~H S03H 503H
OH ~ O-NH OH
CH3 ~NH S03H S03H S03H
Le A 26 260 - 23
-` ZÇ~ 4
OH
~ = CH33~
NH 503H NH2
CH2 - CH2 - CN
. ~
OH ~=~0 - NH O.Y
CH 3 - CO - N !t~ [~
5031t
50~H
OH OH
~O-NH~r ~ ~'1SO3H
503H <~CO-NH
HOOC~_N
$~N - N~3s03 H
OH
HOOC`~=N
~N ~ 35 0 3 H
OH
~0~
OH
C O - N~ 5~ --
S03H 53
Cl
24 --
200G414
HO ~G~S ~1
NH2 ~ o--NH
503H '==~ SO~H
The products obtained from the coupling onto phenols can
be ~sealed~ by subsequent alkylation, for example methyl-
ation using dimethyl sulphate.
Example 2
a~ 17.3 g (0,1 M) of 4-aminobenz~ne sulphonic acid are
dissolved into 200 ml of water in combination wi~h
about 7 ml of sodium hydroxide solution (45 %
strength) and 2~ ml of concentrated hydrochloric
acid are then added all at once. The freshly precip-
1~ itated ~uspension is diazo~ized at 5-10C with 7 g
of sodium nitrite in 15 ml of water. After 15
minutes, the product is'filtered off with suction
and washed on ~he filter with icewat r. The moist
product is immediately stirred into 100 ml of water
(caution: the dry product is explosive). To the
suspension of diazonium salt thus obtained is added
dropwis~, with vi~orous stirring, a cold solution of
- 34.1 g (O.l M) of 8-amino-1-hydro~y-naphthalene-3,6-
disulphonic acid monosodium salt and 5~5 g of sodium
carbonate in 100 ml of water over a period of 45
minutes. The mixture is stirred for 12 hours while
waxming to room temperature, the product is filtered
off with suction and washed neutral. This gives a
dyestuf~ paste of *he formula:
~e A 26 260 - 25 -
. .
NH2 OH
Ho35 ~ N- ~
H035 SO~H
b) The dyes~uff paste from a~ is dissolved together
with 40 g of sodium carbonate in about 500 ml of
water, if necessary with heating, and ~hen coolad to
below 10C. The tetrazonium salt solution from 14.5
g ~0.05 M) of 4 ~ 4 ' -diaminostilbene-2-sulphonic acid
prepared according to Example la is added dropwise
to the suspension obtained over a period of 30
minute~, while maintaining the pH at 6.5 to 7 by
metering in 10 per cent s~rength of sodium hydroxide
solution. The mixture is stirred overnight, the
dyestuff is filtered off with suction, washed
neutral with water and then dissolved in water and
dialyzed to separate off salts. The dyestuff 501u-
tion is evaporated and the residue is dried. The
: 15 dyPstuff obtained has the structure: -
R-N=N ~ H=CH ~ N=N-R
S03H
NH2 OH
-- R = ~ ~
H~S H03S 503H
c) The following coupling componPnts which can be
prepared ~nalogously to 2a) can also be used:
A 26 ?6~ - 26 -
NH2 OH
HO3S ~ / - < ~ N=~
H035 503H
NH2 OH
H03S ~ N=N ~ N=N ~,
~\ .
H03S ~C3H
~Hz OH
HO 3 S{~N = N\~-
¦503H
lH2
H035 ~ / ~ ~ 503H
H035 ¦'
OH
OH
H3S~N=~so3H
_ H03$
OH
NH2
~O~S ~ N- ~ 503H
~3S
NH2
la A 26 260 - 27 -
; '
d) Exactly analogously, the dyestuff of the structure:
R-N=N~H=CH~3 N=N-R
S03H
CH NH 2
~03S HO~S S03~
is obtained by coupling the tetrazonium salt solu-
tion of ~xample l~ first ~t a-p~ of 4.5-5.5 onto 1-
hydroxy-8-aminonaphthalene-3,6-disulphonic acid and
then coupling the diazonium compound from 4-amino-
ben~ene sulphonic acid prepared according to Example
2a twice onto the product at a pH of 7-7.5.
_The other components mentioned in c) can also be
reacted in reverse order to give analogous dye-
stuf~s.
Example 3
a~ At a maximum temperat~lre of 10C, a ~olution of
30.6 g ~O.2 M) of 2,5-dLmethoxyaniline in 500 ml of
water (to which concentrated hydrochloric acid is
added until a clear solution is fonmed) is added
dropwise to-the tetrazonium salt solution prepared
according to Ex~mple la, with stirring, while
maintaining a p~ of 3 to 4.5 by simultaneous meter~
ing in of sodium hydroxide ~olution. After stirring
~ralgh~ and warming to room temperature, the
coupling reaction i8 comple~ed. The product is
filtered off with ~uction and carefully washed
neutral with water. ~he d~estuff obtained after
drying weighs 57.2 g and ha~ the formula:
~e P._6 26rJ - 28 -
~64~
R-N=N~H=CH~3N-N-R
SO3H
~ 3
R - H2N~
OCH 3
Instead of 2,5-dimethoxyanili~e, it is also possible
to use 2-methoxy-5-methylaniline, 2,5-dime~hyl-
aniline, 3-methylaniline, 3-acetylaminoanaline,
1-naphthylamine, 1-amino-2-ethoxy-naphthalene-6-
S sulphonic acid or anilinomethane sulphonic acid etc.
b) The intermediate product obtained in a) is tetrazot-
ized in aqueous hydrochloric acid with sodium
nitrite while letting it stand overnight at room
temperature r and the tetrazonium salt solution
obtained, after destruction of the nitrite excess,
is coupled onto 1-hydroxy-6-benzoylamino-naph-
thalene-3-sulphonic acid at a pH of 6.5 to 8. The
dyestuff obtained has the formula:
R-N=N{~CH=CH~N=N-R
SO3H
OH OCH ~
R = O--C0~ J~ OCH3
SO3H
d~ -- 29 --
c~ The other compounds mentioned in Example le and 2c
can also be used as components of the final coupling
reaction, and phenolic coupling components can
subsequently be "sealed" by alkylation.
The dyestuffs obtained are incorporated according to
Example lb into a sheet, which is subsequently
~tretched.
Example 4
a) 8.8 g (0.01 M) of the dyestuff from Example le
formed by coupling of the tetrazonium salt from la
onto 1-hydroxy-6-acetylaminonaphthalene-3-sulphonic
acid are stirred in 200 ml of 2N sodium hydroxide
solution at 80C until the acetyl groups have been
completely cleaved off (monitoring of the reac~ion
by thin-layer chromatography). The reaction mixture
is neutralized, cooled, and the residue is filtered
off with suction and washed neutral.
b) The dyestuff formed according to a) is dissolvPd in
100 ml of sodium hydroxide solution, 1.8 g of sodium
nitrite are added to the solution, and the solution
is then run into excess hydrochloric acid. After
standing overnight at room temperature, the tetrazo-
nium salt solution has been formed; excess nitrite
is destroyed by means of su~phamic acid, 2 y of
phenol dissolved in sodium hydroxide solution are
then added dropwis~, and the pH is brought to about
9 with sodium hydroxide solution. After stirring for
3 hours, the coupling reaction is completed. The
product is filtered off with suction and washed
neutral.
Instead of phenol, it is also possible to use the
~e A ~6 260 - 30 --
14
other coupling componen~s listed in Tables le and 2c
as Pnd groups.
c) The dyestuff formed according b) is dissolved in
100 ml of lN sodium hydroxide solution, and 4 g of
dimethyl sulphate are added to the solution with
stirring. Afer about 1 hour, the methylation is
completed. The producted is filtered off with
suction, washed neutral and dried. The dyestuff
obtained has the formula:
R-~=N ~ ~-CH ~ N-N-R
S03H
OH
R CH3 ~ N=N 503H
Instead of dimethyl sulphate, it is also possible to
convert the phenolic groups with diethyl sulphate or
benzyl bromide to the ethers.
Exam21e 5
a) The tetrazonium ~alt solution from Example la is
added dropwise at about 10C to the solution of
68.4 g tO.2 M) of l-hydroxy-8-acetylaminonaph-
thalene-3,6-disulphonic acid (mono~odium salt) in
;~ 0.8 1 of water, during which the pH is maintained at
6~5-7.5 by dropwise addition of 2N ~odium hydroxide
~olution. The coupllng reaction i6 then allowed to
go to completion overni~ht, whiIe heating to room
temperature. The ~roduct is filtered off with
suction, washed neutral with water and dried. Yield:
Le A 26 26Q - 31 -
~no~
60.5 g of a ~lue-~iolet soluble dyestu~f.
b~ 20 g of the dyestuff from a) are heated in 200 ml of
2N sodium hydroxide solution at about 80~C, until
the acetyl groups have been cleaved off. The mixture
is then acidified with hydrochloric acid, the pro-
duct is filtered off with suction, washed neutral
and dried. This gives 14 g of a dyestuff which, in
the form of the free acid, has the following for-
mula:
NH2 OH OH NH
= = N--~C H = C H~
S03H
H035 503H H03S SC3.
An analogous dyestuff is also obtained from 1-hydroxy-8-
acetylaminonaphthalene-3,5 disulphonic acid, followed by
clea~age.
The dyestuffs can be incorporated according to Example lb
into a s~eet, which subsequently is stretched according
to lc.
"UnsYmmetrical" dyestuffs
A suitable intermediate for the preparation of "un-
6ymmetrical" compounds is obtained analogously to the
data ~n German Patent 1,065,838 (Geigy) by replacing
benzaldehyde by 4~acet~1aminobenzaldehyde. Likewise, the
product described in DOS (German Patent Specification)
3,80~,~13 Example 2ter can be converted into a suitable
in~e~mediate by reduction of the nitrs group.
Lé A 26 260 - 32 -
~6~
Example 6
a) 4-nitro-4'-acetylaminostilbene-2-sulphonic acid:
45.6 g (O.28 M) of 4-acetylaminobenzaldehyde and
59.8 g (0.25 M) of sodium 4-nitrotoluene-2-sulphonic
acid are stirred into 90 ml of DMF, 9 ml of piperid-
ine are added to the mixture, which is then heated
at 140-150C for 3 hours. The volatile components
(piperidine and water) are then distilled off, 9 ml
of piperidine àre added to the residue, and the
-mixture is again heated at 140-150C for 3 hours;
this process is repeated once more. The DMF is then
distilled off in vacuo, and the residue is taken up
in 200 ml of hot water. After cooling, the product
is filtered off with suction, washed with a small
amount of water and dried: yield: 65 g (68 ~).
b) 4-nitro-4'-aminostilbene~2-sulphonic acid:
I9.2 g (O.05 M) of sodium 4-nitro-4'-acetylamino-
stilbene-2-sulphonic acid and 200 g of half-
concentrated hydrochloric acid are heated to reflux
until the starting material has been completely
converted according to the thin-layer chromatogram.
After cooling, the product i5 filtered off with
suction, washed neutral with small portions of water
and dried. Yield: 14 g (88 %).
c~ 16 g (0.05 ~) of 4-nitro-4'-aminostilbene-2-sul-
pho~ic acid (Example 6b) are suspended in 400 ml of
~ater, and 40 ml of concentra~ed hydrochloric acid
are added~ Diazoti~ation is carried out by dropwise
addition of 12.8 ~1 of 30 percent strength of sodium
nitrite solution (0.0~ M + 10 %~ at a maximum of
13C, and ~tirring i~ then co~tinued at about 20C
Le A 26 260 - 33 ~-
X~ 4
overnight. The nitrite excess is then des~royed by
addition of sulphamic acid.
The diazonium salt solution obtained is added
dropwise to a solution of 17.2 g (0.05 M) of
1-hydroxy-6-benzoylaminonaphthalene-3-sulphonic acid
in 160 ml of water at about 20C, during which the
pH is kept in the range from 7 to 8 by dropwise
addition of sodium hydroxide solution. After stir-
ring o~ernight, the precipit~ted dyestuff is fil-
tered off with suction, washed neutral with a small
amount of water and dried. Yield: 27 g (80 ~).
This gives a dyestuff of the structure:
OH
02N ~ H-CH ~ N=
503H
H03S NH-C ~
Exastly analogously as described above, an analogous
dyestuff is obtained by replacing l-hydroxy-6-
benzoylaminonaphthalene-3-sulphonic acid by 1-
hydroxy-6-anilinonaphthalene-3-sulphonic acid.
Further suitable coupling components are the ones
mentioned in the ~ables of Examples le and 2c.
d~ If the nitro group of the 4-nitro-4'-acetylamino-
~tilbene-2-sulphonic acid obtained according to a)
is reduced in aqueous ethanol with sodium sulphide
or analogously to the procedure in DOS (German
Patent Specification~ 3,805,513, Example 3, 4-~mino-
4'-acetyl~minostilbene-2-sulphonic acid is obtained.
Exactly analogously, it is also possible ~o prepare
Le A 26 260 - 34 -
z~
4-amino-4'-benzoylaminostilbene-2-sulphonic acid.
e) Diazotization of 4-amino-4'-acetylaminostilbene-2-
sulphonic acid in accordance with the procedure of
Example 6c, destruction of the nitrite excess with
S sulphamic acid, and coupling of the product onto 1-
hydroxy-6-benzoylaminonaphthalene-3-sulphonic acid,
while maintaining a pH of 7-8, gives a dyestuff of
the structur~.
~3'ri
H~, ~H-C!~_~ti-N~
S O ~ H /~\ ,~`~,
Y.O3S ,~U-CO--,~,
The corresponding dyestuff which has a benzoylamino group
on the stilbene radical is obtained analogously.
The other compounds mentioned in Examples le and 2c can
also be used as further coupling components.
Exampla 7
a) At a maximum temperature of 10C, a solution of
7.8 g (0.05 M) of 2,5-dimethoxyaniline in 125 ml of
water (to which concentrated hydrochloric acid is
added until a clear solution is formed) is added
dropwise to the diazonium salt solu~ion prepared
according to Example 6c, with stirring, while
maintaining a pH of 3 to 4.5 by metering in sodium
hydroxide solution. After stirring overnight, during
which the tempexature is allowed to rise to room
temperature, the coupling reaction is completed. The
product i8 filtered off with suction and carefully
washed neutxal with water.
Le A 26 260 - 3~ -
: ~,
4~4
Instead of 2,5-dimethoxyaniline, it is also possible
to use 2=methoxy-5-methylaniline, 2,5-dimethylanili-
ne, 3-methylaniline, 3-acetylaminoaniline, 1-naph-
thylamine, l-amino-2-ethoxynaphthalene-6-sulphonic
acid or anilinomethane sulphonic acid etc.
b) The intermediate obtained in a) is diazotized in the
form of a paste in aqueous hydrochloric acid with
sodium nitrite, the diazotization being allowed to
go to completion by standing overnight and warming
to room tempeature. Excess nitrite is destroyed by
means of sulphamic aci~.-
The diazonium salt solution is coupled onto 1-
hydroxy-6-anilinonaphthalene-3-sulphonic acid at pH
6.5 to 7.5. The dyestuff obtained has the formula
O~H3 OH
H-CH~ N ~ ~ N=:
SO3H OCH3
~O35 NH
It is also possible to use the other compounds
mentioned in Examples le and 2c as components of the
end coupling.
The same dyestuffs are obtained by following the
procedure in EP 160,113, ~xcept that the sodium 4-
nitro-4'-aminostilbene~2,~'-disulphonate used there
is replaced by 4-nitro-4'-aminostilbene-2-sulphonic
acid and the middle component (2-methoxy-5-methyl-
aniline) is chosen accordingly.
e A 26 260 - 36 -
- .
4~L
Example 8
a) The dyestuff of Exzmple 6c which still contains a
nitro group is reduced in an ethanolJwater mixture
with sodium sulphide or analogously to the procedure
in DOS (German Patent Specification) 3,805,513,
Example 3, to the amino compound. Another possible
reduction is that using iron powder in weakly acidic
aqueous medium according to Bechamp.
b) 16.1 g (0.025 M) of the dyestuff obtained in a) are
suspended in 300 ml of water, 20 r.l of concentrated
hydrochloric acid are added and the mixture is dia-
zotized by dropwise addition of 6.4 ml of 30 per
cent strength sodium nitrite solution (0.025 M +
10~) at a maximum of 10C, and stirrin~ is allowed
to continue overnigh~ at room temperature. The
nitrite excess is then destroyed by addition of
sulphamic acid.
The diazonium salt solution obtained is added
dropwise to a solution of 8 g ~0.025 M) of l-amino-
B-hydroxynaphthalene-2,4-disulphonic acid in 80 ml
of water at about 20~C, while maintaining the pH at
about 7. After stirring overnight, the precipitated
dyestuff is filtered off with suction, washed with
a small amount of water and dried. The dyestuff
obtained has the ~tructure:
R -.N-N ~ H-CH ~ N=N-R
SO3H
N~2 ~ OH
3~0~5~ ~Q
I HO35 NH-CO-~=~/
s~3~
Le A 26 260 - 37 -
It is also possible to use the other compounds mentioned
in Examples le and 2c as coupling components.
Example 9
a) 5 g tabout 0.05 M) of phenol are dissolved in 100 ml
of water with the addition of sodium hydroxide
solution, until ~ clear solution has been o~tained,
and the diazonium salt solution obtained in Example
6c is then added dropwise at about 10C, during
which a pH of about 9 is maintained by addition of
sodium hydroxide solution. After stirring overnight,
the mixture is neutralized, the precipitate filtered
off with suction and washed.
The moist paste is reacted analogously to the
procedure in Example 4c in aqu~ous alkaline solution
lS with dimethyl sulphate, until complete methylation
has taken place. This gives a dyestuff of the
structure:
~o ~ H=CH ~ N=N~ CH3
so3~
Analogously, it can also be reacted with other
- alkyla~ing agentsl for example diethyl sulphate or
benzyl bromide.
b) The dyestuff obtained in a) is reduced with sodium
~ulphide in ethanol and water or with iron powder
in weakly acidic medium to the amine. This amine is
diazotized analogously to Example 6c with sodium
~5 nitri~e, and excess nitrite is then destroyed by
means o~ sulpharnic acid.
Le A 26 ?60 - 38 -
The dia~onium salt solution obtained is coupled in
accordance with the further procedure in Example 6c
onto l-hydroxy-6-benzoylaminonaphthalene-3-sulphonic
acid at a pH between 7 and 8, which gives a dyestuff
S of the formula below:
r,y 3 -O~N=N~H=CH~N=N
S O ~H /~\
. .C 35 NH ~
It is also possible to use the other compounds mentioned
in Ex~mples le and 2c as componenLs of end coupling, in
particular acetyl I acid, phenyl I acid, Chicago acid SS
etc.
Example 10
a) 4-amino-4'-nitrostilbene-2-sulphonic acid
The compound is pxepared by claavage of the 4-
acetylamino compound analogously to Example 6b
described in DOS IÇerman Patent Specification)
3,805,513, Example 2ter.:
- b) Diazotization of the amino compcund prepared in 10a,
followed by coupling of the product onto l-hydroxy-
6-anilinonaphthalene-3-sulphonic acid analogously to
the procedure in 6c gives the following dyestuff:
OH
2 N~3~ H = C H~3N = ~
SO~H NH
Le A 26 260 - 39 -
Further suitable coupling components are ~he ones
mentioned in the Tables of Examples le and 2c.
The dyestuffs which are isomers with respect to the
position of the sulpho group are obtained analogous-
ly by following the procedures of Examples 6 to 9;
these dyestuffs have exactly analogous hues.
Condensation dvestuffs
Example 11
If the procedure of the examples in Houben-Weyl, Methoden
der Organischen Chemie (Methods of organic chemistry~,
Vol. 10/3, Part 3, P. 343 are followed and 1,2-bis(4-
nitro-2-sulphophenyl)ethylene is replaced by 4,4'-di-
nitrostilbene-2-sulphonic acid prepared according to DOS
(German Patent Specification) 3,805,513, Example 2,
mainly the yellow condensation product of the formula:
R-N=N ~ CH=CH ~ N=N-R
503
R = H035 ~ N=N ~
is obtained analogously to the description found there.
The reaction of 4-amino-4'-nitrostilbene-2,2~-disulphonic
asid descr~ed in J. Org. Chem. USSR 16 (1980) 388 is
applied to the monosulphon~c acid:
Le A 26 260 - 40 -
, ~ " ,
- 2~
a) 25 g (0.1 M) of copper ~2) sulphate pentahydrate are
dissolved with heating in 80 ml of water, and 15.5
g (0.15 M) of sodium bromide are added. A solution
of 6.3 g (O.05 M) of anhydrous sodium sulphite in
20 ml of water are slowly added to the solution with
stirring. After cooling, the precipitate is separa-
ted off by decanting, washed with water and then
dissolved in 40 ml of concentrated hydrobromic acid.
24 g (O.075 M? of the amine of ~xample 6b are
diazotized analogously to the procedure of Example
6c, except that ny~robromic acid is added inst~ad of
hydrochloric acid. The diazonium salt solution is
then stirred into the previously prepared above Cu
salt solution at 0C with stirring. The mixture is
carefully heated, which leads to the formation of
the SANDMEYER product with evolution of nitrogen.
After the evolution of gas h~s stopped, the result-
iny bromine compound of the structure:
02N ~ CH=Cff ~ 3 Br
503H
is precipitated by salting out, filtered off with
suction, washed and dried.
Exactly ~nalogously, it is also possible to prepare
the corresponding chlorine compound or the cyanide
instead of the bromine compound.
If the amine of Example lOa is used instead of the
amine of Example 6b and hydrochloric acid is used
instead of hydrobromic acid, the following compound
is obtained analogously:
_e A 26 260 - 41 -
"
o2N~3CH=C!~ 1
5O3H
b) The compound of Example 12a is reduced analogously
to the procedure in Example 9b to the amino com-
pound. This compound is converted into the corres-
ponding diazonium salt, for example as described in
6c, and then as also described in 6c, coupled onto
l-hydroxy-6~benzoylaminonaphthalene-3-sulphonic
acid, while maintaining a pH of about 7-8. This
gives the dyestuff of the structure:
OH
Br~H=CH~3N=`: ,~^q
HO 3S !`IH - C ~3
.
Further suitable coupling components are those
mentioned in Tables le and 2c.
c) If the procedure of Example 7 is repeated and the
diazonium salt solution prepared in 12b is used
instead of that used in 7a, and the product is first
coupled onto 3-methylaniline and ~hen onto 1-
1~ hydroxy-6-anilinonaphthalene-3-sulphonic acid, a
dyestuff of the structure:
OH
B r~;3~H = CH~3N ~ N~;3N = ~
S03H HO ~S Nlt~2
is obtained. _==,
Le A 26 260 - 42 -
~36~4
Further suitable coupling components are those
mentioned in Tables le and 2c.
Instead of 3-methylaniline, it is also possible to
use2,5-dimethoxyaniline,2-methoxy-5-methylaniline,
2,5-dimethylaniline, 3-acetylaminoaniline, l-naph-
thylamine, l-amino-2-ethoxynaphthalene-6-sulphonic
acid or anilinomethanesulphonic acid etc.
d) If the corresponding chlorine or cyano compound is
used in 12b and c) instead of the bromine compound
from 12a, analogous dyes~C r~ are obtained.
E~ample 13
Analogously to the procedures in Houben-Weyl, Methoden
der Organischen Chemie ~Methods of Organic Chemistry),
Vol. 10/3, Part 3, p. 428, 429, the compound of the
following formula is obtained ~y coupling of diazotized
-~-amino-4'-nitrostilbene-2'-sulphonic acid, see Example
~b, on~o l-aminonaphthalene-4-sulphonic acid:
~2N~;~H~CH~3 N~
SO~H
I~is reduced analogously to the procedu.re of Example 12b
to the amino compound.
The compound which is an isomer with respect to the
position of the sulpho group is obtained ~nalogously by
coupling onta 2-aminonaphthalene-6-sulphonic acid,
followed ~y reduc~ion to the amino compound.
b) ~he amino compound prepared in a) is diazotized
Le A ?6 260 - 43
1 4
according to -the procedure in Example 6c, and the
product is coupled as described there onto 1-
hydroxy-6-anilinonaphthalene-3-sulphonic acid, This
gives a dyestuf f of the structure:
R-N=N ~ H-CH-
~
SO3H
OH
R = ~ NH ^`,-' ~ \
so3H
R = ~ ~
SO3H
Analogously, the use of-2-aminonaphthalene-6-sulphonic
acid give the isomeric dyestuff in which
R' is ~ ~ -N
~50 3H
~xample 14
Light-polarizing sheets having similar good dichroic
properties are obtained by replacing in Example 1 Mowiol~
~8-99 by Mowiol~ 40-88 (hydxolyzed polyvinyl ~cetate;
d2gree of hydrolysis 87.7 ~ 1.0 mole ~, viscosity of the
4~ strength aqueous solutio~ at 20C: 40 + 2.0 mPa.sec2
from ~oechst AG) or ~y ~owiol~ 4-98 (hydrolyzed polyvinyl
acetats; degree of hydrolysis 9~.4 ~ 0.4 mole ~, visco-
~ity of the 4% strength aqueous solution at 20C:
L2 A 26 260 - 44 -
4~
4 i 1.0 mPa.sec2; from Hoechst AG) or by Mowiol~ 66-100
~hydrolyzed polyvinyl acetate; degree of hydrolysis
99.7 + 0.3 mole %; YiSCosity of the 4% strength aqueous
solution at 20C: 66 + 4.0 mPa.sec2. from Hoechst AG).
Exam~le 15
Analogously ~o Examples 1 and 14, light-polarizing sheets
containing the dyestuffs from Examples 2-13 are pxoduced.
The sheets obtained are distinguished by good dichroic
properties.
Le A 26 260 - 45 -
