CA1092099A - Azo dye compounds - Google Patents

Abstract

AZO DYE COMPOUNDS

Abstract of the Disclosure Dye compounds having the formula:

wherein:
R1 is H, COOH, CONH2, -HgSO2NH2, -SO2NH2 or -SO3M
where M is Na+ or NH4;
R2 is a lower alkoxy radical, -OCH2CONH2, or where each of R6 and R7 is a lower alkyl radical;
R3 is H, a lower alkyl radical, a lower alkoxy radical or NO2, R4 is H or ;

where m is 0 or 1, n is 1 when m=0 and 2 when m=1;
Q is OH when m=0 and O- when m=l; and J is a metal cation such as Zn, Cd, Sn, or the like.

Description

9Z~!~9 - ~ield of the Invention:
This invention relates ~o azo dye compounds and particularly to dyes which are the reaction product of 2,3-naphthalenediol and certain diazonium salts. These dyes are particularly useful for making liquid electrographic devel-opers.
Background of the Invention:
Insoluble dyes have been used as pigments in prlor-art electrographic liquid developers. However, pro-cesses using such prior-art developers have generally suf-fered from the poor dispersion stability of such developers and/or poor light stability of the developed lmage. Prior-art processes which use carbon as the pigment in electro-graphic liquid developers yield black developed images with good visual density at 550 nm. but have generally suffered from such problems as batch-to-batch nonuniformity and yield poor continuous tone images on print materials such as vesicular elements. Thus, there is a continuing need for insoluble dyes which can be used as pigments in electro-graphic 11quid developers to provide such developers withimproved dispersion stability and to provide developed images having improved stability to light. In particular, -there is a need to provide an insoluble dye having the desirable neutral density color characteristics of carbon without the previously mentioned problems of carbon when used in liquid developers.
The azo dyes of the present invention can be used to make electrographic liquid developers which have good dispersion stability, which yield good light stability of 3 developed images, and which can provide good continuous tone images and good batch-to-batch uniformity. Electrographic liquid developers made using the azo dyes of the present .. , _ ................... , _ , . ~

~0~2(~9~
, invention further provide high-quality developed images having low contrast and high resolution.
Various azo dyes containing naphthalene and hydroxy-naphthalene groups are described in U.S. Patents 1,718,882,

2,244,339, 2,553,261, 2,758,109, 3,384,632, 3,580,901 and :

3,781,208, British Patent 1,370,197, and Canadian Patent 926,681. Few of these dyes appear to exhibit color in the blue reglon of the spectrum. Most of them are more warmly colored, exhibiting orange-red, red-magenta, and brown hues.
The azo dyes of the present invention differ structurally from those discussed above and generally exhibit blue or `
neutral density coloration.
Summary of the Invention-: .
The present invention provides a new class of dyes ~
which are formed by coupling diazonium salts with 2,3- -naphthalenediol derivatives. Useful dyes generally have a structure according to the following formula:

~ N~

`- R ,, :

;
. : ' wherein:
Rl is H, COOH, CONH2, -HgSO2NH2, -SO2NH2 or -S03M

where M is Na+, NH4+ or like cations;
R is a lower alkoxy radical having from 1 to about 4 carbon atoms (sNch as, for example, -OCH3, -OC2H5, n-C3H7O-, etc.), -OCH2CONH2 or \R7 `~.
~3~ ~

. :. . . : . . . . . .

... . . .. . . .

~t99Zq~3~ `:
where each of R6 and R7 is selected from lower alkyl radicals having 1-4 carbon atoms including substituted lower alkyl radicals such as -C2HLIOH, -C2H4S03M, etc.;
R3 is H, N02, halogen or a lower alkyl radical or lower alkoxy radical having from 1 to about 4 carbon atoms includ-lng substituted such radicals;
R is H or , = -~R 2 ~ R~
where m is O or l;
n is l when m=O and 2 when m=l;
Q is OH when m=O and O when m=l; and J is a metal cation. Useful such metal cations include Ba, Ca, Cd, Cn, Mg, Mn, Sn, Sr, Zn, and the like.
The dyes of this invention are generally useful as dyes and pigments in a variety of known processes. Among the many ~ses of these dyes is their use as pigments in electrographic liquid devçlopers. Such electrographic liquid developers made using the dyes of this invention exhiblt good dispersion stability and yield high-quality ;
developed images having low contrast, high resolution and stability to light.
Certain preferred dyes of this invention exhibit a `~
unique spectral response. These dyes absorb radiakion `
relatively uniformly in the range of from about 400 nm. to about 700 nm. and ~herefore exhibit a neutral density col-oration. The dyes exhibiting this neutral density colora-tion are the disazo dyes of Formula I wherein R4 is an arylazo and R2 is -OCH2CONH2 or a lower alkoxy group having from 1-4 carbon atoms. ' `
3 Figure 1 illustrates a spectral response curve of ~
certain preferred dye compounds of this invention that ` ;
exhibit substantially neutral density coloration.

-4- ;~

, ., ' . ,: : , .: , : ", ,,. . :. :

~ ~L6)9Z()99 Detailed Description of the Invention:
In accordance with the present invention, a new ~ -class of dyes is provided by coupling diazonium salts with 2,3-naphthalenediol derivatives according to the following reaction:

OH )~ +

I X
' Z .'.:
R : -R~ t- OH ~ ~

R 'L :

wherein X is an anion, n is 1 or 2, and the R's are the same as defined hereinabove providing R4 is H when n=l. When the diazonium salt is complexed with a heavy metal cation the dye salt structure of Formula I is obtained. Various heavy .~
metal cations can be used to obtain the dye salt, including the cation of Zn, Cd, Sn and other like metal cations.
~ ~.
As used herein? the terms "lower alkyl radical"
and "lower alkoxy radicals" include those such radicals ~- having from 1 to about 4 carbon atoms in the unsubstituted radlcal, and also include substituted such radicals in which one or more hydrogen atoms have been replaced by an OH, S03M
(where M is Na , NHll , etc.), a halogen, or other similar substituents.
Exampies of the dyes provided by this inven-tion include:

-5-9209~9 1. zinc di-1-[_-(N-ethyl-N-2-hydroxyethyl-amino)phenylazo]-3-hydroxy-2-naphthoxide;
2. 1-[p-(N-ethyl-N-2-hydroxyethylamino)phenyl-azo~-2,3-naphthalenediol;
3. 1,4-bis[_-(N-ethyl-N-2-hydroxyethylamino)-phenylazo]-2,3-naphthalenediol;
4. 1,4-bis[4-(N-ethyl-N-2-hydroxyethylamino)-phenylazo]-2,3-dihydroxy-7-naphthalenesul-fonic acid ammonium salt;
5. 1,4-bis[4-(N-ethyl-N-2-sulfoethylamino)-2-methylphenylazo]-2,3-naphthalenediol disodium salt;

6. 2,3-dihydroxy-1,4-bis[4-(N-ethyl-N-2-sulfo-ethylamino)-2-methylphenylazo]-7-naphtha- ~ -lenesulfonamide disodium salt;

7. 1,4-bis(_-anisylazo)-2,3-naphthalenediol;

8. 1,4-bis(o-anisylazo)-2,3-naphthalenediol;

9~ 1,4-bis(p-ethoxyphenylazo)-2,3-naphthalene-diol;

10. 1,4-bis(4-n-propoxyphenylazo)-2,3-naphtha-lenediol;

11. 1,4-bis(p-anisylazo)-2,3-dihydroxynaphtha-lenesulfonic acid sodium salt;

12. 1,4-bis(o-anisylazo)-2,3-dihydroxynaphtha-lenesulfonic acid sodium salt;

13. 1,4-bis(4-anisylazo)-2,3-dihydroxy-6-naph-thalenesulfonamide;

14. 1,4-bis(4-carbamoylmethoxyphenylazo)-2,3-naphthalenediol;
3 15. 1,4-bis(2-nitro-4-anisylazo)-2,3-naphtha-lenediol; and ;~
16. 1,4-bis(5-nitro-2-anisylazo)-2,3-naphtha-lenediol.
:::
Among the uses for the dyes of this invention is their use as pigments in making electrographic liquid devel-opers. After the dye is ~ormed in accordance with the present invention, it is used to prepare a liquid developer -~ -suitable for developing electrostatic charge patterns.
Typically developers are prepared by grinding or ball-milling 4 one of the pigments with a suitable polymer solution to make a concentrate and diluting this concentrate with an insulating carrier liquid. The resultant developer is in the form of a carrier liquid having dispersed therein toner particles comprised of the pigments of this invention and a suitable ;~
resinous material.

Carrier liquids which may be used to form such developers can be selected from a wide variety of materials.
::
Preferably, the liquid has a low dielectric constant and a ,.

9Z~99 very high electrical resistance such that it will not dis-turb or destroy the electrostatic latent image. In general, useful carrier liquids should have a dielectric constant of less than about 3, should have a volume resistivity of greater than about 101 ohm-cm., and should be stable under a variety of conditions. Suitable carrier liquids include halogenated hydrocarbon solvents, for example, fluorinated lower alkanes, such as trichloromonofluoromethane, trichloro-trifluoroethane, etc., having a typical boiling range of from about 2 C~ to about 55 C. Other hydrocarbon solvents useful as carrier liquids are isoparaffînic hydrocarbons having a boiling range of from about 145 C. to about 185 C., such as Isopar G (a trademark of Exxon Corp.); or cyclo-hydrocarbons having a major aromatic component and a boiling range of from about 145 C. to about 185 C., such as Solvesso 100 (a trademark of Exxon Corp.). Additional useful carrier liquids include polysiloxanes, odorless mineral spirits, octane, cyclohexane, etc.
In addition to the dyes or colorants of the present invention which are dispersed as pigments in the carrier liguid, a resinous material can be used if desired to facilitate binding of the colorant to the surface to be developed.
Suitab]e resinous materials used in the present developers appear to form a coating around each colorant particle and thus also facilitate dispersion of the colorants in the carrier liguid. Useful resins can be selected from a wide variety of substances. The following are illustrative of suitable materials: rosins, including hydrogenated rosins and esters of hydrogenated rosins; alkyl methacrylate copoly- -mers having ~rom 2-5 carbon atoms in each alkyl moiety, such as isobutyl methacrylate and normal butyl methacrylate copolymers, etc.; phenolic resins including modified phe-, , '' ' ', . .: ' .' : ' , .

Z~99 nolic resins such as phenol formaldehyde resins; pentaeryth-ritol phthalate; coumaroneindene resins; ester gum resins;
vegetable oil polyamides; alkyd resins, including modified alkyds such as soya oil-modified and linseed oil-modified alkyds, phthalic, maleic and styrenated alkyds, etc.; and the like.
In addition, the electrostatic charge polarity of toner particles comprising dyes of the present invention can be enhanced or altered by the addition of suitable charge control agents if so desired. A variety of materials can be used as charge control agents. Illustrative of suitable charge agents would be the polyoxyethylated alkyl surfactants such as polyoxyethylated alkylamine, polyoxyethylene palmitate, polyoxyethylene stearate, etc. Other useful materials are magnesium and heavier metal soaps of fatty and aromatic acids as described by Beyer in U.S. Patent 3,417,019.
Useful metal soaps include cobalt naphthenate, magnesium naphthenate and manganese naphthenate, zinc resinate, cal-cium naphthenate, zinc linoleate, aluminum resinate, iso-propyltitanium stearate, aluminum stearate and others, many of which are also described in U.S. Patent 3,259,581. ~
Typically, the amount of such materials used is less than ~-about 2% by weight based on the weight of toner. In certain instances, the resinous binder per se can function as the charge control agent, as can the colorant.
Suitable developer compositions can be prepared simply by grinding the pigments to the appropriate size and ~ `
; dispérsing the pigment powder in a carrier liquid without the addition of a resinous binder and/or charge control 3 agent. A developer which does not contain a binder material produces developed images which are not fixed. Accord- ~ -ingly, it would be necessary to overcoat such images by ':

.. - . ., , , . . . : . , .

~9 spraying with a lacquer composition in order to hold the pigment particles in place. Typical developer compositions comprising the pigments of this invention will conta~n the -pigments in a concentration of from about 0.01 to about 1.0 gram per liter. When a resin binder is used, the pigment- ;
to-binder weight ratio can vary from about 1:20 to about 2:1 The invention is further illustratet by the exam-ples which follow:
Example 1: Preparation of zinc di-l-[p-(N-ethyl-N-2-hydroxyethylamino)phenylazo]-3-hydroxy-2-naphthoxide _ _ N=N ~ -N~( Zn L _ ¦ 2 ~ .

To a solution of 25.0 g. (0.0845 mole) of p-(N-ethyl-N-2-hydroxyethylamino)benzenediazonium zinc chloride double salt and 11.0 g. (0.0688 mole) of 2,3-naphthalenediol in 200 ml. of distilled water was added excess 28% aqueous ammonia. After 1 hr., the solid was collected, slurried in 200 ml. of acetone and dried to give 9.2 g. of green product.
Recrystallization by boiling in 300 ml. of pyridine, filtra-tion, concentration of the filtrate to 50 ml. and cooling overnight to room temperature gave 3.4 g. Recrystallization from 250 ml. of pyridine concentrated to 30 ml. gave 2.8 g.
(5.3% of green crystals, lmaX 523 nm., log E 4.67.

- _9_ ~, .

.' , '' ' ~

~o~z~9 Anal. calc'd. for C40H4oN6o6zn: C, 68 566 H~ 5-?3; N~ 11.0;
Found: C, 62.6; Hj 5.1; N, 11.5;
Zn, 7.9 Example 2: Preparation of l-[p-(N-ethyl-N-2-hydroxyeth-ylamino)phenylazo]-2,3-naphthalenediol N= N~ . N/ ( CH 2) 20H
= q C 2 H 5 I ~I

To a stirred solution of 27.8 g. (0.100 mole) of _-ethyl-N-2-hydroxyethyl-p-phenylenediamine bisulfate (PDA), 34 ml. (0.40 mole) of concentrated hydrochloric acid and 200 ml. of distilled water was added dropwise with stirring at 0-10 C. a solution of 6.9 g. (0.10 mole) of sodium nitrite in 35 ml. of water to yield p-(N-ethyl-N-2-hydroxyethylamino)-benzenediazonium chloride. The resulting green solution was added dropwise with stirring at 0-10 C. to a solution of

15.9 g. (0.0944 mole) of 2,3-naphthalenediol, 60.8 g. (1.00 ;~
mole) of aqueous 28% ammonia and 400 ml. of ethyl alcohol.
The mixture was stirred for 1 hr. after completion of the addition. The solid was collected, washed with water and dissolved in 450 ml. of boiling 2-butanone. The filtered solution was cooled overnight to room temperature, filtered from 1.0 ::.~ ... .
g. of dark green solid, m.p. 220 C. dec., concentrated to 200 ml. and cooled overnight in the refrigerator. A solid .. . ..
was collected from the cooled concentrate, washed with ice-cold 2-butanone and dried to give 10.0 g., m.p. 159 C.
Recrystallization from 200 ml. of 2-butanone gave 5.0 g.
(14%), m.p. 167-170 C., ' AmMaFx ~log E) 512 nm. (4.42), 590 nm. (4.27).

Anal. calc'd. for C20H21N3O3: C, 68-5; H, 5-98; N, 12-0 3 Found: C, 68.o; H, 6.o; N, 11.8 ~, '' '.

~: , , , . . . : . , . . ~ ' Example 3: Preparation of 1,4-bis[p-(N-ethyl-N-2-hydroxy-ethylamlno)phenylazo]-2,3-naphthalenediol ~o-o~ /(CH2)20H
N=N-~ /o-N\ ~-~- N--oSÇ ~ --N
=- \(CH2)20H

A solution of 0.200 mole of _-(N-ethyl-N-2-hydroxy- ~;
ethylamino)benzenediazonium chloride (made as in the procedure in Example 2 except using twice the amount of PDA, sodium ,~
nitrite, hydrochloric acid and water) was added dropwise with stirring at 0-5 C. to a solution of 15.9 g. (0.0994 mole) of 2,3-naphthalenediol, 400 ml. of pyridine and 150 ml. of aqueous 28% ammonia. The mixture was stirred for 1-1/2 hr. after completion of the addition. The solid was collected, washed with methanol and then water, and dried in ; vacuum at 45 C. to give 42.3 g. of green product, m.p. 240 C. Recrystallization from 400 ml. of pyridine gave 33.2 g. -~
(61.6%) of green crystals, m.p. 247 C. (dec.), `; ~

`: ' ' : ' ~ AmMax (log E) 614 nm. (4.82), 657 nm. (4.87).
: ?
Anal- calc'd- for C30H34N6C4 C~ 66-6; H~ 6-28; N~ 15-5 Found: C, 66.2; H, 6.3; N, 15.3 Example 4: Preparation of 1,4-bis[4-(N-ethyl-N-2-hydroxy-ethylamino)phenylazo]-2,3-dihydroxy-7-naph-thalenesulfonic acid ammonium salt ~o-e~ /(CH2)20H
N=N-o\ /o-1 '=- C2Hs -OH

t ~ N~C2H5 . .
~ \(CH2)20H

.

-11- ~ ', ~.

.~ . ' ' ~' ' ' . . ' ~0920~
. :

:;
A solution of 34.5 g. (0.100 mole) of 2,3-diace-toxy-7-naphthalenesulfonic acid sodium salt (see Example 5), 40.0 g. (1.00 mole) of sodium hydroxide and 700 ml. of water was stirred for 2 hr. at 25-30 C., cooled and treated dropwise at 5-10 C. with a solution of 0.200 mole of _-(N-ethyl-N-2-hydroxyethylamino)benzenediazonium chloride made as in the procedure of Example 3. The mixture was stirred overnight. The solid was collected, pressed as dry as possible, dissolved in 1 1. of water and treated dropwise 10 with a hot solution of 28.7 g. ~0.100 mole) of 1,2,3-tri-. :
phenylguanidine, 250 ml. of ethy] alcohol, 15 ml. of glacial acet~c acid and 15 ml. of water. After 1 hr., the solid was collected, washed with water and vacuum-dried at 35 C. to give 71.8 g. of a mixture of blue and violet dyes. It was stirred for 1 hr. in 760 ml. of methanol, collected, washed with 500 ml. of methanol and dried to give 25.1 g., m.p.
.: , 238-239 C. (Thin-layer chromatography of this material showed only the blue component.) Stirring this material for `
1 hr. at reflux with a solution of 2.5 g. (0.032 mole) of ammonium acetate in 350 ml. of et~yl alcohol, collection (without cooling) of the solid, washing with ethyl alcohol -and vacuum-drying at 45 C. gave 20.5 g. (32.1%) of blue powder.
30H37N707S: sC, 56 4; H, 5.78; N, 15.3;
Found: C, 58.8; H, 5.6; N, 13.2;
S, 4.4 ;
Example 5: Preparation of 2,3-diacetoxy-7-naphthalene- -sulfonlc acid sodium salt -A mixture of 72.3 g. (0.276 mole) of 2,3-dihy-droxy-7-naphthalenesulfonic acid sodium salt, 360 ml. of acetic anhydride and 5 drops of concentrated sulfuric acid was stirred 8 hr. on a steam bath and cooled overnight to room temperature. The solid was collected, washed with . ..... ..

' ' ' ' ' ' ' " ' ' ' .. ' ' ', '' "' ' , ' ~, , '" ' ' ' " "'1'; ' 1, ' ' , ' '"

~L~)9Z(:~99 acetic anhydride, pressed as dry as possible, dissolved in 400 ml. of water, mixed with 500 ml. of 20% sodium chloride solution and allowed to stand overnight. The solid was collected, washed with 20% sodium chloride and dried to give 69.9 g. (73.1%) of colorless crystals, m.p. 270-300 C.
(dec.).

Anal. calc'd. for C14HllNaO7S: C, 48.6; H, 3.18; Na, 6.65;
S, 9.25 Found: C, 45j7; H, 3.3; Na, 6.4;

Example 6: Preparation of 2,3 diacetoxy-7-naphthalene-sulfonyl chloride A mixture of 14.4 g. (0.0416 mole) of 2,3-diace-.~. .
toxy-7-naphthalenesulfonic acid sodium salt, 150 ml. of ~
. .
thionyl chloride and 1 ml. of DMF was stirred 1 hr. at room temperature and 1 hr. at reflux, cooled to room temperature and poured into 1 1. of petroleum ether. The solid was collected, washed with petroleum ether and dried to give 11.3 g. (79.9%) of cream-colored product, m.p. 158-167 C.
r C14HllC16S S' 49 ; H, 3.21; Gl, 10.4;
~` Found: C, 48.3; H, 3.4; Cl, 9.8;
S, 10.1 , ~ .

Example 7: Preparation of 2,3-dihydroxy-7-naphthalene-sulfonamide . . .
A solution of 20.0 g. (0.0583 mole) of 2,3-diace-toxy-7-naphthalenesulfonyl chloride in 300 ml. of tetrahydro-~ ~ -furan was treated with 8.7 ml. (0.13 mole) of aqueous 28% ~ -I
ammonia. The solid (9.9 g., infrared spectrum identical 3 with that of 6,7-diacetoxy-2-naphthalenesulfonic acid sodium ` salt) was removed by filtration and the filtrate evaporated to dryness. The residue was dissolved in 150 ml. Or ethyl acetate. The residue from evaporation of the dried (anhydrous sodium sulfate) solution was slurried with four 100-ml.
portions of ether and then dissolved in 150 ml. of 3A alco-hol. The solution was saturated with hydrogen chloride, .
~.,~ ,.

.
'.

` ~O~zl~19 allowed to stand overnight, and then concentrated at the water pump to give 9.7 g. of colorless residue. Recrystal-lization from 50 ml. of water gave 5.1 g. (37%) of pale violet solid, m.p. 218-228 C. ~
Anal. calo'd. for CloHgN04S C, 50 2; H, 3.77; N, 5.85; ; ;
Found: C, 50.2; H, 4.1; N, 5.3;
S, 13.0 Example 8: Preparation of 1,4-bis[4-(N-ethyl-N-2-sul-foethylamino)-2-methylphenylazo]-2,3-naph-thalenediol disodium salt CH
N=N-o~ N/(cH2)2s03Na O I ~=- C2Hs :, ~ ~ / \ ~ '; -~ ~--o~ /C2Hs N= N~ - N~
t=- (CH2)2S03Na `

A solution of 6.4 g. ~0.093 mole) of sodium nitrite in 15 ml. of water was added dropwise with stirring at 0-5 C. to a solution of 24 g. (0.093 mole) of (N ethyl-N-2-sulfoethylamino)-0-toluidine, 27 ml. (0.32 mole) of concentrated hydrochloric acid and 100 ml. of water. The resulting dark solution was added dropwise with stirring at 0-5 C. to a solution of 7.5 g. (0.047 mole) of 2,3-naph-20 thalenediol, 20 g. (0.50 mole) of sodium hydroxide and 500 ml. of water. The mixture was stirred overnight and fil-tered from a small amount of solid. The ~iltrate was diluted to 800 ml. with water and treated dropwise with stirring with a hot solùtion of 15 g. (0.052 mole) of 1,2,3-triphen-ylguanidine, 250 ml. of 3A alcohol, 10 ml. of glacial acetic : . .; . . .
acid and 10 ml. of water. The solid was collected and shown ;
by TLC to be a mixture of blue and violet dyes. The fil-trate was treated with a second portion of 1,2,3-triphenyl-:
.

, , , . I :, . .

. `` . . ~
guanidine acetate made as described above. The 8.9 g. of gummy solid which resulted was stirred at reflux for 1 hr.
with a solution Or 2.0 g. (0.024 mole) of sodium acetate in 250 ml. of ethyl alcohol. The solid was collected, washed with ethyl alcohol and dried at 60 C. to give 6.4 g. (18%) of black powder. TLC showed a trace Or violet contaminant.
Anal- calc'd- for C32H36N6Na28S2 C~ 516 2o HS 48862 N~ 11-3;

Found: C, 49.3; H, 4.8; N, 12.0;
Na, 7.9; S, 8.o Example 9 Preparation of 2,3-dihydroxy-1,4-bis[4-(N-ethyl-_-2-sulfoethylamino)-2-methylphenyl-azo]-7-naphthalenesulfonamide disodium salt CH3 .
1 ( 3 ~ / \CzH5 NH O S ~ GH

N=N-9~ ~--N
(cHz)zso3Na - A solution of 0.042 mole of diazonium salt made as in the preceding procedure from 10.8 g. of D99E, 10.5 ml. of concentrated hydrochloric acid, 2.9 g. of sodium nitrite and 35 ml. of water was added dropwise with stirring at 0-5 C.
to a solution of 5.0 g. (0.021 mole) of 2,3-dihydroxy-7-naphthalenesulfonamide in 150 ml. of 2N sodium hydroxide.
The mixture was stlrred overnight and then treated dropwise with a hot solution of 12.1 g. (0.0420 mole) of 1,2,3-triphenylguanidine, 100 ml. Or ethyl alcohol, 10 ml. Or acetic acid and 10 ml. of water, acidified to pH 4 with acetic acid and allowed to stand overnight. The solid was collected, washed with 300 ml. of water and vacuum-dried at 40 C. The 16.1 g. of blue product was stirred at reflux for 1 hr. with a solution of 3.5 g. (0.043 mole) of sodium .: . : .

9ZO~ ~
acetate in 350 ml. of ethyl alcohol. The solid was col-lected, washed with ethyl alcohol and vacuum-dried at 40 C.
to give 6.9 g. (42%).

Example 10: Preparation of 1,4-bis(p-anisylazo)-2,~-naphthalenediol To a stirred solution of 24.6 g. (0.200 mole) of _-anisidine, 50 ml. (o.60 mole) of concentrated hydrochloric acid and 100 ml. of water was added dropwise at 0-5 C. a solution of 13.8 g. (0.200 mole) of sodium nitrite in 30 ml.
of water. The diazonium salt solution was stirred for 10 min. after the final addition, then was added dropwise to a solution of 15.9 g. (0.0944 mole) of 2,3-naphthalenediol, 110 ml. of 28% aqueous ammonia and 350 ml. of pyridine at 5-10 C. The mixture was stirred for 1-1/2 hr. after com-pletion of the addition. The solid was collected, washed with methanol and then water, and dried to give 26.7 g. of ~
crude product, m.p. 245-251 C. Recrystallization from ~ ~;
pyridine gave 20.7 g. (48.5%) of dark solid, m.p. 258-260 C.

Examples 11-19:
Dyes having Composition Nos. 8-16 1isted in Table I were prepared by the same procedure as that described in Example 10 except using different starting materials. The substituents described ln Table 1 below refer to the R's in ~ormula I. In all of the dyes listed in Table 1, m=0 and n=l. -

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The materials defined hereinbelow are used in the following examples:
.~. . ..
Isopar-G: a trademark of Exxon Corp. for a liguid mixture of aliphatic hydrocarbons obtained from Humble Oil &
Refining Co.
Beckosol 7: a trademark of Reichold Chemical Co.
for a soya-modified alkyd resin con- -taining ~2% phthalic anhydride and 41%
soya fatty acids from Reichold Chemical Co .
-Solvesso 100: a trademark of Exxon Corp. for a -~
hydrocarbon solvent consisting of alkylbenzenes from Esso Standard Oil Co.
VT: vinyl toluene LM: lauryl methacrylate LiM: lithium methacrylate MA: methacrylic acid EA: ethyl acrylate EM: ethyl methacrylate LiSEM: lithium sulfoethyl methacrylate t-BuS: ~ertiary butyl styrene VT/LM/LiM/MA: a mixture of 56% VT, 40% LM, 3.6% LiM
and 0.4% MA solids by weight -EA/EM/LM/LiSEM: a mixture of 46% EA, 26% EM, 16% -LM and 12% LiSEM solids by weight t-BuS/LM/LiM/MA: a mixture of 56% t-BuS, 40% LM, ` 3.6% LiM and 0.4% MA solids by weight . ... -. ... ...
Example 20:
.. .. ..
To 13.5 ml. VT/LM/LiM/MA solution (7% Solvesso 100 ;
solution) was added 0.7 g. of pigment of Example 9. The mixture was ball-milled for a week. To 3.5 g. of the concentrate was added 0.7 g. EA/EM/LM/LiSEM solution (14% Solvesso 100 solution). The mixture was then dispersed in 500 ml.
Isopar-G by ultrasonic means. The resulting developer, when utilized to develop electrostatic charge pattern, yielded good-quality, high-resolution images. Duplicates of such :~' ' .' ' ' . .

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~LO~Z0~9 - ~

images obtained on diazo vesicular materials exhibited low contrast and excellent continuous tone.
Example 21:
With 15.6 ml. VT/LM/LiM/MA solution (7% solution as above~ was mixed 0.8 g. of pigment of Example 8. The mix-ture was then treated as in Example 20. The quality of the first- and second-generation images was similar to the quality of images of Example 20.
Example 22:
To 15.6 ml. VT/LM/LiM/MA solution (7% Solvesso 100 solution) was added 0.8 g. of pigment of Example 4. The mixture was treated as in Example 20. The developed images were of good quality and exhibited high resolution. The images from the second-generation process also show good continuous tone.
Example 23:
With 30 ml. VT/LM/LiM/MA (7% Solvesso 100 solu-- tion), 2.0 g. of the pigment of Example 3 were mixed and ball-milled for 10 days. A developer was then prepared by adding to 2.98 g. of the concentration 0.7 g. binder solu-tion EA/EM/LM/LiSEM (14% Solvesso 100 solution) and dis-persing the mixture in 500 ml. of Isopar-G by ultrasonic means~ The developer was made up of particles less than 1 in size and yielded high-quality images. The second-generation process-exhibited the same characteristics as Example 20.
Example 24:
To 30 ml. VT/LM/LiM/MA 7% solution, 2.0 g. of the pigment of Example 3 were added and ball-milled for 15 days.
3 A developer was then prepared by adding 0.7 g. Beckosol-7 (14% Solvesso 100 solution) and 0.15 g. cobalt naphthanate to 2.98 g. concentrate and dispersing the mixture in 500 ml.

-19- .

., . ~.

', 92~g Isopar-G by ultrasonic means. Images from such a developer exhibited high resolution, high density and very high quality.
Continuous tone and low contrast were again the properties -~
of the second-generation images.
Example 25:
In 83.4 g. t-BuS/LM/LiM/MA (7% Solvesso 100 solu-~ion), 4.0 g. of carbon black were ball-milled for 15 days.
To 3.83 g. of the concentrate was added 0.7 g. EA/EM/LM/LiSEM
solution (14% solution). The mixture was then dispersed in Isopar-G by ultrasonic means. The images from this developer showed very high resolution and good overall quality. The second-generation process, however, produced images with extremely high contrast and thus did not produce acceptable ....... : i,, .
continuo~s tone prints. `
Example 26:
In 41.7 g. VT/LM/LiM/MA (7% solution), 3.0 g. of blue pigment were ball-milled for 15 days. The images from the resulting developer exhibited high quality and good resolution. However, the second-generation diazo process pro-duced no image since actinic light was not absorbed by this pigment. -Example 27:
A concentrated liquid toner was prepared by ball-milling 3.0 g. of the pigment of Example 10 in a 7% Solvesso 100 solution of 3.9 g. of VT/LM/LiM!MA (1.0 to 1.3 pigment-to-polymer ratio). A liquid toner was then obtained by adding to an aliquot of the concentrate a sufficient amount of the EA/EM/LM/LiSEM binder solution to obtain a mixture having a 1/1.3/0.5 pigment-to-stabilizer-to~binder ratio, 30 and diluting the mixture to 1 liter with Isopar-G under ultrasonic shear to yield a liquid toner hsving 0.35 g/l pigment.
~ , .

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.
. .
.

Z~9~ -The resultant developer had particle size ~2~
was positively charged and, when used in the conventional ;~ ~ -electrophotographic process, provided excellent, neutral-toned images.
Example 28:
From the concentrate described in Example 27, another liquid toner was obtained by replacing the poly ~;~
EA/EM/LM/LiSEM binder with chlorinated polyethylene solution ~
at 1/1.3/0.5 pigment-to-stabilizer-to-binder ratio. The final developer was negatively charged, well-dispersed and yielded excellent, neutral images.
Example 29:
A concentrated liquid toner using the pigment of Example 11 was prepared by ball-milling 3.0 g. of the pigment as in Example 27. A diluted developer at 0.35 g./l. pigment content was obtained as in Example 27. Excellent-quality electrophotographic images were obtained.
Example 30:
A concentrated liquid toner was prepared by ball-milling 3.0 g. of the pigment of Example 14 in a 7% Solvesso100 solution of 3.0 g. of poly VT/LM/LiM/MA at 1.0 to 1.0 - pigment-to-polymer ratio. A working developer was then obtained as in Example 27. The electrophotographic images obtained were also of excellent quality.
Although the invention has been described in con-siderable detail with particular reference to certain pre-ferred embodiments thereof, variations and modifications can be effected within the spirit and scope of the invention.

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. . , : .

Claims (15)

We Claim:

1. A compound of the formula wherein:
R1 is hydrogen, -COOH, -CONH2, - SO2NH2 or -SO3M, and M is a cation;
R2 is a lower alkoxy radical, -OCH2CONH2 or R3 is hydrogen, a lower slkyl radical, halogen, nitro, or a lower alkoxy radical; and R4 and R5 are the same or different lower alkyl radicals.

2. A compound of Claim 1 wherein M is Na+ or NH4+.

3. A compound of Claim 1 wherein R2 is - OCH2CONH2.

4. A compound of Claim 1 wherein R2 is methoxy.

5. A compound of Claim 4 wherein R3 is -NO2.

6. A compound of Claim 1 wherein the compound is 1,4-bis(p-anisylazo)-2,3-naphthalenediol.

7. A compound of Claim 1 wherein the compound is 1,4-bis(o-anisylazo)-2,3-naphthalenediol.

8. A compound of Claim 1 wherein the compound is 1,4-bis(p-ethoxyphenylazo)-2,3-naphthalenediol.

9. A compound of Claim 1 wherein the compound is 1,4-bis(4-n-propoxyphenylazo)-2,3-naphthalenediol.

10. A compound of Claim 1 wherein the compound is 1,4-bis(p-anisylazo)-2,3-dihydroxy-6-naphthalenesulfonic acid sodium salt.

11. A compound of Claim 1 wherein the compound i8 1,4-bis(o-snisylazo)-2,3-dihydroxy-6-naphthalenesulfonic acid sodium salt.

12. A compound of Claim 1 wherein the compound is 1,4-bis(4-anisylazo)-2,3-dihydroxy-6-naphthalenesulfonamide.

13. A compound of Claim 1 wherein the compound is 1,4-bis(4-carbamoylmethoxyphenylazo)-2,3-naphthalenediol.

14. A compound of Claim 1 wherein the compound is 1,4-bis(5-nitro-2-anisylazo)-2,3-naphthalenediol.

15. A compound of Claim 1 wherein the compound is 1,4-bis[p-(N-ethyl-N-2-hydroxyethylamino)-phenylazo]-2,3-naphthalenediol.