NO122384B - - Google Patents

Description

Acid-soluble dyes for use

when making permanent reproductions.

The present invention relates to dyes which

is suitable for use as the basic nitrogen-containing

bond that is precipitated on the surface of the photoconductor by the method described and protected in our Norwegian patent no. 103,818.

In our Norwegian patent 95,056, electrolytic electrophotography is described, but the patent does not describe the production of a complete color image with stable image properties.

According to the invention, acid production is provided

soluble dyes for use in making permanent reproductions of slides by electrodeposition on the surface of a photoconductive sheet. The dyes are characterized by the fact that they

6

has the general form

where M is an organic radical with a chromogenic nucleus, R' and R" are both alkyl radicals containing up to 18 carbon atoms, m is 2 or 3, p is an integer less than 6, and n is an integer less than 6. The dye can be produced by an amine containing a radical of the structure

(1) is diazotized and the resulting diazonium product is coupled

in a manner known per se with an organic compound selected to provide a chromogenic core, containing an azo group in the product, or (2) condensed with an organic compound containing said chromogenic core and exhibiting a carboxylic acid group or sulfonic acid group or an acid halide group, acid ester group or a -CH 2 X group, where X is a halogen atom.

Preferred due to their solubility properties are dyes where R' is an alkyl radical with from 6 to 18 carbon atoms and R" radicals are alkyl radicals containing less than 6 carbon atoms. Particularly preferred are dyes where n=2, m=2, p=2 , R'=decyl and R"=ethyl.

Typical chromogenic nuclei are represented by the following general class of dyes:

The dyes according to the invention are suitable for use as the basic nitrogen-containing organic compound in the method according to our patent no. 103,818 where permanent reproductions are made on the surface of a dye-sensitized photoconductor which is uniformly bonded to an electrically conductive support by selective precipitation of a basic nitrogen-containing organic compound which is soluble in the presence of an acid and substantially insoluble in water at a pH above 7, by neutralizing the solution with electrodes which are released at the photoconductor cathode when an electric current is passed through the aqueous solution of the basic nitrogen-containing organic compound and the conductive areas of the photoconductor cathode. The photoconductor surface is exposed to a light source in the selected areas to make the photoconductor conductive in the exposed areas. The photoconductor surface is then brought into contact with an acidic water solution of the basic nitrogen-containing organic compound. An electric current is then passed through the water solution and the conductive areas of the photoconductive cathode to neutralize the acidic solution at the conductive areas with electrons released at the photoconductive cathode. In this way, the basic nitrogen-containing compound is rendered insoluble and precipitates on the photoconductor in the exposed areas.

The dyes dissolve in water by forming a salt with an acid unit. Suitable organic acids include formic acid, acetic acid, lactic acid, levulinic acid and the like. Suitable inorganic acids include hydrochloric acid, nitric acid, sulfuric acid and the like. The finished pH of these solutions is in the range of pH 2 to 7 (preferably 4.5 to 7). These aqueous solutions, which are essentially free of positive ions of a different kind than those exhibited by the dye, are used at solution concentrations of from 0.1 to 5% by weight.

Dye production

Dyes used in the production of the colored reproductions in accordance with this invention are new and appropriate substances. Illustrative representations of preferred dyes and their intermediates are as follows:

I. Preparation of N-decyl-N',N'-diethyl-1,3-propanediamine

N,N-diethyl-1,3-prpandiamine (1950 g, 15 mol) was placed in a 5-liter, three-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser, and dropping funnel. The amine was heated to 125°C and 1-bromodecane (1106 g, 5 mol) was added with stirring at a rate sufficient to maintain the exothermic reaction at about 130-140°C. The reaction mixture was stirred for an additional 1 hour at a temperature of 125-135°C and then cooled to room temperature. Sodium methylate (250 g, 5 mol) was added to neutralize the hydrobromic acid formed. On cooling to room temperature, a solid substance was separated which was removed by filtration and washed with petroleum ether. Unreacted amine and solvent were removed by distillation.

N-decyl-N',N<1>,-diethyl-1,3-propenediamine (1080 g) with

a boiling point of 130°C at 1 mm pressure was; then collected by vacuum distillation.

II. Preparation of N-(2-cyanoethyl)-N-decyl-N1,N',-diethyl-diethyl-1,3-propanediamine

Acrylonitrile (250 g, 4.70 mol) and N-decyl-N',N',-diethyl-1,3-propanediamine (1013 g, 3.76 mol ). The flask was fitted with a reflux condenser and was heated on a mantle for easy reflux. The mixture was heated for 3 days at a temperature not exceeding 110°C.

Unreacted acrylonitrile was removed under reduced pressure and 1206 g of impure N-(2-cyanoethyl)-N-decyl-N',N'-diethyl-1,3-propanediamine was obtained.

III. Preparation of N-(3-aminopropyl)-N-decyl-N',N'-diethyl-1, 3-propanediamine

Lithium aluminum hydride (114 g, 3.00 mol) and diethyl ether (750 mol) were placed under a dry nitrogen atmosphere in a 3-liter, 3-necked flask equipped with a stirrer, reflux condenser, and dropping funnel. After refluxing for 15 minutes and stirring, N-(2-cyanoethyl)-N-decyl-N',N'-diethyl-1,3-propanediamine (969 g, 3.00 mol) was slowly added to give a moderate reflux . After all the nitrile had been added, the reaction mixture was stirred and refluxed and then allowed to stand overnight under dry nitrogen. Excess hydride was decomposed by slow addition of ethyl acetate (264 g, 3.00 mol) so that a slow reflux was obtained. The resulting mixture was hydrolyzed by careful addition of water (270 g, 15.0 mol) under external cooling and addition of ether to facilitate stirring. The solution was filtered to remove insoluble inorganic salts, distilled through a 38 cm Vigreaux column, and redistilled collecting N-(3-aminopropyl)-N-decyl-N',N'-diethyl-1,3-propanediamine (499 g) with a boiling range of 160°C/1.2 mm Hg to 170°c/0.9 mm Hg.

IV. Preparation of N 2 -(3-diethylaminopropyl)-N 2 -decyl-sulfanyl-amide

A solution of N-decyl-N',N'-diethyl-1,3-propanediamine (135 g, 05 mol) in 100 ml of benzene was treated with p-acetylamino-benzenesulfonyl chloride (120 g, 0.5 mol). The resulting homogeneous solution was stirred for one hour. After removal of the solvent, the residue was treated with 200 ml of water and 100 ml of concentrated hydrochloric acid. This mixture was heated on a steam bath for 6 hours. N"*"-(3-diethylaminopropyl)-N1-decylsulfanilamide which separated as an oil was precipitated by addition of excess alkali.

Production of yellow dye

A. Preparation of α,α'-bis-[4-(4-decyl-8-ethyl-4,8-diazadecyl)-sulfamylphenylazo]-4,4'-bi-o-acetoacetotoluide N<1->(4 -decyl-8-ethyl-4,8-diazadecyl)sulfanilamide (93 g, 0.2 mol) was dissolved in 75 ml of glacial acetic acid and diluted with 100 ml of water. This solution was poured into a mixture of ice (500 g)

and concentrated hydrochloric acid (75 mL). The resulting solution was then diazotized by the rapid addition of 5 N sodium nitrite solution (40 mL). Additional ice was added to keep the mixture cold and the solution was rapidly treated with stirring with a solution consisting of 34 g (0.09 mole) of "Naphtol AS-G Supra", a product of General Aniline and Film Corporation, New York, New York, dissolved in 75o ml of dimethylformamide and 150 ml of pyridine. More ice and water were added to ensure good cooling and stirring. After half an hour, the dye was completely precipitated by the addition of concentrated ammonia (300 ml) and the product collected by filtration. The resulting

yellow dye was washed with water and ethanol and then crystallized from a mixture of dimethylformamide and ethanol.

(The diazo compound from N1 -(4-decyl-8-ethyl-4,8-diaza-decyl) sulfanilamide was also reacted with the coupler N-(2-naphthyl)-3-hydroxy-2-naphthamide to form a red dye , and with various salicylamides for the production of yellow dyes.)

The aforementioned preparation "Naphtol AS-G" Supra is a compound with the chemical structural formula:

B. Preparation of N-(4-decyl-8-ethyl-4,8-diazadecyl)-N1 -

( 1- anthraquinonyl) isophthalamide

A solution of 45 g (0.22 mol) of isophthalyl chloride

in 500 ml xylene was heated to near reflux and 1-amino-anthraquinone (23 g, 0.1 mol) was slowly added with stirring. The mixture was heated under reflux until the evolution of hydrogen chloride ceased. The hot mixture was treated with activated charcoal and filtered. After the filtrate was cooled with ice, a solid was collected, washed with xylene and recrystallized from fresh xylene.

The recrystallized product was slowly added

a solution of N-(3-aminopropyl)-N-decyl-N',N'-diethyl-1,3-propanediamine (22 g, 0.067 mol) in 50 ml of toluene. After heating in a steam bath for one hour, the reaction product was precipitated with 300 ml of naphtha, collected and dried. The crude product was then dissolved in hot ethanol and filtered. On addition of water to the filtrate a yellow dye precipitated which was collected and dried.

The corresponding terephthalyl derivative was prepared on

similar way.

C. Preparation of 1'-methyl-4[3(4-decyl-8-ethyl-4,8-diazadecyl-sulfamyl)-4-toluidino]anthrapyridone

"Alizarin Rubinol R-CF" (200 g), a product of General Dyestuff Corporation, New York, New York, was mixed with water (2 liters) and heated on a steam bath. The mixture was made strongly acidic with concentrated hydrochloric acid and stirred and heated until the solid turned dark red. The mixture was then filtered and the solid washed with water. After dispersing the solid in a dilute sodium chloride solution (1 liter), the mixture was made alkaline with sodium carbonate, heated on the steam bath and filtered. The purified product was dried under reduced pressure at 100°C for 24 hours.

The aforementioned "Alizarin Rubinol R-CF" product is a compound with the formula:

Phosphorus oxychloride (250 mL) was added with cooling to the finely powdered purified Alizarin Rubinol R-CF (46.8 g, 0.1 mol). During cooling, phosphorus pentachloride (46 g, 0.22 mol) was added to this mixture. The mixture was then stirred at room temperature for 1/2 hour. The reaction mixture was filtered through a glass sinter funnel. The filter cake was thoroughly stirred into ice to hydrolyse excess phosphorus halides. The mixture was filtered and the solid was washed with cold water. The moist cake was stirred into hot nitrobenzene (500 mL) and dry magnesium sulfate was added to remove water. After removing the water, the mixture was filtered through a glass sinter funnel. On standing overnight at room temperature there were crystals of 1'-methyl-4-(3-chlorosulfonyl-4-toluidino)anthra-pyridone, which were removed from the filtrate by filtration, washed with heptane and twice with petroleum ether.

The chemical structure of the product from the reaction between "Alizarin Rubinol R-CF" and phosphoric acid oxychloride and penta-chloride is as follows:

To a mixture of N-(3-aminopropyl)-N-decyl-N',N',-diethyl-1,3-propanediamine (10 g, 0.0306 mol) and pyridine (50 ml) was added 1< 1->methyl-4-(3-chlorosulfonyl-4-toluidine)anthra-pyridone (7.0 g, 0.0151 mol). The reaction mixture was stirred and heated on a fume cone for one hour and left at room temperature for 16 hours. The reaction mixture was then mixed with water (500ml), made alkaline with concentrated ammonium hydroxide and filtered. The combined solid was washed with water and petroleum ether and dried under reduced pressure to give 1'-methyl-4-[3-(4-decyl-8-ethyl-4,8-diazadecylsulfamyl)4-toluidino]anthrapyridone ( 8.4 g).

D. Preparation of N,N<1->bis(3-diethylaminopropyl)-N,N'-dide-cylthioindigo-7,7',dicarboxamide

3-Hydroxythionaphthene-7-carboxylic acid was prepared from phenyl-1-thioglycol-2-carboxylic acid according to the method described in British patent 360,349.

3-Hydroxythionaphthene-7-carboxylic acid (0.3 mol) was

dissolved in water (1 liter) containing sodium carbonate monohydrate (40 g, 0.32 mol). A solution of potassium ferricyanide (218 g, 0.66 mol) in water (700 ml) was added to this with stirring. An additional amount of sodium carbonate monohydrate (40 g, 0.32 mol) was added to keep the mixture alkaline. The mixture was stirred approx. 1 1/2 hours and filtered. The filter cake was mixed with water (700 mL), and the resulting mixture was acidified strongly with concentrated hydrochloric acid and filtered. The solid was collected and washed with dilute hydrochloric acid and with acetone, and dried under vacuum at 75°C, whereby thioindigo-7,7'-dicarboxylic acid (38 g) was obtained.

To a mixture of phosphorus pentachloride (12 g, 0.057

mol) and phosphorus oxychloride (70 ml) was added thioindigo-7,7'-dicarboxylic acid (10 g, 0.026 mol). This was heated slowly to 90 - 95°C on a steam bath with stirring and kept at this temperature for 5 hours. The red solid obtained by filtering the reaction mixture was washed with benzene, filtered, washed with benzene, and washed with petroleum ether, whereby thio-indigo-7,7'-dicarbonyl chloride (10 g) was obtained.

To a mixture of N-decyl-N',N<1->diethyl-1,3-propane-6. in amine (2.9 g, 0.011 mol) and benzene (80 mL) was added thioindigo-7,7'-dicarbonyl chloride (2.1 g, 0.005 mol). The mixture was stirred and heated under reflux for approx. 5 hours. The solvent was removed under reduced pressure. The residue was dissolved in water (400 ml) with vigorous shaking, and this solution was made alkaline with ammonium hydroxide solution. A small amount of saturated sodium chloride solution was added to agglomerate the dye and the mixture was filtered. The solid N,N'-bis-(3-diethylaminopropyl)-N,N'-didecylthioindigo-7,7'-dicarbonamide was washed twice with water in which it became increasingly soluble, and dried to a final yield of 4 g.

E. Preparation of X,X'-bis(4-decyl-8-ethyl-4,8-diazadecyl-sulfamyl) quinacridone

Chlorosulfonic acid (1.00 L, 15.2 mol) was placed in a 2-liter, three-necked flask equipped with a stirrer, thermometer, and gas discharge tube connected to a drying tube filled with calcium chloride, which was cooled in an ice bath. Quinacridone (100 g, 0.32 mol) which had been dried in a vacuum oven at 90°C was added so that the temperature of the reaction mixture did not exceed 20°C. The mixture was stirred at room temperature for 4 days after which the reaction mixture was divided into two portions. Each portion was added slowly with stirring to acetone (2.5 liters), which was cooled in an ice bath so that the temperature did not exceed 25°C. The resulting mixture was filtered. The solid was washed with acetone and petroleum ether and dried, whereby 136 g of quinacridone-X,X'-disulfonyl chloride were obtained.

N-(3-aminopropyl)-N-decyl-N",N'-diethyl-1,3-propane-diamine (100 g, 0.306 mol) and pyridine (650 mL) were placed in a 1-liter, three-necked flask with a stirrer and cooler. To this was added while stirring quinacridone-X,X<1->disulfonyl chloride (77 g, 0.152 mol). This mixture was stirred and heated on a steam bath for 24 hours. The reaction mixture was poured into water while stirring (1 liter), and concentrated ammonium hydroxide (100 mL, 1.5 mol) was added. The resulting mixture was stirred and digested and then filtered. The filter cake was washed with water, digested and filtered. The solid product was washed with acetone, digested and filtered The resulting filter cake was washed twice with acetone and dried under reduced pressure to yield 110 g of magenta dye.X,X"-bis(4-decyl-8-ethyl-4,8-diazadecylsulfamyl)quinacridone, if color purity was improved by trituration with hot N,N-dimethylformamide.

Cyan dyes

F. Preparation of copper phthalcyanine-

Copper phthalcyanine was chloromethylated in the manner that

is described in British patent no. 586,341. The tetrachloromethyl derivative thus obtained (4 g, 0.005 mol) was added to a solution of N-(3-aminopropyl]-N-decyl-N',N'-diethyl-1,3-propanediamine (15 g , 0.05 mol) in 50 ml of dimethylformamide. The mixture was stirred under reflux for 1 hour and then allowed to cool. The settled solid was collected, washed with dimethylformamide and ethanol and suspended in ethanol. The product was transferred into the hydrochloride by adding an excess of concentrated hydrochloric acid to an ethanolic suspension and the hydrochloride of

was collected by filtration, washed with acetone and dried. Copper phthalocyanine (50 g) was chlorosulfonated according to the method described in British patent no. 515,637. The moist cake of tetrasulfonyl chloride was stirred thoroughly with a mixture of ice and N-(3-aminopropyl)-N-decyl-N',N"-diethyl-1,3-propanediamine (130 g, 0.4 mol). After 1 hour, while stirring, the reaction mixture was poured into 500 ml of water containing 200 ml of concentrated hydrochloric acid.

was collected, washed with cold water and dried.

Resolution representations

The compounds containing basic nitrogen, as illustrated by preparations A to G above, dissolve in water in the presence of acid. The solution concentration and the acid used can be varied. Preferably, the compounds are dissolved as acetate-

or hydrochloride salts in 0.5 to 2% aqueous solution. Illustrative solutions of the compounds shown in Preparations A to G, which can be used to form colored deposits on

a photoconductor sheet is as follows:

(a) Cyan solutions.

The cyan dye (40 g) from preparation G was triturated with 200 ml of hot absolute ethanol and gradually diluted with 150 ml of water. The resulting homogeneous solution was quickly poured, with vigorous stirring, into 1500 ml of water. The solution was filtered and filled up to 2 liters with water.

(b) Magenta solutions.

The magenta dye (4 g) from Preparation E was mixed with ethanol (40 ml), glacial acetic acid (0.58 ml) and water (360 ml) with constant heating and stirring until the mixture was homogeneous.

(c) Yellow solution.

The yellow dye (16 g) in the form of terephthalyl derivative from preparation B was dissolved in absolute ethanol (80 ml)

and concentrated hydrochloric acid (2.8 mL) and was diluted to 800 mL with water.

The procedure used to prepare reproductions by depositing the various dyes shown in Preparations A to G on the surface of a zinc oxide photoconductor sheet was as follows: 1. The negative electrode from a direct current source was connected to the metal base of a developing dish whereby electrical contact with the aluminum layer in the photoconductor sheet. 2. The photoconductor sheet, retained in the developer vessel, was exposed to a light source in the selected areas by projecting an image onto the photoconductor sheet with the projector having a low F projection range and a 500 watt tungsten projection lamp as light source, whereby the selected areas are made conductive. The relative humidity of the atmosphere in the working area should be less than 40%. 3. An electrode connected to the positive end was placed in the developer trough and the various solutions (see under "Solution Preparations" above) were added to the trough. 4. After a total time of approx. 20 seconds after exposure, a 30 volt electrical current was passed through the photoconductor at the conductive areas for a period of 10 seconds. 5. The solution was removed from the developer trough and the photoconductor sheet was thoroughly washed with water. 6. If the photoconductor sheet was to be re-exposed it was placed in contact with water heated to 60°C for a period of at least 20 seconds to return it to a dark-adapted state and the sheet was then dried by placing it under a stream of air. In this method, colored images were selectively deposited on the exposed interphase of the photoconductor sheet while it. were used solutions of the dye shown in the preparations A to G. A preferred combination of solutions for the production of "lifelike" colored reproductions are the solutions a, b and c above, whereby the yellow dye (solution c) is deposited first, the magenta dye (solution b) is then deposited, and the cyan dye (solution c) is deposited

Claims (3)

1. Acid-soluble dyes for use in the production of permanent reproductions of slides by electrodeposition on the surface of a photoconductive sheet, characterized in that the dyes have the formula where M is an organic radical with a chromogenic nucleus, R' and R" are both alkyl radicals containing up to 18 carbon atoms, m is 2 or 3, p is an integer less than 6, and n is an integer less than 6. 2. Dyestuff as specified in claim 1, characterized in that R' is an alkyl radical containing from 6 to 18 carbon atoms and R" is an alkyl radical containing less than 6 carbon atoms. 3. Dyestuff as specified in claim 1, characterized by atn=2, m=2, p=2, R<1> = decyl and R" = ethyl.