US2728659A - N-alkylhydroquinone antistain agents - Google Patents

Description

2,728,65 N-ALKYLHYDROQUINONE IS TAIN S Anthony Loria, John R. Think, and Arnold Weissberger, Rochester, N. Y., assignors to Eastman Kod'akCoin puny, Rochester, N. Y., a corporation of New Jersey No Drawing. Application June 3, 1953, p

Serial No. 359,422

This invention relates to color photography'and par. ticularly to a method for preventing the formationi of color fog or stain in photographic emulsions.

The'method of color photography in which color-- forming or coupler compounds co'rnbine with the development product of aromatic amino photographic deni d aw atsfl o 2,728,659 Fratented Dec. 27, 1955 ice ' layer in which they are incorporated. A further object velopers to produce dyes is Well known. The color formers or couplers may be added directly to the emulsion layers or may be incorporatedin the developing solution as described in Fischer U. S. Patent 1,102,028, granted June 30, 1914, or they may be incorporated-in a water-permeable medium which is insoluble in the carrier for the-sensitive silver salt as described in Mannes and Godowsky U. S. Patent 2,304,940, December 15,

1942, and Jelleyand Vittum U. S. Patent 2,322,027,

granted June 15, 1943.

A difficulty frequently encountered in these processes is the formation of color fog or stain. When the exposed material is developed in a color-forming developer, dye fog is frequently formed'in the emulsion layer. Thisis Because the developing agent has been oxidizedvto-some,

is to provide antistain agents which are non-difiusing in the photographic layer and which are strong enough reducing agents to react rapidly with oxidized 'color developer. A further object is-to provide antistain agents T which do not form highly colored oxidation products V formula: I

extent by the action of the air and the oxidized developer I tends to couple with the color-forming compound at places in the photographic material where no silver image is produced. It is well known 'that in these processes the dye should be formed only where the silver halide is reduced to metallic silver, thereby oxidizingthe developing agent to a form which'couples with the color former. Once the developing agent is oxidized, it couples immediately with the color former whether a photographic image is present or not Aerial oxidation of the developer or oxidation by means other than the photographic image therefore converts the developer to a form which will immediately react with the 'color former to produce acolor fog or stain. This effect is especially noticeable in materials having couplers incorporated in the sensitive layer since there is'no coupler in the dewhen .the material containing them is put through an oxidizing bath. Other objects will appear from the following description 'of'our invention.

These objects are accomplished by the use in an emulsion layer or other layer of a photographic material, especially a silver halide emulsion layer in which a colored image is formed -by development in a color-forming developer, of a normal alkyl hydroquinone having the where 'R is a normal alkyl group having from 5 to 18 carbon atoms, e. g., amyl, hexyl, heptyl, octyl, octadecyl, etc., and R- is hydrogen or the same as R, and is attached to the hydroquinone in the 5 or 6 position. i

The following compounds are illustrative of those which we may use: V 7 1. (|)H veloping solution to react with any' developing agent which is oxidized by the action of the'air. Fog or'stain arising from these causes is not readily controlled bythe same procedures used to control silvertog,

' The control of color fog or stain by incorporating hydroquinone or certain of its derivatives in photographic emulsions is described in Vittum and Wilder U. 8. Patent 2,360,290, granted October 10, 1944. Hydroquinones described therein include ,diamyl hydroquinone. and dio'ctyl hydroquinone.

The dialkyl hydroqu'inones availa.-- on able at that time were the di-secondary and di tertiary hydroquinones. For example Konigsand Mai, Bert 25;

2649 .(1892) describes the preparation of 2,5-di-tertiary amylhydroquinone by the m q qll Of hydroquinone with isoamylene. Tertiary octyl hydroquinone is describedin Niederl U. S. Patent 2,008,032 and Robinson and Hester U; S. Patent 2,008,337; 2,5-di-tertiary octyl hydroquinone has the structure:

H 2-'n-oety1 hydroquinone 2-n-dodecy1 hydroquinone Z-n-oetadecyl hydroquinone 4. 0H

QI H:

HrC (CH r) H r 2,5-di-n-octyl hydroquinone 2,5 di-n-dodecy1 hy q compound Iv-2-caprylylhydrbquinbne on I A 3-liter, 3-neck flask was charged with a mixture of 220g. (2 moles) of hydroquinone, 433 g. (3 moles) of n-caprylic acid, and 500 ml. of s-tetrachloroethane. The flask was fitted with a. gasdhlet tube extending. to the bottom. of the flask, a thermometer, and a gas-outlet tube to the hood, and was counterpoised on a balance pan. Gaseous boron trifluor'ide from a cylinder was then passed directly into the slurry. A yellow color developed and the temperature rose markedly; the rate of addition was regulated to keep the temperature at 50-55" C. without external cooling. The addition was continued until 250 g. (3.7 moles) of boron trifluoride had been absorbed; about three hours was required. The flask should occasionally be swirled by handduring the addition. The reaction mixture gradually formed a deep-yellow solution, from which. a yellow solid separated towards the end of the addition. When the absorption was complete, the inlet and outlet tubes were replaced by solid stoppers and the thermometer by an air-condenser protected by a Drierite tube. The flaskwas left standing overnight (16-20 hours) at room temperature.

The next morning, the flask was heated on a steam bath for 5-6 hours. After a short time, the mixture, which sets to an orange-yellow mush overnight, formed a deep, orange-red solution and drops of water were ap-- parent in the upper part of the flask. At the end of the heating period the mixture was cooled to room temperature with a stream of cold water. It was then poured, with mechanical stirring, into a room-temperature solution of 615 g. (7.5 moles) of sodium acetate in 3100 ml. of water in a 5-liter, 3-neck flask. An additional 100 ml. of tetrachloroethane was used for rinsing the reaction flask. The mixture was'then stirred at room temperature for 30-40 minutes to complete the hydrolysis.

The organic layer was allowed to settle and the supernatant aqueous-layer removed as completely as possible by decantation with suction. The tetrachloroethane solution was washed twice with'2-3 liters of water, by

stirring and decantation as above. Finally, about 2 liters of water were added and the mixture steam-distilled to remove the tetrachlo'roethatie and as much as feasible of the excess caprylic acid. About liters of distillate was eell'ect'ed'.

The residue was cooled to room temperature or below with a stream of cold water; the product crystallized to a somewhat oily yellow-brown solid. This was collected one large Buchner funnel, and sucked and pressed'fairly free of'water and most of the adhering oil. Then, withouttur'ther drying, it was washed with petroleum ether 'until' completely free or oil. About 500 ml. in portions,

was required. The crude product formed yellow crystals, M. P. 84-86 C., with. preliminary softening at about 75 C. The crude yield was 361 g. (76.5%).

For purification, the material was recrystallized from a mixture of 4 volumes of methanol and 1 volume ofwater, using 5 ml. per gram, with the addition of Darco (absorbent carbon). The recovery was 327 g. of bright yellow crystals, M. P. 845-86 C., withv some softening at about 80 C. This amounts to a yield of 69% of the theoretical 472 g.

In a 500-ml., 3-neck flask, with standard-taper ground joints, were placed 23.6 g. (0.1 mole) of Z-caprylylhydroquinone and 2 g. of 10% palladium-on-charcoal catalyst. The air in. the flask was replaced by nitrogen, and 200 m1. of glacial acetic acid was added. The flask was then fitted with a fritted-glass gas-introduction tube extending to the bottom of the flask, a moderately highspeed (1700 R. P. M.) propeller or centrifugal stirrer fitted with a rubber seal, and an air condenser with the outlet connected to a glass tube dipping into a cylinder 0t "water so that the reaction flask was under a pressure of "12 to 14 inches of water.

The stirrer was started and hydrogen gas from a cylinder was passed into the reaction mixture at such a rate that the 'full pressure determined by the depth of the outlet tube in the cylinder of water was maintained in the flask. (A very slo'w streamof bubbles in the water cylinder indicates a safe rate. The speed of reduction may be estimated by shutting off the hydrogen at the inlet and observing ft'he rate at which the water rises in the exit tube due to the absorption of the hydrogen in the flask.

1 Whe'n the water no longer rises at all, the reduction may be consideredcompl'ete.) The reaction was usually allowed 'to run overnight (about 20 hours), but some exper njients have indicated that 8 to '12 hours might be sufficient.

Thecatalyst was removed by gravity filtration, and the flask and filter rinsed with 25 ml. of glacial acetic acid. The light-yellow filtrate was heated to boiling and treated with sma'll portions of zinc dust until no further 'decolori'z'atio'n occurred Z- 3 g.). The zinc dust was filtered oii and washed with 25 ml. of hot glacial acetic acid. The almost colorless (very light yellow) filtrate and washings were treated with 250 ml. of hot Water, mixed thoroughly, and cooled to 0 C. The atflrst oily precipitate soon crystallizes to a white solid. This was collected on a Buchner funnel, washed thoroughly with water, and dried in a vacuum desiccator. The product still contained a small amount of oily impetroleum ether, filtering, and washing on the funnel with 50 ml. of petroleum ether in portions.

The 2-n-octylhydroquinone formed a slightly oft-white crystalline powder, M. P. 96.598 C., with some prespasms Compound 4.2-caprylyl-5-nbctylhydroziuizipna CHM/ Hmon A one-liter, ,3-necked flask was charged with a mixture of 111 g. (0.5 mole) of 2-n-octylhydroquinone, 108 g. (0.75 mole) of n-caprylic acid and 250 ml. of s-tetrachloroethane. The flask was fitted with a gas inlet tube extending to the bottom of the flask, a thermometer, and gas outlet tube to the hood. The whole apparatus was counterpoised on a balance pan. Boron trifluoride from a cylinder is passed directly into the slurry at such a rate that the temperature was maintained at 40-45 C. -Considerable heat was evolved and the n-octylhydroquinone slowly dissolved to form a dark, yellow-brown solution: When about 62 g. (0.9'mole) of boron trifluoride had been absorbed which required about 1% hours, the additionwas stopped; The outlet and inlet tubes were replaced by solid stoppers and the thermometer by an air condenser protected by a Drierite tube, and the flask left at room temperature overnight (16-20 hours).

The flask was then heated on the steam bath for 6 hours. The mixture soon became turbid and drops of water-were apparentin the upper partof the flask. At the end of the heating period the mixture was cooled to room temperature and poured, with stirring, into a room temperature solution of 140 g. (1.7 moles) of sodium acetate in 1260 ml. of water. An additional 50 ml. of s-tetrachloroethane was used for rinsing out the reaction flask. The mixture was stirred at room temperature for about 30 minutes to complete the hydrolysis.

The organic layer was allowed to settle and was separated; the aqueous layer was extracted in a separatory funnel with two SOO-ml. portions of ether.- The ether extracts andthe tetrachloroethane solution were combined, washed once with 250 ml. of water and then with four 250-ml. portions of 5% sodium carbonate'solution. The; at-first dark, yellow-brown solution became lightye'llow on treatment with the carbonate. It was finally washed with 500 ml. of water and dried overnight o'ver magnesium sulfate.

The filtered solution was concentrated under reduced pressure on the steam bath to a volume of about 300 ml. 600 ml. of petroleum ether was added' and the mixture cooled to C. The precipitate was filtered off, washed free-of dark, oily material with petroleum ether, and dried in the air. -It formed yellow crystals, M. P. 82-83" C., with some preliminary softening at 79 C. Weight: 115 g.

- =A second cropwas obtained by concentrating the combined filtrate and washings under reduced pressure on the steam bath to complete removal of the solvents. The dark oily residue was treated with 300 ml. of petroleum ether and left overnight in the ice box. Thev solid was filtered off and washed with petroleum ether to give 13 g. of yellow crystals, M. -P. 8l82 C., softening at 77 C.

The combined crops (128 g.) were recrystallized. from 640 ml. of cyclohexane, cooling the filtered solution overnight'at about C. The precipitate wasfiltered off, washed with a little cold cyclohexane and then with three 100' ml. portions of petroleum ether. After drying'in the. air, the product formed light-yellow crystals, M. P.

:6 82-83 C. with slight softening'at' C. 1 Yield: {122 g. (70% ofthe theoretical 174 g.)'.-] i 154.

t as

In a 3-liter, 3-necked flask with standard-taper ground I joints were placed 69.6 g. (0.2 mole) of, 2 -caprylyl-5- n- The stirrer was started andhydrogen gas from a cylv inderwas passed into the reaction mixture .at such a rate that the full pressure determined by the depth of the outlet" tube in the water cylinder was maintained in the flask. (Avery slow stream of bubbles in the watercylinder indicates a safe rate. Thespeed of reduction may be estimated by shutting off the hydrogen at the inlet and observing the rate at which the water rises in the exit tube due to absorption of hydrogen in the flask. When the water no longer rises at all, the reduction may be considered complete.) A periodof 20 to 22 hours was required; this mayconveniently be overnight. Toward the end of the reaction, a bulky white precipitate formed in the flask.

When the reaction was complete, the reaction flask was warmed on the steam bathto' 50 C.60". C.,'with continued stirring and hydrogen introductiomnntil the white precipitate redissolved. Excessive or..prolongcd heating should. be avoided; The catalyst was filtered off by gravity and washed with ml. of hot glacial acetic acid. The initial filtrate was colorless, but some yellow color developed toward the end of the filtration and during the washing. The light-yellow filtrate and washings were heated on the steam 'bath and treated with small portions of zinc dust until no further decolorization resulted. About .5 g.,was used, .fljhe z inc dusf'was then removed by filtration and washed with'ja little hot'glacial acetic acid. W 1

The almost colorless filtrate was treated slowly, with stirring, with 1 liter of hot water. A white precipitate formed. The mixture is cooled to about 10 C. The precipitate was filtered oil and washed thoroughly-with water. After drying in a vacuum desiccator at room temperature, it formed a very-slightly elf-white powder}, M. P. 80, l04-l09 C. The 'weight was 66 g. i

Recrystallization from 660 ml. ofcyclohexaneffollowed by washing with 25 ml. of cold cyclohexane and three IOU-ml. portions of petroleum ether, yielded 60 g. (9.0%) of white plates, M. P. 109.5 --11Ct.5 C.', with sonie pre liminary softening at l0 6 C.

Compound 6.2 caprylyl-4-rtlethoryph f l Boron trifluoride was passed into a mixture of 124g.

(1 mole) of p-methoxyphenol, 216. g. (1.5 moles) of caprylic acid, and 300 cc. of dry tetrachloroethane for -a of about four hours. The reaction mixture was allowed to stand overnight-at room temperature and was then heated on asteam bath for about .threehours. When cool, the mixture was poured into 130 .g. of sodium acetate Three portions of 2-caprylyl-4-methoxyphenol, totalling 170 g., were hydrogenated using for each approximately 170 cc. of glacial acetic acid, 10-12 g. of 10% palladium on charcoal, and hydrogen at 30-40 p. s. i. The reduction wasiper'form'ed in a Parr hydrogenation appararusanoomit mper mre and was complete overnight. 2

The catalys't wa's filtered off and the filtrate poured into a large volume of water. The organic material was extracted into ether, and 't'he ether layer was neutralized with sodium bicarbonate, washed with water, dried over sodium sulfate, and concentrated. The 4-rnethoxy-2- n-octylphenol wascollected at 187-190/ 10 mm. (yield 141 g3, 88%).

Eighty grams (0.339 mole) of 4-methoxy-2-n-octylphenol, and 65 grams (0.45 mole) of caprylica'cid were dissolved in 150cc. of'dry tetrachloroethane, and boron trifiuoride was passed in for about 6 hours. The mixture was heated on a-stea'm 'bath for about hours'an'd then, 'on cooling, was poured into a large quantity of water and treated withexcess'sodiuin carbonate. Ether was addedto aid separation and then the ether layer was washed thoroughly withwater. Th'e'eth'ereal solution was concentrated, and the forerun removed up to B. P. 24071-0 mm. The product (79g; 64%) was collected atl95-205/1 mm. Crystallizationfrom 95% alcohol gave 52.5 g. (42.5%),M. P. 30-31".

2,6-di-n-octyl-4-methoxyphenoi Three portions totalling 167 g. (0.461 mole) of 2- caprylyl- 4-methoxy-E-n-octylphenol were reduced catalytically'in a Parr hydrogenation apparatus. Each portion was dissolved in about '250 cc. of glacial acetic acid and used approximately l5 .g. of 10% palladium on charcoal with hydrogen at -40 lbs. per'sq. in. Reduction occurred quite slowly (ca. '20 hours) and gentle warm- Recrystallimg was required. After filtering off catalyst, the filtrate was poured into a large quantity of water and extracted with ether. The ether extract was neutralized with sodiumca'rbonate, washed with water,dried over sodium sulfate and concentrated. 2,6 -di -n octyl 4 methoxyphenol was collected at 19o-200/1 (yield 142 'g.; 88.5%; P. 39-41 2,6-di-n-0ctylhydroquinone Twenty-five grams :of 2,6-di-n-octyl-4-methoxyphenol was hydrolyzed by refluxing in a mixture of 400 cc. of glacial acetic acid andso cc. of hydrobromic acidf(48%) for approximately 24 hours. When cool, the-reaction mixturewas poured into at least twice its volume of water and chilled under running water for a few hours. The solid was filtered off and the sticky material was slurried carefully in thefunnel with ice-cold petroleum ether, most of the color and stickiness beingremoved by this proceduref The product was recrystallized from a mixture of approximatelyZlS cc. of ligroin (B. P. 90-l20) and 215 cc. of low boiling petroleum ether, giving 15.5 g. (64%).M. P. 81.5-82.5.

v The 2,6-di n-octylhydroquinone can also be prepared as follows:

4-"rzitr0-'2,6-di-n-octylphenol In a 200-ml. flask were mixed 5.64 g. (0.02 mole) of 10-nona'tlecanone"(5.-A. -C. S., 55, 1697), 2.5 g. (0.02 mole) sodium nitromalonaldehyde (Amer. Chem. 1., 22, 4), ml. of absolute ethyl alcohol, and 5 g. of potassium hydroxide dissolved in 40 ml. of water. The flask was equipped with a water-cooled condenser and the mixture refluxed on a steam bath for 18 hours. The reaction mixture was cooled to about 20 C. and the small amount of colorless precipitate that formed was filtered and washed on the funnel with 25 ml. of cold water. The filtrate and the wash water were combined and evaporated to about 50 ml. and let stand overnight. The yellow crystalline precipitate that formed was filtered and washed on the funnel 'with 25 ml. of ice-cold water. It was suspended in ml. of 50 percent aqueous alcohol and acidified with 4 ml. of dilute hydrochloric acid. The colorless solid that formed was collected and crystallized twice from acetonitrile. There was obtained 4.1 g. of product melting at 75-76" C.

' 2,6-di-n-octylquinone The 4-nitro-2,6-di-n-octylphenol was reduced to the amino compound using Raney nickel catalyst and 10 ml. of 30 percent sodium dichromate in water was added dropwise to an aqueous acetone solution of the 2,6-di-noctyl-4-aminophenol (2.2 g. in 100 ml. of acetone+50 ml. of water) at room temperature with mechanical stirring. After 3 hours, the acetone was evaporated under reduced pressure, and water was added to the residue. The oily yellow solid formed was taken up in ether; the ether solution was washed with water, dried over sodium sulfate, and the solvent evaporated. The yellow solid residue melted at 57-60 C.

2 ,6 -di-n-o'cly lhydroquin one An acetic acid solution of 2,6-di-n-octylquinone (2.2 g. in 50ml.) was heated to reflux and while stirring 3 g. of zinc dust was added to it. in small portions. After 30 minutes refluxing, the excess zinc was removed by filtration, and the filtrate was added to 200 ml. of cold water. The mixture was allowed to stand overnight; the precipitate that formed was filtered, washed well with water, and air-dried. The dried product was crystallized three times from petroleum ether, B. P. 30-60 C. There was thus obtained a white crystalline solid melting at 8283, which, on'standing, turns to a pink color.

Compound 25+2-n-d0decylhydr0quin0ne Z-n-rlodecylhydroquinone (M. P. l06.5108 C.) was prepared as described by Cook, Heilbron, and Lewis, J. Chem. Soc., 1942, 659, with certain modifications, e. g., reduction of the intermediateketone with palladiumon-charcoal catalyst.

Compound "3.-.2-n 0ctadecylhydroquirione 2-n-octadecylhydroquinone (M. P. 114-115 C.) was prepared as described by Cook, Heilbron, and Lewis, J. Chem. Soc., 1942, 65 9., reducing the intermediate ketone, however, with palladium-on-charcoal catalyst.

' Compound 5 .-2,5 -di-n-d0decylhydroquinone Patent 2,423,730, when incorporated in this way, produce dyes upon color development which are prone to fading by the action of visible or ultraviolet light, when known antistain agents such as 2,5-di-tert. octyl hydroquinone are used in the emulsion layer. These are the yellow and cyan dyes. The magenta dyes, such as those formed from couplers described inLoria, Weissberger and Vittum U. S. Patent 2,600,788 are relatively little affected by the known antistain agents upon the action of light.

In order to illustrate the effect of our antistain agents, the following test was made.

A quantity of the antistain agent, the molar equivalent of 0.05 g. of 2,5-di-tert. octyl hydroquinone, was dissolved with 0.5 g. of coupler in 1.5 cc. of dibutylphthalate. To this solution was added 11 cc. of 10% gelatin solution and 2.8 cc. of Alkanol B (sodium alkyl naphthalene sulfonate) solution. The mixture was passed through a colloid mill three times, and to the resulting dispersion, 32 cc. of a gelatino-silver halide emulsion were added, and the mixture blended and coated on a film support so'that the anti-stain agent was equivalent to 5 mg. per sq. ft. of 2,5-di-tert.-octyl hydroquinone.

Two check coatings were made: one containing no anti-stain agent, and one containing 5 mg. per sq. ft. of 2,5-di-tert. octyl hydroquinone.

The film strips were exposed on a Ib sensitometer using a silver wedge varying in density from 0 to 3. They were then developed 10 minutes at 68 F. in the following developer:

G. 2-amin05-diethylamino toluene HCl ,2 Sodium sulfite (desiccated) 2 Sodium carbonate, monohydrate Potassium bromide 2 Water to 1 liter.

This was followed by 5 minutes in the following stop bath:

Sodium sulfite, desiccated g 75 Acetic acid (28%) 235 Boric acid, crystals 3 37.5 Potassium alum g 75 Water to 1 liter.

Loss in density at maximum absorption Cyan Yellow Agent dye dye Cheek (none) 0 0 2 5-di-tert. octylhydroquinone- .08 poun 01 10 .06 10 .09 .04 .08 +.01

These results show that in the case of the cyan dye, all of the agents caused less fading than 2,5-di-tert. octyl hydroquinone. ,In the case of the yellow dye, compounds 1, 3 and 6 showed an increase in density over the standard, and compound 4 produced about half as much loss in density as the standard.

T he antistain agents of our invention may also be used in non-sensitive overcoating or filter layers, such as a colloidal silver interlayer of multilayer photographic material. In general, the antistain agents of our invention are used in the emulsion or other layer in quantities ranging from 0.07 gram to 4.3 grams per liter of emulsion or gelatin solution. These values are, however, merely illustrative.

In certain cases the antistain agents of our invention.

may be incorporated in a processing solution such as a prebath, first developer bath,.or color-forming developer used with color film which is developed with a primary aromatic aminodeveloping agent.

Our materials are particularly useful with color-forming emulsions coated on paper supports where it is especially important to reduce the minimum or fog densities. This applies both to negative developed paper and to reversal paper as well as to transparency materials.

It will be understood that the examples and modifications described herein are illustrative only and that our invention is' to be taken as limited only by the scope of the appended claim.

We claim:

A color-forming photographic emulsion having reduced fogging tendency, comprising a silver halide emulsion having incorporated therein a non-diffusing coupler compound capable of coupling with the oxidation product of a primary aromatic amino developing agent and as an where R and R are normal alkyl groups of from 9 to 18 "carbon atoms, and R is attached to the hydroquinone nucleous in a position selected from the class consisting of 5 and 6 positions.

References Cited in the file of this patent UNITED STATES PATENTS 2,360,290 Vittum et a1. Oct. 10, 1944