US2857372A

US2857372A - Benzothiazole azo isonicotinic acid compounds

Info

Publication number: US2857372A
Application number: US466955A
Authority: US
Inventors: James M Straley; Ralph R Giles
Original assignee: Eastman Kodak Co
Current assignee: Eastman Kodak Co
Priority date: 1954-11-04
Filing date: 1954-11-04
Publication date: 1958-10-21
Anticipated expiration: 1975-10-21

Description

United States Patent BENZOTHIAZOLE AZO ISONI COTINIC ACID COMPOUNDS James M. Straley and Ralph R. Giles, Kingsport,

asignors to Eastman Kodak Company, N. Y., a corporation of New Jersey No Drawing. I Application November 4, 1954 Serial No. 466,955

17 Claims. (Cl. 260-146) Teun., Rochester,

This invention relates to new azo compounds and their ..application to the art of dyeing or coloring. More particularly it relates to certain metallized and non-metallized benzothiazole azo isonicotinic acid compounds and their application to the dyeing or coloration of various materials. Insofar as dyeing or coloration is concerned, the invention is particularly directed to the dyeing or coloration of cellulose acetate textile materials with the metallized azo compounds of the invention.

The non-metallized monoazo compounds of our invention have theformula:

ing the formula I in complex combination with chromium,

cobalt, copper, iron, manganese, nickel or vanadium. The manner of preparing the non-metallized and metallized azo compounds of our invention is fully described hereinafter.

While our invention relates broadly to the non-metallized and the metallized monoazo compounds just described, the azo compounds of our invention are represented for the most part by the non-metallized and the metallized forms of the azo compounds having the formula:

(I C 0 OR wherein Ar represents an ortho-arylene radical of the benzene series and R represents an alkyl group having 1 to 4 carbon atoms.

As is well known, one of the disadvantages dyed cellulose acetate textile fabrics suffer in comparison with (III) 7 i 8.

some of the dyedcompeting textile fabrics, such as cot ton, wool and viscose, for example, is lack of fastness to washing. Many schemes have been proposed to remedy this situation but all suffer from some significant fault. By means of our invention dyed cellulose acetate textile materials having good to excellent fastness to washing, light and gas are obtainable. These results may be obtained by dyeing the cellulose acetate textile material with the non-metallized dye compounds of the invention and then treating the dyed cellulose acetate textile material with suitable metal salts which cause the original dye to form metallic complexes which are resistant, for example, to the action of washing, light and gas. Thus, by means of the present invention, the disadvantage noted above with respect to the wash fastness of dyed cellulose acetate textile materials is either entirely or largely overcome.

While reference has been made to the dyeing of cellulose acetate textile materials, itis to be understood that the invention is generally applicable to the dyeing of textile materials made of or containing a cellulose alkyl carboxylic acid ester having two to four carbon atoms in the acid groups thereof. By cellulose alkyl carboxylic acid esters having two to four carbon atoms in the acid groups thereof, we mean to include, for example, both hydrolyzed and unhydrolyzed cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate-propionate and cellulose acetate-butyrate. Cellulose acetate has been particularly referred to because it is the most widely used cellulose alkyl carboxylic acid ester.

The non-metallized monoazo compounds of our invention are prepared by diazotizing a Z-aminobenzothiazole compound having the formula:

C-NH:

wherein Ar represents an ortho-arylene radical of the benzene series and coupling the diazonium compound obtained with an isonicotinic acid compound having the formula:

( COOR no ox N wherein R and X have the meaning previously assigned to them.

The metallized monoazo compounds of our invention are prepared by treating the non-metallized azo compounds having the formula I with salts of nickel, cobalt, copper, chromium, manganese, iron or vanadium. The non-metallized monoazo compounds can be metallized either on or off the fiber. Metallization can be carried out, for example, by treating the non-metallized dye with a solution or dispersion of the metallizing agent. Although the metal complex is often formed at room temperature, we prefer to accelerate the process by heating,

usually with steam, for a short-time. The preparation of the metallized monoazo compounds of our invention is fully described hereinafter.

Illustrative of the metallizing agents that can be employed are the halides, the sulfates, the acetates, the cyanides, and the thiocyanates of nickel, cobalt, chromium, manganese, iron and vanadium as well as various copper compounds. Thus, nickel chloride, nickel bromide, nickel sulfate, nickel acetate, nickel cyanide, nickel formate, nickel thiocyanate .[Ni(SCN) cobaltous bromide, cobaltic chloride, cobaltous chloride, cobaltous acetate, cobaltous cyanide, cobalt thiocyanate cupric chloride, cupric bromidecupric-acetate, cupric lactate, chromium trichl o ride, chromium tribromide, chromic Sulfate r m sass ate chr miu thiocyanate C .3L ma an s shl x tle a anou sulfate, manganese acetate, manganese thi qcyanate [Mn($CN) ferric chloride, ferric fluoride, ferrous .a c ctate, ferrous thiocyanate [Fe(SCN) ferric thiocyanate ['Fe(SCN) and vanadium thiocyanate, are illustratiye of the metallizing agents that canbe employed.

When the metal complex is formed on a cellulose alkyl carboxylic acid ester, such as cellulose acetate, fiber the use of a metal thiocyanate appears to be advantageous and is preferred. Nickel thiocyanate appears to be especially useful and particular claim is laid to its use. Next to nickel thiocyanate the use ofcobalt thiocyanate is preferred.

2 amino 6 methylsulfonylbenzothiazole, 2 amino- 6 ethyl sulfonylbenzothiazole, 2 arnino v6 n propylsulfonylbenzothiazole, 2 amino 6 n butylsul' fonylbenzothiazole, 2 aminobenzothiazole 6 N methylsulfonamide, 2 aminobenzothiazole 6 N ethylsulfonamide, 2 aminobenz othiagole 6 N npropylsulfonamide, 2 aminobenzothiazole 6 N nbutylsulfonamide, 2 amino 6 -.rnethoxybenzothiazole, 2 amino 6 ethoxybenzothiazole, 2 amino -.6 n propoxybenzothiazole, 2 1' amino 6 n butoxybenzothiazole, 2 amino 6 methylbenzothiazole, 2 amino- 6 ethylben zothiazole, 2 amino 6 npropylbenzothiazole, 2 amino- 6 n butylbenzothiazgile, 2- amino- 6 p hydroxyethylbenzothiazole, 2 amino 6 'y hydroxypropylbenzothiazole, 2 amino 6 3 hydroXybutylbenzothiazole, 2 amino -.6 acetylaminobenzothiazole, 2 amino 6 n propionylaminobenzothiazole, 2 amino 6 n butyrylaminobenzothiazole, 2 amino- 6 thiomethylbenzothiazole, 2 4 amino 6 thiocyanobenzothiazole, 2 amino 6 cyanobenzothiazole, 2- amino 6 trifluoromethylbenzothiazole, -2 amino ,6- chlorobenzothiazole, 2 amino ,6 nitrobenzothiazole, 2 amino 4 i sth ybsn gth a qle 2 amin 5,6 dimethoxybenzothiazole, 2 amino 4,7 diethoxybenzothiazole, and 2 amino 4,6 dimethylbenzothiazole are representative of the 2-aminobenzothiazole compounds used in the preparation of the azo compounds of our invention.

Citrazinic acid (2,G-dihydroxyisonicotinic acid), methyl citrazinate (methyl 2,6-dihydroxyisonicotinate), ethyl citrazinate, n-propyl citrazinate, "isopropyl citrazinate, n-butyl citrazinate, isobutyl citrazinate, secondary butyl citrazinate, cyclohexyl citrazinate, fi-rnethoxycthyl citrazinate, B-ethoxyethyl citrazinate, B-n-propoxyethyl citpaz i fih l tezit tetm th w2-113 .dr wmethoxyisonicotinate, ethyl 2-hydroxy-6-ethoxyisonicotinate, ethyl 2-hYdIQXY-6IlPIOPOXYiSQIliQOtiHfltB, ethyl 2- y y- -b y on wt ate s pr py i2-hyd xymethoxy-isonicotinate, n-butyl 2-hydroxy 6 n butoxyisonicotinate, isobutyl 2-hydroxy-6-ethoxyisonicotinate, secondary butyl 2-hydroxy-6-methoxyisonicotinate, cyclohexyl 2-hydroxy-6-methoxyisonicotinate, cyclohexyl 2- hydroxy-6-ethoxyisonicotinate, cyclohexyl 2-hydroxy-6- n butoxyisonicotinate, 2 hydroxy 6 methoxyiso iCQ tinic acid, 2-hydroxy-6-ethoxyisonicotinic acid, Z-hydroxy- 6-n-propoxyisonicotinic acid and 2-hydroxy-6-n-butoxyisonicotinic acid, for example, are illustrative of the isonicotinic acid compounds used in the preparation of the azo compounds of our invention.

The non-metallized monoazo dye compounds of our invention have varying utility for the dyeing of cellulose alkyl carboxylic acid esters having two to four carbon atoms in the acid groups thereof, nylon, acrylonitrile polymers, such as polyacrylonitrile and acrylonitrile graft polymers, and polyesters, such as polyethylene terephthalate. After application to these materials, usually in the form of textile materials, the dye may be metallized thereon, if desired. The metallized azo compounds of our invention can be applied by ordinary dyeing or printing techniques to nitrogenous textile materials such as wool, silk, nylon: and acrylonitrile polymers, for example. Coloration can also be effected by incorporating the nonmetallized or metallized azo-compounds into the spinning dope, spinning the fiber as usual and converting the nonmetallized azo compounds to their metallizedform if desired. Also the metallizing agent can be incorporated in the spinning dope, the fiber spun as usual and then dyed with the non-metallized monoazo compounds to form the metal complex on the fiber. The new metallized dyes of our invention are preferably formed by heating the nonmetallized azo dye with the metallizing agent in organic solvents, ,such as, for example, cellulose acetate, cellulose acetate-propionate, acrylonitrile polymers, polyarnides, ethylene glycol monomethyl ether and formamide.

Both the non-metallized and metallized monoazo compounds of our invention are dyes for fibers prepared from graft polymers obtained by graft polymerizing acrylonitrile alone or together with one or more other monoethylenic monomers with a preformed polymer. The preformed polymer can be a homopolymer (a polymer prepared by polymerization of a single monomer) or it can be an interpolymer such as a copolymer (a polymer prepared by the simultaneous polymerization in a single reaction mixture of two monomers) or a terpolymer (a polymer prepared by the simultaneous polymerization in a single reaction mixture of three monomers), or the like, and the graft polymers for which the dyes are particularly useful are those containing atleast 5% by weight of combined acrylonitrile grafted to the preformed polymer molecule. V

The graft polymers which can be dyed using the nonmetallized and metallized dyes are thus polymers having directed placement of the polymerized monomeric units in the graft polymer molecule as distinguished from the t random distribution obtained in interpolymers which are prepared by simultaneous polymerization of all of the monomeric materials in the polymer. The preformed polymer can be either ahomopolymer of any of the wellknown polymerizable monomers containing a single CH=C group and desirably a CH =C group, or an interpolymer of two or more of such monomers; and the grafting can be effected with the preformed homopolymer or interpolymer in the polymerization mixture in which it was formed (i. e. a live polymer) or with the .preformedpoly-merisolated from the polymerization mixture in which it was formed (i. e. a dead polymer).

The preformed polymer desirably is a homopolymer of a vinyl pyridine, an acrylamide, a maleamide, a fumaramide, an acrylate, a methacrylamide, a methacrylate, an itaconamide, a citraconamide, a fumaramate, an itaconamate, a .citraconamate, a maleamate, or a vinyl ester; or an interpolymer of two or more of such monomers with each other or of at least one of such monomers with one or more different monoethylenic monomers characterized by a CH=C group such as styrene, acrylonitrile, substituted styrenes, vinyl or vinylidene chlorides, vinyl ethers, dialkyl maleates, alkenyl ketones, dialkyl fumarates, acrylic acid, methacrylic acid, substituted acrylonitriles, fumaronitrile, ethylene and the like.

The graft polymerization is-efiected by polymerizing acrylonitrile or a mixture of acrylonitrile with any other monoethyl'enic monomer, including any of the monomers enumerated hereinabove, with the preformed live or dead homopolymer or interpolymer' whereby the acrylonitrile alone or together with another grafting monomer is combined with the preformed polymer molecule to give a graft polymercontaining from '5 to 95% by weight of combined acrylonitrile.

The new azo compounds of our invention are of parcular utility for dyeing fibers prepared from a graft polymer obtained by graft polymerizing acrylonitrile and an acrylamide or methacrylamide with a preformed copolymer of acrylonitrile and the ide or methacrylamide.

U. S. Patent 2,620,324, issued December 2, 1952; U. S. Patent 2,649,434, issued August 18, 1953, and U. S. Patent 2,657,191, issued October 27, 1953, disclose other typical graft polymers that can be dyed with the new azo compounds of our invention.

The following examples in which parts are expressed as parts by weight illustrate our invention.

same or different acrylam- EXAMPLE 1 10.8 grams of sodium nitrite were dissolved in 78 cc. of concentrated sulfuric acid (94% The resulting solution was then cooled to C. and 155 grams of propionic-acetic 1:5) acids were added at a temperature below C. To the well stirred solution there were added 23.2 grams of Z-aminobenzothiazole while maintaining the temperature of the reaction mixture at 3 C. to 5 C. 155 grams of propionic-acetic (1:5) acids were then added at a temperature of 3 C. to 5 C. and this temperature was maintained for an additional two hours. The reaction mixture thus obtained was then added, with stirring, below 5 C. to a suspension of 32.7 grams of secondary butyl citrazinate in 230 cc. of propionic-acetic (1:5) acids. The cooling bath was removed and the mineral acid present was made neutral to Congo red paper with ammonium acetate. During the neutralization the temperature rose to about 28 C. The reaction mixture Was then allowed to stand for 2 hours after which it was drowned in 3 liters of water. The reaction product which precipitated was recovered by filtration,

washed well with cold water and dried. 34 grams of the dye compound having the formula:

CH3 S COOHCHnCHs were obtained as an orange colored product. This dye compound dyes cellulose acetate bright orange sha'des having good light-fastness and dyes the acrylonitrile graft polymer specifically described hereinafter shades having good fastness to light.

EXAMPLE 2 of propionic-acetic (1:5) acids. The mineraliacid prestion mixture was 'The dye product formic acid, 4 cc.

cut was made neutral to'Congo red paper by the addition of ammonium acetate and the reaction mixture was allowed to stand at room temperature for 2 hours and then poured into 2000 parts of tap water. The reaction product which precipitated was recovered by filtration, washed with cold water until neutral and dried at 60 C. 18 parts' of a dye compound which dyes cellulose acetate and nylon, for example, orange shades were obtained.

EXAMPLE 3 parts of concentrated sulfuric acid were added at room temperature to a slurry of 11.4 parts of Z-amino- 6-methylsulfonylbenzothiazole in 120 parts of water. The temperature of the reaction mixture rose to about 90 C. and the 2-amino-6-methylsulfonylbenzothiazole dissolved. After cooling to -10 C., a solution of 4.2 parts of sodium nitrite in 47 parts of concentrated sulfuric acid was carefully added to the reaction mixture with stirring while keeping the temperature of the reaction mixture at 5 C. or below. After stirring for 2 hours at -5 C., the diazonium solution resulting was added to a solution of 11.8 parts of cyclohexyl citrazinate in parts of propionic-acetic (1:5) acids at 5 C. The mineral acid present in the reaction mixture was made neutral to Congo red paper by the addition of sodium or. ammonium acetate following which the reaction mixture was poured into 2000 parts of cold water. The dye product which precipitated was recovered by filtration, washed well with cold water and dried at 60 C. 21.1 parts of a dye compound which dyes the acrylonitrile graft polymer specifically described hereinafter shades having good fastness to light were obtained as an orange solid.

EXAMPLE 4 with stirring while keeping the temperature of the reaction mixture at 5 C. or below. After stirring for 2 hours at --5 C., the diazonium solution resulting was added to a solution of 10.6 grams of secondary butyl citrazinate in 150 parts of propionic-acetic 1:5 acids the mineral acid present in the reaction mixture was made neutral to Congo red paper by the addition of sodium or ammonium acetate following which the reacwhich precipitated was filtration, washed well with cold water and dried at 60 C. 19.2 parts of a dye compound which dyes cellulose acetate yellow] shades having good light fastness andthe acrylonitrile graft polymer specifically described hereinafter shades having good light fastness were obtained.

recovered by EXAMPLE 5 By the use of 9.2 parts of ethyl citrazinate in Example 4 in place of secondary butyl citrazinate 16.8 parts of a dye compound which dyes the acrylonitrile graft polymer specifically described hereinafter shades having good fastness to light were obtained.

EXAMPLE 6 3.6 grams of 2-amino-6-methoxybenzothiazole were dissolved in a mixture consisting of 6 cc. of 80% aqueous poured into 2000 parts of cold water.

of glacial acetic acid and 8 cc. of l concentrated.-HCl. The resulting solution was cooledto 5: .C. and a solution of 1.42 grams of sodium nitritein 3 cc. of water. -.was added. at. a, temperaturebelow 5 C; following which the reaction mixture was stirred for 2' hours longer while maintaining the temperature below C. The diazonium solution thus obtained was run into a mixture of 3.66 grams of ethyl citrazinate, 8- grams ofanhydrous sodium. acetate and 60 cc. of 60% aqueous formic acid. The coupling. reaction which takes place was allowed to proceed for 2 hours at room temperature following which the reaction mixture was poured into! 800 cc. of water. The dye compound which precipitated was. recovered by filtration, washed well with water and dried. 6.1 grams of a dye compound which dyes the acrylonitrile graft polymer specifically described hereinafter shades of good light fastness were obtained as. an orange solid. When applied, to a cellulose acetate fabric and metallized thereon, brilliant red-violet dyeings having excellent resistance to the action of light and laundering are obtained. The dye compound of' this example is the same as the dye-compoundof Example 2.

EXAMPLE 7 130 parts of concentrated sulfuric acid were added at room temperature to a slurry of 11.4 parts of 2-amino-6- methyl-sulfonylbenzothiazole in 120 parts of water. The temperature of the reaction mixture rose to about 90 C. and the 2-amino-6-methyl-sulfonylbenzothiazole dissolved. After cooling to -10 C., a solution of 4.2 parts of sodium nitrite in 47 parts of concentrated sulfuric acid was carefully added to the reaction mixture with stirring while keeping the temperature of the reaction mixture at 5 C. or below. After stirring for 2 hours at 5 C., the diazonium solution resulting was added to a solution of 13.4 parts of n-butyl-2-hydroxy-6-n-butoxyisonicotinate in 125 parts of propionic-acetic (1:5) acids .at 5 C. The mineral acid present in the reaction mixture was made neutral to Congo red paper by the addition of sodium or ammonium acetate following which the reaction mixture was pouredinto 2000 parts of water. The dye product which precipitated was recovered by filtration, washed well with water and dried at 60 C. 18.5 parts of a dye compound which dyes cellulose acetate yellow shades were obtained.

EXAMPLE 8 50 parts of propionic-acetic (1:5) acids were added at 10 C. to a solution of 3.8 parts of sodium nitrite in 45 parts of concentrated sulfuric acid (94%). 8.9 parts of 4,6-dimethyl,-2-aminobenzo-thiazole were added below 5 C. to the sodium nitrite solution and the resulting reaction mixture was stirred for 2 hours at 0 C.5 C. The diazonium solution thus obtained was run into 11.8 parts of cyclohexyl citrazinate in 140 parts of propionic-acetic (1:5) acidsand the resulting solution was stirred for 1 hour at a temperature below 10 C. following which it was poured into 2000 parts of water and the reaction product which precipitated was recovered by filtration, washed with water and dried at 60 C. under vacuum. 16 parts of a dye compound which dyes cellulose acetate orange shades were obtained.

EXAMPLE 9' By the use of 4.22 grams of the isobutyl ester of citrazinic acid in Example 6 in place of ethyl citrazinate an orange colored dye compound which dyes the acrylonitrile graft polymer specifically described hereinafter shades having good fastness to light was obtained. When applied to a cellulose acetate fabric and metallized thereon, brilliant red-violet dyeings having excellent resistance to the action of light and laundering are obtained.

8? EXAMPLE 10 By the use of an equivalent amount of 2-amino-6- methyl-benzothiazole in Example 1 in place of Z-aminobenzothiazole an orange dye compound was obtained. It dyes cellulose acetate bright orange shades having good light, fastness and dyes the acrylonitrile graft polymer specifically described hereinafter shades having good fastness to light.

EXAMPLE 11 1 gram of the dye compound of Example 1 was refluxed in 16 cc. of acetone and 2.2 cc. of 28% aqueous ammonium hydroxide were added followed by the addition of 0.74 gram of Ni(OOCCI- I -4H O in 16 cc. of acetone. The resulting solution was refluxed with stirring for 2.5 hours and then poured into 450 cc. of water. The metallized dye product which precipitated was recovered by filtration, washed well with water and dried. 1.15 grams of a red pigment were thus obtained. When this pigment is intimately dispersed (as by grinding) in finely divided condition in a cellulose acetate-acetone dope which is then cast into film or extruded in filaments, brilliant red products having excellent fastness to light and washing are obtained.

EXAMPLE 12 1.01 grams of the dye compound of Example 2 were refluxed in 16 cc. of acetone and 2.2 cc. of 28% aqueous ammonium hydroxide were added followed by the addition of 0.74 gram of Ni(OOCCH -4H O in 16 cc. of acetone. The resulting solution was refluxed with stirring for 2.5 hour-s and then poured into 450 cc. of water. The metallized dye product which precipitated was recovered by filtration, washed well with water and dried. 1.16 grams of a reddish-violet pigment were thus obtained. When this pigment is intimately dispersed (as by grinding) in finely divided condition in a cellulose acetate-acetone dope which is then cast into film or extruded in filaments, reddish-violet products having excellent fastness to light and washing are obtained.

EXAMPLE 13 1.25 grams of the dye compound of Example 3 were refluxed in 16 cc. of acetone and 2.2 cc. of 28% aqueous ammonium hydroxide were added followed by the addition of 0.74 gram of Ni(OOCCI-I -4H O in 16 cc. of acetone. The resulting solution was refluxed with stirring for 2.5 hours and then poured into 450 cc. of water. The metallized dye product which precipitated was recovered by filtration, washed well with water and dried. 1.40 grams of a red pigment were thus obtained. When this pigment is intimately dispersed (as by grinding) in finely divided condition in a cellulose acetate-acetone dope which is then cast into film or extruded in filaments, red products having excellent fastness to light and washing are obtained.

EXAMPLE 14 1.21 grams of the dye compound of Example 4 were refluxed in 16 cc. of acetone and 2.2 cc. of 28% aqueous ammonium hydroxide were added followed by the addition of 0.74 gram of Ni(OOCCH -4H O in 16 cc. of acetone. The resulting solution was refluxed with stirring for 2.5 hours and then poured into 450 cc. of water. The metallized dye product which precipitated was recovered by filtration, washed well with water and dried. 1.36 grams of a red pigment were thus obtained. When this pigment is intimately dispersed (as by grinding) in finely divided condition in a cellulose acetate-acetone dope which is then cast into film or extruded in filaments, red products having excellent fastness to light and Washing are obtained. i

1.15 grams of the dye compound of Example 5 were A refluxed in 16 cc. of acetone and 2.2 cc. of 28% aqueous ammonium hydroxide were added followed by the addi tion-of 0.74 grams of Ni(OCCH -4H O in 16 cc. of acetone. The resulting solution was refluxed with stirring for 2.5 hours and then poured into 450 cc. of water. The metallized dye product which precipitated was recovered by filtration, washed well with water and dried. 1.30 grams of a red pigment were thus obtained. When this pigment is intimately dispersed (as by grinding) in finely divided condition in a cellulose acetate-acetone dope which is then cast into film or extruded in filaments, red products having excellent fastness to light and washing are obtained.

EXAMPLE 16 A cellulose acetate fabric dyed with a 3% dyeing of the dye product of Example 7 was padded with a 2% aqueous solution of nickel thiocyanate under conditions such that a 60 to 100% pick up, based on the weight of the goods, was obtained. The cellulose acetate fabric was air dried and then aged in a steam chest under p. s. i. pressure for 10 to minutes after which it was scoured at 60 C. with soap and water, rinsed well with water and dried. The cellulose acetate fabric was dyed a bright red shade in contrast to its original yellow color. The metallized dyeing thus obtained showed no alteration when subjected to a standard AATCC wash test at 160 F. Further, while the original yellow dyeing showed a break after 5 hours on the Fade-Ometer, the metallized dyeing showed no fading after hours exposure on the Fade-Ometer.

The above example was repeated replacing the nickel thiocyanate solution with a 2% aqueous solution of cobalt thiocyanate. The metallized dyeing thus obtained possessed a similar red shade having excellent fastness to washing and light.

EXAMPLE 17 A cellulose acetate fabric dyed with a 3% dyeing of the dye product of Example 2 was padded with a 2% aqueous solution of nickel thiocyanate in accordance with the procedure described in Example 16. The cellulose acetic fabric was dyed an attractive violet shade having EXAMPLE 18 A cellulose acetate fabric dyed with a 3% dyeing of the dye product of Example 8 was padded with a 2% aqueous solution of nickel thiocyanate in accordance with the procedure described in Example 16. The cellulose acetate fabric was dyed an attractive red shade which has excellent fastness to light. The metallized dyeing bled slightly upon being subjected to a standard AATCC wash test at 160 F. with soap and water. However, no bleeding was observed when the wash test was conducted at 140 F.

When the above example was repeated using a 2% aqueous solution of cobalt thiocyanate in place of the nickel thiocyanate solution, an attractive red dyeing which has substantially the same fastness to light andwashing as the dyeing of the example was obtained.

EXAMPLE 19 I 5 parts of the dye product of Example 7, 60 parts of the monomethyl ether of ethylene glycol, 2 parts of 28% 10 pigment which precipitated was recovered by filtration, washed well with hot water and then dried at 110 C. A yield of 6.5 parts was thus obtained. When this red pigment is initimately dispersed (as by grinding) in finely divided condition in a cellulose acetate-acetone dope which is then cast into film or extruded in filaments and woven or knitted into cloth, a pleasing red fabric of excellent resistance to the action of light and laundering is obtained.

EXAMPLE 20 A cellulose acetate fabric dyed with a 3% dyeing of the dye product of.Example 1 was padded with a 2% aqueous solution of nickel thiocyanate in accordance with the procedure described in Example 16. The cellulose acetate fabric was dyed a brilliant bluish-red shade which has excellent resistance to the action of light and laundermg.

EXAMPLE 21 The dye of Example 3 was prepared as before except that after filtering and washing the dye product was suspended in 500 cc. of water and brought to 60 C. 100 cc. of a 20% aqueous solution of nickel thiocyanate was added at a temperature of 60 C.- C. with good stirring over a period of about 30 minutes after which the temperature of the reaction mixture was raised to about 90 C. with stirring and while keeping the mixture slightly alkaline by the addition of 28% aqueous ammonium hydroxide. When the reaction was complete, as evidenced by no more acid formation, the reaction mixture was filtered to obtain 28 parts of metallized dye as a red solid. This metallized dye product, when incorporated into objects cast, molded or extruded from cellulose acetate compositions, yields bright scarlet objects of excellent fastness to light and Washing.

EXAMPLE 22 1.11 grams of the dye compound of Example 9 were refluxed in 16 cc. of acetone and 2.2 cc. of 28% aqueous ammonium hydroxide were added followed by the addition of 0.74 gram of Ni(OOCCH -4H O in 16 cc. of acetone. The resulting solution was refluxed with stirring for 2.5 hours and then'poured into 450 cc. of water. The metallized dye product which precipitated was recovered by filtration, washed well with water and dried. 1.26 grams of a reddish-violet pigment were thus obtained. When' this pigment is intimately dispersed (as by grinding) in finely divided condition in a cellulose acetateacetone dope which is then cast into film or extruded in filaments, reddish-violet products having excellent fastness to light and washing are obtained.

EXAMPLE 23 1.06 grams of the dye compound of Example 10 were refluxed in 16 cc. of acetone and 2.2 cc. of 28% aqueous ammonium hydroxide were added followed by the addition of 0.74 gram of Ni(OOCCH -4H O in 16 cc. of acetone. The resulting solution was refluxed with stirring for 2.5 hours and then poured into 450 cc. of water. The metallized dye product which precipitated was recovered by filtration, washed well with water and dried.

' 1.21 grams of a bluish-red pigment were thus obtained.

When this pigment is "intimately dispersed (as by grinding) in finely divided condition in a cellulose acetateacetone dope which is then cast into film or extruded in filaments, bluish-red products having excellent fastness to light and washing are obtained.

The following tabulation further illustrates the monoazo compounds of our invention and sets forth (1) the colors the non-metallized compounds yield on cellulose acetate and (2) the colors obtained on cellulose acetate when the non-metallized compounds are metallized on the fiber. C. A. refers to cellulose acetate, Original refers to the non-metallized dyeing and Final refers to the metallized dyeing.

Color on CA 2-Aminobenzothiazo1e C om- Coupling Component Metalliz ing Y pound Aggnt Original Final G-Methoxy Ni(SCN)a orangenu violet. Do do CO(SCN)2 d0 Do. G-Methylsulfonyl n-Butyl 2-hyd10 N KSON )2"...

o fi-Metliylthio Do isonicotinate.

do u-Butyl 2-Hydroxy imamcotinate.

. 0 fl-Megzhoxyethyl citrazinate o sec-gutyl citrazinate o Oyclohexyl citmzinate Cyclohexyl citrazinate Isobutyl citrazinate 13 Preparation of acrylonitrile graft polymer 3.0 g. of acrylonitrile and 7.0 g. of N-methyl methacrylamide were emulsified in 40 cc. of water containing 0.15 g. of potassium persulfate and 0.01 g. of tertiary dodecyl mercaptan. The emulsion was heated at 60 C. until 94% or more of the monomers had copolymerized. This result is usually accomplished by heating for about 12 hours. The copolymer contained approximately 30% by weight of acrylonitrile and 70% by weight of N-methyl methacrylamide. The mixture was then cooled to room temperature, 50 cc. of Water added and the mixture agitated until a homogeneous solution of dope containing 10% by weight of the copolymer resulted.

30.7 g. (3.07 g. of copolymer) of the above prepared solution or dope of the copolymer were placed in a jacketed reactor provided with an agitator and heat exchanger. There were then added 10 g. of acrylonitrile, 114 cc. of water, 0.58 g. of 85% phosphoric acid, 0.1 g. of potassium persulfate, 0.17 g. of potassium metabisulfite, 0.1 g. of tertiary dodecyl mercaptan and 0.56 g. of a 30% solution in water of N-methyl methacrylamide and the mixture heated, with stirring, to 35 C. and then allowed to level oii at 3739 C. After the heat of polymerization had been removed and when the conversion of the acrylonitrile to polymer had reached 96% or more, which is usually accomplished in a period of about 12 hours, the temperature was raised to 90 C. The mother liquor was removed by centrifuging the polymerization mixture, the polymer precipitate being reslurried twice with water and centrifuged to a 70% moisture cake. The cake was dried under vacuum at 80 C. in an agitated dryer. The overall yield of modified polyacrylonitrile product was over 90%. After hammermilling, the dry powder, now ready for spinning, was stored in a moisture proof container.

The acrylonitrile graft polymer prepared as above and containing about 18% by weight of N-methyl methacrylamide was soluble in N,N-dimethylformamide. Fibers spun by extruding a solution of the polymer prod uct in N,N-dimethylformamide into a precipitating bath had a softening temperature of about 240 C., an extensibility of about 2030 percent depending on the drafting an relaxing conditions, and showed excellent aflinity for dyes.

In order that the preparation of the azo compounds of our invention may be entirely clear, the preparation .of certain intermediates used in their manufacture is described hereinafter.

Preparation of 2-amino-6-methylsnlfonylbenzothiazole A solution of 200 parts of bromine in 300 parts of acetic acid was added over the course of about 1 hour to a mixture of 171 parts of p-aminophenylmethylsulfone and 202 parts of sodium thiocyanate in 1750 parts of acetic acid. The temperature was held below 35 C. during the addition and after complete addition of the bromine-acetic acid mixture, the reaction mixture was stirred for 18 hours. The reaction product was recovered on the filter by filtration, washed with acetic acid and then dispersed in 6000 parts of water. The reaction mixture thus obtained Was heated to boiling and then an alkali such as caustic soda or sodium carbonate was added until the pH of the reaction mixture was about 6. The reaction mixture was then cooled, filtered and the reaction product which collected on the filterwas washed well with water and dried at 120 C. 145 to 160 parts of 2-amino-6-methylsulfonylbenzothiazole were obtained as light yellow crystals melting at 226 228 C.

Preparation of Z-acetylamin-6-thiocyanobenzothiazole To a soltuion of 18.6 parts of aniline and 30.4 parts of ammonium thiocyanate in 300 parts of acetic acid at 15 C. 14.2 parts of chlorine were bubbled in at 15 C.-17 C. 30 minutes after addition of the chlorine 15.6 parts of sodium acetate and 30.4 parts of ammonium thiocyanate were added to the reaction mixture. Whileacid and then suspended in 600 parts of water. The mixture thus obtained was heated to boiling and filtered. 30 parts of sodium acetate were added to the filtrate and the solid which precipitated was collected at C. on a filter, washed with 200 parts of cold water and dried at 100 C. 30 parts of a product melting at 187 C.-188 C. were thus obtained.

30 parts of acetic anhydride were added at C. to a solution of 52.6 parts of the above product in 81 parts of acetic acid, and the temperature of the reaction mixture was held at 80 C. C. for one hour. The reaction mixture was then poured into 1000 parts of cold water and the product which precipitated was recovered by filtration, washed with 500 parts of water and-then dried at 60 C. 62 parts of 2-acetylamino-6-thiocyanobenzothiazole melting at 247 C.-249 C. were thus obtained.

Preparation of Z-amino-6-ethylsulfonylbenzothiazole 10 minutes and after cooling the reaction mixture tov 20 C., 16.3 parts of ethyl iodide were added at one time and the reaction mixture resulting was refluxed for one hour. The reaction mixture was then poured into 1000 parts of water and the product which precipitated was recovered by filtration, washed well with water and dried at 60 C. 23.6 parts of 2-acetylamino-6-ethylthiobenzothiazole melting at 168 C.169 C. were, obtained. If desired, the quality of the product can be checked by hydrolyzing a little of the product with acid to 2-amino- 6-ethylthiobenzothiazole melting at 137 C.139 C.

19 parts of 30% aqueous hydrogen peroxide were added to a solution of 15.5 parts of 2-acetylamino-6- ethylthiobenzothiazole in 53 parts of acetic acid while maintaining the temperature of the reaction mixture between 80 C.-90 C. The reaction mixture was maintained at this temperature for one hour and then poured into 500 parts of cold Water. The solid present in the reaction mixture was recovered by filtration and then suspended in a mixture of 800 parts of water and parts of concentrated hydrochloric acid. The reaction mixture thus obtained was heated to boiling and then filtered. The filtrate was neutralized with sodium acetate, cooled to 25 C. and filtered. The product collected on the filter was washed with cold water and dried at 60 C. 8.5 parts of 2-amino-6-ethylsulfonylbenzothiazole melting at 173 C.-175 C. were thus obtained.

Preparation of 2-amin0-6-is0propylsalfonylbenzothiazole prepared by the use of 17.76 parts of n-propyl iodide in place of isopropyl iodide in the foregoing example.

. Preparation of 2-amin0-6-isobatylsalfonylbenzothiazole bromide in place of ethyl iodide. The melting point of the Z-acetylamino-6-isobutylthiobenzothiazole obtained 1 was 167 C.-168 C. while that of the final product Z-amino-6-isobutylsulfonylbenzothiazole was 206 C.- 207 C.

2-amino-6-n-butylsulfonylbenzothiazole is similarly prepared by using 14.3 parts of n-butyl bromide in place of isobutyl bromide in the foregoing example.

Preparation of 2-amino-6-triflu0romethylsulfonylbenzothiazole 75 parts of bromine in 120 parts of acetic acid were added gradually with stirring to a solution of 98 parts of p-aminophenyltrifiuoromethylsulfone and 76 parts of sodium thiocyanate in 700 parts of acetic acid. The additionof the bromine was-begun at room temperature and the temperature of the reaction mixture Was kept below 35C. during the addition. The temperature ordinarily rises to about 32 C. The reaction mixture resulting was stirred for'24 hours at-ro0m temperature following which it was poured into 5000 parts of cold water and the mineral acid therein neutralized by the addition of sodium acetate with good stirring. The product which formed was recovered by filtration, washed well With cold water and dried at 110 C. 33 to 70 parts of 2-amino-6-trifluoromethylsulfonylbenzothiazole melting at 206-208 C. were thus obtained.

Preparation of 2-amino-dvtrifluoromethylbenzothiazole 12.5 parts of bromine in 20 parts of acetic acid were added dropwise, with stirring, to a solution of 12.4 parts ofp-aminobenzotrifiuoride and 12.7parts of sodium thiocyanate in 115 parts of acetic acid While maintaining the temperature of the reaction mixture below 35 C. The reaction mixture resulting was stirred for 12 hours following which the' solid presentv therein was removed by filtration. The filtrate was poured into 1000 parts of water and the mineral acid therein was neutralized by the addition of sodium acetate with good agitation. The product whichformed was recovered by filtration,,washed well with. cold Water and, dried under vacuum at 45 C. 717 -102 parts of 2-amino-6-trifiuoromethylbenzothiazole melting at 115.5-116.5 C. were thus obtained.

Preparation of 2-amino-6-,B-hya'roxyethylbenzothiazole 255.7 grams of bromine in 400 cc. of acetic acid were added gradually over a period of 1 hour with good stirring to a solution of 219.2 grams of p-aminophenylethyl alcohol and 259.2 grams of sodium thiocyanate in 2400 cc. of acetic acid while maintaining the temperature of the reaction mixture below 15 C. The reaction mixture resulting was stirred for 2 hours at C.-12 C. and the product which formed was recovered on the filter by filtration and washed with 300 cc. of acetic acid. The product filter cake thus obtained was dissolved in 1600 cc. of water at about 40 C. and the reaction mixture was made alkaline by the addition of sodium hydroxide. The reaction mixture thus obtained was heated to boiling and then cooledto C. and filtered. The product obtained onthe filter was washed with Water until neutral and then dried at 100 C. 206 to 230 grams of 2-amino-6- 3-hydroxyethylbenzothiazole were thus obtained in the form of white crystals melting at 175 C.177 C.

Preparation of secondary butyl citrazinate 50 grams of citrazinic acid, 15 grams of sulfonic acid (94% and 200 cc. of secondary butyl alcohol were refluxed together for 6 hours using a water trap in the condenser to remove the water formed. The reaction mixture-was then cooled, 100 cc. of water were added and the crystals of secondary butyl citrazinate which precipitated' were recovered by filtration and washed with coldethyl alcohol. 38 grams of product melting at 212 C.2l3 C. were thus obtained. Upon recrystallization from hot ethyl alcohol the secondary butyl citrazinate product melted at 217 C.218 C.

Preparation of isobutyl citrazinate 200 grams of citrazinic acid and 500 cc. of isobutyl alcohol were stirred in a suitable reaction vessel and dry HCl was passed through the reaction mixture until the temperature rose to reflux. The reaction mixture was refluxed overnight following which Water was added until a solid formed. The solid formed was recovered by filtration and dissolved in an aqueous sodium hydroxide solution. Acetic acid was added until a pH of 6 was reached. 2-isobutoxy-6-hydroxyisonicotinic acid isobutyl ester precipitated as a solid and was recovered by filtration and dried. A yield of 48 grams melting at 110 C.- 1105 C. was obtained. 50 cc. of acetic acid were added to the filtrate obtained from the ester recovery o eration. isobutyl citrazinate precipitated and was recovered by filtration and dried. 110 grams of product melting at 191 C.192 C. were thus obtained.

Preparation of cyclohexyl citrazinate 50 grams of citrazinic acid, 200 cc. of cyclohexanol and 15 cc. of concentrated sulfuric acid (94%) were refluxed together for 6 hours, using a water trap in the condenser to remove the Water as formed. The reaction mixture was then cooled, poured in 500 cc. of water and filtered. The solid recovered on the filter was washed with cold ethyl alcohol and recrystallized from hot ethyl alcohol. 30 to 40 grams of cyclohexyl citrazinate were recovered in the form of white crystals melting at 217 C.-218 C.

Preparation of isopropyl citrazinate 50 grams of citrazinic acid, 200 cc. of isopropyl alcohol and 15' cc. of concentrated sulfuric acid (94%) were refluxed together for 6 hours using a water trap in the condenser to remove the water as formed. The reaction mixture was cooled, poured into 500 cc. of water and filtered. The solid recovered on the filter was washed with cold ethyl alcohol and then recrystallized from hot ethyl alcohol. 25 to 35 grams of isopropyl citrazinate were thus obtained as crystals melting at 232 C.233 C.

Preparation of ,B-methoxyethyl citrazinate 50 grams of citrazinic acid were suspended in 200 cc. of the monomethyl ether of ethylene glycol. Dry HCl was passed through the reaction mixture at a temperature of about 70 C. and the citrazinic acid went into solution. Admission of dry HCl was continued at C. C. for 3 hours longer. Then an equal volume of water was added and the reaction mixture was cooled to 10 C. The crystals of B-methoxyethyl citrazinate which precipitated were recovered by filtration and recrystallized from the monomethyl ether of ethylene glycol. Since the product contains some high melting material, it was dissolved in an aqueous sodium carbonate solution and brought to a pH of 4.5 with acetic acid. The purified product precipitated and was recovered by filtration and dried. 31 grams of product melting at 183 C. were thus obtained.

By the use of the monomethyl ether of ethylene glycol and the mono-n-butyl ether of ethylene glycol in the above example in place of the monomethyl ether of ethylene glycol, fi-ethoxyethyl citrazinate and [3-n-butoxyethyl citrazinate, respectively, are obtained.

Another alkali metal thiocyanate such as potassium thiocyanate, for example, can be used in place of sodium thiocyanate in the foregoing examples dealing with the preparation of Z-aminobenzothiazole compounds. Similarly, another alkaline agent, such as sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium acetate or potassium acetate, for example, can be used to neutralize the mineral acid in place of sodium acetate.

The preparation of p-aminophenyltrifluoromethylsulfone is described in British Patent 485,592.

The non-metallized monoazo dye compounds of our invention can be applied to cellulose alkyl carboxylic acid esters having 2 to 4 carbon atoms in the acid groups thereof, nylon, an acrylonitrile polymer, such as polyacrylonitrile and acrylonitrile graft polymers, and polyester, such as polyethylene terephthalate, textile materials and the metallized azo dye compounds of our invention can be applied to nitrogenous textile materials such as, for example, wool, silk, nylon and acrylonitrile polymers, such as polyacrylonitrile and acrylonitn'le graft polymers, in the form of an aqueous dispersion and are ordinarily so applied.

To illustrate, the dye compound is finely ground with a dispersing agent such as sodium lignin sulfonate, Turkey red oil, soap, or an oleyl glyceryl sulfate and the resulting mixture is dispersed in wate The dye bath thus prepared is heated to a temperature approximately 45 C.-

' 55 C. and the textile material to be dyed is immersed in the dyebath, following which the temperature is gradually raised to 80 C.-90 C. and maintained at this temperature until dyeing is complete, usually one-half to two hours. From time to time throughout the dyeing operation, the material is worked to promote even dyeing. Upon completion of the dyeing operation, the textile material is removed from the dye bath, washed with an aqueous soap solution, rinsed well with water and dried. In the case of certain of the acrylonitrile graft polymers described hereinbefore it is necessary to dye at the boil for an extended period of time. Instances may be encountered where the fiber is not satisfactorily colored by the dyeing procedure just described. In these instances special dyeing techniques, such as the use of pressure, for example, developed by the art for the coloration of materials diflicult to color may be employed.

Widely varying amounts of dye can be used in the dyeing operation. .The amount of dye used can be, for example, /3 to 3% (by weight) of that of the textile material although lesser or greater amounts of the dye can be employed.

The following example illustrates one satisfactory way in which the fibers of the acrylonitrile graft polymers can be dyed using either the non-metallized or metallized azo compounds of our invention. 16 milligrams of dye are ground with an aqueous solution of sodium lignin sulfonate until well dispersed or alternately the dye can be dissolved in 5 cc. of hot Cellosolve. The dispersion or solution, as the case may be, is then poured into 150 cc. of water to which a small amount of a surface-active agent such as Igepon T Nekal BX (sodium alkylnaphthalenesulfonate)v or Orvus (sodium lauryl sulfate-type) has been added. The dye bath is then brought to the desired temperature and 5 grams of Well wet-out fibers of the graft polymer are added thereto. Dyeing is continued until the proper shade is reached. From time to time throughout the dyeing operation, the material is Worked to promote even dyeing.

The expression propionic-acetic (1:5) acids refers to a mixture of propionic and acetic acids in which there are five parts by volume of acetic acid to 1 part of volume of propionic acid.

The non-metallized azo compounds dye nylon substantially the same shade as they dye acrylonitrile polymers.

Acrylonitiile graft polymers including those of the type specifically described hereinbefore are described and claimed in Coover U. S. application Serial No. 408,012, filed February 3, 1954. 2-amino-6-trifluoromethylsulfonylbenzothiazole is described and claimed by Straley and Fisher U. S. application Serial No. 413,954 filed March 3, 1954, now abandoned. 2-amino-6-trifluoromethylben zothiazole is described and claimed by Straley and Fisher, U. S. application Serial No. 413,955, filed March 3, 1954, now abandoned.

We claim:

1. The monoazo compounds selected from the group consisting of the monoazo compounds and their metal complexes containing a metal selected from the group consisting of chromium, cobalt, copper, iron, manganese, nickel and vanadium, said monoazo compounds having the formula:

Ar\ ci OX N \N wherein Ar represents an ortho-arylene radical of the benzene series devoid of a sulfonic acid group, R represents a member selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxyalkyl group having 3 to 6 carbon atoms and a cyclohexyl group and X represents a member selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms.

2. A complex metal compound which contains one of the metals selected from the group consisting of chromium, cobalt, copper, iron, manganese, nickel and vanadium in complex combination with a monoazo compound having the formula:

COOR

Ar \GN=N HO oxwherein Ar represents an ortho-arylene radical of the benzene series devoid of a sulfonic acid group, R represents a member selected from the group consisting of a hydrogen atom, an alkyl group having 1 .to 4 carbon atoms, an alkoxyalkyl group having 3to 6 carbon atoms and a cyclohexyl group and X represents a member selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms.

3. A complex metal compound which contains one of the metals selected from the group consisting of chromium, cobalt, copper, iron, manganese, nickel and vanadium in complex combination with a monoazo compound having the formula:

wherein Ar represents an ortho-arylene radical of the benzene series devoid of a sulfonic acid group and R represents an alkyl group having 1 to 4 carbon atoms.

4. Complex nickel compounds of the monoazo compounds having the formula set forth in claim 2.

5. Complex nickel compounds of the monoazo compounds having the formula set forth in claim 3.

6. The monoazo compounds having the formula:

wherein Ar represents an ortho-arylene radical of the benzene series devoid of a sulfonic acid group, R represents a member selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxyalkyl group having 3 to 6 carbon atoms and a cyclohexyl group and X represents a member selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms.

7. The monoazo compounds having the formula:

COOR

8. A complex nickel compound of the azo compound having the formula:

5 O O CHCHzCHs 9. A complex nickel compound of the azo compound having the formula:

S COOCHzCI-Ia HO OH N 10. A complex nickel compound of the azo compound having the formula:

HO OH N 11. A complex nickel compound of the azo compound having the formula:

r S C O O CHCHaCHa CHaO:S

,CN=N

HO OH 12. A complex nickel compound of the azo compound having the formula:

s COOCHgOHi CHaOaS- HO OH 13. The azo compound having the formula:

CH3 s\ ooohflomom CN=N HO OH N 14. The azo compound having the formula:

N HO OH 15. The azo compound having the formula:

S COO-eye] hcxyl HO OH N 25 16. The azo compound having the formula:

References Cited in the file of this patent UNITED STATES PATENTS 2,068,353 Schneiderwirth Jan. 19, 1937 2,149,051 Helberger et a1. Feb. 28, 1939 2,441,612 Argyle et a1. May 18, 1948 2,560,502 Bestehorn et al. July 10, 1951 2,594,803 Riat et al Apr. 29, 1952 2,662,806 Menzi et al Dec. 15, 1953 OTHER REFERENCES 7 Kalman: American Dyestuff Reporter, vol. 30, No. 20,

September 29, 1941, pp. 499-503 and 524.

UNITED STATES PATENT OFFICE Certificate of Correction Patent No. 2,857,372 October 21, 1958 James M. Straley et al. It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, Formula 1, for the upper right-hand portion of the formula reading COOA read COOR--; column 9, line 45, Example 17, for acetic read acetate; column 13, line 14, for an read -and-; column 18, lines 47 to 52, claim 3, and column 19, lines 2 to 7, claim 7, the formula, each occurrence, should appear as shown below instead of as in the patent:

CODE 5 l column 19, claim 9, for the upper left-hand portion of the formula reading GH O- read CH O- Signed and sealed this 7th day of April 1959.

Attest:

KARL H. AXLINE, ROBERT C. WATSON, Attracting Ofiicer, Commissioner of Patents,

Claims

1. THE MONOAZO COMPOUNDS SELECTED FROM THE GROUP CONSISTING OF THE MONOAZO COMPOUNDS AND THEIR METAL COMPLEXES CONTAINING A METAL SELECTED FROM THE GROUP CONSISTING OF CHROMIUM, COBALT, COPPER, IRON MANGANESE, NICKEL AND VANADIUM SAID MONOAZO COMPOUNDS HAVING THE FORMULA: