WO1994004613A1

WO1994004613A1 - Watersoluble disazodyes for dyeing leather

Info

Publication number: WO1994004613A1
Application number: PCT/GB1993/001655
Authority: WO
Inventors: Brian Lamble; Denis Robert Annesley Ridyard; David Greenwood; Gordon Alexander Thomson
Original assignee: Zeneca Ltd
Current assignee: Syngenta Ltd
Priority date: 1992-08-14
Filing date: 1993-08-05
Publication date: 1994-03-03
Anticipated expiration: 1995-02-14
Also published as: AU4721493A; GB9217358D0

Abstract

Compounds of formula (1) wherein: R?1, R3 and R4¿ are each independently H, alkyl, alkoxy, halo, nitro, sulpho or carboxy; R2 is H, alkyl, alkoxy, halo, phenyl, nitro or carboxy; W is -SO¿2?O-, -CO2O-, -SO2NR?5-, -NR5¿-, -CH¿2NR?5-, or -CH¿2O-; R?5 is H or alkyl; and n has a value of 1 or 2 are dyes for leather.

Description

WATERSOLUBLE DISAZODYES FOR DYEING LEATHER

THIS INVENTION relates to azo dyes, their preparation and use, particularly for dyeing leather.

According to the present invention there is provided a water-soluble compound of the Formula (1) or salt thereof:

wherein:

R¹, R³ and R⁴ are each independently H, alkyl, alkoxy, halo, nitro, sulpho or carboxy;

R² is H, alkyl, alkoxy, halo, phenyl, nitro or carboxy;

W is -SO₂O-, -CO₂O-, -SO2_NR⁵-, -NR⁵-, -CH₂NR⁵-, or -CH₂O-;

R⁵ is H or alkyl; and

n has a value of 1 or 2.

R¹, R³ and R⁴ are preferably H, C_1-4-alkyl, C_1-4-alkoxy, C1, nitro, sulpho or carboxy. When R¹, R³ or R⁴ is C_1-4-alkyl it may be methyl, ethyl, n-propyl, sec-propyl, n-butyl, sec-butyl or tert-butyl. When R¹, R³ or R⁴ is C_1-4-alkoxy it is preferably methoxy or ethoxy.

In one class of dyes according to the invention R¹ is H, methyl or sulpho; R³ is H; and R⁴ is H.

R² is preferably H, C_1-4-alkyl, C_1-4-alkoxy, chloro or phenyl, more preferably H, methyl, ethyl, tert-butyl, methoxy of phenyl.

R⁵ is preferably H or C_1-4-alkyl, especially H.

W is preferably -SO₂O-, -CO₂O-, -SO₂NH- or -CH₂NH-, more preferably -SO₂O-.

The groups represented by W preferably connect rings A and B in Formula (1) in the order illustrated, for example when W is -SO₂O- the sulphur atom is attached to ring A and the right hand oxygen atom is attached to ring B.

n preferably has a value of 2. When n has a value of 2 the sulpho groups shown in Formula (1) are preferably at the 6-and 8- positions relative to the azo group.

It is preferred that W is connected to ring B shown in Formula (1) para with respect to the azo group.

The dyes and compounds mentioned in this specification may be in the form of a salt with any cation, preferably an alkali metal cation, for example soditim, potassium, lithium or a mixture thereof.

A preferred water-soluble dye according to the invention is of the Formula (2) or salt thereof:

wherein:

R¹, R² and W are as hereinbefore defined.

Dyes according to the invention may be prepared by condensation of a compound of Formula (3) with a compound of Formula (4) or salt thereof:

Wherein:

one of X and Y is -SO₂-L, -CO₂-L. or -CH₂-L and the other is hydroxy or a group of formula HN(R⁵)-;

L is a leaving group; and

R¹, R², R³, R⁴, R⁵ and n are as hereinbefore described.

The condensation is preferably performed in aqueous solvent, especially water.

Preferably a temperature of 40°C to 100°C, especially 50ºC to 90°C, is used for the condensation. It is preferred that the condensation is performed above pH 7, more preferably above pH 8, especially Ph 8.5 to 10.

The leaving group represented by L is preferably halo, especially chloro or bromo.

It is preferred that Y is hydroxy or a group of formula HN(R⁵)- as hereinbefore defined.

As will be appreciated by those skilled in the dyestuff art compounds of Foirmula (4) may be prepared by azo coupling of suitable starting materials, for example by diazotising an amino phenylazo naphthalene compound using NaNO₂ and coupling with a desired phenol or amine at below 5ºC.

Compositions comprising a compound of formula (1) or (2) and an inert carrier form a further feature of the invention. The compound and carrier are preferably in a weight ratio of 95:5 to 5:95, more preferably 90:10 to 10:90. The inert carrier preferably comprises alkali metal salts and optionally a de-dusting agent. Alkali metal salts include sodium and potassium chloride, sulphate, nitrate, carbonate, bicarbonate and mixtures thereof. Dodecyl benzene is a suitable de-dusting agent.

According to a further aspect of the present invention there is provided a process for the coloration of a substrate by applying thereto a compound of Formula (1) or (2) as hereinbefore defined.

The dyes of the invention may be used to colour a wide range of substrates such as wool, nylon and cotton and have been found to be particularly well suited for the coloration of leather due to their good dyeing properties, attractive shade and notable light fastness.

The present dyes can be applied to leather as an aqueous solution by spray, paddle, brush, tray or solvent dyeing, but are preferably applied by drum dyeing. It is preferred that dyeing is carried out at a temperature in the range of 35ºC to 70ºC, more preferably 55 to 65ºC, and at a weakly acid pH, e.g. pH 3.8 to 5.5. The ratio of dye solution to leather (by weight) can be quite low, for example in the range 2:1 to 8:1. The aqueous solution preferably contains 0.1 to 20 grammes of a dye according to the invention per 100g of water.

The present dyes may be applied to all types of leather, and in particular to wet full chrome leather, retanned side leather, suede, mordant leather (e.g. nappa sheepskin full grain leather) and vegetable tanned leather.

According to further aspects of the present invention there is provided leather coloured with a dye according to the present invention or when coloured according to the present process.

In the following examples, which are not intended to limit the scope of the present invention, all parts and percentages are by weight unless stated otherwise.

Example 1

Preparation of

Stage 1 - Preparation of Monoaso Compound

4-Aminoacetanilide (0.04M, 6.0g) was stirred in water (130ml) and 35% hydrochloric acid (0.1M, 8.8ml, SG-1.18) and the mixture cooled to 0-5°C. Sodium nitrite solution (20.5ml, 0.041M) was added evenly over 15 minutes to maintain an excess of nitrous acid for 10 minutes. A solution of sulphamic acid (10%) was added to remove excess nitrous acid followed by a solution of Azoguard (0.04M, 17.4g, at 100%) in water (50ml) at 0-5°C to give a diazonium solution.

G-Acid (2-hydroxy-6,8-disulphonapthalene, 0.42M, 23.44g) was stirred in water (200ml) at 30°C and the pH adjusted from 2.5 to 9.0 by addition of sodium carbonate solution (2M). The resultant solution was cooled to 0-5ºC.

The above diazonium solution was added quickly to the G-acid solution followed by sodium carbonate solution (2M) to pH 9.0, maintaining the temperature at 6°C. The coupling was maintained at pH 9.0 for a further 2 hours using sodium carbonate solution allowing the temperature to rise to 10°C. Precipitation of the product occurred after about 30 minutes. The mixture was stirred a further 2 hours at 15°C and room temperature overnight to give a suspension.

The suspension was neutralised to pH 7 using 35% hydrochloric acid and sodium chloride was added (90g, 20% w/v). After stirring for 30 minutes the product was collected by filtration, washed with 25% sodium chloride solution (4×25ml) and dried at 50°C to give 28.0g (58.6% strength) of monoazo product (85% yield).

Stage 2 - Hydrolysis

The monoazo product from Stage 1 (28g, 0.034H) was added to water (265ml) containing sodium hydroxide (11.0g of 1M solution) and the mixture held at 70 ± 2°C for 6 hours maintaining constant volume after which hydrolysis was judged to be complete by TLC.

Sodium Chloride (80g) was added to the reaction mixture at 70ºC and 35% hydrochloric acid added to give a pH of 1.0.

The yellow suspension was cooled to room temperature, the product filtered off, washed with saturated sodium chloride solution (2x65ml) and dried at 50°C to give 22.0g (56.5% strength) of yellow solid (90% yield).

Stage 3 - Preparation of Disazo Coapound

Sodium nitrite solution (16.5ml, 2M) was added to a solution of the yellow solid from Stage 2 (22.5g, 0.03M) in water (430ml) at a temperature of 50ºC and pH 7.3. The resultant solution was cooled to 0-5ºC and 35% hydrochloric acid added dropwise to pH 1.3. The mixture was stirred for 30 minutes during which a crystalline orange suspension was obtained. Excess nitrous acid was then destroyed with sulphamic acid solution (10%) to give a diazo solution.

A solution of 3-cresol (3.65g, 0.033M), water (430ml), sodium hydroxide solution (4ml of 46% strength) and sodium carbonate (6g) was cooled to 0-5ºC.

The above diazo solution was added quickly to the 3-cresol solution at pH 7.0 and the pH adjusted to 9.5 using sodium hydroxide solution (46%).

The reaction mixture was stirred for 1 hour at pH 9.5 and 0-5°C after which coupling was judged to be complete by TLC. Sodium Chloride (96.5g, 10% w/v) was added and mixture heated to 50ºC. A further 5% w/v βodium chloride (48g) was added and the suspension heated to 80°C to obtain a good physical form. After cooling to 40°C the product was filtered off and the filter cake pressed to remove excess liquid.

Stage 4

A solution of toulene-4-sulphonyl chloride (8.6g, 0.045M) in methanol (250ml) was added dropwise over 30 minutes to a stirred solution of the total product of Stage 3 in water (850ml) at 65ºC maintaining the pH at 9.0-9.5 using sodium hydroxide solution (2M). The mixture was held at pH 9.0-9.5 and 65°C for a further 1 hour after which TLC showed complete condensation of the toluene-4-sulρhonyl chloride and the product from Stage 3.

Sodium chloride (5% w/v) was added and the dye collected by filtration. The resultant filter cake was pressed and resuspended in water (215ml) at 60°C and pH 9.0. The mixture was stirred, cooled to room temperature, the final dye collected by filtration and dried at 50ºC to give 19.5g of product (94% strength) having a lambda max at 510nm (E_max45,000).

Examples 2 - 5

The method of Example 1 was followed except that in Stage 3 there was used the compound mentioned in Column II in place of 3-cresol.

The absorbtion maxima of the resultant compound is shown in Column III, the extinction co-efficient (E_max) is shown in Column IV and the shade on leather is stated in Column V.

Example 6

Preparation of

The monoazo product from Example 1, Stage 2, (14g) was diazotised according to the general method of Example 1, Stage 3, first paragraph to give a diazo solution.

A solution of N-ethyl-benzylaniline-3-sulphonic acid (8g) was prepared by stirring in water (400ml) at pH 2, adjusting the pH to 4 and heating the mixture to 55°C. on cooling to 0-5°C a complete solution was obtained.

The diazo solution was added at 0-5°C to the above complete solution at pH 2. The pH was gradually raised to 7-8 and the mixture stirred for 1½ days. 30% w/v salt was added and the precipitate filtered-off, redissolved in water (500ml), heated to 50°C and potassium acetate (30% w/v) added. After 20 minutes the resultant precipitate was filtered-off and washed with ethanol to give the product (12.5g), having a lambda max at 552nm, E_max 53,300.

Example 7

Preparation of

Stage 1

The monoazo product prepared according to Example 1, Stage 2 (27.45g) was diazotised according to the general method of Example 1, Stage 3, first paragraph to give a diazo solution.

The diazo solution was added to a solution of 3- methylaniline (8.025g) in water (800ml) at pH 5. The pH was adjusted to pH 5.5 and the mixture stirred for 1 hour. The resultant precipitate was filtered-off and used in Stage 2 without further purification.

Stage 2

A solution of toβyl chloride (10g) in acetone (100ml) was added dropwise to the product from Stage 1 (15g) in water (500ml) at pH 9 and 50°C.

The reaction was monitored by thin layer chromatography and, when complete reaction appeared to have occurred, NaCl (15% w/v) was added at 50°C and the product filtered-off, washed with acetone and dried.

15g of the product was obtained and was found to have a lambda max at 514nm, E_max 55,200.

Example 8

The dye from each of Examples 1, 2, 4 and 7 was applied to various leather substrates as described below.

a) Dyeing on Wet Pull Chrome Leather

A dyebath drum was prepared containing water at 60°C ± 5°C (80 to 200ml per piece of leather), 0.3% by weight of the Dye based in the leather and pieces of wet full chrome leather, approximately 18cm × 24cm. After 35 minutes emulsified anionic fat liquor (i.e. a water-oil emulsion, 1.5%) was added, followed 15 minutes later by formic acid (equivalent to half the weight of dye used). After a further 15 minutes the dyed leather pieces were removed from the dyebath, rinsed for 5 minutes with cold, soft running water, sammed, dried at 55°C ± 5°C and staked (staked means that the leather was softened by working it over a blunt blade),

b) Dyeing of Retanned Side Leather

Dyeing was carried out by running pieces of retanned side leather, approximately 18cm × 24cm in a drum containing a 1.5% by weight of dye based in the leather in water, at 60ºC over 30 minutes, followed by addition of fat liquor and 30 minutes later by 0.75% of formic acid. After 30 minutes running the pieces were rinsed, horsed up for 24 hours (horsed up means the leather pieces were placed over a special stand called a

"horse" to drain), sammed, dried, sawdusted, staked and suspended by a clamp in a dryer.

c) Dyeing on Dried Chrome Retanned Leather (Suede)

Pieces of chrome tanned leather retanned with syntans, fat liquored, dried and buffed (suede) were cut along the spine to give pieces of approximately 18cm × 24cm.

The pieces were re-wetted over 2 hours in a bath containing water at 60ºC ± 5ºC (80-200ml/piece), ammonia (2%), and a wetting agent (e.g. SUNAPTOL MB, 0.5%), rinsed and sammed.

The pieces were dyed over 50 minutes in a drum containing water at 60ºC ± 5°C (80-200ml/piece) and 8-10% by weight of dye based in the leather. Formic acid (equivalent to half the weight of dye used) was then added to the liquor and after 30 minutes the pieces were rinsed, sammed, dried at 55°C ± 5°C and staked.

d) Dyeing on Dried Chrome Retanned Leather (Nappa

Sheepskin - Full Grain)

Pieces of Nappa sheepskin (full grain) approximately 18cm × 24cm were treated as described above for dried chrome retanned leather (suede).

•) Dyeing on Dried Vegetable Tanned Leather

Crust vegetable tanned leather (i.e. leather which had been converted to the crust state by drying in the tanned, but not finished, state) was cut along the spine into pieces of approximately 18cm × 24cm.

The pieces were rewetted in a bath containing 80 to 200ml of water per piece, at 45°C ± 5°C over 45 to 60 minutes, and sammed.

Dyeing of the pieces was carried out over 45 minutes in a drum containing 50 to 70ml of water at 45°C ± 5ºC per piece of leather and 4% of dye by weight based in the leather. The liquor was then acidified using formic acid (equivalent to half the weight or dye used) and after 30 minutes the dyed pieces of leather were rinsed for 5 minutes with cold, soft running water, sammed and dried at 55°C ± 5°C. DYE/RESULTS

LEATHER DYE OF EXAMPLE 1 DYE OF EXAMPLE 2 DYE OF EXAMPLE 4 DYE OP EXAMPLE 7 a) Wet Full Chrome Leather dyed an Leather dyed an Leather dyed a Leather dyed a attractive red attractive red yellowish-red strong red shad shade with shade with good shade with good with good acceptable light penetration. levelling. penetration. fastness.

b) Retanned side- The dye penetrated The dye penetrated The dye gave an Leather dyed a Leather the leather pieces the leather pieces attractive strong bluish red shad well and gave strong well and gave bluish red shade on the with good red shades with red shades with good leather pieces with levelling.

acceptable light light fastness. good build up.

fastness.

c) Chrome reThe leather pieces Dyed leather a Dyed leather pieces The dye found tanned (suede) were dyed an bright bluish red a neutral red shade to have dyed attractive red shade shade with good with good light the leather an with good light light fastness. fastness. attractive red fastness. shade showing good

penetration.

LEATHER DYE OF EXAMPLE 1 DYE OP EXAMPLE 2 DYE OF EXAMPLE 4 DYE OF EXAMPLE 7 d) Nappa The leather pieces Leather pieces Leather pieces Leather pieces

Sheepskin were dyed a deep dyed strong red dyed deep red dyed deep red red shade. shades. shades with good shades showing wet fastness good build-up properties. properties.

e) Vegetable The leather pieces Leather dyed an Dyed attractive Leather pieces Tanned were dyed an attractive red red shade with dyed a bluish attractive red shade. good levelling. red shade with shade with good levelling. acceptable light

fastness.

93TJL09S MS - 14 Jul 1993

Claims

1 A water-soluble compound of the Formula (1) or salt thereof:

wherein:

R¹, R³ and R⁴ are each independently H, alkyl, alkoxy, halo, nitro,

sulpho or carboxy;

R² is H, alkyl, alkoxy, halo, phenyl, nitro or carboxy;

W is -SO₂P-, -CO₂O-, -SO₂NR⁵-, -NR⁵-, -CH.NR⁵-, or -CH₂O-;

R^s is H or alkyl; and

n has a value of 1 or 2.

2 A water-soluble dye according to Claim 1 of the Formula

(2) or salt thereof:

3 A compound as claimed in Claim 2 of formula (3) or salt thereof:

4 A process of producing a dye according to Claim 1, 2 or 3 which comprises reacting a compound of formula (3) with a compound of formula (4) wherein:

one of X and Y is -SO₂-L, -CO₂-L or -CH.-L and the other is hydroxy or a group of formula HN(R⁵)-;

and L is a leaving group

5 A process according to Claim 4 in which the leaving group is chloro or bromo.

6 A process according to Claim 4 or 5 in which the reaction is performed in an aqueous solvent, the temperature is 40 to 100°C and the pH is above 7.

7 A process according to Claim 4, 5 or 6 in which the group Y is a hydroxy group or group of formula HNR⁵-.

8 A composition which comprises an alkali metal salt, a compound according to Claim 1, 2 or 3 and optionally a dedusting agent.

9 A process of dying a substrate leather in which the dye is a compound according to Claim 1, 2 or 3.

10 A process as claimed in Claim 9 in which dyeing is carried out at a temperature of 35 to 70°C in a weakly acid aqueous medium which contains 1.0g of dye per 100g of water.

11 A process as claimed in Claim 9 or 10 in which the substrate is leather.