GB2027443A

GB2027443A - New anthraquinone compounds

Info

Publication number: GB2027443A
Application number: GB7925962A
Authority: GB
Original assignee: Ciba Geigy AG
Current assignee: Novartis AG
Priority date: 1978-07-26
Filing date: 1979-07-25
Publication date: 1980-02-20
Also published as: JPS5519295A; DE2930003A1; FR2433507A1

Abstract

Disperse and cationic blue anthraquinone compounds and mixtures thereof of the formula <IMAGE> in which X is a halogen atom, R1 is a straight-chain or branched- chain alkyl group, and R2 is the -OH group, the -NH2 group, the -NH-alkyl group, wherein the alkyl group can be substituted by a quaternary nitrogen atom, or R2 is the -NH-A-O-R3 group, wherein A is an alkylene group which can be interrupted by O or S atoms, or A is a cycloalkylene group or the phenylene group, and R3 is hydrogen, an alkyl group, an -SO2-alkyl or -SO2- phenyl group, wherein the phenyl group can be further substituted, or R3 is the -NH-A-O- CO-R4 group, wherein A has the meaning already given, and R4 is an unsubstituted or substituted alkyl group or alkene group, or it is an -O-alkyl or -S-alkyl group; process for producing them; and their use as dyes for dyeing and printing in particular textile materials. Intermediates in which R2 is a halogen atom are also disclosed.

Description

SPECIFICATION New anthraquinone compounds The invention relates to new 6- and/or 7-halogenoanthraquinone compounds, to processes for producing them, to their use as dyes for dyeing and printing textile materials, and also, as an industrial product, the textile materials dyed and printed with these new anthraquinone dyes.

The new anthraquinone compounds, and mixtures thereof, according to the invention correspond to the formula I

in which X is a halogen atom, R, is a straight-chain or branched-chain alkyl group, and R2 is the -OH group, the -NH2-group, the -NH-alkyl group, wherein the alkyl group can be substituted by a quaternary nitrogen atom, or R2 is the -NH-A-O-R3 group, wherein A is an alkylene group which can be interrupted by O or S atoms, or A is a cycloalkylene group or the phenylene group, and R3 is hydrogen, an alkyl group, an -S02-alkyl or -SO2-phenyl group, wherein the phenyl group can be further substituted, or R3 is the -NH-A-O-CO-R4 group, wherein A has the meaning already given, and R4 is an unsubstituted or substituted alkyl group or alkene group, or it is an -O-alkyl or -S-alkyl group.

If the anthraquinone compounds of the formula I form a mixture, there is given here and in the following just one formula for the sake of simplicity. There is in fact preferably obtained a mixture of a 6-halogenoanthraquinone compound of the formula

with a 7-halogenoanthraquinone compound of the formula

in which formulae the symbols X, R and R2 have the meanings given under the formula I.

Preferred anthraquinone compounds consist of a mixture of a 6-halogenoanthraquinone compound of the formula I and a 7-halogenoanthraquinone compound of the formula I. The two components in the 6/7-halogenoanthraquinone compound mixture of the formula I are advantageously in the ratio of about 1:1.

As a halogen atom, X is for example a fluorine, chlorine or bromine atom. It is preferably the chlorine atom.

As a straight-chain or branched-chain alkyl group, R, is such a group having in particular 1 to 6 carbon atoms. This alkyl group is for example the methyl, ethyl, n- or iso-propyl, n-, sec-, or tert-butyl, or n- sec- or tert-pentyl group or -hexyl group. Preferably R, is a branched-chain alkyl group having 1 to 4 carbon atoms, and in particular R, is the isopropyl group.

When R2 is the -NH-alkyl group, the alkyl group can be straight-chain or branched-chain, and preferably has 1 to 4 carbon atoms. In this connection, R2 groups are for example: the NHmethyl, NH-ethyl, NH-n- and NH-iso-propyl group, and the NH-n-, NH-sec- or NH-tert-butyl group. These alkyl groups can be further substituted by a quaternary nitrogen atom.Quaternary nitrogen atoms are for example:

In these cases, the compounds concerned are cationic anthraquinone compounds which can contain both organic and inorganic anions, for example the halide ion, such as the chloride, bromide or iodide ions, also the sulfate, methylsulfate, aminosulfonate, perchlorate, carbonate, bicarbonate, phosphate, phosphomolybdic, phosphotungstic, phosphotungstomolybdic, benzenesulfonate, 4-chlorobenzenesulfonate, naphthalenesulfonate, oxalate, maleinate, acetate, propionate, lactate, succinate, chloroacetate, tartrate, methanesulfonate, benzoate and rhodanide ions, or complex anions, such as those of chlorine-zinc double salts.

If R2 is the NH-A-O-R3 grouping, A is alkylene (C1 to C6, straight-chain or branched-chain, and the alkylene bridge can be interrupted by hetero atoms such as 0 and/or S), or A is cycloalkylene (C5-C7, particularly cyclohexylene) and phenylene, whilst R3 is hydrogen, a straight-chain or branched-chain alkyl group (C1 -C4) or an SO2-alkyl-(C1-C4) or SO2-phenyl group, with the phenyl group being able to be further substituted, especially mono- or polysubstituted by alkyl groups (C,-C4).

If R2 is the NH-A-O-CO-R4 grouping, A has the above-given meaning, and R4 is an alkyl group (C1 -C6) which is unsubstituted or substituted by halogen (fluorine, chlorine or bromine); or an alkene group which is unsubstituted or substituted by halogen or alkyl (C1 -C4); or an 0alkyl-(C,-C4) or S-alkyl-(C1-C4) group.

In preferred anthraquinone compounds, R2 is either the NH2 group or the NH-alkyl group, wherein the alkyl group has 1 to 4 carbon atoms and is branched-chain, it is particularly the NH-iso-propyl group or the NH-CH2-CH2-O-R3 group wherein R3 is hydrogen or CH3, or especially the NH-CH2-CH2-O-CO-R4 group wherein R4 is CH3 or CH2CI.

Interesting anthraquinone compounds are both cationic compounds of the formula I wherein X is chlorine, R1 is the isopropyl group and R2 the group -NH-(CH2)3-N(CH3)3(03, and, in particular, disperse compounds of the formula I wherein X is the chlorine atom, R1 the iso-propyl group or the sec-butyl group, and R2 is the NH2 group, the -NH- isopropyl group, the -NH-CH2-CH2-OH group, or the -NH-CH2-CH2-OCO-R4 group wherein R4 is CH3, C2H5 or CH2CI.

The anthraquinone compounds according to the invention are blue to violet compounds, and on application in the dyeing process they are distinguished by good build-up properties on textile materials.

The anthraquinone compounds or mixtures thereof of the formula I are produced for example by reacting a 1.6- and/or 1 .7-halogenoanthraquinone compound of the formula II

in which the X's are identical halogen atoms, preferably chlorine, with an alkylamino compound introducing the NH-R, group, and subsequently halogenating the resulting product, in the 4position of the anthraquinone nucleus, to an intermediate of the formula Ill

in which X has the meaning already defined, and "Hal" is a halogen atom, and reacting the intermediate with an amine introducing the R2 group, or hydrolysing it to an anthraquinone compound of the formula I wherein R2 is the OH group, and if the resulting products contain a quaternisable N atom in the alkyl group of the -NH-alkyl group optionally quaternising this, or if in the products obtained R3 according to Claim 1 is hydrogen optionally acylating this.

The anthraquinone compounds of the formula II are known.

The condensation of compounds of the formula II with a compound introducing the -N H-B1 group, is performed by amination with an alkylamine in a known manner (see for example German Offenlegungsschrift No. 2,513,950). The subsequent reaction with halogen, preferably bromine, is performed for example in an organic solvent at a temperature of about 40-60"C.

There are obtained in this way anthraquinone compounds of the formula Ill

in which X and "Hal" independently of one another are each a halogen atom, and R1 is a straight-chain or branched-chain alkyl group, which compounds constitute new intermediates, and form a further part of the subject matter of the invention.

In preferred intermediates, X is the chlorine atom, Hal" the bromine atom, and R1 is a branched-chain alkyl group having 1 to 4 carbon atoms.

The further condensation of the intermediates of the formula Ill with a compound introducing the R2 group is performed with amines which introduce the group of the formula NH2, -NHalkyl, -NH-A-O-R3 or NH-A-O-CO-R4, or alternatively by hydrolysis of intermediates of the formula Ill, with the halogen atom in the 4-position being converted into the -OH group.The condensation reaction of the intermediates of the formula Ill with the amine is carried out for example in an organic medium (for example cellosolve or butanol) at a temperature of about 100 to 1 50 C, depending on the boiling point of the employed solvent, in a known manner and in the presence of a catalyst, such as copper powder or copper salt, and of a base, whereas the hydrolysis reaction is performed for example in a mixture of oleum with about 10% of free SO3 and boric acid, at a temperature of about 1 00 C.

Suitable alkylamines introducing the group of the formula -NH-R1 into the compound of the formula II are for example: methylamine, ethylamine, isopropylamine and sec-butylamine.

Amines which introduce the R2 group are for example: ethanolamine, methylamine, ethylamine, isopropylamine and 3-dimethylaminopropylamine.

Subsequent to the condensation reaction, the anthraquinone compounds containing in the alkyl moiety of the alkylamino group a quaternisable amino group in the R2 position can be quaternised. The quaternisation is peformed in a known manner, for example in an inert solvent, such as chlorobenzene, or optionally in an aqueous suspension, or without solvent in an excess of the alkylating agent, at a temperature of about 20"C to 1 20 C.

Suitable alkylating agents are for example: alkyl halides, such as methyl or ethyl chloride, methyl, ethyl or butyl bromide, or methyl or ethyl iodide; alkyl sulfates, such as dimethyl, diethyl and dibutyl sulfate, benzyl chloride, chloroacetic acid amide, acrylic acid ester, epoxides such as ethylene oxide, epichlorohydrin, and in particular alkyl esters of aromatic sulfonic acids, such as methyl-p-toluenesulfonate, methylbenzenesulfonate, and also the propyl and butyl esters of benzenesulfonic acid.

When anthraquinone compounds containing as R2 the group NH-A-O-CO-R4 are produced, they are produced, subsequent to the condensation reaction, by acylation of compounds wherein R2 is the NH-A-OH group with, for example, acetic anhydride or propionic anhydride, or with a 1:1 mixture of the two anhydrides, in an organic solvent, for example dimethylformamide, at room temperature, in a manner known per se.

After condensation, or quaternisation or acylation, the new anthraquinone compounds are separated from the reaction medium and dried.

The new 6/7-halogenoanthraquinone compounds of the formula I are used as disperse dyes or cationic dyes for dyeing and printing materials, particularly textile materials.

If the dyes are disperse dyes, especially those of the formula I in which X is chlorine, R1 is a branched-chain alkyl group and R2 is the NH2, NH-iso-propyl, NH-CH2-CH2OH, NH-CH2CH20CH3, NHCH2CH20COCH3 or NHCH2CH20COCH2CI group, it is possible to dye or print textile material which is dyeble with disperse dyes, such as copolymers formed from dicyanoethylene and vinyl acetate, fibres made from polyurethanes and polypropylene, and also fibres made from cellulose tri- and -2 1 /2-acetate, and especially fibres made from aromatic polyesters, such as those from terephthalic acid and ethylene glycol, and copolymers formed from terephthalic and isophthalic acid and ethylene glycol.These materials are dyed in a known manner, and the dyeings obtained can be subjected to an after treatment, for example by heating in an aqueous solution of an ion-free detergent. There are thus obtained full dyeings and printings having good fastness properties, particularly fastness to light, to sublimation and to wet processing.

Deeply coloured dyeings are likewise obtained when the dyes are applied from organic solvents, by which method the dye is applied from a solvent, in which it is present in the dissolved form or as a fine dispersion, to the textile material to be dyed. Suitable organic solvents are for example petroleum fractions, and above all chlorinated hydrocarbons (for example perchloroethylene), all of which can be used on their own or as a dispersion together with water.

If the dyes concerned are cationic dyes of the formula I, particularly those in which X is chlorine, R1 is a branched-chain alkyl group, and R2 is the group -(NH-(CH2)3-N0+ (CH3)3) SO4CH3, they are used for dyeing and, with the addition of binders and solvents, for printing materials dyeable with cationic dyes, especially textile materials which consist advantageously of homo- or copolymers of acrylonitrile, or synthetic polyamides or polyesters which are modified by acid groups. The new cationic dyes are also used for dyeing wet tow, plastics materials, leather and paper.Dyeing is preferably performed from an aqueous, neutral or acid medium using the exhaust process, optionally under pressure, or using the continuous process, by which processes there are obtained dyeings which are distinguished by good fastness properties, such as good fastness to light and to rubbing.

Finally, some of the new dyes can also be used in transfer printing.

Instead of being applied by impregnation, both the disperse dyes and the cationic dyes can also be applied by printing. For this purpose there is used for example a printing ink containing the dye together with auxiliaries customarily used in printing, such as wetting agents and thickeners.

All these materials can be in the most varied forms of make-up, and can be dyed by conventional exhaust or padding processes.

The particular advantage of the invention is that it is possible to use as starting compounds for producing the anthraquinone dyes of the formula I and intermediates of the formula Ill waste products which were hitherto worthless (for example residues from anthraquinone nitrations).

The invention is further illustrated by the following Examples but is not limited by them. Parts are given as parts by weight, and temperatures are in degrees Centigrade.

Example 1 37.8 parts of a mixture of 1-isopropylamino-4-bromo-6-chloroanthraquinone and 1-isopropyl4-bromo-7-chloroanthraquinone (1:1), which mixture is obtained by reacting 1,6/1 ,7-dichloro- anthraquinone is xylene with isopropylamine, in an autoclave at a temperature of 155 to the corresponding 1-isopropylamino-6/7-chloroanthraquinone, and brominating this in chlorobenzene to the 4-bromine derivative, are stirred up in 200 parts of isopropyl alcohol with the addition of 10 parts of potassium acetate and 0.4 part of cuprous chloride and, after the addition of 21.3 parts of ethanolamine, the mixture is kept at 70 to 80 for 7 hours. On cooling to room temperature, the 1,6/1,7-anthraquinone compound mixture of the formula

precipitates and is isolated by filtration.

In the form of its finely dispersed aqueous dispersion, it is suitable in particular as a dye for dyeing cellulose di- and triacetate in pure greenish-blue shades.

A considerable increase in the substantivity of the above dye on polyethylene glycol terephthalate is obtained by acylating this dye, in a manner known per se, preferably dissolved in 120 parts of N,N-dimethylformamide, at room temperature with 30.6 parts of acetic anhydride. On precipitation by dilution of the acylation mixture with water and subsequent filtration, the resulting dye of the formula

dyes, from its finely dispersed aqueous dispersion, cellulose triacetate fibres and particularly polyethylene glycol terephthalate fibres in pure greenish-blue shades having excellent fastness to wet processing, to rubbing and to light.

Very similar greenish-blue dyeings are obtained with dyes which are obtained by replacement of the 30.6 parts of acetic anhydride with 45 parts of propionic anhydride, or with 38 parts of a 1:1 mixture of the two anhydrides, and likewise by replacement of the 120 parts of N,Ndimethylformamide with 1 50 parts of pyridine, and at the same time the 30.6 parts of acetic anhydride with 25 parts of chloroacetic anhydride, or with 1 6.3 parts of chloroformic acid ethyl ester, or with 1 8.7 parts of chlorothioformic acid-S-ethyl ester, or with 1 7.2 parts of methanesulfochloride or with 28.6 parts of p-toluenesulfochloride, and otherwise performing the acylation reaction under analogous conditions.

Example 2 260 parts of isopropylamine are added in a steel autoclave to 37.8 parts of 1-isopropylamino 4-bromo-6/7-chloroanthraquinone obtained according to Example 1, and the temperature is held at 110 for 24 hours. The unreacted isopropylamine is subsequently distilled off with steam, and the anthraquinone compound of the formula

is separated by filtration and dried.

From its finely dispersed aqueous dispersion, the dye dyes polyester fibres in fast, brilliant blue shades.

Dye mixtures producing very similar deep blue dyeings are obtained by using as starting material in the above Example, instead of 37.8 parts of 1-isopropylamino-4-bromo-6/7chloroanthraquinone, 39.2 parts of 1 -sec-butylamino-4-bromoanthraquinone-6 / 7-chloroanthra- quinone, or by using, instead of 260 parts of isopropylamine, equivalent parts of secbutylamine, or by combining these two modifications, the procedure otherwise being as described in Example 1.

Example 3 37.8 parts of ? -isopropylamino-4-bromo-6 /7-chloroanthraquinone obtained according to Example 1, 34 parts of p-toluenesulfamide, 10 parts of potassium acetate and 1 part of copper powder in 300 parts of 1-pentanol are mixed together as 130 for 3 hours by stirring. After cooling, the reaction product of the formula

is filtered off, and dried under vacuum.

The intermediate thus obtained is introduced into 200 parts of 98% sulfuric acid, and the temperature is kept at 25-30" for 5 hours. At the end of this period, the sulfuric acid solution is poured into ice water, and the anthraquinone compound mixture of the formula

is isolated by filtration.

Applied as dye from a finely dispersed aqueous suspension, this mixture dyes cellulose di- and tri-acetate fibres and polyethylene glycol terephthalte fibres in fast blue shades.

Example 4 37.8 parts of 1 -isopropylamino-4-bromo-6 / 7-chloroanthraquinone obtained according to the data given in Example 1, 41 parts of 3-dimethylaminopropylamine, 10 parts of potassium acetate and 0.2 part of cuprous chloride with 100 parts of n-butanol are heated at 100-105" for 6 hours with stirring. The mixture is allowed to cool, the product of the formula

which has precipitated is filtered off, washed with methanol and subsequently with hot water.

Five parts of the product obtained are dissolved in 50 parts of chlorobenzene, and to the solution at 50-60" are added 1.3 parts of dimethylsulfate diluted with 10 parts of chlorobenzene. The quaternary trimethylammonium-methosulfate of the formula

immediately precipitates out. The product is filtered off and is subsequently washed with chlorobenzene until the liquid running off is colourless.

The water-soluble blue compound mixture dyes polyacrylonitrile fibres in pure blue shades fast to light.

Five parts of the unquaternised product according to Example 4 in 50 parts of chlorobenzene with 6 parts of benzyl chloride are heated at 95-100" for 10 hours; at the end of this time, the quaternary chloride of the formula

has precipitated out and, after cooling, is filtered off and dried.

When dyeing is performed with the above product on polyacrylonitrile fibres, there is obtained a blue dyeing very similar to that obtained with the quaternary methosulfate mentioned.

Example 5 Two parts of the acylated dye obtained according to Example 1 are dispersed in 4000 parts of water. To this dispersion are added 1 2 parts of the sodium salt of o-phenylphenol and 1 2 parts of diammonium phosphate, and 100 parts of polyethylene glycol terephthalate yarn are dyed at 95-98" for 90 minutes in this liquor. The dyeing is subsequently rinsed, and then treated with aqueous sodium hydroxide solution and a dispersing agent. A greenish-blue dyeing having fastness to light and to wet processing is obtained.

Example 6 In a pressure dyeing apparatus, 2 parts of the acylated dye obtained according to Example 1 are finely suspended in 2000 parts of water containing 4 parts of oleyl polyglycol ether. The pH value of the dye bath is adjusted- to 4 to 5 acetic acid. 100 parts of polyethylene glycol terephthalate fabric are introduced into this dye bath at 50 ; the bath is then heated within 30 minutes to 140 , and dyeing is performed for 50 minutes at this temperature. The dyeing is subsequently rinsed with water, soaped and dried. A greenish-blue dyeing having fastness to light and to wet processing is obtained.

Example 7 Polyethylene glycol terephthalate fabric is impregnated at 40 on a padding machine using a liquor of the following composition: 20 parts of the acylated dye obtained according to Example 1, finely dispersed in 10 parts of sodium alginate, 20 parts of triethanolamine, 20 parts of octyiphenolpolyglycol ether, and 930 parts of water The fabric squeezed out to about 100% is dried at 1 00 C, and subsequently fixed for 30 seconds at a temperature of 210 . The dyed material is rinsed with water, soaped and dried. A greenish-blue dyeing having fastness to light and to wet processing is obtained.

Example 8 5 g of the dye produced according to Example 4 and quaternised with dimethyl sulfate or with benzyl chloride is stirred to a paste with 2 g of 40% acetic acid, and then taken into solution by the addition of 4000 g of hot water. There are also added 1 g of sodium acetate and 2 g of an addition product of 1 5 to 20 equivalents of ethylene oxide with Noctadecyldiethylenetriamine, quaternised with dimethyl sulfate, and 100 g of polyacrylonitrile fabric are subsequently introduced at 60 . The bath is heated within 30 minutes to 100 , and dyeing is performed in the boiling liquor for 90 minutes. The liquor is afterwards allowed to cool to 60 in the course of 30 minutes. The material dyed in this manner is then removed from the bath, and is rinsed with lukewarm water and with cold water.

A blue polyacrylonitrile dyeing having fastness to light is obtained.

Claims

1. Anthraquinone compounds and mixtures thereof of the formula I

in which X is a halogen atom, R1 is a straight-chain or branched-chain alkyl group, and R2 is the -OH group, the -NH2 group, the -NH-alkyl group, wherein the alkyl group can be substituted by a quaternary nitrogen atom, or R2 is the -NH-A-O-R3 group, wherein A is an alkylene group which can be interrupted by O or S atoms, or A is a cycloalkylene group or the phenylene group, and R3 is hydrogen, an alkyl group, an -SO2-alkyl or -SO-phenyl group, wherein the phenyl group can be further substituted, or R3 is the -NH-A-O-CO-R4 group, wherein A has the meaning already given, and R4 is an unsubstituted or substituted alkyl group or alkene group, or it is an -O-alkyl -S-alkyl group.

2. Anthraquinone compounds according to Claim 1, which constitute a mixture of a 6halogenoanthraquinone compound of the formula I and a 7-halogenoanthraquinone of the formula I.

3. Anthraquinone compounds according to Claim 1 or 2, wherein X is the chlorine atom.

4. Anthraquinone compounds according to any of Claims 1 to 3, wherein R, is a branched chain alkyl group having 1 to 4 carbon atoms.

5. Anthraquinone compounds according to Claim 4, wherein R1 is the isopropyl group.

6. Anthraquinone compounds according to any of Claims 1 to 5, wherein R2 is the -NH2 group.

7. Anthraquinone compounds according to any of Claims 1 to 5, wherein R2 is the -NHalkyl group, in which the alkyl group has 1 to 4 carbon atoms and is branched-chain.

8. Anthraquinone compounds according to Claim 7, wherein R2 is the NH-isopropyl group.

9. Anthraquinone compounds according to any of Claims 1 to 5, wherein R2 is the NH-CH2-CH2-O-R3 group, in which R3 is hydrogen or CH3.

10. Anthraquinone compounds according to any of Claims 1 to 5, wherein B2 is the -NH-CH2-CH2-O-CO-R4 group, in which R4 is CH3 or CH2CI.

11. Anthraquinone compounds according to Claim 1, in which X is chlorine, R1 is the isopropyl group, and R2 is the group -NH-(CH2)3-N(CH3)3(3.

1 2. Anthraquinone compounds according to Claim 1, in which X is the chlorine atom, R1 is the iso-propyl group or the sec-butyl group, and R2 is the NH2 group, the -NH-isopropyl group, the -NH-CH2-CH2-OH group, or the -NH-CH2-CH2-OCO-R4 group, in which R4 is CH3 or CH2CI.

1 3. A process for producing anthraquinone compounds or mixtures thereof of the formula I according to Claim 1, which process comprises reacting a 1.6- and/or a 1 .7-halogenoanthraqui- none compound of the formula II

in which the X's are identical halogen atoms, with an alkylamino compound introducing the NH-R1 group, and subsequently halogenating the resulting product, in the 4-position of the anthraquinone nucleus, to an intermediate of the formula Ill

14. A method of dyeing or printing textile materials which comprises the use of anthraquinone compounds as claimed in any of Claims 1 to 1 2.

1 5. A method as claimed in Claim 14, in which the textile material is a polyester.

16. A method as claimed in Claim 14, in which the material is a polyacrylonitrile, and the anthraquinone compounds contain a quaternary nitrogen atom.

1 7. The material dyed and printed with the anthraquinone dyes or mixtures thereof according to Claims 14 to 1 6.

1 8. Intermediates or mixtures thereof of the formula Ill

in which X and "Hal" independently of one another are each a halogen atom, and R, is a straight-chain or branched-chain alkyl group.

1 9. Intermediates according to Claim 18, wherein X is the chlorine atom.

20. Intermediates according to Claims 1 8 and 19, wherein "Hal" is the bromine atom.

21. Intermediates according to Claims 18 to 20, wherein R1 is a branched-chain alkyl group having 1 to 4 carbon atoms.

22. An anthraquinone compound as claimed in Claim 1 to 12, substantially as herein described with reference to any one of the foregoing Examples 1 to 4.

23. A method as claimed in Claim 14, substantially as hereinbefore described, with reference to any one of the foregoing Examples 5 to 8.