”2 JORDINSON AND LOCKWOOD- IDENTIFICATION OF REACTIVE DYES J.S.D.C. 80

21 Whewell, C. S., Charlesworth, A., and Kitchen, R. L., 26 Peters, L., and Stevens, C. B., Dyer, 115, 327 (1956). 2’ Hadfield, H. It., and Lemin, D. R., J . Textile Inst., 51,

22 Williams, V. A., Text. Research J . , 32, 977 (19G2). 23 McPhee, J. R., ibid. , 31, 770 (1961). 2R Stovenson, M. C . , arid Stevenson, F. &I., ;bid., 53, 24 Moore, J. E., and O’Connell, R. A., ibid., 28, 687 (1958). 2; Maclarcn, J. A., Leach, S. J., and O’Donnoll, I. J., 28 Schmitt, C. H. A., Arne?. Dyestuff Rep . , 48, No. 18,

J . Textile Insf . , 40, P7G9 (1949). T1351 (I9GO).

P649 (1962).

40 (1969). Biochim. Biophys. Acta, 35, 280 (1059).

PUBLICATIONS SPONSORED BY THE SOCIETY’S IDENTIFICATION O F DYES COMMITTEE- IV

Further Notes on Reactive Dyes and their Identification on Cellulosic Fibres

F. JORDINSON and R. LOCKWOOD

The reactive systems and chromophores present in reactive dyes aro briefly discussed, with reference to the wct fastness of tho dyeings produced on ccllulosic fihres. The results are described of tests on selected reactive dyes on cotton carried out to distinguish between the various types of reactive dycs.

The second rcviscd edition of Clayton’s Tablcs includes a note dealing with the identification of some types of reactive dyes on cellulosic fibres. As a rough generalisation, when dyeings of reactive dyes are treated a t the boil in tho various alkaline solutions recommended by Clayton [viz. dilute ammonia; 5%) caustic soda then ammonium chloride; 5% caustic soda (2 min)], no colour is removed by the first two reagents, but dyeings of somc reactive dyes, i.e. Remazols (FH), do lose much colour when treated in caustic soda. Dyeings of other types of reactive dycs- Procion, Cibacron, Drimarenc, Rcactone, Levafix- withstand treat- ment in all tlicse alkaline solutions.

Tlic Rcmazol dyes thus fall into the same category in Clayton’s Tables as the direct (sub- stantive) dyes, whereas the otlier reactive dyes fall into the category in which thc vat, azoic, sulphur, and mordant dyes are to be found. In each case the reactive dyes may be differentiated from the other dyes mentioned in the tables by carrying out further specific tests z .

Much information has been published by the makers of reactive dyes on the mechanism of the reactions between cellulose and reactive dyes, particularly thosc containing triazinyl and tri- chloropyrimidyl groups 3, 4, An article by Reuben and Hall5 refers also to tho Remazol dyes in a similar manner and gives their characteristic formula, viz.

(whcre D = clwomophoric residue, R l , R 2, and R 3 = hydrogen or low-molecular-weight hydro- carbon residue, and OZ = residue of a multibasic acid, e.g. sulphate).

In the Remazol dyes, the vinyl sulphone group (D.SO,CH:CH,), derived ;from the action of alkali on the dyc solution, reacts with the cellulosic fibres by means of an addition reaction, forming a cellulose ether (D~SO,.CH,.CH,~O.Cell), whereas, with the other reactive dyes mentioned, rcaction with the fibre takes place by substitution. Dyciiigs of Remazol dyes are not as fast to alkaline reagents as those of the other reactive dyes mentioned above, since the dye-fibre link can hydrolyse under hot alkaline conditions to give reactive dye in the

D~S02~CH(R’)*CH(R*R8)~OZ

solution. This can react again with cellulose to give a stain which is difficult to remove. On the other hand, they are faster to acid treatments, e.g. acid cross-dyeing. A suitable cross-dyeing test has been devclopcd by Bode which differentiates Remazol dyeings, which withstand the test, from dyeings of most other reactive dyes, which bleed on to the white wool.

However, this acid cross-dycing test fails to differentiate the black reactive dyes, since dyeings of the disazo (2.1. Reactive Black 5 (Remazol Black B) and of the monoazo C.I. Reactive Black 1 (Cibacron Black BG; Procion Black H-GS) bleed distinctly and stain white wool. We have confirmed and extended Bode’s tests for distinguishing between these two types of reactive blacks.

Bode gives two tests, as follows- (1) Place the black dyeings on filter paper,

spot with conc. nitric acid, squeeze between the filter paper, and observe any alteration in colour and any bleeding. The Remazol Black B dyeing becomes blue-green and stains the paper the same colour, whercas the Cibacron Black BG and Procion Black H-GS dyeings change colour to khaki.

(2) Stecp a sample of dyed material in cold conc. sulphuric acid. With Remazol Black B a greenish black solution is obtained, but the other two blacks give a blue solution. We have extended this latter test by diluting the acid extracts with water. The extract from the Remazol Black dyeing changes to blue-green, whereas the Cibacron Black and Procion Black extracts turn distinctly red. This test provides a very satisfactory means of differentiating between these three dyes.

Primazin Dyes These dyes are of recent introduction and are

not mentioned in the second edition of the Colour Index. Even in the Supplement, the only reference to them is that they are a range of reactive dyes for cellulose made by BASF.

state that these dyes all possess the acrylamide residue as the main basis of the reactive group, viz.

Meyer and Wirth

D.NHCO*CH:CH,

April 1964 JORDINSON AND L O ~ W O O D - IDENTIFICATION O F REACTIVE DYES 303

(where D = chromophoric residue). In the presence of alkali they react with the hydroxyl groups of cellulose by an addition reaction, as do the Remazol dyes.

Dyeings on cotton of six members of the Primazin range, kindly supplied by Allied Colloids Ltd, Bradford, were subjected to systematic examination, first in order to place them in Clayton’s Tables and then to gain information as t o the nature of the chromophore present and the behaviour of individual members of the range. The Primazin dyes examined were Yellow 3GL. Scarlet GGL, Red R, Brilliant Pink 3B, Brilliant Blue BL, and Turquoise G.

After a preliminary “soaping” with a non-ionic detergent to remove from the fibre any dye not chemically combined with it, the dyeings were treated with tlie alkaline solutions used in Clayton’s Tables. Their behaviour closely followed that of the Remazol dyeings, i.e. a considerable amount of colour was removed by boiling 5% caustic soda solution, although adjacent white cotton remained unstained. On the Grey Scale for assessing Change in Colour, the effect on the pattern was 1, except for Primazin Turquoise G, for which i t was 1-2.

The Primazin dyes therefore fall into the same category in Clayton’s Tables as the direct (substantive) dyes. They do not, however, stain white cotton and they were found to respond to the confirmatory tests for reactive dyes suggested by Hoechst 2. I n fact, the Primazin dyeings were remarkably stable towards successive treatments with the four solvents, viz. a mixture of glacial acetic acid and ethanol, 1% ammonia solution, a mixture of dimethylformamide and water, and dimethylformamide.

So far as Clayton’s Tables are concerned, therefore, the Primazin dyes behave exactly like the Remazols, which is in line with what is known of the chemical nature of these two types of reactive dyes and of the nature of the dye-fibre bond, The possibility of distinguishing between Primazin and Remazol dyes was examined by com- paring pairs of dyeings, one from each range, of similar hue, with respect to their behaviour towards

(a) the Hoechst solvent tests, ( b ) boiling 4% caustic soda (10 min), (c) Bode’s acid cross-dyeing test.

The dyeings were- Primazin Yellow 3GL Remazol Yellow G (C.I. Reactive Yellow 14),

Primazin Scarlet GGL Remazol Brilliant Orange RR (C.I. Reactive

Primazin Red R Remazol Red B ((2.1. Reactive Red 22), a

Primazin Brilliant Pink 3B Rernazol Red Violet It (C.I. Reactive Violet 4),

Primazin Brilliant Blue BL Remazol Brilliant, Blue R (C.I. Reactive Blue

Primazin Turquoise G (no Remazol blue dye of

a monoazo dye

Orange 7), a monoazo dye

monoazo dye

a monoazo metal-complex dye

19), an anthraquinone dye

similar hue was available).

The results of the Hoechst tests and of the tests with boiling caustic soda were almost identical for each pair of the whole series of dyeings tested. There was complete resistance to the Hoechst solvents but a marked loss of colour in boiling caustic soda. In most cases the effect on tlie pattern was Grade 1 on the Grey Scale for assessing Change in Colour. The exceptions were Primazin Turquoise G (1-2), Remazol Brilliant Blue R (1-2), and Remazol Red Violet R (2). I n the acid cross-dyeing test, the Remazol dyeings showed excellent stability; there was no bleeding and no staining, except with ltcmazol Brilliant Blue R (4-5 on the Grey Scale for assessing Staining). The Primazin dyeings varied in their fastness t o acid cross-dyeing, some being completely unaffected in regard to both bleeding and staining. These were Yellow 3GL, Brilliant Pink 3B, and Turquoise G, but the remaining three dyeings, although showing no bleeding, staincd white wool as follows- Red R (4-5), Scarlet GGL (4), Brilliant Blue BL (3). It is interesting to note that in each series the Brilliant Blues were most affected by the cross-dyeing test. Unfortunately, the rcsults of this test did not show a sufficient degree of difference between the Primazin and Rcmazol dyeings to serve as a mcans of distinguishing between them.

It is known that hydrazine can break the linkagcs between certain rcactive dyes and cellulose. Nevell 8 treated samples of rcactive- dyed cotton in 40% hydrazine a t the boil under reflux and found that, in most cascR, the dye was removed from the cotton after boiling for three hours. We tried this method, using a shorter time of treatment (S-1 h) with the Primazin and Remazol dyeings used in the series just described. In two cases (pairs 1 (yellow) and 4 (bluish red)) the Primazin dyeing was less affected than the corresponding Remazol dyeing. In two other cases (pairs 2 (orange) and 5 (blue) ) the reverse effect was obtained, and in pair 3 (red) removal of dye took place a t the same rate from each dyeing. The dyeing of Primazin Turquoise G was stripped after 30 min at the boil. These results are obviously inconclusive and indicate that treatment in hydrazine will not serve to differentiate between Primazin and Remazol dyeings.

Further tests were carried out on the six Primazin dyeings to determine their behaviour towards various reducing agents and consequent behaviour on treatment with persulphate. With Formosul G (Clayton’s Tables), the yellow, scarlet, red, and pink dyeings were permanently decolorised, indicating that each is an azo dye. The dyeing of Primazin Brilliant Blue BL changed to brown on reduction, the original blue colour being restored by persulphate, indicating that the dye is an anthraquinone dye, like the reactive blues (C.I. Reactive Blue 2, 12, and 19) tested in our previous paper 2. Thc remaining dye, Primazin Turquoise G, first changed to purple on reduction, a t which stage the colour of the original dyeing could be restored with persulphate, but further treatment resulted in slow but permanent decolorisation. It is concluded that, like the turquoise blues previously tested2 (C.I. Reactive Blue 3, 7, and 18), Primazin

204 JORDINSON AND LOCKWOOD- IUENTIFICATION O F REACTIVE DYES J.S.D.C. 80

Test Prooions Remazols Levafix Cibaorons Priniazins Drimarenes Reactones

Boil for 10 niin in 401” caustic soda Little or no colour Colour largely removod No colour removed removed

Boil under reflux together with a piece of Bleeding on to whito white wool for 15 min in a solution containing wool

Little or no bleeding No bleeding ” - on to white wool

sulphuric arid ( 1 ml ronc./l.) and anhydrous sodium sulphate (2 g/l.)

Turquoise G is a phthalocyanine dye, since it givcs a bright green colour when spotted with conc. nitric acid. This changes to a deep purple when tlic material is spotted with a solution of stannous chloride in hydrochloric acid.

When warm allraline hydrosulphite was used as thc reducing agent, similar results were obtainccl but the reaction was slower and in some casrs reduction was incomplete. On the other hand, acid stannous chloride was a more encrgctic reducing agent, dyeings of the four azo dyes being dccolorised in the cold.

Levafix Dyes Information is now available on the chemical

character of this range of reactive dyes. I-Gihnel states that they contain two or more reactive groups based on the allcyl esters of mineral acids-

(where D = dye residue having no sulphonic acid group in the chromogen).

These dyes react with the hydroxyl groups of cellulose to form a very stable ether linkage. The presence in one dye molecule of sevcral rcactivc groups enables one molceulc of Levafix dye to form sevcral bonds with cellulose. This results in very high wet fastness, which is demonstratcd in the tests described below. Somc Levafix dyes (Olive IT; Grey IG) are derived from vat dyes by adding a reactive group to the vat pigment. These are claimed by Kuhnel to be much more difficult to remove from the fibre than the original vat dycs. There is also a new range of Levafix E dyes lo,

which are more reactive than the standard Levafix rangc, but a t present their chemical nature has not been disclosed.

A brief reference to a few tests carried out on dyeings on cotton of four Levafix dyes is made in our previous paper 2. They are the only reactive dyes so far examined which withstand both treatment in boiling 4% caustic soda and Bode’s acid cross-dyeing test. Since they are not removed from the fibre by any of the alkaline solutions uscd in Clayton’s Tables, they fall into the same section of the Tables as the Procion, Cibacron, Drimarene, and Reactone dyes. If subsequent members of the Levafix range are as fast to boiling 4% caustic soda solution and to acid cross-dyeing as the four mentioned above, i.e. Yellow 4G (C.I. Reactive Yellow 10); Golden Yellow IR (C.I. Reactive Yellow 9); Brilliant Blue RR (C.I. Reactive Blue 12); Brilliant Blue 1-30 (C.I. Reactive Blue l l ) , their complete rcsistance to acid eross-dyeing may be used to differentiate them from the other typcs of reactive dye with which they are grouped in Clayton’s Tables. Similarly, although Remazol and some Primazin dyes are also fast to cross-

D~SO,NHCH,CH,~OSO,H

dyeing, they do not withstand treatment in boiling 4y0 caustic soda solution.

Although the above table is substantially correct, there are a few exceptions among the dyes examined prcviously 2, as follows-

(1) Caustic soda test- Colour was partially removed from dyeings of C.I. Reactive Blue 2 (Procion B~LIC H-BS; Cibacron Blue 3G) and C.I. Reactive Red 17 (Reactone Red 2B).

( 2 ) Acid cross-dyeing test- No bleeding on to the white wool occurred with some phthalocyanine blues, viz. in pale depths of C.I. Reactive Blue 3 (Procion Brilliant Blue H-7GS) and C.I. Reactive Blue 7 (Cibacron Turquoise Bluc G), and in pale to medium depths of C.I. Reactive Blue 18 (Drimarene Turquoise Y-G; Reactone Turquoise Blue FGL).

Rather surprisingly, dyeings of the two Levafix Brilliant Blues bled a little in the Hoechst solvent tests. Incidentally, although the supplement to the Colour I n d e x lists Levafix Brilliant Blue I-3G as a phthalocyanine dye, it did not give the expectcd colour changes in the confirmatory test for phthalocyanines mentioned above. A dyeing on cotton of Levafix Brilliant Green IB ((3.1. Reactive Green 2), which is listed in the Supplement to the Colour I n d e x as a phthalocyanine dye, behaved very similarly to a dyeing of Levafix Brilliant Blue I-3G, viz.- ( a ) some bleeding occurred in the Hocchst test, (b) i t was unaffected by boiling 4% caustic soda and by the acid cross-dyeing test, and (c) on reduction with Formosul G or alkaline hydrosulphite i t changed to blue-green, the original colour being restored in air. The more powerful acid stannous chloride, however, brought about complete decolorisation. Subsequent treat- ment with persulphate produced only a slight restoration of colour. Like tlic Brilliant Blue I-3G, the Brilliant Green dyeing did not give the con- firmatory test for phthalocyanine dyes. ~hCPARTMIFNT OF CHEMISTRY

COLLEGE OF TECHNOLOGY HUI>I>ERSFIICLD

CoLoUR CHEMISTRY A N D DYEING

References Clayton, “Identification of Dyes on Textile Fibres”

(Bradford: Society of Dyers and Colourists, Second Revised Edition, 1963).

Jordinson and Lockwood, J.s.D.r., 78, 122 (1962). Preston and Fern, Chimia, 15, 177 (1961).

Reubon and Hall. Amer. Dyestuff Rep . , 51, 811 (1962). Rode, Mellinnd Teztilher. (En</. Edn), 41, 34 (1960).

* Rattee, Endeavour, 20, 164 (1961).

’ Mryer and Wirth, ihid., 43, 216 (1962). a Nevell, J.S.D.C. , 77, 158 (1961). 9 Knhnel, Buyer Farhen Reaue, No. 1, 8 (1962).

McCartney, Dyer , 129, 335 (1963).