Dyeing of multiple types of fabrics with a single reactive azo disperse dye

Article abstract of DOI:10.2478/s11696-013-0444-3

Three novel reactive azo disperse dyes were prepared using 7-acetamide-4-hydroxy-2-naphthalene sodium sulphate as the precursor. The structure of the dyes has the combined characteristics of reactive, disperse, and cationic dyes. Under alkaline conditions (pH 9), the dyes can be applied to cotton, silk, wool, and nylon. Under neutral conditions, they can be used to dye polyester. Under acidic conditions (pH 4.5), they can colour acrylic fabric after conversion of the tertiary amine group to the quaternary ammonium cation. The colour-fastness of the dyed fabrics were also evaluated.

Full text of DOI:10.2478/s11696-013-0444-3

Chemical Papers
DOI: 10.2478/s11696-013-0444-3
ORIGINAL PAPER
Dyeing of multiple types of fabrics with a single reactive
azo disperse dye
Wei Zhang, Cheng Wei Wu*
State Key Laboratory of Structural Analysis for Industrial Equipment, Faculty of Vehicle Engineering and Mechanics,
Dalian University of Technology, 116024 Dalian, China
Received 2 April 2013; Revised 14 May 2013; Accepted 16 May 2013
Three novel reactive azo disperse dyes were prepared using 7-acetamide-4-hydroxy-2-naphthalene
sodium sulphate as the precursor. The structure of the dyes has the combined characteristics of
reactive, disperse, and cationic dyes. Under alkaline conditions (pH 9), the dyes can be applied to
cotton, silk, wool, and nylon. Under neutral conditions, they can be used to dye polyester. Under
acidic conditions (pH 4.5), they can colour acrylic fabric after conversion of the tertiary amine group
to the quaternary ammonium cation. The colour-fastness of the dyed fabrics were also evaluated.
c
ꢀ 2013 Institute of Chemistry, Slovak Academy of Sciences
Keywords: reactive dye, disperse dye, cationic dye, synthesis of dye, coloration, affinity
Introduction
cotton by the benzoylating reaction and used a dis-
perse dye to colour wool and cotton. They also inves-
tigated the coloration properties of benzoylated cot-
ton with a disperse dye in supercritical carbon diox-
For any given type of fabric, only a limited range
of dyes can be applied to obtain the desired aesthetic
effect with satisfactory exhaustion values and fastness
properties (Gordon & Gregory, 1987). Owing to the
distinctive properties of each dye, different dyeing pro-
cesses are necessary and multiple types of dyeing fa-
cilities are needed. In addition, each dyeing process
produces its own effluent, which requires unique treat-
ment prior to discharge into the environment. All these
factors contribute to increasing the cost of dyeing. If
one dye can be applied to all types of fabrics, both
the dyeing process and the effluent treatment can ef-
fectively be simplified. Moreover, as the dye bath may
be reused, the amount of dyeing effluent can be re-
duced substantially. It is evident that the development
of a novel type of dyes that can be applicable to multi-
ple types of fabric will not only reduce the dyeing cost
but will also provide an environmental advantage.
As conventional dyeing processes have already at-
tained their mature stage, the modification of fab-
ric and the modification of dye are regarded as two
feasible approaches to achieving this goal. Lewis and
Broadbent (1997) modified the structure of wool and
¨
ide (Ozcan et al., 1998). In these cases, disperse dyes
were used to dye hydrophilic fabric instead of the hy-
drophobic one, which clearly extends the application
range of disperse dyes. The effect of this treatment on
the wearability of fabric remains uncertain, and this
method has not achieved significant commercial suc-
cess to date. In parallel, various approaches have been
proposed to modify the structure of dyestuffs. Lee and
Kim (1999) and Lee et al. (2002) used temporarily
solubilised disperse dyes to dye polyester in the ab-
sence of a dispersing agent and they further extended
the application of this kind of dyestuff to wool (Lee et
al., 2001). Sokolowska-Gajda and Freeman (1990) and
Suwanruji et al. (2004) incorporated a dichlorotriazine
reactive group to the structure of acidic dye, and ap-
plied the resultant dye to poly(ethyleneterephthalate),
polyester, and acrylic fibres. They noted that the pres-
ence of naphthalene sulphonamide might account for
the good sublimation fastness on polyester, and as-
cribed the low exhaustion on cotton to the hydropho-
bic nature of the dye molecules.
*Corresponding author, e-mail: cwwu@dlut.edu.cn

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W. Zhang, C. W. Wu/Chemical Papers
Fig. 1. Synthesis route for reactive azo disperse dyes: i) POCl3, DMA, CH3CN, 55–60◦C, 4 h, 92 %; ii) N,N-dimethylethylenedi-
amine, K2CO3, acetone, 40◦C, 4 h, 61 %; iii) diazonium salt of p-amino-benzene-β-hydroxyethylene sulphonate (diazonium
salt of p-amino-benzene-β-hydroxyethylene sulphonate), H2O, < 5◦C, 1 h, 65 % (68 %); iv) diazonium salt of m-amino-
benzene-β-hydroxyethylene sulphonate, H2O, < 5◦C, 1 h, 81 %.
In light of the above, this work seeks to syn-
thesise reactive azo disperse dyes with a naph-
thalene sulphonamide structure. To improve the
water solubility of dye, the sodium salts of β-
sulphatoethylsulphonyl and N,N-dimethylethylenedi-
amine moieties are imparted simultaneously. It is
probable that these novel structured dyes may be ap-
plied to all types of fabrics.
Synthesis of N,N-dimethylethylenediamine
N,N-dimethylethylenediamine were synthesised us-
ing ethanol amine in accordance with the reference
(Akihiro et al., 1983).
Synthesis of II
Phosphorus oxychloride (4.9 mL, 0.050 mol) was
added to the mixture of I (5.4 g 0.018 mol), N,N-
dimethylacetamide (DMA; 6.6 mL, 0.090 mol), and
acetonitrile (28 mL) The resultant mixture was stirred
at 55–60◦C for 4 h and poured into cold water. II
(5.0 g) was then collected by filtration.
Experimental
General
All chemical reagents were commercial products of
analytical grade (Tianjin Chemical Reagent, China).
The mass spectra were obtained on a HP 1100 System
of HPLC/MSD or HP6890 Series GC System/5973
Mass Select Detector (Hewlett Packard, USA). The
IR spectra (the sample was formed into a KBr pel-
let) were recorded on an FT/IR-430 infrared spec-
trophotometer (JASCO, Japan). UV-VIS spectra were
recorded on a UV-VIS-NIR scanning spectrophotome-
ter (Cary 5000, Varian, UK). A quartz cuvette with
10 mm optical path length (CXA-145-055M, Fisher
Scientific, UK) was adopted as the solution-holder.
The dyeing of polyester was performed on a Roaches
TFO (Roaches, UK) and the light-fastness was tested
on a Xenotest150s (Heraeus, Germany).
Synthesis of III and IV
III and IV were synthesised by a similar pro-
cedure (Zhang, 2013). Take III as an example: in
a typical procedure, a suspension of II (4.9 g,
0.016 mol) in acetone (100 mL) was added drop-
wise into N,N-dimethylethylenediamine (0.6 g, 0.007
mol), K2CO3(4.2 g, 0.030 mol), and acetone (30 mL).
The mixture was stirred at 40◦C for 4 h. After extrac-
tion with ethyl acetate, III (3.5 g) was obtained.
Synthesis of dye V, VI, VII
The diazotisation of p-aminophenyl sulphatoethyl
sulphone was performed in accordance with the liter-
ature (Biolchi et al., 2006). Under stirring, a solution
of III (2.0 g, 0.006 mol) in N,N-dimethylformamide
(DMF; 10 mL) was slowly added into water (200 mL).
Then, the diazonium salt of p-amino-benzene-β-
Synthesis of dye and intermediate
Fig. 1 illustrates the synthesis routes for the three
reactive azo disperse dyes and the related intermedi-
ates.

W. Zhang, C. W. Wu/Chemical Papers
Table 1. Spectral data of synthesized dyes and intermediates
iii
Dyes
Spectral data
I
II
IR, ν˜/cm−1: 3480 (–SO2–OH), 3387 (–NH–), 1672 (–C O)
—
—
IR, ν˜/cm−1: 3383 (–NH–), 1677 (–C O), 1358 (–S O), 1167 (–S O)
— —
— —
—
—
III
IV
V
VI
VII
MS, m/z (Ir/%): 352.1 (100) (M + H)+ , 353.1 (19), 374.1 (12) (M + Na)+
MS, m/z (Ir/%): 615.1 (69.6) (M + H)+ , 637.1 (100) (M + Na)+
MS, m/z (Ir/%): 546.1 (100) (M – NaHSO4) UV, λmax, 465nm, ε · 10−4 (L mol−1 cm−1): 2.1
MS, m/z (Ir/%): 546.2 (100) (M – NaHSO4) UV, λmax, 472nm, ε · 10−4(L mol−1 cm−1): 1.5
MS, m/z (Ir/%): 929.0 (80) (M + H)+ , 827.2 (100) (M – NaHSO4) UV, λmax: 408nm, ε · 10−4(L mol−1 cm−1): 1.2
hydroxyethylene sulphonate (1.9 g, 0.006 mol) was
added drop-wise and the mixture was stirred under
5◦C for 1 h, giving 2.6 g of red brown V. Similarly, VI
(2.71 g) was synthesised when the diazonium salt of m-
amino-benzene-β-hydroxyethylene sulphonate (1.9 g,
0.006 mol) was used as the diazo component. Using
IV (1 g, 0.002 mol) as the coupling component, VII
(1.2 g) was prepared.
Polyester
The dye bath consisting of VII (0.15 g, 0.16 mmol,
liquid ratio 20 : 1) was heated to 130◦C at 2.5◦C min−1
maintained for 3 h and cooled to ambient temperature
,
at 3◦C min−1
.
Acrylic
The pH of the VII (0.15 g, 0.16 mmol) dye bath
was adjusted to pH 10 by 10 mass % Na3PO4, then
to pH 4.5 by formic acid. The dye bath was allowed
to boil for 1 h, then cooled to ambient temperature.
Application of dye to fabric
Since the dyeing processes for V, VI, and VII are
similar, VII is selected as an example to show how the
dyes are applied to different types of fabrics. The mass
of fabrics used was 3.0 g. Unless specified, the liquid
ratio (the ratio between the volume of dyeing solution
and the mass of fabric) was 60 : 1 and the quantity
of dispersing agent was twice that of the dye. After
dyeing, the coloured fabric was rinsed with water and
air-dried.
Results and discussion
Structure characteristics of dyes
To examine the optical properties, the UV-VIS
spectra of the synthesised dyes were recorded and the
maximum absorption (λmax) and molar extinction co-
efficient (ε) are listed in Table 1.
Cotton
By β-elimination reaction, the β-sulphatoethysul-
phone group can be converted to the vinylsulphone
group, which is the active reactant for nucleophilic
addition. As a consequence, the reactive azo disperse
dyes thus prepared may be used as reactive dyes to
colour hydrophilic fabrics, for instance cotton, wool,
silk, and nylon, that can provide nucleophile species.
The tertiary amine group can be converted to quater-
nary ammonium salt and the dyes thereby obtained
can be used as cationic dyes to colour acrylic by the
formation of salt- bonding. As no strong hydrophilic
group is present in the aromatic rings, the water sol-
ubility of the dyes is limited and the dyes can be em-
ployed as disperse dyes to colour hydrophobic fabrics
like polyester. In essence, the dyes thus prepared pos-
sess the combined characteristics of reactive, disperse
and cationic dyes and may be applied to multiple types
of fabrics, as illustrated in Fig. 2.
NaCl (6 g, 0.100 mol) in water (20 mL) was added
to a dye bath containing VII (0.03 g, 0.03 mmol) and
pH was then adjusted to 9 using 10 mass % Na2CO3.
The temperature of the dye bath was increased to
80◦C at 1◦C min−1 and maintained for 1 h.
Silk and wool
The pH of VII (0.09 g, 0.10 mmol) dye bath was
adjusted to 4.5 using formic acid. The temperature of
the dye bath was increased to 95◦C and maintained for
1 h, then cooled to 90◦C. The pH of the dye bath was
adjusted to 9 by 10 mass % Na2CO3 and maintained
for 15 min.
Nylon
The pH of the dye bath containing VII (0.15 g,
0.16 mmol) was adjusted to 4.5 using formic acid, then
the dye bath was allowed to boil for 1 h and then
cooled to 90◦C. The pH of the dye bath was adjusted
to 9 by 10 mass % Na2CO3 and maintained for 1 h.
Coloration performance of dyes
By measuring the absorbance of the dye solution
prior to and after dyeing, the dyeing exhaustion values
were calculated and are plotted in Fig. 3. It is clear

iv
W. Zhang, C. W. Wu/Chemical Papers
Table 2. Fastness properties of dyed fabrics
Wash-fastnessa
Staining on fabric
Compound
Fabric
o.m.f./%
Light-fastnessa
Colour change
Cotton
Other
V
Wool
Silk
Nylon
Acrylic
3
3
5
5
3–4
2–3
2
3–4
4–5
4–5
3
4
4
4–5
4
4–5b
3c
4d
4
4–5e
VI
Wool
Silk
Nylon
Acrylic
3
3
5
5
4
3–4
2
4
4–5
4–5
4–5
4
4–5b
3–4c
4d
4–5
4–5
3–4
3–4
4–5e
VII
Wool
Silk
Nylon
3
3
5
2
2
1–2
3
3–4
4
4
4
4–5
4–5b
4–5c
4–5d
a) Grey scale ratings ranged from 1 (poor) to 5 (excellent); if the depth of shade is light, the fastness of the dyed fabrics is not
included; b) wool; c) silk; d) nylon; e) acrylic.
Fig. 2. Application of dye to various types of fabrics.
that dyes V, VI, VII have a reasonable affinity for
wool, silk, and nylon, but a poor affinity for cotton
and polyester. As far as acrylic is concerned, only dyes
V and VI have a good affinity.
After washing with reference to the method de-
noted by Standards Association of China (1997), the
wash-fastness of the dyed fabrics was examined by the
method denoted by Standards Association of China
(1998) and the results are given in Table 2. All the
dyed fabrics exhibit moderate to excellent properties
in respect of fastness to laundering, as the grey scale
values are all over 3, in some cases up to 5. The dyed
fabrics also exhibit reasonable staining properties on
undyed fabrics: the scale of the cross-staining of fab-
rics is over 3, indicating insignificant dye transfer from
Fig. 3. Dyeing exhaustion values of reactive azo disperse dyes
on different fabrics: – V; – VI; – VII.
◦

W. Zhang, C. W. Wu/Chemical Papers
v
Table 3. Elemental composition of dyes
Compound
(M+
)
(M+
)
Formula
Content of –SO3Na in molecule/%
calculated
found
V
VI
VII
665.6914
665.6914
928.9606
546.2a
546.1a
929.0
C24H28N5NaO10S3
C24H28N5NaO10S3
C36H37N6NaO14S4
15.5
15.5
11.1
a) Found as (M – NaHSO4).
the dyed fabrics. The dyed fabrics have low to mod-
erate colour-fastness, which is presumably due to the
scarcity of electron-withdrawing groups in diazonium
salt (Yang & Zhang, 1989).
amount of dye molecule adsorbed, resulting in a re-
duced exhaustion value.
Although VII displays an exhaustion value of
11.2 %, the promotion of the affinity for cotton is still
desirable. This may be explained in terms of the low
hydrophilicity of the dye molecules. The strong hy-
drophilic group (–SO3Na) is attached to the aromatic
ring via an alkyl bridge and its percentage in the dye
molecules is lower than 16 % (Table 3); this means that
its contribution to the improvement of hydrophilicity
is limited. Compared with V and VI, dye VII has a
higher exhaustion to cotton (Fig. 3). This may stem
from the presence of one extra naphthalene ring in the
VII molecule, which leads to the increase in molecular
mass (Table 3) and is beneficial for the improvement
of substantivity to cotton. This is consistent with the
results reported by Smith et al. (2006) and Lewis and
Siddigue (2006). The exhaustion values of V, VI, and
VII to polyester range from 14.2 % to 17.3 %, which
may be associated with the high molecular mass and
poor planarity of the dye molecules.
The key issue in the design and synthesis of a sin-
gle dye molecule that is applicable to multiple types
of fabrics is to calculate the balanced points between
hydrophilicity and hydrophobicity. In addition, the
dye molecule should have a suitable molecular mass
and good planarity. For the dyes obtained here, fur-
ther structural modification is needed; this will fo-
cus on increasing the hydrophilicity by the incorpo-
ration of moderate hydrophilic groups and improving
the molecular planarity.
Effect of dye composition and structure on col-
oration
The macro dyeing properties of a dye molecule are
highly dependent on its composition and microstruc-
ture. If a dye is to be applied to multiple types of
fabrics, several factors need to be taken into account
and balanced: (i) the dye molecule should be neither
too hydrophilic nor too hydrophobic; either extreme
will repel the opposite type of fabric; (ii) molecular
mass is another concern. A low molecular mass dye
is preferable for the coloration of hydrophobic fabrics
as the diffusion of the dye molecule into the fabric is
strengthened. However, a low molecular mass dye is
likely to show poor substantivity for hydrophilic fab-
rics; (iii) a further issue affecting the dyeing perfor-
mance is the planarity of the dye molecule. In general,
good planarity facilitates penetration of the dye into
the fabric, and the occurrence of hydrogen-bonding
and van der Waal’s forces due to the close contact
between the dye molecule and the fibre, resulting in
good substantivity to the fabric. The atomic compo-
sition, molecular mass, and percentage of the sodium
sulphonate group (–SO3Na) in the molecules for dyes
V, VI, and VII are listed in Table 3.
Fig. 3 shows that dyes V, VI, and VII have rea-
sonable dyeing exhaustion values on wool, silk, and
nylon; this means that the dyes as prepared have
a good affinity for these fabrics. Table 2 indicates
that the coloured fabrics have good fastness to laun-
dering, which may be ascribed to the formation of
covalent bonding through operation of the nucle-
ophilic addition between the vinylsulphone group of
the dye molecule and functional groups such as hy-
droxyl (–OH) and amine (–NH2) of the fibre: see
Fig. 2. For acrylic, dyes V and VI have good exhaus-
tion values but VII has a poor one. This may be re-
lated to the higher molecular mass of VII (Table 3).
Under acidic conditions, the tertiary amine group in
dyes can be converted to the quaternary ammonium
cation, which may form salt bonds with anionic dye-
ing sites, hence the acrylic fabric is dyed. However,
once adsorbed, the bulky VII molecule may shield the
adjacent anionic dyeing sites and, in turn, reduce the
Conclusions
The synthesised dyes possess the characteristics
of a reactive dye (containing β-sulphatoethysulphone
group), a disperse dye (without the strong hydrophilic
group present in the aromatic rings), a cationic
dye (containing the tertiary amine group, which can
be converted to the quaternary ammonium group);
hence, they have the potential to be applied to mul-
tiple types of fabrics. The dyes thus obtained demon-
strate a reasonable performance on wool, silk, ny-
lon, and acrylic. Their performance on cotton and
polyester needs to be improved by enhancement of
their hydrophilicity and molecular planarity.
Acknowledgements. The financial support received from
the National Natural Science Foundation of China (51105051,
11272080) and the Fundamental Research Funds for the Cen-

vi
W. Zhang, C. W. Wu/Chemical Papers
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cation to cotton cellulose. Coloration Technology, 122, 217–
226. DOI: 10.1111/j.1478-4408.2006.00031.x.
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