Synthesis of disperse dyes derived from 4-amino-N-decyl-1, 8-naphthalimide and their dyeing properties on polyester fabrics

Article abstract of DOI:10.1016/j.dyepig.2018.04.050

Novel series of amphiphilic monoazo dyes were synthesized using 4-amino-N-decyl-1, 8-naphthalimide by coupling with different substituted anilines and naphthalenes in appropriate reaction condition. The intermediates and the dyes were purified by recrystallization methods. The structures of the newly synthesized intermediates and the dyes were confirmed from elemental analysis (CHN), FT-IR, ¹H and ¹³C NMR, MS and UV spectroscopic techniques. Spectrophotometric investigations of the synthesized dyes in different solvents were carried out in order to obtain their absorption maxima, molar extinction coefficients and solvatochromic effects. These dyes were applied on polyester fabrics as disperse dyes using high temperature exhaust dyeing method. The relevant dyeing characteristics, such as buildup on fabrics, wash, perspiration and light fastness were evaluated. Fabrics dyed with these dyes furnished generally deep and bright intense hues ranging from light yellow to orange to light red. The colour fastness of the dyed fabrics to washing and perspiration was assessed to be very good, however, the light fastness was found to be poor, moderate to very good.

Full text of DOI:10.1016/j.dyepig.2018.04.050

Accepted Manuscript
Synthesis of disperse dyes derived from 4-amino-N-decyl-1, 8-naphthalimide and
their dyeing properties on polyester fabrics
Umar Salami Ameuru, Mohammed Kabir Yakubu, Kasali Ademola Bello, Peter
Obinna Nkeonye, Azim Ziyaei Halimehjani
PII:
S0143-7208(18)30179-7
10.1016/j.dyepig.2018.04.050
DYPI 6711
DOI:
Reference:
To appear in: Dyes and Pigments
Received Date: 24 January 2018
Revised Date: 14 March 2018
Accepted Date: 25 April 2018
Please cite this article as: Ameuru US, Yakubu MK, Bello KA, Nkeonye PO, Halimehjani AZ, Synthesis
of disperse dyes derived from 4-amino-N-decyl-1, 8-naphthalimide and their dyeing properties on
polyester fabrics, Dyes and Pigments (2018), doi: 10.1016/j.dyepig.2018.04.050.
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ACCEPTED MANUSCRIPT
Graphical Abstract
Synthesis of disperse dyes derived from 4-amino-N-decyl-1, 8-
naphthalimide and their dyeing properties on polyester fabrics
Umar Salami Ameuru, Mohammed Kabir Yakubu,* Kasali Ademola Bello, Peter Obinna Nkeonye and
Azim Ziyaei Halimehjani*

ACCEPTED MANUSCRIPT
Synthesis of disperse dyes derived from 4-amino-N-decyl-1, 8-naphthalimide and their
dyeing properties on polyester fabrics
1
, 1
1
1
Umar Salami Ameuru , Mohammed Kabir Yakubu,* Kasali Ademola Bello , Peter Obinna Nkeonye
,2
and Azim Ziyaei Halimehjani*
1
Department of Polymer and Textile Engineering, Ahmadu Bello University, Zaria, Nigeria.
2
Faculty of Chemistry, Kharazmi University, 49 Mofateh St., Tehran, Iran. Tel.: +98(21)88848949, Fax:
+
98(21)88820992.
Corresponding Author: Azim Ziyaei Halimehjani (ziyaei@khu.ac.ir); Mohammed Kabir Yakubu
mkyakubu@abu.edu.ng).
(
Abstract: Novel series of amphiphilic monoazo dyes were synthesized using 4-amino-N-decyl-1, 8-
naphthalimide by coupling with different substituted anilines and naphthalenes in appropriate reaction
condition. The intermediates and the dyes were purified by recrystallization methods. The structures of
the newly synthesized intermediates and the dyes were confirmed from elemental analysis (CHN), FT-IR,
1
13
H and C NMR, MS and UV spectroscopic techniques. Spectrophotometric investigations of the
synthesized dyes in different solvents were carried out in order to obtain their absorption maxima, molar
extinction coefficients and solvatochromic effects. These dyes were applied on polyester fabrics as
disperse dyes using high temperature exhaust dyeing method. The relevant dyeing characteristics, such as
buildup on fabrics, wash, perspiration and light fastness were evaluated. Fabrics dyed with these dyes
furnished generally deep and bright intense hues ranging from light yellow to orange to light red. The
colour fastness of the dyed fabrics to washing and perspiration was assessed to be very good, however,
the light fastness was found to be poor, moderate to very good.
Highlights: ►Novel series of amphiphilic monoazo dyes were synthesized using 4-amino-N-decyl-1, 8-
naphthalimide
► absorption maxima, molar extinction coefficients and solvatochromic effects were
1

ACCEPTED MANUSCRIPT
obtained
evaluated
Keywords: Azo dyes, 4-amino-N-decyl-1, 8-naphthalimide, Solvatochromic effect, Fastness properties
►
dyeing characteristics such as buildup on fabrics, wash, perspiration and light fastness were
►
deep and bright intense hues ranging from light yellow to orange to light red was observed
1. Introduction
Heterocyclic derivatives of naphthalimides, phenylazophthalimides and 1, 8-naphthalic anhydrides have
been studied to assess their role as intermediates for dye synthesis [1]. These compounds have been
investigated for the synthesis of disperse dyes, dyes for other polymer fibres, acid dyes, dyes for
polymeric materials and dyes capable of copolymerization. It has been shown in the last decade that the
use of diazo components such as 4-aminonaphthalimides have advantageous effects on the dyeing
properties of the derived disperses azo dyes. The presence of the naphthalimide system also leads to a
deep and intense colour [2]. The 4-aminonaphthalimide compounds have an amino group in their 4-
position which tends to impart fluorescent property and acts as a donor group, and two carbonyl groups
which act as the acceptor groups. The acceptor and donor characters of these substituents should bring
about a considerable bathochromic effect. 4-Amino-N-(substituted)-naphthalimide is a useful diazo
component for the synthesis of azo dyes [3-5]. Naphthalimide derivatives have a great industrial
importance because of excellent fastness of some of these dyes obtained from them [6]. When substituted
with electron donating groups, naphthalimides are useful for colour chemists, preferably in the 4-position.
The substitution of an amino group into the 4-position yields brilliant greenish yellow compounds [7]. 4-
Amino-N-(substituted)-1, 8-aphthalimides were used for synthesis of azo and non-azonaphthalimide dyes
[
8]. The range of applications for these dyes are very wide; alongside classical fields such as dyeing
natural and synthetic textile fibres, plastics, paints and coatings. Increasingly novel applications of
naphthalimide dyes are coming to light, in which aesthetic considerations are no longer of primary
importance. These include applications in solar energy collectors, light emitting diodes, liquid crystal
2

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displays, and laser active media, potential photosensitive biologically active units, as fluorescent markers
in biology and in medicine as antiviral compounds or as analgesics [9].
Aminonaphthalimides are known to produce fluorescent yellow dyes for synthetic polymer fibres.
In these compounds, when the N- substituent of naphthalimide is an aryl, most of the dyes exhibit
properties similar to typical organic colorants, due to strong aggregation. The dyes with alkyl group in N-
substituted naphthalimides can be converted into disperse dyes which are used in the colouration of
synthetic fibres [10]. Generally, monoazo disperse dyes derived from naphthalimides show exceptionally
good thermal stability and good dyeing fastness properties [11]. However, the 4-amino-N-alkyl (ester)-1,
8
-naphthalimide derivatives of monoazo disperse dyes have relatively low heat fastness properties.
Previously formulated disperse dyes requires milling to a very low particle size and dispersion in water
using dispersing agent during application, hence results to prolong application time. Therefore, this work
aimed at synthesis of disperse dyes with in-situ incorporation of amphilphiles to enhance its solubility.
This will eliminate the milling and additions of dispersing agent associated with the application of
conventional disperse dyes.
2
2
. Experimental
.1. Materials and Methods. All the chemicals used in the synthesis were of commercial grade and were
used as received. The confirmatory establishment of structure of all the newly synthesized compounds
1
13
was done by melting point, FT-IR, H and C-NMR, MS and elemental analysis (CHN). The purity of the
synthesized compounds was checked by TLC using ethyl acetate - n-hexane (90:10). Thin-Layer
Chromatography (TLC) was performed on aluminium sheet, silica gel 60 coated plates, F , 0.2 mm. All
2
54
the melting point was recorded on Barnstead electrothermal 9200 apparatus and are uncorrected. Infra-red
1
13
were recorded using Perkin-Elmer Spectrum RXI FT-IR spectrometer. H and C NMR were reported on
a 300 MHz Bruker instrument using deuterated chloroform (CDCl ) and dimethylsulphoxide (DMSO-d )
3
6
as solvent. Chemical shifts were reported in parts per million (ppm) downfield from internal
3

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tetramethysilane (TMS). Elemental analyses (CHN) were recorded on Perkin-Elmer PE 2400 series II and
mass spectra were reported using Agilent Technologies 5975C VL MSD mass spectrometer.
2
.2. Synthesis of 5-Nitroacenaphthene. Acenaphthene (15.4 g, 0.1 mol.) was dissolved in 60 g (57.2
mL) of hot acetic acid and was cooled with vigorous stirring to separate crystalline acenaphthene as fine
o
as possible. Nitric acid (d = 1.40 g/mL) (9.84 g) was dropped for 1 h at 22-27 C, then stirred 1 h more at
o
o
2
1
5 C, warmed gradually for 30 mins to 68 C then cooled, and the crystals were filtered, washed with
o
:1 acetic acid – water and water to give yellow needles [12].Yield = 85%; Mp: 101-102 C; FT-IR (KBr,
-
1
1
cm ) 3085, 2946, 1620, 1596, 1508; H NMR (300 MHz, CDCl
3 2 2
): δ (ppm) 3.43 (4H, s, CH -CH ),
7
.31(1H, d, J = 7.8 Hz, 1-H), 7.45 (1H, t, J = 7.0 Hz, 9-H), 7.66 (1H, dd, J = 6.7, 7.1 Hz, 2-H), 8.47 (1H,
1
3
d, J = 7.7 Hz, 8-H), 8.54 (1H, d, J = 8.6 Hz, 3-H); C NMR (75 MHz, CDCl ):
δ
(ppm) 30.6, 33.1, 117.9,
20.1, 121.2, 122.7, 124.3, 127.7, 131.7, 140.1, 146.6, 155.7. Anal.Calcd for C12 NO : C, 72.35; H,
.55; N, 7.03 %; found C, 72.18; H, 4.57; N, 7.04 %.
.3. Synthesis of 4-Nitro-1, 8-naphthalic anhydride. 5–Nitroacenaphthene (24.87 g, 0.125 mol) was
3
1
H
9
2
4
2
dissolved in 248.75 mL of hot acetic acid, 158.5 g of sodium dichromate (Na Cr O .2H O) was added for
2
2
7
2
o
o
3
h at 65-70 C. This was warmed gradually to 98-100 C for 30 mins and further refluxed for 5 hours.
The contents were washed out with 0.6 L of hot water, cooled, filtered and the solid was washed with
dilute HCl. It was further boiled for 30 mins with 200 mL of 5 % Na CO solution for 30 mins, filtered,
2
3
o
the filtrate was acidified and the separated crystals dried at 120 C for 4 h to obtain 4-nitro-1,8–naphthalic
anhydride, which was recrystallized from HNO (d = 1.40 g/mL) to afford colourless needles [12]. Yield
3
o
-1
1
=
74 %; Mp: 231-232 C; FT-IR (KBr, cm ) 3078, 2914 2849, 1789, 1756, 1624, 1526; H NMR (300
MHz, DMSO-d ): (ppm) 8.09 (1H, t, J = 7.8 Hz, 3-H), 8.54 (1H, d, J = 7.9 Hz, 8-H), 8.61 (1H, s, 2-H),
.64 (1H, d, J = 7.5 Hz, 9-H), 8.73 (1H, dd, J = 8.2, 8.7 Hz, 4-H); C NMR (75 MHz, DMSO-d ):
6
δ
13
8
δ
6
(
ppm) 120.1, 122.6, 124.0, 124.3, 129.8, 130.3, 130.6, 131.1, 133.2, 149.5, 159.4, 160.0; Anal. Calcd for
C
12
H
5
NO
5
: C, 59.27; H, 2.07; N, 5.76 %; found C, 59.17; H, 2.02; N, 5.75 %.
4

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2
.4. Synthesis of 4-Nitro-N-decyl-1, 8-naphthalimide. A suspension of 4-nitro-1,8-naphthalic anhydride
(
0.02 mol, 4.86 g) and decylamine (0.03 mol, 4.71 g) was stirred under reflux for 7 h in ethanol (102 mL).
o
The cooled suspension was filtered out and recrystallized with ethanol. Yield = 61 %; Mp: 85-87 C; FT
-
-
1
1
IR (KBr, cm ) 3079, 2954, 2923, 1705, 1658, 1623, 1593; HNMR (300 MHz, CDCl3):
δ
(ppm) 0.85
(
3H, t, J = 6.9 Hz, CH ), 1.25-1.77 (m, 16H, Aliphatic), 4.15 (2H, t, J = 7.7 Hz, N-CH ), 7.96 (1H, t, J =
3 2
7
2
2
1
.4 Hz, 3-H), 8.39 (1H, d, J = 8.0 Hz, 8-H), 8.68 (1H, d, J = 8.0 Hz, 9-H), 8.72 (1H, dd, J = 7.2, 7.9 Hz,
1
3
-H), 8.82 (1H, d, J = 8.7 Hz, 4-H); C NMR (75 MHz CDCl3):
9.2, 29.3, 29.5 31.8, 40.8, 123.0, 123.6, 123.8, 127.0, 129.0, 129.2, 129.7, 129.9, 132.3, 149.4, 162.4,
63.3; Anal. Calcd for C22 : C, 69.08; H, 6.85; N, 7.32 %; found C, 69.35; H, 6.97; N, 7.31 %.
.5. Synthesis of 4-amino-N-decyl-1, 8- naphthalimide. A mixture of 4-nitro-N-decyl-1,8-
δ (ppm) 14.1, 22.7, 27.1, 27.9, 29.1,
26 2 4
H N O
2
naphthalimide (18 mmol, 6.88 g) and stannous chloride (90 mmol, 20.25 g) in ethanol (81 mL) was
refluxed for 1h with hydrochloric acid (10.1 mL) till the reaction was completed. The mixture was poured
into 100 mL of water and then the precipitate was filtered out. The crude product was purified by
recrystallization from ethanol to afford the pure product as orange crystals [12]. Yield = 53 %; Mp:141
-
o
-1
1
1
42 C; FT-IR (KBr, cm ) 3419, 3352, 3253, 2954, 2920, 2851, 1675, 1636, 1613; HNMR (300 MHz,
CDCl ): (ppm) 0.82 (3H, t, J = 6.9 Hz, CH ), 1.20-1.75 (m, 16H, Aliphatic), 4.10 (2H, t, J = 7.7 Hz, N-
CH ), 5.24 (2H, s, NH ), 6.83 (1H, d, J = 8.2 Hz, 8-H), 7.54 (1H, t, J = 7.6 Hz, 2-H), 8.12 (1H, d, J = 7.8
3
δ
3
2
2
1
3
Hz, 9-H), 8.34 (1H, d, J = 8.2 Hz, 3-H), 8.52 (1H, d, J = 7.2 Hz, 1-H); C NMR (75 MHz CDCl3):
δ
(
ppm) 14.1, 22.5, 27.2, 28.2, 29.2, 29.3, 29.4, 29.5, 31.8, 40.3, 109.4, 111.7, 119.9, 122.9, 124.8, 126.9,
1
29.7, 131.3, 133.9, 149.4, 163.9, 164.5; MS(EI): m/z 352 (M+), 212, 140 (100), 69, 41.
2
.6. Synthesis of dyes
2
1
.6.1. Synthesis of (E)-2-decyl-6-((2-hydroxnaphthalen-1-yl)diazenyl)-1H-benzo[de]isoquinoline-
,3(2H)-dione (1a). Dry sodium nitrite (1.5 mmol, 0.104 g) was added to cold conc. H SO (98 %, 1.1
2
4
mL) at such a rate that yellow fume was not evolved. The reaction temperature was gradually increased to
o
6
5 C using water bath until all the sodium nitrite was dissolved. The resulting solution was cooled to 0-5
5

ACCEPTED MANUSCRIPT
ºC and then added drop wise at 5-20 ºC with the mixture of propionic acid and acetic acid (10 mL,
1
.5:8.5). The finely ground powder of 1.5 mmol 4-amino-N-decyl-1, 8-naphthalimide was added portion
o
wise at less than 10 C, and then the liquor was stirred for 3 h. The obtained clear diazonium salt solution
was used immediately in coupling reactions with 2-naphthol (1.5 mmol) dissolved in ethanol. The
previously prepared diazonium solution was added over 30-40 mins with vigorous stirring. The mixture
o
was stirred further for 2 h at 0-5 C and then the pH of the solution was adjusted to 4-5 using 10 %
sodium acetate and stirred for 1 h. The resulting product was then collected by filtration, washed with
o
warm water and then cold water till neutral and dried at 60 C for 8 h in an oven. The crude product was
purified by recrystallizing from DMSO several times to obtained dye 1a. Yield = 98.6 %; Mp: 154-157
o
-1
1
C; FT-IR (KBr, cm ) 3332, 3061, 2952, 2924, 2852, 1700, 1655, 1623, 158, 1382; HNMR (300 MHz,
CDCl ): (ppm) 0.85 (3H, t, J = 6.9 Hz, CH ), 1.24-1.69 (m, 16H, Aliphatic), 4.01 (2H, t, J = 7.7 Hz, N-
CH ), 6.52-8.85 (m, 11H, Aromatic), 16.85 (1H, s, OH); MS(EI): m/z 507 (M+), 367, 212, 143 (100),
3
δ
3
2
114, 43.
2
1
.6.2. Synthesis of (E)-2-decyl-6-((2,3-dihydroxynaphthalen-1-yl)diazenyl)-1Hbenzo[de]isoquinoline-
,3(2H)-dione (1b). The same procedures as in (1a) were used, except that 2,3-dihydroxynaphthalene
o
-1
was used for coupling. Yield = 86 %; Mp: 197-201 C; FT-IR (KBr, cm ) 3374, 3065, 2922, 2852, 1669,
1
1
657, 1620, 1588, 1381; HNMR (300 MHz, CDCl ):
δ
(ppm) 0.83 (3H, t, J = 6.7 Hz, CH ), 1.24-1.72
3
3
(
m, 16H, Aliphatic), 4.12 (2H, t, J = 6.6 Hz, N-CH ), 6.64-9.16 (m, 10H, Aromatic), 16.62 (1H, s, OH),
2
1
6.69 (1H, s, OH); MS(EI): m/z 523(M+), 352, 228, 212 (100), 115, 41.
2
1
.6.3. Synthesis of (Z)-2-decyl-6-((4-(dimentylamino)phenyl)diazenyl)-1H-benzo[de]isoquinoline-
,3(2H)-dione (1c). The same procedures as in (1a) were used, except that N, N-dimethylaniline was used
o
-1
for coupling. Yield = 88.8 %; Mp: 125-127 C; FT-IR (KBr, cm ) 3071, 2952, 2921, 2849, 1698, 1657,
1
1
603, 1588, 1395; HNMR (300 MHz, CDCl3):
δ
(ppm) 0.85 (3H, t, J = 6.9 Hz, CH ), 1.26-1.77 (m, 16H,
3
Aliphatic), 3.15 (6H, s, 2CH
3 2
), 4.15 (2H, t, J = 7.7 Hz, N-CH ), 6.75-9.21 (m, 9H, Aromatic); MS(EI):
m/z 484(M+), 352, 228, 212 (100), 120, 41.
6

ACCEPTED MANUSCRIPT
2
.6.4. Synthesis of (Z)-2-decyl-6-((4-diethylamino)diazenyl)-1H-benzo[de]isoquinoline-1,3(2H)-dione
(
1d). The same procedures as in (1a) were used, except that N, N-diethylaniline was used for coupling.
o
-1
Yield = 97.8 %; Mp: 148-150 C; FT-IR (KBr, cm ) 2954, 2920, 2850, 1693, 1657, 1623, 1559, 1378;
1
HNMR (300 MHz, CDCl3):
δ (ppm) 0.85 (3H, t, J = 6.9 Hz, CH ), 1.26 (6H, t, J = 7.0 Hz, 2CH ), 1.26-
3 3
1
.78 (m, 16H, Aliphatic), 3.48 (4H, q, J = 7.1 Hz, 2CH ), 4.16 (2H, t, J = 7.6 Hz, N-CH ), 6.77-9.24 (m,
2
2
9
H, Aromatic); MS(EI): m/z 512 (M+), 352, 338, 228, 212 (100), 148, 41.
2
1
.6.5. Synthesis of (Z)-6-((2-aminonaphthalen-1-yl)diazenyl)-2-decyl-1H- benzo[de]isoquinoline-
,3(2H)-dione (1e). The same procedures as in (1a) were used, except that 2-naphthamine was used for
o
-1
coupling.Yield = 88.9 %; Mp: 212-214 C; FT-IR (KBr, cm ) 3350, 3071, 2950, 2921, 2850, 1696, 1646,
1
1
622, 1580, 1378; HNMR (300 MHz, CDCl3):
δ
(ppm) 0.86 (3H, t, J = 6.9 Hz, CH ), 1.27-1.77 (m, 16H,
3
2
Aliphatic), 4.17 (2H, t, J = 7.6 Hz, N-CH ), 6.92-8.91 (m, 11H, Aromatic); MS(EI): m/z 506(M+), 480,
3
52, 212 (100), 118, 41.
.6.6. Synthesis of (Z)-N-(4-((2-decyl-1,3-dioxo-2,3-dihydro-1H-benzp[de]isoquinolin-6-
2
yl)phenyl)acetamide (1f). The same procedures as in (1a) were used, except that N-phenylacetamide was
o
-1
used for coupling. Yield = 62.3 %; Mp: 227-229 C; FT-IR (KBr, cm ) 3344, 3068, 2952, 2921, 2852,
1
1
1
697, 1662, 1615, 1587, 1384; HNMR (300 MHz, CDCl
3
):
δ
(ppm) 0.87 (3H, t, J = 6.7 Hz, CH
3
), 1.27-
.73 (m, 16H, Aliphatic), 2.63 (3H, s, CH ), 4.15 (2H, t, J = 7.6 Hz, N-CH ), 7.26-8.90 (m, 9H,
3
2
Aromatic), 15.99 (1H, s, NH); MS(EI): m/z 498(M+), 352, 228, 212(100), 41.
2
1
.6.7. Synthesis of (Z)-6-((2-amino-5-nitrophenyl)diazenyl)-2-decyl-1H-benzo[de]isoquinoline-
,3(2H)-dione (1g).The same procedures as in (1a) were used, except that 4-nitroaniline was used for
o
-1
coupling. Yield = 75.8 %; Mp: 156-158 C; FT-IR (KBr, cm ) 3364, 3099, 2953, 2923, 2851, 1699,
1
1
661, 1617, 1589, 1395; HNMR (300 MHz, CDCl ):
δ
(ppm) 0.86 (3H, t, J = 6.7 Hz, CH ), 1.27-1.73
3
3
(
m, 16H, Aliphatic), 4.14 (2H, t, J = 7.3 Hz, N-CH ), 7.27-8.72 (m, 8H, Aromatic), 16.00 (2H, s, NH );
2
2
MS(EI): m/z 501(M+), 352, 228, 212(100), 140, 41.
7

ACCEPTED MANUSCRIPT
2
.6.8. Synthesis of (Z)-2-decyl-6-(4,5-diaminonaphthalen-1-yl)-1H-benzo[de]isoquinoline-1,3(2H)-
dione (1h). The same procedures as in (1a) were used, except that 1, 8-diaminonaphthalene was used for
o
-1
coupling. Yield = 67.2 %; Mp: 118-121 C; FT-IR (KBr, cm ) 3309, 3062, 2921, 2850, 1695, 1657, 1584,
1
1
384; HNMR (300 MHz, CDCl3):
δ
(ppm) 0.84 (3H, t, J = 6.7 Hz, CH ), 1.25-1.75 (m, 16H, Aliphatic),
3
4
.14 (2H, t, J = 7.6 Hz, N-CH ), 5.82 (2H, s, NH ), 6.45 (2H, s, NH ), 7.26-8.59 (m, 10H, Aromatic);
2 2 2
MS(EI): m/z 521(M+), 352, 212(100), 41.
.7. Dyeing procedure. KMS-IRE Laboratory Dyeing Machine – ELITE was used with a material to
2
liquor ratio of 1:50 (w/v). 2% shade was used for dyeing (OWF). All the synthesized dyes were dissolved
in 5 mL N, N-dimethylformamide. To this, water (45 mL) was added with stirring and the pH was
adjusted to 5 using glacial acetic acid. The dye suspension (50 mL) was added to a beaker provided with a
lid and a screw cap. Before closing the lid and tightening the metal cap over the beaker, a wetted pattern
of polyester fabric (1 g) was rolled into the beaker. The beaker was then placed vertically on the rotatory
carrier inside the tank and the clamp plate was firmly tightened. The rotatory carrier was then allowed to
o
o
rotate in the glycerin-bath and the temperature was raised to 130 C at the rate of 2 C/min. The dyeing
o
was continued for 1 h, under pressure. After cooling to 70 C the beaker was removed from the bath. The
dyed pattern was removed, thoroughly washed with water and dried at room temperature.
2
.7.1. Reduction clearing. Dyed fabric was treated by stirring in an aqueous solution containing 2 g/l of
o
sodium dithionite and 2 g/l of sodium hydroxide for 45 min at 70 C. The dyed fabrics were washed with
water and dried.
2
.7.2. Colour measurement. A Gretag Macbeth Colour-Eye 7000A spectrophotometer was used for
o
colour measurement of the dyed polyester fabrics using a D65 source, 10 collection angle and small area
view aperture (3 x 8mm).
2
.7.3. Fastness properties. The fastness to light, wash and perspiration of the dyed fabrics were assessed
in accordance with the standard test method [13].
8

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3
3
. Results and Discussion
.1. Synthesis of intermediates and dyes
Acenaphthene was nitrated directly giving yellow needles of 5-nitroacenaphthene when recrystallised
from ethanol as shown in reaction Schemes. 5-Nitroacenaphthene can be oxidized by various methods,
but the most satisfactory method was found to be that of Okazaki et al. [12] in which sodium dichromate
was used as the oxidizing agent and hot glacial acetic acid as the solvent as shown in the reaction
Schemes. The precipitation was recrystallised from nitric acid and pale yellow needles of 4-
nitronaphthalic anhydride was obtained. The imidation of aromatic cyclic anhydrides is a nucleophilic
displacement reaction in which the amine is the attacking group, and this reaction is carried out in
alcoholic medium under reflux condition for 7 hours. To prepare 4-nitro-N-decyl-1, 8-naphthalimide, 4-
nitro-1, 8-naphthalic anhydride was reacted with decylamine, as shown in the reaction Scheme 1. The
reaction was examined by TLC, The products of 4-nitro-N-decyl-1, 8-naphthalimides was recrystallised in
ethanol to obtain off white crystals.
Preparation of 4-amino-1,8-naphthalimide plays a very important role in the series of naphthalimide
dyestuffs. The naphthalimides with an amino group at the 4-position are also very fluorescent. In previous
works, some aminonaphthalimide dyestuffs were made by the nucleophilic attack of ammonia on various
naphthalic anhydrides or imides [14]. Thus, 4-amino-N-decyl-1, 8-naphthalimide was obtained by the
reaction of 4-nitro-N-decyl-1, 8-naphthalimide with tin (II) chloride and hydrochloric acid as a reducing
agent and ethanol as a solvent. The 4-amino-N-decyl-1, 8-naphthalimides obtained was recrystallised in
ethanol to obtain orange crystals.
The diazotisation of 4-amino-N-decyl-1, 8-naphthalimide was carried out using nitrosylsulphuric acid
method and coupling with various electron-rich arenes produce the dyes (Scheme 1). The structure dyes
1
13
and intermediates were characterized using IR, H and C NMR NMR, MS and UV spectroscopic
methods. Figures 1-4 show the IR and Mass spectra of the selected compounds 1a and 1e.
9

ACCEPTED MANUSCRIPT
CH (CH ) CH
3
2
2 8
O
O
O
O
N
O
Nitration
Oxidation
Imidation
NO2
NO2
NO2
Acenaphthene
4-nitronaphthalic
anhydride
5
-nitroacenaphthene
4
-nitro-N-decyl-
1,8-naphthalimide
CH (CH ) CH
CH (CH ) CH
2
2 8
3
CH (CH ) CH
2 2 8 3
2
2 8
3
O
N
O
O
N
O
O
N
O
Coupling
Diazotisation
N
N
NH2
-amino-N-decyl-
+
-
N
N HSO
4
Ar
4
Diazonium salt
1
1,8-naphthalimide
OH
OH
OH
where Ar =
NMe2
NEt2
1a
1c
1b
1d
NH2
NH2
NH2
CH3
O N
2
NH2
NH
O
1e
1f
1g
1h
Scheme 1. Synthesis of intermediates and the dyes.
1
0

ACCEPTED MANUSCRIPT
Figure 1a. FT-IR of dye 1a
-
1
Wave number (cm )
Figure 2. FT-IR spectra of dye 1e
11

ACCEPTED MANUSCRIPT
Figure 3. Mass spectra for dye 1a
Figure 4. Mass spectra for dye 1e
1
2

ACCEPTED MANUSCRIPT
3
.2. Visible absorption spectra of the dyes
It is a well-accepted fact that the constitutions of dyestuffs have a fundamental role in producing desired
colour over substrates. The correlation between the colour and constitution is a highly increasing aspect of
dyestuff development and commercialization. Due to this matter, dye manufacturers have a considerable
interest in producing azo disperse dyes [15-16]. In this respect, the wavelength of maximum absorption
(
λmax), extinction coefficient (Ɛmax) and half- band width (∆ν1/2) of the dyes are all important. The λmaxof
the visible band indicates the hue of the dyes and the quantity of the intensity of the visible band is of
economic importance as it is a measure of the strength of the dyes. The Ɛmax should be above ca. 20,000 1
-1
-1
mol cm for acceptable commercial purposes [17]. The absorption spectra of the synthesized dyes were
measured in various solvents, its molar extinction coefficient are listed in Table 1. Wavelength of
maximum absorption (λmax) and molar extinction coefficients ranged from 440 to 630 nm and 10588 to
-1
-1
3
9705 1mol cm for the synthesized dyes in DMF respectively. The λmax shifts in different solvents are
brought about by the solvatochromic effect resulting from changes in the dielectric constant of the
solvent.
Generally, the colour of naphthalimideazo dyes depends on the delocalization of electrons
through the conjugated chromogen depicted by the energy difference between structures I and II as shown
below [18].
.
.
-O
CH3
O
CH3
CH3
N+
N
N
N
N
N
R N
O
CH3
R N
O
I
II
The bathochromic effect of these compounds increases when the energy difference between
resonances structure is low. Contribution of the high energy stabilized structure II, could be initially
enhanced by the presence of a conjugated electron acceptor (i.e naphthalimide residue) and secondly by
1
3

ACCEPTED MANUSCRIPT
an electron donor on the coupling component (i.e dialkylamino group) which results in a considerable
bathochromic shift. Dye 1a was obtained by diazotising 4-amino-N-decyl-naphthalimide and coupling to
2
-naphthol and absorbed at 520 nm in DMF. When OH group was introduced into meta-position of the
coupling component (2,3-dihydroxnaphthene) the resulting dye 1b absorbed at 515 nm in the same
solvent and thus the dye 1b was hypsochromic by 5 nm when compared with dye 1a. It is well known that
the colour of dyes is influenced by the introduction of additional donor groups into the coupling
component. It can easily be deduced from Table 1 that the presence of N,N- dimethyl in the coupling
component of dye 1c resulted in the bathochromic effect when compared with dye 1a. Replacement of
coupling component (N, N-dimethylaniline) in dye 1c by N, N-diethylaniline gave dye 1d which absorbed
at 586 nm and showed a bathochromic shift of 12 nm and 66 nm respectively when compared with dye 1c
and 1a. Similarly, dye 1e and 1h were obtained with 2-napthylamine and 1, 8-diaminonaphthalene
respectively. The dye 1h showed a strong bathochromic shift of 45 nm when compared with 1e which
may be attributed to the presence of electron donor (NH ) in the 8-position of the coupling component.
2
Dye 1g showed bathochromic shift by about 8 nm when compared with dye 1f which may be attributed to
the presence of NO in the coupling component of dye 1g.
2
The measurement of λmax in chloroform and DMF showed that λmax of the intramolecular charge
transfer bonds exhibits a marked red shift on transfer from nonpolar to polar solvent. This behavior
indicates that the polar excited states of the synthesized dyes are stabilized by polarization
interactionforces as the polarizability of the solvent is increased [19].
1
4

ACCEPTED MANUSCRIPT
Table 1. The UV- visible Spectroscopic of the dyes
Dye
No.
Ɛmax in
DMF
Chloroform
Ethanol
λmax(nm)
a
Ethanol +HCl
Change in
λmax(nm)
(b-a)
DMF
λmax(nm)
λmax(nm)
λmax(nm)
4
×
10
b
-1
-1
(
lmol cm )
2.47
1
1
1
1
1
1
1
1
a
b
c
d
e
f
520
515
574
586
585
592
600
630
515
515
510
525
530
530
420
575
515
510
510
525
546
430
420
610
515
510
515
528
546
465
420
560
0
1.94
3.60
3.97
3.88
2.05
2.71
1.53
0
+5
+3
0
+35
0
g
h
-50
3
.3. Dyeing and Fastness properties of the synthesized dyes
The synthesized dyes were subsequently applied to polyester fabrics and finally their dyeing
properties such as light fastness, wash fastness and perspiration fastness were determined. The
dyes were applied by the high temperature dyeing method. Visual evaluation of the dyeing on
polyester fabrics showed that the nature of the alkyl residue in the amine group of the coupling
component affects both the intensity of dyeing and their shade obtained. The highest intensity is
shown by the dyes which contain N, N-dimethyl and N, N-diethyl groups. These substituents
bring about an increase in the nucleophilic character of the tertiary nitrogen atom and the
stability of polar forms [20] especially when there are no substituents in the phenyl ring causing
steric effects.
1
5

ACCEPTED MANUSCRIPT
The electron donor substituent (-OH) in the ring of the coupling components in ortho
position to the azo band also considerably affects the colour of the dyeing in 1a and 1b. This
phenomenon is described in terms of structures III and IV.
The results of the wash fastness ratings are summarized in Table 2. The dyes gave good levelness
and fibre penetration on polyester. The wash fastness rating is very good with rating of 4. The good wash
fastness obtained on polyester is due to the crystalline structure of the polyester which disallowed the
migration of dye out of the fabric when this has entered the fabric. The dyed fabrics have poor to
moderate light fastness rating as shown in Table 2. Disperse dyes have a tendency to deposit on the fibre
surface during dyeing as well as during cooling [21] and therefore in order to obtain a satisfactory
combination of light and sublimation fastness, a judicious choice of substituent is required. Several
reports [22] suggest that fading of azo dyes is mainly a consequence of decomposition of the –N=N–
moiety either by oxidation, reduction or photolysis. The rates of these processes should be sensitive to the
chemical structure of the dye, the type of substrate and treatment conditions. The dyed substrate
employed in this study is polyester fabric, the fading process likely occur by oxidation [23]. The ease of
oxidation of azo linkages should be a function of electron density. Therefore, electron donating
substituents on this moiety should increase the fading rate while electron withdrawing groups should
decrease the rate. This is in agreement with the observed results (Table 2) which demonstrate that the
presence of a hydroxyl group in some synthesized dyes causes decrease of light fastness to 2 and 3. The
1
6

ACCEPTED MANUSCRIPT
introduction of polar groups can adversely affect the dyeing properties of a dye but the hydroxyalkyl
group appears to be particularly useful in increasing polarity without excessive undesirable side effects.
The free hydroxyl group and also short alkyl chain favour formation of compact aggregates of dyes,
which confers low surface activity and this causes dye to spread as multilayer on the surface of the fabric;
the multilayer is less susceptible to fading. This may account for why the dyes from N, N-dimethylaniline
and N, N-diethylaniline have acceptable results in light fastness.
Colour fading and alteration can be caused by the reaction between dyes on garments and the
constituents of human perspiration, such as skin waste. It varies for different individuals and conditions.
There are cases where more colour fading and alteration is caused, depending on the conditions under
which garments are worn. Coupled with the eventual accumulation and concentration of perspiration, the
reaction with sunlight is regarded as the cause for such occurrences, casting an influence on certain
elements in the dye structure. To forecast such occurrences, methods for examining the components of
perspiration under different conditions (acid and alkaline pH values) have been investigated by the
standards as showed in Table 2. The fastness to perspiration was generally good both in acidic and
alkaline medium.
Table 2. Fastness properties of the synthesized dyes on polyester fabrics
Dye Fastness
No.
Light
Washing
Perspiration
Acidic
Alkaline
1
1
a
3
2
4
4
4
4
4
4
3
3
4
4
5
4
4
4
4
4
5
4
4
4
4
4
4
3
b
1
c
2
1
d
5
1
e
1-2
5
1
f
1
1
g
1-2
1-2
h
1
7

ACCEPTED MANUSCRIPT
The colour parameter of the dyed polyester fabrics were measured using spectrophotometer(Gretag
o
Macbeth colour-Eye 7000A, USA) under illuminant D65, with a 10 standard observer. The assessment of
colour dyed fabrics was in terms of tristimuluscolormetry. The following CIELAB coordinates were
o
o
measured, lightness (L*), chroma (C*), hue angle from 0 to 360 (h), a* value represent the degree of
redness (positive) and greenness (negative) and b* represent the degree of yellowness (positive) and
blueness (negative). The K/S value which has been employed as the dye up take or colour strength was
calculated for each dyed specimen from the reflectance values using the Kubelka-Munk equation as
follows:
2
)
(
1− R
K
=
S
2R
where K is the coefficient of absorption, S is the coefficient of scattering and R is the reflectance value of
the fabric at peak wavelength.
The colour hues of the dyes under investigation on polyester fabrics are shifted to the yellowish direction
on the yellow – blue axis according to the positive values of b*. The b* results range from 3.20 to 357.73
shows that as the b* increases positively the deeper the colour (yellow).
The colour hues of the synthesized dyes on polyester fabrics are shifted to the reddish direction on the red
–
green axis according to the positive values of a* for these dyes.
The K/S values are used to represent the depth of dyeing as they are proportional to the amount of
colourant present in the dyed fabrics [24]. The K/S values listed in Table 3 show that 4-amino-N-decyl-
naphthalimide disperse dyes showed the best build-up for polyester fabric and have high affinity for the
polyester fabric.
1
8

ACCEPTED MANUSCRIPT
Table 3: Colourimetric and spectrophotometric data of the synthesized dyes on polyester fabrics
o
Dye
L*
a*
b*
C*
h
K/S
No.
1
a
38.41
39.65
30.09
29.96
33.60
62.04
54.14
36.48
52.57
41.81
39.82
36.58
22.39
11.39
49.83
10.08
14.15
357.73
14.24
3.20
54.44
360.17
42.29
36.72
348.98
39.71
95.00
254.14
15.06
83.33
19.68
4.99
14.57
8.95
1
b
1
c
16.61
15.63
8.22
1
d
1
e
348.27
38.04
80.89
253.94
86.32
73.33
58.36
87.72
1
f
2.69
1
g
15.28
5.84
1
h
4
. Conclusion
New series of amphilphilic naphthalimide dyes based monoazo disperse have been synthesized in good
yields. The dyes and their corresponding intermediate were characterised by the use of elemental analysis
1
13
(
CHN), FTIR, H-NMR, C NMR, UV-visible, and mass spectroscopic techniques. Spectrophotometric
investigation of the synthesized dyes in different solvents was examined in order to obtain their
absorption maxima, molar extinction coefficients and solvatochromic effects. The dyes were applied on
polyester fabrics using high temperature dyeing method without addition of dispersing agent and their
usage properties examined. The wash and perspiration fastness properties were generally very good. Dyes
1
e, 1g and 1h showed poor light fastness whereas, dyes 1a, 1b 1c, 1d and 1f showed a moderate to very
good respectively. The K S (Kubelka-Munk) value which is representative of the colour depth of the
dyed fabric was also evaluated. The value of the coordinates L*, a* and b* represent lightness/darkness,
red/green and yellow/blue tones of colours respectively. From the values of a* and b*, it is clear that the
synthesized dyes have positive values which indicates yellowish red colour. Most of the dyes have fairly
high values of L* confirming their colour brilliancy. The chroma or chromatic purity (C*) of the dyeings
were equally high. The net effect of high chroma and high L* is the good colour brilliance of the dyes.
1
9

ACCEPTED MANUSCRIPT
Acknowledgment
We are grateful to the Faculty of Chemistry of Kharazmi University for supporting this work. Umar
Salami Ameuru also thanks the staff of the Faculty of Chemistry of Kharazmi University for their kind
collaboration.
References
[
1] Peters AT, Bide MJ. Phenylazo derivative of 1, 8 naphthalimide and of 7 H- benzimidiazo
2,1-a) benz(d,e) isoquinolin – 7-ones: dyes for polymeric fibres, Dyes and Pigments 1986;7:
37-247.
(
2
[
2] Wojciechowski K. Properties and structure of naphthalimide dyes derived from pyrazolones.
Dyes and Pigments 1993;22:239-254.
[
[
[
3] Khosravi A, Mordian S, Gharanjig K, AfsharTaromi F. Synthesis and spectroscopic studies of
somenaphthalimide based disperse azo dyestuffs for the dyeing of polyester fibres. Dye and
Pigments 2006;69:79-92.
4] Sadeghi-Kiakhania M, Safapour S. Functionalization of poly(amidoamine) dendrimer-based
nano-architectures using a naphthalimide derivative and their fluorescent, dyeing and
antimicrobial properties on wool fibers. Luminescence 2016;31:1005–1012.
5] Parvizi P, Khosravi A, Moradian S, Gharanjig K. Synthesis and Application of Some Alkali-
clearableAzo Disperse Dyes Based on Naphthalimide Derivatives. J Chin ChemSoc
2
009;56:1035-1042.
6] Konstantinova T, Spirieva A, Petkova T. The Synthesis, Properties and Application of some 1,
-naphthalimide dyes. Dyes and Pigments 2000;45:125-129.
[
[
8
7] Qian X, Zhu K, Chen K. The synthesis, application and prediction of stokes shift in fluorescent
dyes derived from 1,8-naphthalic anhydride. Dyes and Pigments 1989;11:13-20.
[
8] SadeghiKiakhani M, Gharanjig K, Arami M, Mokhtari J, Mahmodi N. Synthesis and
2
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ACCEPTED MANUSCRIPT
characterization of novel monoazonaphthalimide disperse dyes containing carboxylic acid
group with high heat fastness properties. JChinChemSoc 2008;55:1300-1307.
[
9] Wu A, Xu Y, Qian X. Novel naphthalimide-amino acid conjugates with flexible leucine
moiety as side chain: design, synthesis and potential antitumor activity. Bioorg Med Chem
009;17:592-599.
2
[
10] Stolarski R. Fluorescent Naphthalimide Dyes for PolyesterFibres. Fibres and Textiles in
Europe 2009;17:91-95.
[
11] Szadowski J, Wojciechowski K, Malinowski W. Synthesis and properties ofamide derivatives
of 4-N, N-dialkylaminoazobenzenes. Coloration Technology1985;101:105-108.
[
12] Okazaki M, Tanaka T, Taniguchi S. Synthesis of 5-nitroacenaphthene. TokoyoInstTechnol
Yuki Gosei Kagaku Kyokai Shi 1956;14:344-346; Chem Abs 1957;51: 8050.
th
[
[
13] Chryster LP. Methods of Test for Colour Fastness of Textile and Leather, 7 ed; Bradford:
London, UK, 1990; pp. 89-94.
14] Christie RM. Fluorescent brighteners based on naphthalimides, Rev Prog Colour 1993;22:2-
3.
[
[
[
15] Christie RM. Colour Chemistry. Royal Society of Chemistry: Cambridge 2001, 1st edn, p. 45.
16] Zollinger H. Colour Chemistry. Wiley-VCH: Zurich, 2003; pp.165-166.
17] Griffiths J. Developments in the Chemistry and Technology of Organic Dyes; Blackwell
Scientific: Oxford, 1984;pp. 2, 31-49.
[
[
18] BojinovV,IvanovaG,ChovelonJM,Grabchev I. Photophysical and photochemical properties
of some 3-bromo-4-alkylamino-N-alkyl-1, 8-naphthalimide. Dyes and Pigments 2003;58:65-
7
1.
19] Abd El-AalRM,Koraierm AI. Synthesis, Absorption Spectra Studies and Biological Activity
of some Novel Conjugated Dyes. J ChinChemSoc2000;47:389-395.
[
20] Wojciechowski K. Spectral properties of disperse dyes, derivative of N-
methy lnaphthalimidazobenzene. Dyes and Pigments1990;12:273-286.
2
1

ACCEPTED MANUSCRIPT
o
[
21] Datyner A. The solubilisation of disperse dyes by dispersing agents at 127 C. J Soc Dyers
Col 1978;94:256-260.
[
[
22] Al-Etaibi AM, El-Apasery MA, Ibrahim MR, Al-Awadi NA. A facilesynthesis of new
monoazo disperse dyes derived from 4-hydroxyphenylazopyrazole-5-amines: evaluation of
microwave assisted dyeing behaviour. Molecules 2012;17:13891–13909.
23] Chipalkatti HR, Desai NF, Giles CH, Macaulay N. The influence ofthe substrate upon the
light fading of azo dyes. J Soc Dyers Col 1954;70:487–501.
[
24] Wang J, Asnes H. One-bath dyeing of wool/polyester blends with acid and disperse dyes.
Part 2- disperse dye distribution on polyester and wool. JSoc Dyers Col1991;107:314-318.
2
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Highlights: ►Novel series of amphiphilic monoazo dyes were synthesized using 4-amino-N-decyl-1, 8-
naphthalimide
obtained dyeing characteristics such as buildup on fabrics, wash, perspiration and light fastness were
evaluated deep and bright intense hues ranging from light yellow to orange to light red was observed
► absorption maxima, molar extinction coefficients and solvatochromic effects were
►
►