Synthesis and characterization of some monoazo disperse dyestuffs based on naphthalimide derivatives for dyeing of polyester fabrics

Article abstract of DOI:10.1002/jccs.200500071

A series of monoazo dis perse dye stuffs de rived from naphthalimide were prepared. 4-Amino-N-methyl (alternatively N-ethyl, N-propyl,N-butyl) derivatives of naphthalimide were utilised as the diazo components and β-naphthol, N,N-diethyl-m-toluidine, and p-aminoacetophenone constituted the coupling components. To this end, acenaphthene was nitrated and then various unit processes such as oxidation, amination, reduction, diazotization, and coupling were carried out. The syn the sized monoazo dis perse dye stuffs were applied toalocally manufactured polyester fabric and their optical properties were in vestigated. Characterisation of the various intermediates as well as the dye stuffs were carried out by DSC, FTIR, H-NMR and UV-vis analytical techniques.

Full text of DOI:10.1002/jccs.200500071

Journal of the Chinese Chemical Society, 2005, 52, 495-502
495
Synthesis and Characterization of Some Monoazo Disperse
Dyestuffs Based on Naphthalimide Derivatives for Dyeing of
Polyester Fabrics
A. Khosravi,a S. Moradian,a* K. Gharanjigb and F. Afshar Taromia
aAmirkabir University of Technology, Faculty of Polymer and Color Engineering, P.O. Box 15875-4413,
Tehran, Iran
bIran Color Research Center, P.O. Box 1665618481, Iran
A series of monoazo disperse dyestuffs derived from naphthalimide were prepared. 4-Amino-N-methyl
(alternatively N-ethyl, N-propyl, N-butyl) derivatives of naphthalimide were utilised as the diazo components
and b-naphthol, N,N-diethyl-m-toluidine, and p-aminoacetophenone constituted the coupling components.
To this end, acenaphthene was nitrated and then various unit processes such as oxidation, amination, reduc-
tion, diazotization, and coupling were carried out. The synthesized monoazo disperse dyestuffs were applied
to a locally manufactured polyester fabric and their optical properties were investigated. Characterisation of
the various intermediates as well as the dyestuffs were carried out by DSC, FTIR, H-NMR and UV-vis analyt-
ical techniques.
Keywords: Disperse; Dyeing; Polyester; Naphthalimide dyestuffs; 4-Amino-N-substituted
naphthalimides.
INTRODUCTION
Pioneering work on naphthalimides and their deriva-
photometric properties of the prepared disperse dyestuffs in
C6H5Cl were examined. The absorption maximum of the dye-
stuffs and their intensities have also been obtained. The pre-
pared dyestuffs were subsequently dyed on polyester fabric
and finally their optical and dyeing properties, light fastness,
wash fastness, and sublimation fastness were determined.
tives has been researched to assess their role as intermediates
for dyestuff preparation.1,2 Other related compounds have
also been investigated such as heterocyclic derivatives of
naphthalimides, phenylazophthalimides, and 1,8-naphthalic
anhydrides.3,4 These compounds have been considered for
the preparation of disperse dyestuffs, dyestuffs for other
polymer fibers, acid dyestuffs, dyestuffs for polymeric mate-
rials, and dyestuffs capable of copolymerization.
EXPERIMENTAL
Synthesis of 5-nitroacenaphthene was carried out ac-
cording to the method of Okazaki, Tanaka and Taniguchi.5
The method used for preparing 4-nitro-1,8-naphthalic anhy-
dride is based on that of Okazaki, Suhara, and Fujiyama.6
Preparation of 4-nitro-N-substituted-1,8-naphthalimides and
their reduction to the amino group were carried out according
to the method of Dongwu and Alexiou.7,8 The dyes were pre-
pared by the diazotisation of N-substituted 4-amino-naph-
thalimides with nitrosylsulphuric acid and their subsequent
coupling to the mentioned couplers.9 Analysis and charac-
terisation of the synthesized samples were carried out instru-
mentally.
In the present study, a series of monoazo disperse dye-
stuffs have been obtained utilizing 4-amino-N-methyl (alter-
natively N-ethyl, N-propyl, N-butyl) derivatives of naph-
thalimide as the diazo components and b-naphthol, N,N-di-
ethyl-m-toluidine, and aminoacetophenone as the coupling
components. To this end, acenaphthene (as the starting mate-
rial) was nitrated and further reacted by various unit pro-
cesses such as oxidation, amination, reduction, diazotisation,
and coupling to obtain synthesized monoazo disperse dye-
stuffs. The dyestuffs were then purified and characterized to-
gether with their corresponding intermediates. The spectro-
* Corresponding author. Tel: 0098-21-6468243; Fax: 0098-21-2350397; E-mail: moradian@aut.ac.ir

496 J. Chin. Chem. Soc., Vol. 52, No. 3, 2005
Khosravi et al.
RESULTS AND DISCUSSION
and Elemental Analysis (EA) of 5-nitroacenaphthene are
given in Tables 1 and 2.
5-Nitroacenaphthene is the main product when ace-
naphthene reacts with nitric acid in an acetic acid medium at
room temperature,5 because the meta-directing effect of the
carbonyl group in naphthalic acid or anhydride only the 3-
substituted naphthalic anhydrides can be prepared directly by
electrophilic substitution.10 However 2- and 4-substituted
naphthalic anhydrides can be prepared by the direct substitu-
tion of acenaphthene in which the -CH2 group directs elec-
trophilic substituents into the ortho- or para-positions de-
pending on the chosen conditions. Therefore for preparing
4-nitronaphthalic anhydride, acenaphthene was nitrated di-
rectly giving yellow needles of 5-nitroacenaphthene having a
m.p. of 101-102 °C when recrystallised from EtOH. The
yield of the reaction was 88.6%. The FTIR, H-NMR spectra
5-Nitroacenaphthene can be oxidised with various
methods, but the most satisfactory method was found to be
that of Okasaki et al.,6 in which sodium or potassium dichro-
mate was used as the oxidizing agent and hot glacial acetic
acid as the solvent. The precipitation was recrystallised from
nitric acid, the m.p. of which was 231-232 °C. The yield of
the pale yellow needles of 4-nitronaphthalic anhyride was
45.55%. The FTIR, HNMR spectra and EA of 4-nitro-1,8-
naphthalic anhydride are shown in Tables 1 and 2.
The imidation of aromatic cyclic anhydrides is a nu-
cleophilic displacement reaction in which the amine is the at-
tacking group, and this reaction is carried out in alcoholic me-
dium under reflux condition. To prepare 4-nitro-N-substi-
tuted-1,8-naphthalimide, 4-nitro-1,8-naphthalic anhydride
Table 1. The M.P., yield percent, FTIR, and H-NMR spectra of 4-nitro-N-substituted of naphthalimide derivatives
Compounds
M.P. °(C) Y (%)
FTIR (cm-1)
H-NMR (d)
5-nitroacenaphthene
101-102
231-232
211.02
88.6
C-H str. Ar. 3070
C-H str. Aliphatic 2947.68 (1H, 8-H); 7.43-7.47 (1H, 3-H); 7.66-
C=C str. 1620.07, 1596.16
NO2 str. 1326.33, 1508.96
3.43-3.49 (4H, CH2-CH2); 7.31-7.33
7.73 (1H, 7-H); 8.47-8.49 (1H, 6-H);
8.52-8.56 (1H, 4-H).
8.06-8.1 (1H, 6-H); 8.46-8.48 (1H, 5-
4-nitro-1,8-naphthalic
anhydride
45.55 C-H str. Ar. 3079.86
C=O str., 1756.88, 1787.32 H); 8.74-8.76 (1H, 7-H); 8.79-8.80
C=C str., 1583.96
(1H, 2-H); 8.94-8.96 (1H, 3-H).
NO2 str., 1302.91, 1526.76
C-H str. Ar. 3079.24
C=O str. 1671.6, 1707
C=C str. 1583.86
NO2 str., 1351.55, 1524.99
C-H str. Ar. 3077.61
4-nitro-N-methyl
naphthalimide
85
82
3.58 (3H, NCH3); 7.98 (1H, 6-H);
8.40 (1H, 5-H); 8.69 (1H, 7-H); 8.73
(1H, 2-H); 8.83 (1H, 3-H).
4-nitro-N-ethyl
naphthalimide
192.85
1.32-1.37 (3H, NCH2CH3); 4.21-4.25
C=O str. 1660.95, 1691.89 (2H, N-CH2CH3); 7.94-8 (1H, 6-H);
C=C 1614.67
NO2 str. 1331.19, 1527.14
8.37-8.42 (1H, 5-H); 8.65-8.68 (1H,
7-H); 8.69-8.75 (1H, 2-H); 8.77-8.80
(1H, 3-H).
4-nitro-N-(n-propyl)
naphthalimide
138.18
103.78
73.3
72.5
C-H str. Ar. 2962.02
C=O str., 1660.47, 1707.62 1.81 (2H, NCH2CH2CH3); 4.14-4.17
C=C str. 1582.94
NO2 str. 1345.37, 1525.62
1.01-1.04 (3H, NCH2CH2CH3); 1.75-
(2H, NCH2CH2CH3); 7.96-8 (1H, 6-
H); 8.39-8.41 (1H, 5-H); 8.67-8.69
(1H, 7-H); 8.72-8.74 (1H, 2-H); 8.82-
8.84 (1H, 3-H).
0.99 (3H, NCH2CH2CH2CH3); 1.45-
1.46 (2H, NCH2CH2CH2 CH3); 1.57-
1.72 (2H, NCH2CH2CH2CH3); 4.19
(2H, NCH2CH2CH2CH3); 7.98-8 (1H,
6-H); 8.39-8.41 (1H, 5-H); 8.68-8.69
(1H, 7-H); 8.73-8.74 (1H, 2-H); 8.82-
8.84 (1H, 3-H).
4-nitro-N-(n-butyl)
naphthalimide
C-H str. Ar. 2965
C-H str. Aliphatic 2864
C=O str. 1659, 1704
NO2 str. 1346, 1533

Synthesis and Characterization of NaphthalimideDyestuffs
J. Chin. Chem. Soc., Vol. 52, No. 3, 2005 497
Table 2. The elemental analysis (EA) of 4-nitro-N-substituted of naphthalimide derivatives
Compounds
EA Found (%)
H
Required (%)
C
N
C
H
N
5-nitroacenaphthene
4-nitro-1,8-naphthalic
anhydride
72
59.5
4.4
2.4
6.6
5.6
72.36
59.26
4.52
2.06
7.04
5.76
4-nitro-N-methyl
naphthalimide
4-nitro-N-ethyl
naphthalimide
4-nitro-N-(n-propyl)
naphthalimide
4-nitro-N-(n-butyl)
naphthalimide
61
3.3
3.9
4.4
4.8
10.8
10.4
9.8
60.94
62.20
63.38
64.43
3.13
3.70
4.24
4.70
10.93
10.37
9.85
62.1
63.3
64.8
9.2
9.40
was reacted with various amines, and the complete reaction
was examined by TLC on silica gel 60. The products of 4-
nitro-N-substituted-1,8-naphthalimides are shown in Tables
1 and 2.
Table 3. The M.P., yield percent, FTIR, and H-NMR spectra of 4-amino-N(9)-substituted of
naphthalimide derivatives
Compounds M.P. °(C) Y (%)
4-amino-N-methyl 359.82
FTIR (cm-1)
H-NMR (d)
93
N-H str. 3429.55,
3354.02
3.54 (3H, NCH3); 5.30-5.37 (2H,
NH2); 6.91 (1H, 3-H); 7.72 (1H, 6-
naphthalimide
C-H str. Ar. 2925.68 H); 8.11-8.15 (1H, 2-H); 8.52-8.56
C=O str. 1676.09,
1645.83
(1H, 5-H); 8.62-8.71 (1H, 7-H).
4-amino-N-ethyl
naphthalimide
289.67
258.46
99
N-H str. 3456.3,
3346.91
C-H str. Ar. 2980
C=O str. 1672.52,
1654.73
1.25-1.33 (3H, NCH2CH3); 4.22-
4.23 (2H, NCH2CH3); 4.95 (2H,
NH2); 6.88-6.9 (1H, 3-H); 7.64-7.69
(1H, 6-H); 8.09-8.11 (1H, 2-H);
8.41-8.43 (1H, 5-H); 8.60-8.66 (1H,
7-H).
4-amino-N-
(n-propyl)
97.9 N-H str. 3435.34,
3356.81
0.99-1.02 (3H, NCH2CH2CH3);
1.73-1.79 (2H, NCH2CH2CH3);
naphthalimide
C-H str. Ar. 2928.96 4.10-4.14 (2H, NCH2CH2CH3); 4.94
C=O str. 1675.9,
1637.66
(2H, NH2); 6.88-6.90 (1H, 3-H);
7.64-7.67 (1H, 6-H), 8.1-8.11 (1H,
2-H); 8.41-8.43 (1H, 5-H); 8.60-8.61
(1H, 7-H).
4-amino-N-
(n-butyl)
180.97
70
N-H str. 3437.98,
3359.16
0.95-1 (3H, NCH2CH2CH2CH3);
1.42-1.47 (2H, NCH2CH2CH2CH3);
naphthalimide
C-H str. Ar. 2956.23 1.68-1.74 (2H, NCH2CH2CH2CH3);
C=O str. 1674.93,
1639.93
4.14-4.18 (2H, NCH2CH2CH2CH3);
4.88-5.18 (2H, NH2); 6.87-6.88 (1H,
3-H); 7.62-7.65 (1H, 6-H); 8.09-8.11
(1H, 2-H); 8.39-8.43 (1H, 5-H);
8.57-8.63 (1H, 7-H).

498 J. Chin. Chem. Soc., Vol. 52, No. 3, 2005
Khosravi et al.
Table 4. The elemental analysis of 4-amino-N(9)-substituted of naphthalimide derivatives
Compounds
EA Found (%)
Required (%)
C
H
N
C
H
N
4-amino-N-methyl
naphthalimide
68.6
4.3
12.3
69.03
4.42
12.39
4-amino-N-ethyl
naphthalimide
4-amino-N-(n-propyl)
naphthalimide
4-amino-N-(n-butyl)
naphthalimide
69.6
70.65
71.2
5.2
5.6
6.1
11.3
11
70
5
11.67
11.02
10.45
70.87
71.64
5.51
5.97
10.3
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 earlier works, some aminonaphthalimide
dyestuffs were made by the nucleophilic attack of ammonia
on various naphthalic anhyrides or imides.11 Thus, 4-amino-
N-substituted-1,8-naphthalimides were obtained by the reac-
tion of 4-nitro-N-substituted-1,8-naphthalimide with tin(II)
chloride as a reducing agent and hydrochloric acid as a sol-
vent. The 4-amino-N-substituted naphthalimides together
with their FTIR, H-NMR, and EA are shown in Tables 3 and
4.
hues and 9, dyed polyester yellowish cream of generally good
build up.
Visual evaluation of the dyeings on polyester fabrics
showed that the nature of the alkyl residue in the amine group
of the coupling component affects both the intensity of
dyeings and their shade. The highest intensity is shown by the
dyeings of dyes 2,4,6 and 8, which contain N,N-diethyl
groups. These substituents bring about an increase in the
nucleophilic character of the tertiary nitrogen atom and of the
stability of polar forms,13 especially when there are no sub-
stituents in the phenyl rings causing steric effects.
The dyeings were violet or bluish red. The electron ac-
ceptor group on the coupling component such as -COCH3 in
dye 9 causes considerable hypsochromic effect (yellowish
cream). The colour of naphthalimide dyes depends on the
delocalisation of electrons through the conjugated azo chro-
mophore and depends on the energy difference between
structures 1 and 2. The lower this difference, the higher is the
bathochromic effect of the basic absorption band.14 The con-
tribution of the higher energy stabilized dipolar structure 2 is
enhanced by the presence of a conjugated electron acceptor
(naphthalimide residue) and electron donor (dialkylamino
group) and this results in a considerable bathochromic shift.
The diazotisation of naphthalimides was carried out
with nitrosyl sulphuric acid.9 The m.p., the yield of the prod-
ucts and FTIR, H-NMR, and EA of the synthesized dyestuffs
are shown in Tables 5 and 6.
These results show that the synthesized dyestuffs were
of a red or bluish red hue with good colour strengths. The syn-
thesized dyestuffs were applied to a polyester fabric at a con-
centration of 0.5 percent of the dyestuffs on the weight of fab-
ric. 0.5% Acetic acid and 1% dispersing agent were added,
and a liquor to goods ratio of 50:1 was used and the dyeing
was carried out at 130 °C. The dyed fabrics had very good
levelling and exhaustion properties. The spectral reflectance
and the colour coordinates were measured, the L*a*b*, L.F.,
S.F., I.S.P., lmax and log e in PhCl are shown in Tables 7 and 8.
Light fastness, wash fastness, and sublimation fastness
of all dyes were also measured according to ISO 105/B, ISO
105/C and ISO 105 POl standards respectively. The wash
fastness of all dyestuffs was 5 and the staining of polyester
was 4-5.
The imides 2,4,6 and 8, dyed polyester in bright violet
(bluish red) hues and 1,3,5 and 7, dyed polyester in bright red

Synthesis and Characterization of NaphthalimideDyestuffs
Table 5. The yield percent, FTIR, H-NMR spectra of dyestuffs
J. Chin. Chem. Soc., Vol. 52, No. 3, 2005 499
Diazo
component
Coupling
component
Dye
1
Y (%)
FTIR (cm-1)
H-NMR (d)
4-amino-N-
methyl
b-naphthol
74a N=N 1591.88
3.36-3.78 (3H, NCH3); 6.70-6.72 (1H, OH); 7.17 (1H, 3¢-
H); 7.39-7.46 (1H, 8¢-H); 7.49-7.51 (1H, 6¢-H); 7.66-7.72
C-N str. 1366.21, 1140.77
naphthalimide
C=O str. 1702.28, 1662.13 (1H, 7¢-H); 7.87-7.91 (2H, 4¢,5¢-H); 8.23-8.26 (1H, 6-H);
O-H str. 3416.65.
8.31-8.33 (1H, 5-H); 8.62-8.67 (2H, 2,7-H); 8.74-8.78
(1H, 3-H).
4-amino-N-
methyl
naphthalimide
N=N 1588.25
C-N str. 1355.35, 1184.04
C=O str. 1693.46, 1656.6
2
3
4
N,N-diethyl-
meta-toluidine
81
1.26-1.29 (6H, 4¢-N(CH2CH3)2); 2.75 (3H, CH3, m-
toluidine); 3.48-3.51 (4H, 4¢-N(CH2CH3)2); 3.55 (3H, N-
CH3); 6.61 (2H, 3¢-H, 5¢-H); 7.77-7.80 (1H, 6-H); 7.86-
7.88 (1H, 5-H); 7.91-7.93 (1H, 6¢-H); 8.57-8.59 (1H, 7-
H); 8.61-8.62 (1H, 2-H); 9.20-9.21 (1H, 3-H).
1.33-1.34 (3H, NCH2CH3); 4.16-4.17 (2H, NCH2CH3);
6.6-6.62 (1H, 3¢-H); 7.38-7.39 (1H, 8¢-H); 7.43-7.44 (1H,
-OH); 7.45-7.47 (1H, 7¢-H); 7.57-7.59 (1H, 5¢-H); 7.70-
7.73 (2H, 6,6¢-H); 8-10-8.12 (1H, 4¢-H); 8.19-8.24 (1H,
5-H); 8.31-8.33 (1H, 7-H); 8.49-8.52 (2H, 2,3-H).
1.26-1.29 (6H, 4¢-N(CH2CH3)2); 1.34-1.37 (3H, N-
CH2CH3); 2.77 (3H, 2¢-CH3); 3.47-3.51 (4H, 4¢-
N(CH2CH3)2); 4.24-4.28 (2H, N-CH2); 6.62 (2H, 3¢-H,
5¢-H); 7.79-7.82 (1H, 6-H); 7.91-7.92 (1H, 5-H); 7.95-
7.97 (1H, 6¢-H); 8.61-8.62 (1H, 7-H); 8.63-8.64 (1H, 2-
H); 9.24-9.25 (1H, 3-H).
N=N 1582.68
4-amino-N-
ethyl
naphthalimide
b-naphthol
73
C-N str. 1339.98, 1066.06
C=O str. 1693.89, 1654.74
O-H str. 3423.98
N=N 1593.42
C-N str. 1344.69, 1068.45
C=O str. 1691.87, 1654.5
4-amino-N-
ethyl
naphthalimide
N,N-diethyl-
meta-toluidine
72.1
N=N 1578.85
5
6
4-amino-N-(n- b-naphthol
propyl)
naphthalimide
95.03
78.2
0.87-1.02 (3H, NCH2CH2CH3); 1.77 (2H, NCH2
CH2CH3); 4.12 (2H, NCH2CH2CH3); 6.72-6.73 (1H, 3¢-
H); 7.37-7.44 (1H, 8¢-H); 7.54-7.56 (2H, 7¢-H, 1H, OH);
7.69-7.74 (1H, 5¢-H); 7.78-7.82 (2H, 6,6¢-H); 8.28-8.30
(1H, 4¢-H); 8.45-8.48 (2H, 5, 7-H); 8.62 (2H, 2, 3-H).
1.01-1.04 (3H, NCH2CH2CH3); 1.25-1.28 (6H, 4¢-
N(CH2CH3)2); 1.76-1.80 (2H, NCH2CH2CH3); 2.75 (3H,
C-N str. 1066.78, 1343.17
C=O str. 1651.43, 1696.57
O-H str. 3437.02
N =N 1588.76
C-N str. 1326.74, 1075.04
4-amino-N-(n- N,N-diethyl-
propyl)
meta-toluidine
naphthalimide
C=O str. 1691.89, 1655.92 2¢-CH3); 3.47-3.51 (4H, 4¢-N(CH2CH3)2); 4.13-4.16 (2H,
NCH2); 6.61 (2H, 3¢-H, 5¢-H); 7.77-7.80 (1H, 6-H); 7.85-
7.88 (1H, 5-H); 7.93-7.95 (1H, 6¢-H); 8.57-8.59 (1H, 7-
H); 8.60-8.62 (1H, 2-H); 9.21-9.22 (1H, 3-H).
N=N 1584.64
7
8
4-amino-N-(n- b-naphthol
butyl)
naphthalimide
77
67
0.93-1.01 (3H, NCH2CH2CH2CH3); 1.26-1.37 (2H,
NCH2CH2CH2CH3); 1.65-1.74 (2H, NCH2CH2CH2CH3);
4.12-4.19 (2H, NCH2CH2CH2CH3); 6.75-6.79 (1H, 3¢-H);
7.46-7.47 (1H, 8¢-H); 7.55-7.60 (2H, 7¢-H, 1H, OH);
7.72-7.76 (1H, 5¢-H); 7.84-7.90 (2H, 6,6¢-H); 8.31-8.35
(1H, 4¢-H); 8.50-8.54 (2H, 5,7-H); 8.63-8.68 (2H, 2,3-H).
0.98-1.01 (3H, NCH2CH2CH2CH3); 1.26-1.29 (6H, 4¢-
N(CH2CH3)2); 1.45-1.51 (2H, NCH2CH2CH2CH3); 1.71-
1.77 (2H, NCH2CH2CH2CH3); 2.77 (3H, 2¢-CH3); 3.49-
3.50 (4H, 4¢-N(CH2CH3)2); 4.18-4.21 (2H,
C-N str. 1353.2, 1075.38
C=O str. 1693.34, 1656.46
O-H str. 3417.67
N=N 1577.23
C-N str. 1354.13, 1078.31
C=O str. 1696.41, 1651.6
4-amino-N-(n- N,N-diethyl-
butyl)
meta-toluidine
naphthalimide
NCH2CH2CH2CH3); 6.63 (2H, 3¢-H, 5¢-H); 7.80-7.83
(1H, 6-H); 7.87-7.93 (1H, 5-H); 7.96-7.98 (1H, 6¢-H);
8.59-8.62 (1H, 7-H); 8.63-8.64 (1H, 2-H); 9.24-9.26 (1H,
3-H).
9
4-amino-N-(n- P-aminoaceto
86
N=N, 1576.28
C-N str. 1347.12, 1163.94
1.04 (3H, NCH2CH2CH3); 1.78 (2H, NCH2CH2CH3);
2.59-2.66 (3H, COCH3); 4.15 (2H, NCH2CH2CH3); 7.50-
propyl)
Phenone
naphthalimide
C=O str. 1693.35, 1660.07 7.52 (1H, 3¢-H); 7.70-7.73 (1H, 6-H); 7.90-7.92 (2H,
N-H overtone bend 3205.26 NH2); 8.01-8.02 (1H, 5-H); 8.06-8.08 (1H, 7-H); 8.58-
C=O str. Ketone
8.63 (2H, 2,3-H); 9.03-9.07 (2H, 4¢, 6¢-H).
acetophenone 1739.08
a Percentage yield being more than reported by K. Wojciechowski (i.e. 51.2%).12

500 J. Chin. Chem. Soc., Vol. 52, No. 3, 2005
Khosravi et al.
Table 6. The M.P., and EA of dyestuffs
Coupling
Dye
Diazo component
M.P.
EA
component
Found (%)
Required %
C
H
N
C
H
N
11.02
1
2
3
4
5
6
7
8
9
4-amino-N-methyl
naphthalimide
4-amino-N-methyl
naphthalimide
4-amino-N-ethyl
naphthalimide
4-amino-N-ethyl
naphthalimide
4-amino-N-(n-propyl) b-naphthol
naphthalimide
4-amino-N-(n-propyl) N,N-diethyl-
naphthalimide
4-amino-N-(n-butyl)
naphthalimide
b-naphthol
230.70
195.70
283.04
174.52
279.43
157.75
260
71.85
4.2
10.55
72.44
3.94
N,N-diethyl-
meta-toluidine
b-naphthol
71.5
73
5.8
4.5
6.3
4.8
6.4
5.2
6.7
5.0
13.5
10.2
13.1
10.2
12.6
09.5
12.2
14.1
72
6
14
72.91
72.46
73.35
72.9
73.76
73.3
69.0
4.3
10.63
13.53
10.26
13.08
9.93
N,N-diethyl-
meta-toluidine
71.9
73.5
72.7
73.3
72.85
69.0
6.28
4.65
6.54
4.96
6.79
5.0
meta-toluidine
b-naphthol
4-amino-N-(n-butyl)
naphthalimide
4-amino-N-(n-propyl) P-aminoaceto
naphthalimide Phenone
N,N-diethyl-
meta-toluidine
142.47
228
12.67
14.0
Table 7. The lmax, log e in PhCl and the values of the L*, a*, b*
Dyestuffs
lmax in PhCl
Log e in PhCl
L*
a*
b*
1
2
3
4
5
6
7
8
9
526.5
535.2
527.0
532.8
525.3
534.3
526.1
534.9
425.4
4.175
4.52
4.417
4.55
4.49
4.50
4.44
4.53
4.59
46.358
28.933
42.902
29.217
46.441
26.287
51.413
29.789
63.605
50.850
35.079
56.452
35.394
54.722
34.221
48.263
35.349
16.400
9.531
-12.397
11.233
-12.404
6.681
-10.163
4.674
-10.248
23.298
The electron donor substituents in the ring of the cou-
pling components also considerably affect the colour of the
dyeings, especially those in an ortho position to the azo bond
such as dyes 1,3,5, and 7; this phenomenon is describeable in
terms of structures 3 and 4.
The naphthalimide derivatives show exceptionally good
thermal stability and their dyeings have good fastness proper-
ties.3,15 Generally, the highest initial sublimation points were
shown by the dyes containing a naphthalimide group in their
structure. They tended to undergo association in the crystal-
line state, which was confirmed by their i.r. spectra, and high
melting points. This propensity for association provides dyes

Synthesis and Characterization of NaphthalimideDyestuffs
Table 8. L.F.,a S.F.,b I.S.P.,c of dyestuffs
J. Chin. Chem. Soc., Vol. 52, No. 3, 2005 501
tive. In a protic solvent the substitution only occurs in the 9-
position. 4-Aminonaphthalimides have been synthesized by
reduction of the 4-nitro group of the appropriate naphthalic
imides.
Dyestuffs
L.F. 180 °C S.F.
210 °C
I.S.P. °C
1
2
3
4
5
6
7
8
9
5-6
5-6
4-5
4-5
5-6
5-6
4-5
4-5
4
4-5
4
4
4
5
5
5
4-5
4-5
3-4
3-4
3-4
3-4
4-5
4-5
4-5
4-5
4-5
200
150
200
150
200
150
200
150
180
From the investigations into the use of N-substituted
naphthalimide as an intermediate for monoazo disperse dye-
stuffs, it was found that dyestuffs derived from 4-amino-N-
methyl (alternatively N-ethyl, N-propyl, N-butyl) were suit-
able for dyeing polyester. The various dyestuffs obtained and
their corresponding intermediates were identified by the use
of elemental analysis, DSC, FTIR, H-NMR, and UV-visible
spectroscopic techniques.
a Light Fastness
b Sublimation Fastness
The spectrophotometric properties of the prepared
monoazo disperse dyestuffs in PhCl solvent were examined.
The absorption maxima of these dyestuffs and their intensi-
ties have also been obtained.
c Initial Sublimation Point
with good thermal stability as reflected in the sublimation
fastness of dyeings and their high initial sublimation points.
Practical applications of the naphthalimide dyes, de-
spite their undeniable advantages, are limited because of
their complicated synthesis and high cost of intermediates.
The use of these dyes is further restricted due to their strong
tendency to aggregate, making the dye sorption and diffusion
in polyester fibre difficult. The synthesis of these dyes in Iran
may be economically viable because of the availability of
coal tar which can provide acenaphthene, the primary starting
material for naphthalimide dyes.
The synthesized dyestuffs were utilized for dyeing a
polyester fabric and were found to be very suitable for the
H.T. dyeing method. General dyeing properties such as ex-
haustion and leveling of the dyestuffs on polyester fabric
were found to be extremely good.
From these investigations, it may be concluded that
naphthalimides and related compounds are reasonable mono-
azo disperse dyestuffs giving good all round properties on
polyester fabrics.
4-Amino-N-methylnaphthalimide is a useful diazo
component for the synthesis of azo disperse dyes. Its acceptor
“force” is comparable with that of 2,4-dinitroaniline, and its
use additionally ensures high-performance properties of the
dyestuffs.15,16
Received October 20, 2004.
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CONCLUSION
3. Peters, A.-T.; Bide, M.-J. Dyes and Pigments. 1986, 7, 237.
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6. Okazaki, M.; Suhara, Y.; Fujiyama, M. Yuki Gosei, Kagaku
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The solvent plays an important role in the nucleophilic
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Some naphthalimides with different substituents in the 9-
position have been prepared.7,8 The naphthalic anhydride is
reacted with an amine in a protic solvent such as alchohol or
acetic acid to give the corresponding 9-substituted deriva-
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