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W. Ma et al. / Chinese Chemical Letters 22 (2011) 1489–1491
O
O
O
HO
O
N
N
N
N
N
N
NBS, AIBN
N2, reflux
Ac2O/H2SO4
heat
N
N
N
CH3
CH2Br
CH3
a
b
H2
C
H2 H
H2
C
H
C
H
C
C
C
m
NH2
n
y
NH2
n
x
CONH2
NH
CONH2
H2C
THF/H2O
N
N
N
x+y=m
OH
c
Scheme 1. Synthesis of the polymeric UV absorber.
the polymeric UV absorber would be good. In addition, after being finished on cotton, the polymeric UV absorber
could be further crosslinked with cotton fibers to improve its fastness properties.
The synthesis of polymeric UV-absorber c is shown in Scheme 1. Compound 2-(20-acetoxy-50-methylphenyl)-2H-
benzotriazole a was synthesized through protection of hydroxyl group of UV-P, and then hydrogen of benzyl group of
a was brominated to get 2-(20-acetoxy-50-bromomethylphenyl)-2H-benzotriazole b. Amination of b with PVAm and
deprotection of hydroxyl group of b were carried out at the same time to obtain product c under alkaline and high
temperature conditions. The yield of a (mp 104–106 8C), b (mp 126–128 8C) and c was 95.1%, 60% and 99.0%,
respectively. Agilent 8453 UV-vis spectrophotometer, FT-IR 430 spectrophotometer, HP1100 mass spectrometer and
Varian Inova 400 NMR were used to determine the structures of the intermediates and the polymeric UV absorber.
1H NMR (400 MHz, CDCl3) data of a were as follows: d 2.30 (s, 3H), 2.46 (s, 3H), 7.19 (d, 1H, J = 8.28 Hz), 7.31
(d, 1H, J = 7.78 Hz), 7.43 (dd, 2H, J = 6.53, 3.01 Hz), 7.92 (dd, 2H, J = 6.78, 3.01 Hz), 7.95 (s, 1H). MS m/z of a was
at 290 [M+Na]+. FTIR (KBr) n: 1758 cmꢀ1 (stretching vibration of C O), 1610, 1508 cmꢀ1 (skeleton vibration of
benzene ring C C), 1371 cmꢀ1 (deformation vibration of C–H of CH3), 1226, 1206, 1190 cmꢀ1 (stretching vibration
of C–O–C), and 743 cmꢀ1 (deformation vibration of C–H of benzotriazole ring). UV–vis: lmax = 310 nm.
1H NMR (400 MHz, CDCl3) data of b were: d 2.33 (s, 3H), 4.57 (s, 2H), 7.29 (d, 1H, J = 8.28 Hz), 7.44 (dd, 2H,
J = 6.78, 2.76 Hz), 7.54 (d, 1H, J = 8.28 Hz), 7.92 (dd, 2H, J = 6.53, 2.76 Hz), 8.22 (s, 1H). MS m/z data of b was: 346
[M+H]+, 348 [M+H+2]+, 368 [M+Na]+, 370 [M+Na+2]+, and the peak intensity ratios (M+H):(M+H+2) and (M+Na):
(M+Na+2) were both 1:1, which demonstrated one bromine existing in b. FT-IR(KBr) n: 1754 cmꢀ1 (stretching
vibration of C O), 1610, 1507 cmꢀ1 (skeleton vibration of benzene ring C C), 1368 cmꢀ1 (deformation vibration C–
H of CH3), 1215 cmꢀ1 (stretching vibration of C–O–C), 740 cmꢀ1 (deformation vibration of C–H of benzotriazole
ring), and 648, 638 cmꢀ1 (stretching vibration of C–Br). UV–vis: lmax = 302 nm.
The target compound c with grafting ratio of 30% of the amino group of PVAm was characterized by TLC, FT-IR
and UV–vis spectra. TLC of b and c was made with dichloromethane as developer. Rf of b is 0.65, while that of the
grafting product c is zero, which demonstrates that b has been grafted onto PVAm. FT-IR (KBr) data of c were as
+
follows: 3421 cmꢀ1 (stretching vibration of N–H), 2943 cmꢀ1 (stretching vibration of NH3 ), 1638 cmꢀ1 (asymmetric
deformation vibration of NH3 ), 1517 cmꢀ1 (symmetric deformation vibration of NH3 ), 746 cmꢀ1 (deformation
+
+
vibration of C–H in aromatic ring).
It was observed from the UV spectrum of c (Fig. 1) that the characteristic absorption peaks of o-hydroxy-
phenylbenzotriazole UV-absorbers appeared at 300 nm and 332 nm, which also showed that that UV-absorber had
been grafted onto PVAm. In addition, appearance of the peak at 332 nm in UV spectrum of c proved the deprotection
of the hydroxyl group of the UV absorbing component.
As benzotriazole group was water insoluble, with the increase of the grafting ratio of it, the water solubility of c
decreased gradually. It showed when the grafting ratio was 30.0%, the solubility of the polymeric UVabsorber c was
still good. However, when the grafting ratio increased to 38.5%, c was difficult to dissolve in water. In the study, the
polymeric UVabsorber c with grafting ratio of 30% was applied to finishing of cotton fibers through exhaust method.
Ma, Wei
