Synthesis, identification and application of aldehyde reactive dyes

Article abstract of DOI:10.1016/j.dyepig.2015.05.033

Nine aldehyde reactive dyes, designated D₁- D₉, were synthesized. Among them, D₁ and D₂ were synthesized by "grafting" alizarin red and alizarin yellow GG, respectively, to the α-C of n-butyl-aldehyde; D₃ and D₄ were synthesized by "grafting" alizarin red and alizarin yellow GG, respectively, to the methyl-C of 4-methyl-cinnamaldehyde; D₅- D₉ were synthesized by "grafting" alizarin red, alizarin yellow GG or self-prepared colorants to the α-C of glutaraldehyde. UV-Vis, FTIR, ESI-MS, elemental analysis and ¹H NMR were applied to identify the target products. Aluminum-tanned wet-white sheep leather was chosen as substrate for the application experiments, and their four dyeing property indexes, i.e., substantivity (S), exhaustion (E), fixation (F) and reactivity (R) were measured. The results indicated that, without adding of neutral salts and under mild conditions (T = 35-45 °C, pH = 4.0-6.5), all these dyes could dye wet-white leather within 1.5 h, and the dyed leather possessed a satisfactory washing-fastness.

Full text of DOI:10.1016/j.dyepig.2015.05.033

Accepted Manuscript
Synthesis, identification and application of aldehyde reactive dyes
Xiao Chen, Ding Keyi, Liu Jun
PII:
S0143-7208(15)00212-0
10.1016/j.dyepig.2015.05.033
DYPI 4796
DOI:
Reference:
To appear in: Dyes and Pigments
Received Date: 14 January 2015
Revised Date: 12 May 2015
Accepted Date: 28 May 2015
Please cite this article as: Chen X, Keyi D, Jun L, Synthesis, identification and application of aldehyde
reactive dyes, Dyes and Pigments (2015), doi: 10.1016/j.dyepig.2015.05.033.
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ACCEPTED MANUSCRIPT
Synthesis, identification and application of aldehyde reactive dyes
1
2
2*
Chen Xiao , Keyi Ding , Jun Liu
1
. Chemistry Department, Yibin University, Yibin 644000, PR China
.College of Chemistry & Environmental Protection Engineering, Southwest University for Nationalities, Chengdu
10041, PR China
Corresponding author. E-mail address:LIUJUN106 @SOHU.COM
2
6
*
Abstract: Nine aldehyde reactive dyes, designated D - D , were synthesized. Among them, D
1
1
9
and D were synthesized by “grafting” alizarin red and alizarin yellow GG, respectively, to the α-C
2
of n-butyl-aldehyde; D and D were synthesized by “grafting” alizarin red and alizarin yellow GG,
3
4
respectively, to the methyl-C of 4-methyl-cinnamaldehyde; D - D were synthesized by “grafting”
5
9
alizarin red, alizarin yellow GG or self-prepared colorants to the α-C of glutaraldehyde. UV-vis,
1
FTIR, ESI-MS, elemental analysis and H NMR were applied to identify the target products.
Aluminum-tanned wet-white sheep leather was chosen as substrate for the application experiments,
and their four dyeing property indexes, i.e., substantivity (S), exhaustionꢀEꢁ, fixationꢀFꢁand
reactivityꢀRꢁwere measured. The results indicated that, without adding of neutral salts and under
mild conditions (T = 35-45 °CꢂpH =4.0-6.5), all these dyes could dye wet-white leather within 1.5
h, and the dyed leather possessed a satisfactory washing-fastness.
Keywords: aldehyde, reactive dyes, synthesis, identification, application
1
Introduction
Reactive dyes are widely used to dye protein fibers (such as wool, silk, fur and
leather) and cotton fiber because of their good rub fastness and washing fastness.
However, research results [1-3] showed that the problem of the currently available
reactive dyes are: (1) the hydrolysis of their reactive groups during the process of
storage and application results in the lost as high as 20-50% of reactive dyes; and (2) a
large quantity of neutral salts (20-40 g/L) required in the dyeing process may cause
environmental pollution.
1

ACCEPTED MANUSCRIPT
The idea of reactive aldehyde dyes derived from the research of our laboratory
on the color-forming mechanism of natural iridoids (such as genipin, loganin
aglycone, oleuropein aglycone and E-6-O-methoxycinnamoyl scandoside methyl ester
aglycone) with primary amino (–NH ) containing materials (such as silk, leather and
2
wool) [4-5]. This mechanism indicated that there was an inter-conversion isomer with
a glutaraldehyde backbone present in the reaction system, which caused genipin, for
example, to crosslink with collagen fiber (Fig. 1). Two effects would produce during
this process: collagen fiber was dyed to dark-blue and its hydrothermal stability was
increased [4-5].
Glutaraldehyde is a commonly used tanning agent for leather manufacture. During
the tanning process a crosslinking reaction could occur between glutaraldehyde and
collagen molecules through a Schiff base reaction. This mechanism suggested that a
new kind of reactive dye could be made by “grafting” bio-friendly colorants to the
backbone of glutaraldehye. Unlike the normally used reactive dyes, this alternative
reactive aldehyde dyes do not hydrolysis and neutral salts do not need during their
application. Theoretically, a simultaneous tanning — dyeing process could be
achieved when this novel kind of reactive dye is applied to leather.
Generally, glutaraldehyde is preserved as a 25% - 50% (w/w) aqueous solution
and it is almost impossible to “graft” colorant compounds to its backbone directly. So
an “easy to difficult” strategy was adopted, during which colorant compounds were
grafted to the α-C of n-butyl-aldehyde and the methyl-C of 3-(4-methyl) phenyl
-acrylaldehyde, so that a series of reactive dyes with mono-aldehyde as reactive group
was obtained. Their capacity to dye aluminum pre-tanned wet-white leather were
investigated; after that, colorant compounds were grafted to the precursor of
glutaraldehyde, and target products were obtained by an oxidation reaction or
hydrolysis reaction. In this way, nine reactive dyes with aldehyde as the reactive
group were synthesized. Their structures were identified and their application
properties were investigated.
2

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2
2
Experimental
.1 Materials
3,4-Dihydro-2H-pyran-2-methanol(ꢃ97%) was supplied by Huachem Industry
Ltd., Japan; sodium 1-amino-4-bromoanthraquinone-2-sulfonate ( ꢃ89%) was
supplied by Longsheng Dye Chemical Corp., Zhejiang, ChinaꢄSilica GF254 was
supplied by Qingdao Haiyang Chemical Corp., China; n-butyl-aldehyde,
N,N-dimethylformamide (DMF), N-chlorosuccinimide (NCS), N-bromosuccinimide
(NBS), L-ProlineꢂAlizarin red, Alizarin yellow GG, 4-methylcinnamaldehyde,
Benzoyl peroxide (BPO), cyclopentene, dimethyl sulfoxide (DMSO), 1,4-dioxane,
sodium 2,4-diamino-benzenesulfonate, m-phenylenediamine, hydroquinone and other
commonly used chemicals were supplied by Chengdu Kelong Chemical Corp., China
(all analytical grade); aluminum pre-tanned sheep wet white leather was provided by
the Leather Department of Sichuan University, China.
2.2 Synthesis of mono-aldehyde reactive dyes
2
.2.1 Synthesis of D ꢅD based on n-butyl-aldehyde [6]
1
2
(
1)Synthesis of α-chlorobutanal
In a 0 °C ice bath, n-butyl-aldehyde (5 mmol) and L-Proline (1 mmol) were
dissolved in CH Cl (10 mL), and NCS (6.5 mmol) was added slowly with stirring.
2
2
After 1 h, the temperature of the solution was raised to 25 °C and the reaction
proceeded for another 8 h. After removal of CH Cl by rotary evaporation, n-pentane
2
2
(30 mL) was added to precipitate NCS and other side products. α-chloro
butyl-aldehyde was obtained after filtration and removal of n-pentane by evaporation
under vacuum (Fig. 2).
ꢀ
2ꢁSynthesis of D1
To a 100-mL three-necked flask, alizarin red (1.80 g, 5 mmol), potassium
carbonate (2.07 gꢂ15 mmol) and 50 mL of DMF were addedꢂthe temperature was
raised to 30 °C with stirring. Then α-chloro butyl-aldehyde (1.06 gꢂ0.01 molꢁwas
added and the reaction proceeded for 12 h. After removal of DMF by rotary
evaporation, D , the target product, a red purple powder (1.86 g) was obtained in a
1
yield of 75.4% (Fig. 3).
3

ACCEPTED MANUSCRIPT
ꢀ
3ꢁsynthesis of D2
To a 100-mL three-necked flask, alizarin yellow GG (1.546 gꢂ5 mmol),
potassium carbonate (2.07 gꢂ15 mmol) and 50 mL DMF were addedꢂthe temperature
was raised to 40 °C under stirring, then α-chloro butyl-aldehyde (1.06 gꢂ0.01 mol)
was added and the reaction proceeded for 12h. After removal of DMF by evaporation
in vacuum, D , a light yellow powder (1.41 g) was obtained in a yield of 74.6%
2
(Fig.4).
2
.2.2 Synthesis of D ꢅD based on 4-methylcinnamaldehyde[7]
3
4
(1) Preparation of 3- (4- (bromomethyl) phenyl) acrylaldehyde
To a 250-mL three-necked flask, 4-methylcinnamaldehyde (4.38 g, 0.03 mol),
NBS (6.23 g, 0.035 mol), BPO (10 mg) and 50 mL CCl were addedꢂthe
4
temperature was raised to 40 °C with stirring and the reaction proceeded for 4 h. After
2
h at room temperature without stirring, the floating materials were filtered and
washed three times (3×10 mL) with CCl and the CCl fractions were combined.
4
4
Water soluble impurities were removed by washing the CCl solution with 60 mL
4
water in a separatory funnel. The CCl phase was collected and dried by adding
4
MgSO (anhyd). MgSO was removed by filtration after 12 h, leaving the pure
4
4
product in CCl solution. CCl was removed by rotary evaporation. The yield of 3- (4-
4
4
(bromomethyl) phenyl) acrylaldehyde was 4.48 g in a yield of 66.7% (Fig. 5).
(2) Synthesis of D3
To a 100-mL three-necked flask, alizarin yellow GG (6.18 gꢂ0.02 mol) ,
potassium carbonate (4.14 gꢂ0.03 mol) , 3- (4- (bromomethyl) phenyl) acrylaldehyde
6.72 g, 0.03 mol) and 100 mL DMF were addedꢂthe temperature was raised to
0 °C under stirring and the reaction proceeded for 12 h. After cooling to 25 °C and
(
4
removal of DMF by evaporation in vacuum, the yellow powder was washed with
CHCl to remove excess 3- (4- (bromomethyl) phenyl) acrylaldehyde, then filtered
3
and dried. The product, D , a yellow powder (5.87 g) was obtained in a yield of
3
64.8% (Fig. 6).
(3) Synthesis of D4
Alizarin red (7.20 gꢂ0.02 mol), potassium carbonate (4.14 gꢂ0.03 mol), 3- (4-
4

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(bromomethyl) phenyl) acrylaldehyde (6.72 g, 0.03 mol) and 100 mL DMF was
combined. The synthesis process was the same as described for the synthesis of D3.
D , a dark red powder (7.03 g) was obtained in a yield of 72.4% (Fig. 7).
4
2
2
.3 Synthesis of reactive dyes with glutaraldehyde backbone
.3.1 Synthesis of D and D [8]
5
6
(1) Preparation of α-bromocyclopentene
CCl (50 mL), cyclopentene (6.8 gꢂ0.1 mol), NBS (17 gꢂ0.092 mol) and BPO
4
(
30 mg) were combined. The synthesis process was the same as described in section
.2.2 (1). α-bromocyclopentene (9.8 g), a light yellow liquid was obtained in a yield
of 71% (Fig. 8).
2
(2) Synthesis of D5
To a 250-mL three-necked flask, alizarin red (18 g, 50 mmol), potassium
carbonate (20.7 gꢂ150 mmol) and 100 mL DMF were addedꢂ the temperature was
raised to 50 °C within 0.5 h with stirring, then α-bromocyclopentene (13.8 g) was
added dropwise within 0.5 h, and the reaction proceeded for 12 h. After removal of
DMF by evaporation in vacuum, the precursor of D (15.8 g) was obtained in a yield
5
of 67%.
The precursor of D (9.84 g) was dissolved in tert-butanol (50mL) in advance.
5
Then, to a 250-mL three-necked flask, H WO (0.5 g), B O (0.5 g), tert-butanol
3
3
2
3
(
100 mL) and H O (30% (w/w), 2.4 mL,) were addedꢂthe temperature was raised
2 2
to 35-40 °C within 0.5 h with stirring, then the dissolved precursor of D was added
5
dropwise within 0.5 h and the reaction proceeded for12 h, then Na S O (4.5 g) was
2
2
3
added three times (1.5 g ×3) to remove excess H O . After filtering and removing
2
2
solvent by evaporation in vacuum, D , a red powder (8.72 g) was obtained in a yield
5
of 83% (Fig.9).
(3) Synthesis of D6
Alizarin yellow GG
(28.7 g), potassium carbonate (13.8 g),
α-bromocyclopentene (13.8 g), and 100 mL DMF were combined to synthesize the
precursor of D6 (28.5 g) as described in section 2.3.1(2), then the precursor was
oxidized by H O to give D (26.91 g) in a yield of 87% (Fig. 10).
2
2
6
5

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2
.3.2 Synthesis of D and D [9]
7 8
(1) Synthesis of 3-Bromo-2, 6-dimethoxytetrahydropyran
To a 100-mL three-necked flask, 3, 4-dihydro-2-methoxy-2H-pyran (15 mL) and
17.5 mL MeOH were combined and put in a –5 °C ice-salt bath, then NBS (17.8 g)
was added slowly within 70 min, the temperature was raised to 20-22 °C with stirring
and the reaction proceeded for 4 h, then it was filtered and washed two times (2×20
mL) with diethyl ether and the organic fractions were combined. Water soluble
impurities were removed by washing the liquid fractions two times (2×20 mL) with
saturated NaHSO (aq.) in a separatory funnel. The organic phase was collected and
3
dried by adding MgSO (anhyd). MgSO was removed by filtration after 12 h, leaving
4
4
the pure product in diethyl ether solution, after ether was removed by rotary
evaporation, 3-Bromo-2, 6-dimethoxytetrahydropyran was obtained (18.2 g) in a yield
of 85% (Fig. 11).
(2) Synthesis of colorantꢆand colorant ꢇ
Composite catalyst (n (CuSO4•5H2O) : n (SnCl2•2H2O ) = 1:1 , 20% aq.) was prepared in
advance, then sodium 1-amino-4-bromoanthraquinone-2-sulfonate (8.08 g),
m-phenylenediamine (2.16 g) and H O (50 mL)were added to a 100-mL three-necked
2
flask, the temperature was raised to 65-70 °C with stirring; newly prepared composite
catalyst (10 mL) was add dropwise slowly within 10 min, and pH was adjusted to
9
-10 with 10% (v/w) Na CO aq. The reaction was monitored by thin layer
2 3
chromatography (n butyl alcohol : n acetic acid : nwater= 4:1:5) and the end point was marked
as the disappearance of 1-amino-4-bromoanthraquinone-2-sulfonic, usually within 10
h. As soon as the reaction was finished, the solution was filtered and 20 g NaCl was
added to the liqiud fractions. After 12 h with stirring, it was put in a separatory funnel,
the upper fraction was collected and driedꢂthe product was referred to as colorantꢆ
(
Fig. 11).
Sodium 1-amino-4-bromoanthraquinone-2-sulfonic (8.08 g) , hydroquinone
8.8 g) and H O (90 mL) were added to a 250-mL three-necked flask, rise temperature
(
2
to 80-85 °C under stirring, composite catalyst (10 mL) was dripped slowly within 10
min, adjust pH= 9-10 with 10% (v/w) Na CO aq. solution. The reaction was
2
3
monitored by thin layer chromatography (n butyl alcohol : n ethanol : nwater= 2ꢈ1ꢈ1) and
making the disappearance of 1-amino-4-bromoanthraquinone-2-sulfonic as the end
6

ACCEPTED MANUSCRIPT
point, usually the reaction lasted for 18 h. As soon as the reaction was finished, the
solution was filtered and 30g NaCl was added to the liqiud fractions. After 12 h with
stirring, it was put in a separatory funnel, the upper fraction was collected and driedꢂ
the product was referred to as colorant ꢇ(Fig. 11).
(
3) Synthesis of the precursor of D and D8
7
Water (10 mL) , acetone (10 mL) , 3-bromo-2,6-dimethoxytetrahydropyran
(2 mL) and colorantꢆ (4.1 g) were added to a 50-mL three-necked flask, the
reaction was lasted for 3 h under stirring at 0-5 °C, then the temperature was raised to
0 °C and reacted for another 8 h, then it was filtered and the solid product was
7
dissolved in 15mL DMF and filtered for the second time. The liqiud fractions were
washed with 100 mL diethyl ether at 5 °C for 1 h and then filtered, the solid product
was vaccum dried, it was refered to as precursor of D (Fig. 11) .
7
DMF (20 mL) , colorantꢇ (4.32 g) , NaOH (0.5 g) were added to a 50mL
three-necked flask, the reaction was lasted for 2 h under 80-85 °C with stirring, then
the temperature was raised to 100 °C, NaI (0.5 g) and
3
2
-Bromo-2,6-dimethoxytetrahydropyran (2 mL) were added and reacted for another
4h; then it was filtered and the solid product was dissolved in 15mL DMF and
filtered for the second time. The liqiud fractions were washed with 100 mL diethyl
ether at 5 °C for 1 h and then filtered, the solid product was vaccum dried and refered
to as precursor of D (Fig. 11) .
8
(
4) Obtaining the target products D , D8
7
The precursor D or D (2.0 g) and HCl (10 mL, 10% (v/v) ) were added to a
7
8
5
0-mL three-necked flask, pH was adjusted to 3-4 with 20% (v/w) NaHCO (aq). The
3
reaction was proceed for 3 h at 80-85 °C with stirring, then the solvent was removed
by evaporation under vacuum and the product was dried at room temperature. The
target products D and D were obtained (Fig. 11).
7
8
2
.3.3 Synthesis of D [10]
9
(1) Synthesis of colorant ꢉ
Sodium 1-amino-4-bromoanthraquinone-2-sulfonic (24.30 g), sodium
2
,4-diamino-benzene-sulfonic (16.92 g), H O (200 mL) and NaHCO (18.00 g) were
2 3
added to a 500-mL three-necked flask, the temperature was raised to 75-85 °C with
stirring, newly prepared composite catalyst (30 mL) from section 2.3.2 (2) was added
7

ACCEPTED MANUSCRIPT
dropwise slowly within 20 min, pH was adjusted to 8.0-8.5 with 10% (v/w) Na CO3
2
aq. The reaction was monitored by thin layer chromatography (n butyl alcohol : n 2-Propanol
:
n ethyl acetate: nwater = 2: 4 ꢈ1 ꢈ3) and making the disappearance of
1
-amino-4-bromoanthraquinone-2-sulfonic as the end point, usually the reaction
would last for 12 h. As soon as the reaction was finished, active carbon was added and
the solution was filtered, then 80 g NaCl was added to the liqiud fraction. After 12 h
with stirring, it was put in a separatory funnel, the upper layer was collected and
vaccum driedꢂ24.36 g blue powder, which was referred to colorant ꢉwas obtained
with a yield of 85.24% (Fig. 12).
(2) Synthesis of D9
With DMSO as solvent and KI as catalyst, colorant ꢉ(4.5 g) and 3-Bromo-2,
6-dimethoxytetrahydropyran (2 mL) were reacted as described in section 2.3.2 (3) to
obtain the precursor of D9.
Precursor of D (5 g) and 1,4-dioxane (50 mL, 50% aq. (v/v) ) were added to a
9
100-mL three-necked flask and the pH was adjusted to 2-3 using 1 M HCl aq. and the
temperature was raised to 90 °C with stirring. The reaction was monitored hourly by
thin layer chromatography (n ethyl acetate : n pyridine : nwater= 6 : 3 : 1). The reaction was
regarded as complete when the size of the spot of D remained unchanged after three
9
consecutive hourly tests. A 1 M solution of HCl (aq.) was added until the product
precipitated; then it was filtered and the solid part was dried at room temperature, the
target product, D , a black powder (3.60 g) in a yield of 82% (Fig. 12) was obtained.
9
2.4 The isolation and purification of dyes [9]
(1) Isolation
To purify the raw products, 1 g of raw dyestuff was dissolved in 5 mL DMF.
Undissolved impurities were removed by filtration and washing with an additional 1
mL DMF. The DMF fractions were combined and DMF was removed by rotary
evaporation. The remaining solid material was washed in 50 mL diethyl ether to
remove non-polar impurities. Purified product was collected by filtration and the yield
was calculated.
(
2) Purification
The powdered product from the previous step was mixed with diatomaceous
earth and dried in an oven at 80 °C. The dried mixture was added to the top of a
8

ACCEPTED MANUSCRIPT
column packed with GF254 silica stationary phase. A mixture of n-butyl alcohol and
acetic acid (20:1, v/v) was added to the column as mobile phase. Passage of the
colored dye through the column was easily monitored, and the main colored band was
collected as it was eluted from the column. After removal of solvent by rotary
1
evaporation at 85 °C, the pure sample for UV-vis, FTIR, elemental analysis, H NMR
and ESI-MS spectrometry analyzing was obtained.
2.5 Identification of dyes
UV-Vis absorption for determination of the λmax of dyes was performed using
TU-1901, FTIR (KBr) was performed with FTS3000, elemental analysis were
1
performed on an Carlo-Erba-1106, H NMR were recorded on a Bruker Avance DPX
–
400 using Methanol-d as solvent and TMS as internal standard, ESI-MS were
4
carried out with Finnigan-LCQ via negative ion mode.
2
.6 The measurement of SꢅEꢅFꢅR (making D as an example) [11]
7
Aluminum pre-tanned sheep wet-white pelt (5 cm × 5 cm) was weighed and
making its weight as reference for other regents: liquor ratio was 300% (w/w), the
dosage of D was 2% (w/w), pH of the dye-bath was adjusted to 6.0-6.5 with 10%
7
(
w/w) Na CO aq., leather pelt was dyed for 30 min under 35-40 °C; then pH was
2 3
adjusted to 4.0-4.5 with 10% (w/w) HAc aq., and the pelt was dyed for another 60
min under 45 °C. The nine intervals of sample picking for measuring the exhaustion
and fixation values were shown as Fig. 13.
(1) Calculation of exhaustion (Et)
In each interval of ꢊ-ꢋ, the absorbance (A ) of the diluted dye solution was
t
measured at the wavelength of maximum absorption (λmax). The exhaustion value
of the dye at a certain period (E ) was calculated as belowꢈ
t
E /%= (1–A /A ) ×100%
t
t
0
Where A and A are the absorbance values of the dyeing-bath for a certain period
t
0
and the original dyeing-bath, respectively.
(2) Calculation of fixaion (Ft)
In each interval of ꢌ-ꢋ, the dyed leather sample was picked up and soaped-off
using a weakly anionic detergent (2 g/L) at 40 °C for 10 min. The soap-bath was
diluted to a certain volume and its absorbance value (A ) was measured at the
t
9

ACCEPTED MANUSCRIPT
wavelength of maximum absorption (λmax). The fixation value of the dye at a certain
interval (F ) was calculated as belowꢈ
t
F /%= (1–A /A ) ×100%
t
t
0
Where A and A are the absorbance values of the soap-bath for a certain period
t
0
and the original dye-bath (2 g/L detergent was added also), respectively.
Making dyeing time as X-axe, E and F as Y-axe, the exhaustion and fixation
t
t
curve of D was achieved (Fig. 14). According to Fig. 14, S (substantivity), E
7
(
exhaustion), F (fixation) and R (reactivity) of D could be obtained, where the value
7
of S refers to the exhaustion value when t = 30 min; R refers to the value of fixation
when t = 35 min, i.e., after 5 min of the adding of HAc; E and F refer to the final
value of exhaustion and fixation, respectively.
The values of S, E, F and R of the other eight dyes could be obtained in the same
way as above. These values are very useful in dyeing practice, especially for the
choice of color-matching dyeing process when two or more than two dyes are needed
to be combined [11].
2.7 The washing fastness testing
The washing color fastness of the dyed leather was tested according to Chinese
standard methods GB/TC3921-97.
3
3
Results and discussion
.1 Identification of dyes
-
1
D : C H O SNa, purple-red powder, λ = 525 nm. IR (KBr): 2852 cm , 2742
1
18 13
8
max
-1
-
1
-1
cm (double ʋ of the aldehyde), 2744cm (quinone ʋ ), 1345 cm (-SO ), 1256
C-H
C=O
3
-1
-1
1
cm (Ar-OH), 1047 cm (Ar-O-CH). ESI-MS, m/z: 389.13 [M-Na]¯ . H NMR: δ :
H
9
1
.23 (d, 8.7 Hz, 1H), 8.01 (dd, 6.4, 4.5 Hz, 1H), 7.73 (s, 1H), 6.84 (m, 1H), 6.82 (m,
H), 6.79 (m, 1H), 4.25 (dd, 6.7, 4.3 Hz, 1H), 2.13 (m, 1H), 1.87 (m, 1H), 0.96 (t, 7.4
Hz, 3H). Elemental Anal. CalcdꢈCꢂ52.47; H, 3.16; O, 31.76; S, 7.78; Na, 5.58.
FoundꢈCꢂ52.43; H, 3.18; O, 31.72; S, 7.75; Na, 5.56%.
-1
D : C H O N Na, yellow powder, λ = 353 nm. IR (KBr): 2850 cm , 2742
2
17 14
6
3
max
-1
-1
-1
-1
cm (double ʋ of the aldehyde), 1447 cm (ʋ
), 1390 cm (ʋ-NO2), 1067 cm
-N=N-
C-H
1
(
Ar-O-CH). ESI-MS, m/z: 356.12 [M-Na]¯ . H NMR: δ : 9.28 (d, 8.1 Hz, 1H), 8.47 (t,
H
1
6
.7 Hz, 1H), 8.41 (d, 6.5 Hz, 1H), 8.21 (m, 1H), 8.18 (m, 1H), 8.17 (m, 1H), 7.43 (t,
.7 Hz, 1H), 7.36 (d, 8.1 Hz, 1H), 4.23 (m, 1H), 2.05 (m, 1H), 1.87 (m, 1H), 1.06 (t,
1
0

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7.3 Hz, 3H). Elemental Anal. CalcdꢈCꢂ53.87; H, 3.69; O, 25.33; N, 11.08; Na, 6.06.
FoundꢈCꢂ53.79; H, 3.66; O, 25.37; N, 11.10; Na, 6.02%.
-1
D : C H O N Na, yellow powder, λ = 381 nm. IR (KBr): 2852 cm , 2745
3
23 16
6
3
max
-1
-1
-1
-1
cm (double ʋ of the aldehyde), 1451 cm (ʋ
), 1390 cm (ʋ-NO2), 1069cm
-N=N-
C-H
1
(
Ar-O-CH). ESI-MS, m/z: 430.21 [M-Na]¯ . H NMR: δ : 9.18 (dd, 8.1, 2.3 Hz, 1H),
H
8
1
2
.70 (s, 1H), 8.12 (t, 1.7 Hz, 1H), 7.92 (m, 1H), 7.88 (m, 1H), 7.79 (m, 1H), 7.67 (dd,
4.3, 2.3 Hz, 1H), 7.63 (m, 3H), 7.25 (m, 3H), 6.84 (dd, 14.3, 8.1 Hz, 1H), 5.44 (s,
H). Elemental Anal. CalcdꢈCꢂ60.98; H, 3.53; O, 21.19; N, 9.27; Na, 5.07. Foundꢈ
C, 60.10; H, 3.55; O, 21.16; N, 9.25; Na, 5.05%.
D : C H O SNa, red powder, λ = 535 nm. IR (KBr): 2851 cm , 2740 cm
-1
-1
-1
4
24 15
8
max
-1
-1
(
double ʋC-H of the aldehyde), 2746cm (quinone ʋ ), 1358cm (-SO ), 1254cm
C=O 3
-1
1
(
Ar-OH), 1047cm (Ar-O-CH ). ESI-MS, m/z: 463.08 [M-Na]¯ . H NMR: δ : 9.29 (d,
2
H
4
8
.8 Hz, 1H), 8.56 (s, 7.4 Hz, 1H), 8.40 (d, 4.8 Hz, 1H), 8.10 (m, 1H), 8.08 (m, 1H),
.07 (m, 1H), 7.85 (d, 12.3 Hz, 1H), 7.79 (d, 6.7 Hz, 2H), 7.36 (d, 6.7 Hz, 2H), 6.64
(dd, 12.3, 4.8 Hz, 1H), 4.58 (s, 2H). Elemental Anal. CalcdꢈCꢂ59.31; H, 3.09; O,
2
6.34; S, 6.65; Na, 4.73. FoundꢈC, 59.22; H, 3.12; O, 26.37; S, 6.49; Na, 4.69%.
-1
-1
D : C H O SNa, red powder, λ = 522 nm. IR (KBr): 2849 cm , 2738 cm
5
19 13
9
max
-1
-1
-1
(
(
(
double ʋC-H of the aldehyde), 2744 cm (quinone ʋ ), 1356 cm (-SO ), 1266cm
C=O 3
-1
1
Ar-OH), 1049 cm (Ar-O-CH ). ESI-MS, m/z: 417.15 [M-Na]¯ . H NMR: δ : 9.27
2
H
d, 4.8 Hz, 1H), 9.08 (t, 7.4 Hz, 1H), 8.68 (s, 1H), 8.13 (t, 1.8 Hz, 1H), 7.91 (m, 1H),
.89 (m, 1H), 7.76 (m, 1H), 4.20 (m, 1H), 2.75 (m, 2H), 2.26 (m, 1H), 2.10 (m, 1H).
Elemental Anal. CalcdꢈCꢂ51.86; H, 2.96; O, 32.73; S, 7.29; Na, 5.22. FoundꢈC,
1.62; H, 3.01; O, 32.75; S, 7.26; Na, 5.18%.
7
5
-
1
D : C H O N Na, yellow powder, λ = 361 nm. IR (KBr): 2852 cm , 2745
6
18 14
7
3
max
-1
-1
-1
-1
cm (double ʋ of the aldehyde), 1443 cm (ʋ
), 1529 cm (ʋ-NO2), 1249 cm
-N=N-
C-H
1
(Ar-O-CH). ESI-MS, m/z: 385.12 [M-Na]¯ . H NMR: δ : 9.38 (d, 4.5 Hz, 1H), 9.29 (t,
H
7
8
2
.3 Hz, 1H), 8.74 (brs, 1H), 8.62 (d, 1.8 Hz, 1H), 8.25 (m, 1H), 8.24 (m, 1H), 8.20 (dd,
.4, 1.8 Hz, 1H), 7.65 (t, 8.0 Hz, 1H), 7.42 (d, 8.4 Hz, 1H), 4.20 (m, H), 2.43 (m, 2H),
.31 (m, 1H), 2.15 (m, 1H). Elemental Anal. CalcdꢈCꢂ52.99; H, 3.43; O, 27.45; N,
1
0.29; Na, 5.63. FoundꢈCꢂ52.94; H, 3.46; O, 27.48; N, 10.23; Na, 5.69%.
-1
D : C H O N S, dark-blue powder, λ = 634 nm. IR (KBr): 2847 cm , 2741
7
25 21
7
3
max
-1
-1
-1
cm (double ʋ of the aldehyde), 2743 cm (quinone ʋ ), 1624cm (ʋ-NH-),
C-H
C=O
-1
1
1
9
1
1
577cm (ʋ
). ESI-MS, m/z: 506.11 [M-H]¯ . H NMR: δ : 9.31 (d, 4.6 Hz, 1H),
NH2 H
-
.25 (t, 7.1 Hz, 1H), 9.16 (brs, 1H), 8.15 (m, 1H), 8.13 (m, 1H), 8.09 (m, 1H), 8.08 (m,
H), 7.75 (brs, 1H), 7.59 (s, 1H), 7.21 (m, 1H), 6.89 (m, 1H), 6.43 (m, 1H), 6.30 (m,
H), 3.65 (m, 1H), 2.64 (m, 2H), 1.97 (m, 2H). Elemental Anal. CalcdꢈCꢂ59.22; H,
4
6
.14; O, 22.09;N, 8.28; S, 6.32. FoundꢈCꢂ59.17; H, 4.11; O, 22.07; N, 8.26; S,
.29%.
-1
D : C H O NS, purple-red powder, λ = 498 nm. IR (KBr): 2851 cm , 2745
8
25 19
9
max
11

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-
1
-1
-1
cm (double ʋ of the aldehyde), 2741cm (quinone ʋ ), 1620cm (-SO ),
C-H
C=O
3
-1
1
1
9
1
1
465cm (ʋ
). ESI-MS, m/z: 508.25 [M-H]¯ . H NMR: δ : 9.41 (d, 4.6 Hz, 1H),
Ar-NH2 H
.27 (t, 7.3 Hz, 1H), 8.10 (m, 1H), 8.07 (m, 1H), 8.04 (m, 1H), 8.00 (m, 1H), 7.50 (s,
H), 7.20 (d, 8.2 Hz, 2H), 6.87 (d, 8.2 Hz, 2H), 4.27 (m, 1H), 2.64 (m, 2H), 2.35 (m,
H), 2.14 (m, 1H). Elemental Anal. CalcdꢈCꢂ58.99; H, 3.73; O, 28.29;N, 2.75; S,
6
.29. FoundꢈC, 58.93; H, 3.76; O, 28.25; N, 2.79; S, 6.25%.
D : C H O N S , black powder, UV-Vis analysis indicated it had an mean
9
25 21 10
3 2
-
1
-1
absorption within 400-600nm. IR (KBr): 2858 cm , 2795 cm (double ʋ of the
C-H
-1
-1
-1
aldehyde), 2733cm (quinone ʋ ), 1489cm (-SO ), 1498cm (ʋAr-NH-Ar). ESI-MS,
C=O
3
1
m/z: 586.32 [M-H]¯ . H NMR: δ : 9.07 (d, 4.8 Hz, 1H), 9.05 (t, 4.9 Hz, 1H), 8.10 (brs,
H
1
7
5
H), 8.06 (m, 1H), 8.04 (m, 1H), 7.83 (m, 1H), 7.67 (d, 6.4 Hz, 1H), 7.65 (brs, 1H),
.52 (d, 6.5 Hz, 1H), 6.45 (dd, 6.5, 1.8 Hz, 1H), 6.41 (d, 1.8 Hz, 1H), 5.91 (brs, 1H),
.40 (brs, 1H), 4.01 (m, 1H), 2.35 (m, 2H), 2.14 (m, 2H). Elemental Anal. CalcdꢈCꢂ
5
7
1.15; H, 3.58; O, 27.26;N, 7.16; S, 10.63. FoundꢈCꢂ51.12; H, 3.61; O, 27.24; N,
.19; S, 10.61%.
The above analysis data not only identified the target products, but confirmed the
feasibilities of the synthesis routes also.
3
3
.2 The application properties of dyes
.2.1 The advantage for the dyeing process of the dyes
Unlike the normally used reactive dyes, aldehyde reactive dyes don’t hydrolysis
during storage and application process. The dyeing practice of the nine aldehyde
reactive dyes showed that, they could dye wet-white leather at a condtion of 35-45 °C,
pH=4.0-6.5 within 1.5 h, this condition is relatively mild comparing with the
commonly used reactive dyes at present; and what was more, no neutral salts were
needed during the dyeing process. So, enegy would be saved and the environmental
pollution from waste water could be reduced.
3.2.2 The SꢅEꢅFꢅR values and Washing fastness
From Table 1, we could notice that, SꢅEꢅFꢅR values of the five reactive dyes
with glutaraldehyde back-bone were superior than that of mono-aldehyde reactive
dyes. Nevertheless, washing fastness values for all of the nine reactive dyes reached 4
grade and possessed the fundamental property of reactive dyes; the washing fastness
values of the five reactive dyes with glutaraldehyde back-bone reached 5 grade, i.e.,
the highest grade.
Table 1 Values of SꢅEꢅRꢅF and washing fastness of nine reactive dyes
(mean of values from three experiment times)
1
2

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Dye
number
D1
S/%
52.54
E/%
R/%
48.35
F/% Washing fastness
(grade)
57.87
61.07
65.27
63.21
91.37
88.33
90.65
89.77
92.13
52.17
4
4
4
4
5
5
5
5
5
D2
D3
D4
D5
D6
D7
D8
D9
55.73
60.35
58.43
84.22
85.47
83.26
82.54
85.25
50.94
53.74
51.25
82.05
82.85
81.93
81.47
82.76
56.21
59.86
57.33
83.27
84.12
86.14
85.92
84.32
4
Conclusions
(1) The analysis results from FTIRꢅUV-VisꢅESI-MS indicated that, some colorant
compounds such as alizarin red and alizarin yellow GG could be “graft” to the
back-bone of glutaraldehyde or some mono-aldehyde, so that a novel series of
aldehyde reactive dyes could be developed.
(
2) The dyeing practice to wet-white leather indicated that, without the adding of
neutral salts, the dyeing process could be undertaken at a relatively mild condition of
5-45 °C, pH=4.0-6.5 within 1.5 h; all of the washing fastness values of the nine
3
reactive dyes reached 4 grade and possessed the fundamental property of reactive
dyes.
(3) S (substantivity), R (reactivity)ꢂE (exhaustion) and F (fixation) values of the five
reactive dyes with glutaraldehyde back-bone were superior than that of
mono-aldehyde reactive dyes, and their washing fastness values reached the highest
grade, i.e., 5 grade.
The authors wish to thank National Natural Science Foundation (“The color-forming
mechanism and structural — property relationship for natural iridoids and their
structural-like synthesis products”, Project No. 21176202) for financial support.
[
1] Li Y, Zhang S, Yang J, Jiang S, Li Q. Synthesis and application of novel
1
3

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crosslinking polyamine dyes with good performance. Dyes and Pigments, 2008;
7
6:508-514
2] Wu Z, Wu G, Wang Z, Lin L. The relationship between dyes’ structure designing
new products developing and energy saving and pollution reducing. Shanghai
[
/
Dyes, 2010; 38 (2) ꢈ25-39
[
[
3] Song X. The developing on the concept and technology of dyeing process for
reactive dyes. Shanghai Dyes, 2008; 36 (4) ꢈ1-3
4] Zhang Bꢂ Xu LꢂDing K. Dyeing/cross-linking property of natural iridoids to
protein fibers ꢂ Partꢆ ꢈ Preparation of four natural iridoids and their
dyeing/cross-linking (tanning) property to hide powder. The Journal of the
American Leather Chemists Association, 2011ꢂ106 (4) ꢈ121-126
5] Zhang Bꢂ Xu Lꢂ Ding Ke. Dyeing/Cross-linking property of natural iridoids to
protein fibers, Partꢇ: color-forming rules and mechanism of methylamine and
protein fibers dyed by four natural iridoids. The Journal of the American Leather
Chemists Association, 2011ꢂ106 (10) ꢈ303-308
[
[
[
6] Zhang B. Synthesis and application of new type of reactive dyes for protein fiber.
Graduate thesis of Southwest University for nationalities, Chengdu, China (2012)
7] Liang P. Synthesis and applying research on reactive dyes containing
aldehyde-group special for protein fibers. Graduate thesis of Southwest University
for nationalities, Chengdu, China (2012)
[
[
[
[
8] He D. Synthesis and application of tanning-dyeing agents based on the backbone
of glutaraldehyde. Graduate thesis of Southwest University for nationalities,
Chengdu, China (2011)
9] Chen X. Synthesis and application of two anthraquinone reactive dyes with
glutaraldehyde backbone. Graduate thesis of Southwest University for
nationalities, Chengdu, China (2014)
10] Xu L. Synthesis and application of simultaneous tanning-dyeing agent with
glutaraldehyde backbone. Graduate thesis of Southwest University for
nationalities, Chengdu, China (2013)
11] He P. Study on dyeing property of six reactive dyes for protein fibers. Graduate
1
4

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thesis of Southwest University for nationalities, Chengdu, China (2014)
1
5

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List of Figures
Fig. 1 The crosslinking and color forming mechanism of genipin with collagen fiber
Fig. 2 The synthesis of α-chloro butyl-aldehyde
Fig. 3 The synthesis of D1
Fig. 4 The synthesis of D2
Fig. 5 Preparation of 3- (4- (bromomethyl) phenyl) acrylaldehyde
Fig. 6 The synthesis of D3
Fig. 7 The synthesis of dye D4
Fig. 8 Preparation of α-bromocyclopentene
Fig. 9 The synthesis of dye D5
Fig. 10 The synthesis of dye D6
Fig. 11 The synthesis of dye D , D8
7
Fig. 12 The synthesis of dye D9
Fig. 13 Nine intervals of sample picking for measurement of exhaustion and fixation
Fig. 14 The exhaustion and fixation curve of D7

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O
O
O
OH
O
O
O
OH
OH
SO Na
Cl
K CO
2
3
OHC C Et
H
+
SO Na
DMF
3
3

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COONa
K CO
COONa
O
Cl
2
3
OHC C Et
H
+
N N
OH
N N
DMF
O N
2
O N
2
O

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O
NaOOC
OH
NaOOC
O
K2CO3
DMF
+
N N
N N
O
O N
2
O2N
Br

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O
O
O
O
OH
O
O
O
OH
SO3Na
OH
K CO
2 3
+
DMF
SO Na
3
Br

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BPO
Br
+
NBS
CCl4

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OH
COONa
K CO
Br
2
3
O
+
N
N
DMF
O N
N
2
N
COONa
O N
2
O
O
O
H O , tert-Butanol
O N
2
COONa
2
2
H WO , B O
3
3
3
2
N
N

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O
NH2
O
O
NH2
Br
SO3Na
SO3Na
SnCl2 , CuSO4
NaHCO3 H2O
+
H2N
NH2
O
HN
Colorant I
NH2
O
NH2
O
O
NH2
SO3Na
SO H
Bromo-derivation, acetone
3
HCl
H2O
HN
O
HN
O
precursor D7
O
D7
NH
NH
O
O
O
O
O
NH2
Br
OH
O
NH2
SO3Na
3
SO Na
SnCl2 , CuSO4
+
NaHCO3 ,Na2CO3
H2O
OH
O
O
colorant II
OH
O
O
NH2
O
NH2
SO Na
SO H
3
3
Bromo-derivation, NaOH
NaI , DMF
HCl
H O
2
O
O
O
O
O
O
precursor D8
D8
O
O
O
O

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