1.
Synthesis of a phthalimide-based alkali-clearable azo disperse dye and analysis of its alkali-hydrolysis kinetics
Minyoung Eom
Advisor: Prof. Joonseok Koh
Department of Textile Engineering
The Graduate School of Konkuk University

2. Contents
Introduction
Experimental
Results & Discussion
Conclusions

3. Introduction Dyesolid Dyemicelles Dyedissolved Dyefiber
Disperse Dyeing Mechanism
Dyesolid
Dyemicelles
Dyedissolved
Dyefiber
Dye
Dispersing agent
POLYESTER

4. Introduction Reduction Clearing(R/C) of dyed Polyester R/C
Before R/C
Penetrated dyes
Non-penetrated dyes
Laundering
Low Fastness
Staining
R/C
80oC, 20min
After R/C
Wash off
Laundering
Fastness improvement
No staining

5. “high BOD and pH values”
Introduction
Reduction Clearing(R/C) of azo disperse dye
“Carcinogenic”
“high BOD and pH values”
Colorless / No substantivity for PET
- R/C conditions : 80℃, 20min ( Na2S2O4 2g/L + NaOH 2g/L )
Environmental
problem
Alkali-clearable
disperse dye
Solution ?

6. Introduction Alkali-clearable disperse dyes 1. Diesters 2. Thiophenes
Water-insoluble
Substantivity for PET
Water-soluble
No substantivity for PET
1. Diesters
Dispersol PC (ICI,1976)
Water-insoluble
Substantivity for PET
Colorless
Decomposition Product
2. Thiophenes
Dispersol PC (ICI,1977)

7. No substantivity for PET
Introduction
Alkali-clearable disperse dyes
Water-insoluble
Substantivity for PET
Water-soluble
No substantivity for PET
3. Phthalimides
Dyes and Pigments (J. Koh,1998)
Water-insoluble
Affinity for PET
Water-soluble
No affinity for PET
4. Fluorosulfones
Dyes and Pigments (J. Koh,2000)

8. (a) reduction clearing
Introduction
Previous study
< UV-Visible spectra of dye at reduction clearing(a) and alkali clearing(b) condition. >
(a) reduction clearing
(b) alkali clearing
< I.R. spectrum of alkali-hydrolyzed dye. >
< Mass spectrum of alkali-hydrolyzed dye (X1, X2 = H, Na). >
* J. S. Koh, J. P. Kim, J. Soc, Dyers. Colour., 114(4), 121, 1998
* J. S. Koh, J. P. Kim, Dyes and Pigments, 37(3), 265, 1998

9. Introduction Objectives
Phthalimide-based alkali-clearable azo disperse dye and its hydrolyzed form were synthesized in order to investigate the hydrolysis kinetics.
Hydrolysis kinetics of the synthesized dye at various conditions was investigated by using a HPLC to assess their feasibility of the alternative clearing process in polyester dyeing.

10. Experimental Dye synthesis Synthesis of dye intermediates
Nitration
Alkylation
Amination
Diazotization and Coupling reaction
Diazotization
Coupling

11. Experimental Hydrolyzed dye synthesis
Diazotization and Coupling reaction
Diazotization
Coupling

12. Experimental Alkali-hydrolysis analysis
Determination of optimum dyeing pH
Procedure
20min
30℃
130℃
Dilution with same amount of acetonitrile
Immediate Cooling
Sample preparation for HPLC (ACN:Water = 80:20)
HPLC anlaysis
2.0℃/min
‘Blank dyeing’
1 wt% Dye stock solution
Buffer solution
(pH 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0)

13. Experimental Alkali-hydrolysis analysis
Hydrolysis behavior at various pHs and temperatures
40min
70/80/90/100℃ 5 10 15 20 25 30 35
40 (min)
Hydrolysis analysis
pH buffer solution
(pH 8.0, 9.0, 10.0, 11.0, 12.0)
1 wt% Dye stock solution
Temp. : 70, 80, 90, 100oC
withdrawing
at 5min intervals
for 40min
Thermostatted
oil bath
Procedure
Sampling from dye solution at 5min intervals
Immediate neutralizing to pH
(with dilute HCl followed by Cooling)
Sample preparation for HPLC(ACN:Water=80:20)
HPLC anlaysis A

14. Results and Discussion
Characterization of synthesized Intermediates and Dyes a b c d
Intermediates
1) 4-nitrophthalimide d NH
NO2
asym
sym
FT-IR a b c
1H-NMR

15. Results and Discussion
Characterization of synthesized Intermediates and Dyes a b c d
Intermediates
2) 4-nitro-N-methylphthalimide
C-H
C-N
FT-IR a b c d
1H-NMR

16. Results and Discussion
Characterization of synthesized Intermediates and Dyes a b c d e
Intermediates
3) 4-amino-N-methylphthalimide
FT-IR NH
asym
sym
NH2
1H-NMR a b c d e

17. Results and Discussion
Characterization of synthesized Intermediates and Dyes a b c d e f g h
HPLC
(Purity)
99.87 %
Spectral properties
λmax : 489 nm (in DMF)
εmax : 34,108 lmol-1cm-1 (in DMF)
m.p.
 oC
Dye-1
FT-IR
C-N
1H-NMR a b c d h
e~g

18. Results and Discussion
Characterization of synthesized Intermediates and Dyes a b c d e f g h
HPLC
(Purity)
 %
Spectral properties
λmax : 445 nm (in DMF)
εmax : 38,196 lmol-1cm-1 (in DMF)
m.p.
 oC
Dye-2
(Hydrolyzed form)
FT-IR
C-N
C=O OH
1H-NMR a b c
d~g h

19. Results and Discussion
Alkali-hydrolysis analysis
Determination of optimum dyeing pH
Blank dyeing
Polyester dyeing
< Stability of Dye at various pHs >
< Color strength(K/S) of dyed polyester fabrics at various pHs >

20. Results and Discussion
Treatment : 20min at 80oC
R/C - Na2S2O4 2g/L + NaOH 2g/L
A/C (1) - NaOH 2g/L
A/C (2) - Na2CO3 20g/L, 10g/L, 5g/L
HPLC analysis
 ACN : Water = 80:20, at 449nm
Alkali-hydrolysis analysis
Determination of optimum clearing conditions
Parent dye
(RT: 5.5min) p
H (RT: 1.1min)
Synthesized
hydrolyzed dye
Reference peaks
Hot Rinse p H
Reduction Clearing
(Na2S2O4 2g/L
+ NaOH 2g/L) H

21. Results and Discussion
Alkali-hydrolysis analysis
Treatment : 20min at 80oC
HPLC analysis
 ACN : Water = 80:20, at 449nm
Determination of optimum clearing conditions H
Alkali Clearing
(NaOH 2g/L)
(Na2CO3 20g/L)
(Na2CO3 10g/L)
(Na2CO3 5g/L)
The synthesized dye is expected to be washed off at mild alkaline condition.

22. Results and Discussion
Alkali-hydrolysis analysis
Hydrolysis behavior at various pHs and temperatures
< Hydrolysis behavior of Dye in buffers of various pHs at 70oC >
pH 8
pH 9
pH 10
pH 11
pH 12
● Parent dye
Hydrolyzed dye
━ Regression

23. Results and Discussion
Alkali-hydrolysis analysis
Hydrolysis behavior at various pHs and temperatures
< Hydrolysis behavior of Dye in buffers of various pHs at 80oC >
pH 8
pH 9
pH 10
pH 11
pH 12
● Parent dye
Hydrolyzed dye
━ Regression

24. Results and Discussion
Alkali-hydrolysis analysis
Hydrolysis behavior at various pHs and temperatures
< Hydrolysis behavior of Dye in buffers of various pHs at 90oC >
pH 8
pH 9
pH 10
pH 11
pH 12
● Parent dye
Hydrolyzed dye
━ Regression

25. Results and Discussion
Alkali-hydrolysis analysis
Hydrolysis behavior at various pHs and temperatures
< Hydrolysis behavior of Dye in buffers of various pHs at 100oC >
pH 8
pH 9
pH 10
● Parent dye
Hydrolyzed dye
━ Regression

26. Results and Discussion
Alkali-hydrolysis analysis
Hydrolysis behavior at various pHs and temperatures
90oC
100oC
80oC
70oC

27. Results and Discussion
Alkali-hydrolysis analysis
Hydrolysis behavior at various pHs and temperatures
< Residues of parent dye vs time of hydrolysis t at various pHs and temperatures >
pH 8
pH 9
pH 11
pH 12
70 oC
80 oC
90 oC
100 oC
pH 10

28. Pseudofirst-order rate law
Results and Discussion
Alkali-hydrolysis analysis
P + OH H
Alkali-hydrolysis
Pseudofirst-order rate law
Integrated rate law

29. Results and Discussion
Alkali-hydrolysis kinetics
Hydrolysis behavior at various pHs and temperatures
< Plot of ln(A0/A) vs time of hydrolysis t at various temperatures >
ln(A0/A) = kps1t
pH 8
pH 9
pH 10
pH 11
pH 12

30. Results and Discussion
Alkali-hydrolysis kinetics
Hydrolysis behavior at various pHs and temperatures
ln(A0/A) = kps1t
< Correlation coefficients (r) in the linear regression and pseudofirst-order hydrolysis rate constants at different pHs and temperatures >
70oC
80oC
90oC
100oC
kps1 r
pH 8.0
N/A
0.0030
0.976
0.0130
0.984
0.0303
0.975
pH 9.0
0.0035
0.0153
0.993
0.0356
0.998
0.5361
0.992
pH 10.0
0.0096
0.997
0.0634
0.989
0.2653
pH 11.0
0.1319
0.2441
0.6105
0.963
pH 12.0
0.2366
0.999
0.4293
0.6646
0.948

31. Perspiration (Staining)
Results and Discussion
Fastness properties
* R/C (Reduction Clearing) : Na2S2O4 2g/L + NaOH 2g/L
* A/C (Alkali Clearing) : Na2CO3 1g/L
Wash fastness (ISO 105-C06 A2S)
Conditions
Staining
Change
Dyeing
Clearing
Wool
Acryl
PET
Nylon
Cotton
Acetate
2%owf
R/C
4-5 4
2-3
3-4
A/C 3
Perspiration (ISO 105-E04) / Rubbing (ISO 105 X12) fastness
Conditions
Perspiration (Staining)
Rubbing
Dyeing
Clearing
Wool
Acryl
PET
Nylon
Cotton
Acetate
Dry
Wet
Alkaline
Acid
2%owf
R/C 4
4-5 5
A/C

32. Conclusions
Hydrolysis kinetics of a phthalimide-based alkali-clearable azo disperse dye was investigated :
The dye was most stable at the pH of less than 4.5 and it was almost completely hydrolyzed at the pH of over 7.0 at dyeing temperature.
The alkaline hydrolysis of the synthesized dye in buffered alkaline solution at constant temp. followed pseudofirst-order kinetics.
The phthalimide-based azo disperse dye showed an excellent alkali-clearable property under mild alkaline condition, which enables alkaline treatment to substitute for reduction clearing : ex. 98% hydrolyzed at pH 11, 80℃ for 20min

33. Thank You !