STUDIES ON THE USE OF REDUCING SUGAR
AS A SUBSTITUTE OF SODIUM SULPHIDE
FOR DYEING OF COTTON WITH SULPHUR DYES
by
SHIRISHKUMAR B. VHANBATTE
DEPARTMENT OF TEXTILE TECHNOLOGY
Submitted in fulfillment of the requirements of the degree of
DOCTOR OF PHILOSOPHY
to the
INDIAN INSTITUTE OF TECHNOLOGY, DELHI
APRIL 2004
te,
Dedicated
to
my parents
CERTIFICATE
This is to certify that the thesis entitled "STUDIES ON THE USE OF REDUCING
SUGAR AS A SUBSTITUTE OF SODIUM SULPHIDE FOR DYEING OF COTTON
WITH SULPHUR DYES" being submitted by Mr. Shirishkumar Balasaheb Vhanbatte, to
the Indian Institute of Technology, Delhi, for the award of the degree of Doctor of
Philosophy in the Department of Textile Technology is a record of bonafide research
work carried out by him. Mr. Shirishkumar Balasaheb Vhanbatte has worked under my
guidance and supervision and has fulfilled the requirements for the submission of the
thesis.
The results contained in this thesis have not been submitted, in part or in full, to any other
University or Institute for the award of any degree or diploma.
Dr. R. B. Chavan
Professor,
Department of Textile Technology,
Indian Institute of Technology, Delhi (India) — 110 016.
(i)
ACKNOWLEDGEMENTS
I wish to express my heartiest regard to Prof. R. B. Chavan for his excellent and valuable
guidance throughout the course of this research work, in spite of his busy schedule.
I am very thankful to my SRC members, Prof. R. C. Anand, Prof. Kushal Sen and Prof.
Ravi Chattopadhyay for their valuable suggestions. Thanks are due to Prof. B. L. Deopura
and Prof. V. K. Kothari, during their tenure as the heads of the department for their timely
help and cooperation.
My sincere thanks are due to Mr. V. A. Passi, Mr. Rajendra Prasad, Mr. Shiv Charan, Mr.
Jagdish Prasad and others in Textile Chemistry Laboratory for their immense help,
cooperation and cordial behavior during the period of my research. I am extremely
grateful to the staff members of various laboratories in the Textile Department for their
time to time help and cooperation.
I appreciate the cooperation extended by friends, especially Dr. J. N. Chakraborty, Mr.
Ninad Save, Ms. Ruchira Gupta, Mr. Vinayak Ogale, Mr. Anindya Ghosh, Mr. Rajkishore
Nayak, Mr. Rajesh Kumar, Mr. Shiv Mohan, Mr. Anil Herwade and Mr. Milind Patankar.
They supported me during the various stages of my research work.
At the end, I offer my heartiest thanks to my wife Madhavi and daughter Sonali for their
understanding, encouragement and constant cooperation during this research.
Date: April, 2004
Shirishlx Balasaheb Vhahhatte
ABSTRACT
Sulphur dyes represent the best economic alternative for specific fields of application and
are preferred because of their good to excellent fastness to washing and light. The entire
dye class is known for poor image since the commercial use of sodium sulphide as a
reducing agent for sulphur dyes is regarded as foul-smelling and ecologically unsafe.
Among the various reducing agents suggested in literature for the replacement of sodium
sulphide, glucose along with equal weight of sodium hydroxide found to be satisfactory
substitute for sulphur black. In the present thesis the detailed investigations on the use of
reducing sugar - essentially consists of glucose and fructose, as a reducing agent for
sulphur dyeing have been reported. The research work consists of
- In-house preparation of reducing sugar by acid hydrolysis of sugar
Comparison of reducing sugar and sodium sulphide as a reducing agent for dyeing of
cotton with sulphur dyes which includes various factors like effect of sodium sulphide
concentration and temperature, development of reduction potential, stability, their
consumption during reduction and dyeing and leuco potential of sulphur dyes.
The sulphur dyes are reduced at lower reduction potential of about — 600 mV. Reducing
sugar along with equal weight of sodium hydroxide provides the required reduction
potential for reduction of sulphur dyes. This combination of reducing sugar and sodium
hydroxide produced lower colour yield and tonal variation of sulphur dyes other than
black. The effect of sodium hydroxide concentration and temperature have been studied
in detail and it has been found that concentration of sodium sulphide played an important
role in development of reduction potential and colour yield in terms of K/S.
Methods for quantitative estimation of sodium sulphide in reduced bath based on complex
formation of reduced dye with calcium chloride and in case of reducing sugar
acidification method based on precipitation of leuco acid dye have been suggested. The
parameters like effect of sodium hydroxide concentration on development of reduction
potential, colour yield, stability of reducing sugar and sodium sulphide at dyeing
conditions and their consumption during reduction and dyeing process have been
correlated. It has been established that though individual sulphur dye required different
quantity of reducing sugar for optimum dyeing, the concentration of sodium hydroxide
and reducing sugar in 2.7:1 molar ratio (0.55:1 by weight ratio) gave satisfactory dyeing
results. Because of lower stability of alkaline reducing sugar further addition of reducing
sugar during dyeing is found necessary to maintain sufficient reduction potential and to
obtained better colour yield.
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CONTENTS
Page
(i)
CERTIFICATE
ACKNOLEDGEMENT
(ii)
ABSTRACT
(iii)
LIST OF FIGURES
(xi)
LIST OF TABLES
(xiv)
CHAPTER 1 INTRODUCTION AND LITRATURE REVIEW
1.1
INTRODUCTION
1
1.2
DEVELOPMENT OF SULPHUR DYES
3
1.2.1Historical background and development
3
1.2.2Structure and properties of sulphur dyes
6
1.2.3Classification of sulphur dyes
6
1.2.4Commercial forms of sulphur dyes
8
1.3
1.4
1.5
10
DYEING WITH SULPHUR DYES
1.3.1
Dyeing principle
10
1.3.2
Pretreatment
12
1.3.3
Wetting agents
12
1.3.4
Sequestering agents
13
1.3.5
Stabilizing agents
13
1.3.6
Exhausting agents
14
1.3.7
Reducing agents
14
ALTERNATIVE REDUCING AGENTS
16
1.4.1
Glucose
16
1.4.2
Thiourea dioxide
20
1.4.3
Hydroxyacetone
22
1.4.4
M ercapto ethanol
23
1.4.5
Electrochemical reduction
23
24
OXIDISING AGENTS
1.5.1
Potassium dichromate
25
1.5.2
Iodate
26
1.5.3
Sodium chlorite
26
(v)
1.5.4 Sodium bromate
27
1.5.5Hydrogen peroxide
27
1.5.6 Alkylation
28
1.6 AFETR TREATMENTS
28
1.7 SULPHUR DYE EFFLUENT
30
1.7.1Oxidation treatment
30
1.7.2Biological treatment
31
1.7.3Chemical oxidation
31
1.7.4 Precipitation
31
1.7.5 Removal of chromium
32
1.8 SULPHUR DYEING AND ENVIRONMENTAL PROBLEMS
33
1.9 APPLICATION METHOD
37
1.9.1Dyeing on jig
37
1.9.2 Pad — jig method
39
1.9.3 Winch dyeing
40
1.9.4 Loose cotton dyeing
41
1.9.5Hank dyeing
41
1.9.6 Dyeing on circulating liquor machine
42
1.9.7 Warp dyeing on sizing machine
44
1.9.8 One bath pad - steam method
44
1.9.9 Two bath pad - steam method
46
1.9.10 Dyeing of blends
47
48
1.10 SPECIAL PROBLEMS
1 . 1 0.1 Bronziness
48
1.10.2 Tendering
49
49
1.11 SUMMARY
CHAPTER 2 IN-HOUSE PREPARATION OF REDUCING SUGAR
2.1 INTRODUCTION
51
2.2 MATERIALS AND EXPERIMENTAL METHODS
2.2.1 Materials
2.2.2Hydrolysis of sucrose
2.2.3Determination of reducing sugar concentration
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54
54
54
56
2.2.4 Measurement of pH
57
2.2.5Storage stability of reducing sugar
58
2.3 RESULTS AND DISCUSSION
58
2.3.1Hydrolysis of sucrose from different sources
58
2.3.2 Effect of hydrochloric acid concentration and temperature
59
2.3.3Rate of reaction
63
2.3.4Scaling up
70
2.3.5Effect of pH on storage stability of reducing sugar
70
2.4 CONCLUSIONS
72
CHAPTER 3 USE OF REDUCING SUGAR IN EXHAUST DYEING OF
COTTON WITH SULPHUR DYES
3.1 INTRODUCTION
73
3.2 MATERIAL AND EXPERIMENTAL METHODS
74
3.2.1 Materials
74
3.2.2 Preparation of reducing sugar
77
3.2.3 Dyeing
77
3.2.4 Measurement of pH
78
3.2.5Measurement of reduction potential
78
3.2.6 Evaluation of dyed samples
78
3.3 RESULTS AND DISCUSSION
80
3.3.1Dyeing conditions
80
3.3.2Optimization of reducing agents in exhaust dyeing
3.3.3General observations and discussion
81
i) Dye reduction
98
98
ii) Colour yield
100
iii) Tonal variation
102
iv) Fastness properties
107
v) pH and redox potential
110
3.4 CONCLUSION
116
CHAPTER 4 EFFECT OF SODIUM HYDROXIDE CONCENTRATION
AND TEMPERATURE ON SULPHUR DYEING
4.1 INTRODUCTION
118
4.2 MATERIAL AND EXPERIMENTAL METHODS
4.2.1 Materials
4.2.2Preparation of reducing sugar
4.2.3 Dyeing
4.2.4 Measurement of pH
4.2.5Measurement of reduction potential
4.2.6Evaluation of dyed smples
4.3 RESULTS AND DISCUSSION
4.3.1Redox potential of reducing agents
119
119
119
119
119
119
119
119
119
124
4.3.2 Effect of sodium hydroxide concentration on dyeing using
reducing sugar
4.3.3 Effect of sodium hydroxide concentration on dyeing using sodium132
sulphide
4.3.4 Effect of temperature on dyeing
134
139
4.4 CONCLUSIONS
CHAPTER 5 REDUCTION PROPERTIES OF REDUCING AGENTS
5.1 INTRODUCTION
140
5.1.1Reducing action of sodium sulphide
140
5.1.2 Reducing action of reducing sugar
141
5.2 MATERIALS AND EXPERIMENTAL METHODS
144
5.2.1 Materials
144
5.2.2Quantitative estimation of reducing agents
145
i) Reducing sugar
145
ii) Sodium hydroxide
146
iii) Sodium sulphide
146
5.3 RESULTS AND DISCUSSION
5.3.1 Consumption of reducing sugar in blank bath
149
149
i) Equal weight of sodium hydroxide concentration
150
ii) 1.5 g/L sodium hydroxide
153
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iii) Relationship between consumed quantity of reducing sugar161
and sodium hydroxide
iv) Relationship between dyeing results and consumption of 162
reducing sugar
162
Use of sodium carbonate in reducing sugar bath
5.3.2 Consumption of sodium sulphide in blank bath
163
5.3.3 Consumption of reducing agents during dye reduction and dyeing165
166
Selection of precipitating agent
5.3.4 Consumption of sodium sulphide during dye reduction
169
5.3.5 Consumption of sodium sulphide during dyeing
181
5.3.6 -Consumption of reducing sugar in blank bath
184
5.3.7 Consumption of reducing sugar during dye reduction
185
5.3.8 Consumption of reducing sugar during dyeing
194
5.4 CONCLUSIONS
197
CHAPTER 6 REDOX BEHAVIOR OF SULPHUR DYES
6.1 INTRODUCTION
199
6.2 MATERIALS AND EXPERIMENTAL METHODS
201
6.2.1 Materials
6.2.2Redox titration
6.3 RESULTS AND DISCUSSION
201
201
203
6.3.1Blank titrations
204
6.3.2 Redox titration of Sandozol Black pdr
6.3.4 Redox titration of sulphur dyes other than black
206
208
6.3.5 Leuco potential of dyes and consumption of reducing sugar and214
sodium sulphide
216
6.4 CONCLUSION
CHAPTER 7 CORRELATION BETWEEN THEORY AND PRACTICE
OF SULPHUR DYEING
7.1 INTRODUCTION
7.2 MATERIAL AND EXPERIMENTAL METHODS
217
217
217
7.2.1 Materials
7.2.2Preparation of reducing sugar
217
7.2.3 Dyeing
217
7.2.4 Measurement of pH
217
7.2.5Measurement of reduction potential
7.2.6 Evaluation of dyed samples
217
217
7.3 SELECTION OF SODIUM HYDROXIDE CONCENTRATION 218
218
7.3.1 Effect of NaOH on development of reduction potential
7.3.2 Effect of NaOH on depth of sulphur dyes
7.13 Effect of NaOH on consumption of reducing sugar
218
7.3.4 Correlation between NaOH and depth of sulphur dyeing
220
7.4 SELECTION OF REDUCING SUGAR CONCENTRATION
219
222
222
7.4.1Development of reduction potential
7.4.2 Consumption of reducing sugar and concentration suggested for222
dyeing
7.5 OPTIMISATION OF REDUCING SUGAR CONCENTRATION 223
DURING DYEING OF COTTON WITH SULPHUR DYES
223
7.5.1Reducing sugar concentration
7.5.2 Optimization of reducing sugar during dyeing with Sulfast Blue225
7.5.3 Optimization of reducing sugar during dyeing with other dyes227
229
7.5.4 Colour value
7.6 PREDICTION OF REDUCING SUGAR AND SODIUM HYDROXIDE234
CONCENTRATION FOR REDUCTION AND DYEING WITH
SULPHUR DYES
235
7.6.1Reducing sugar concentration for reduction
7.6.2Selection of reducing sugar concentration for dosing during236
dyeing
240
7.7 CONCLUSION
CHAPTER 8 SUMMARY AND CONCLUSIONS
241
REFERENCES
243
(xviii)
CURRICULUM VITAE
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