An investigation of the addition of nicotinic acid, as a catalyst, to the pad

liquor of a one-pass process for the continuous dyeing of polyester/cotton

blends.

Presented by

DR ARSHAD MEHMOOD

Textiles & Paper, School of MaterialsThe University of Manchester,

Manchester, UK

Email: dr.arshadmehmood@yahoo.com

Undertaking general contract chemical synthesis. Undertaking chemical research in colour-related areas (e.g.

textiles, paper, new ink jet applications etc). Providing consultancy on colour-related topics. Providing specialist (coloured) test fabrics for use in laundering

protocols.

The study was conducted at the University of Manchester under the Supervision of CSS

Introduction of CSS

Colour synthesis solutions Ltd. is based at Hexagon Tower, Blackley, Manchester, UKwww.coloursynthesissolutions.co.uk

The main features of CSS’s business are as follows. 

Catalytic quantities of tertiary amines, for example trimethylamine, N,N-dimethylhydrazine, pyridine and substituted pyridine such as nicotinic acid etc. were used to take advantage of this enhanced reactivity.

Background of the Study

In 1959, chemists at ICI showed that a series of tertiary amines can react with monochlorotriazines, the important observation was made that the quaternary ammonium products fixed more rapidly to cellulose than the chloro precursors.

Dawson in1964, reported that the tertiary amine is an easier leaving group than the chloride ion. Additionally, due to an extra positive charge, the quaternised dye exhibits a greater substantivity, for cellulosic fibres, than the parent MCT dye.

In 1987, ICI launched the Procilene N range products for polyester/mercerised cotton printing, which employed nicotinic acid as a catalyst in the print pastes to allow fixation to take place under neutral conditions, thereby protecting the disperse dyes from alkaline degradation.

Dyes containing quaternary ammonium

reactive group

N N

N NHR

N

CO2

NH

Dye

+

N-O2C

N N

N

NHC2H4HN

NHR

N

O

O

N

SO3Na Cl

Cl SO3Na

NHC2H4HN

N

N

N

NHR NCO2

+

+

In 1979, ICI launched Procion Blue H-EG (C.I. Reactive Blue 187), the first reactive dye carrying a quaternary ammonium reactive group

In 1984, Nippon Kayaku introduced a range of bis-s-triazinyl reactive dyes, the Kayacelon Reacts, which also utilised 3-carboxypyridine (nicotinic acid) as the leaving group.

Nicotinic acid was added to the pad liquor of the one-pass continuous dyeing process, to allow in-situ formation of the quaternary species, which, being more reactive than the parent dye, would be expected to react with cellulose more quickly and, possibly, more efficiently. This would allow a higher colour yield on unmercerised cotton than that obtained from the parent reactive dyes.

Aim of the Current Study

R3N

NR3

X

N

N

N

Cl

O R3NCell -

NR3

X

N

N

N

X

ClN

N

N

O-Cell

X

N

N

N

Dye-NH Dye-NH

+

+ +

Dye-NH+ +Dye-NH

+

X = usually a substituted arylamino group

PAD LIQUOR INCLUDES:

o REACTIVE DYE y g/lo MIGRATION INHIBITOR 10-20 g/lo WETTING AGENT 2-4 g/lo SEQUESTERING AGENT 0-4 g/lo FIXATION ASSISTANT 15 g/lo ALKALI (SODIUM BICARBONATE) 2-10 g/lo PAD LIQUOR TEMPERATURE 20-30oCo NICOTINIC ACID 30

g/l

One-Pass Continuous Dyeing process

Padder

I.R. pre dryer to reduce moisture to

50% Wash off

Drying 1’@110’C

Thermofixation 1’@210’C

Investigation of the addition of nicotinic acid to the pad liquor of one-pass process.(PROCION PX DYES)

   

     

Investigation of the addition of nicotinic acid to the pad liquor of one-pass process.(LEVAFIX CA DYES)

0

4

8

12

16

20

0 10 20 30 40 50

K/

S

Depth applied(g/l)

(b)

0 g/l Na

30 g/l NA

0

1

2

3

4

5

6

0 10 20 30 40 50

K/S

Depth applied (g/l)

(a)

0 g/l NA

30 g/l NA

0

5

10

15

20

25

30

0 10 20 30 40 50

K/S

Depth applied (g/l)

(c)

0 g/l NA

30 g/l NA

Reasons for the Poor Performance of

the Reactive Dyes with Addition of Nicotinic Acid

(ii) the nicotinic acid derivative, once formed, exhibited a lower degree of chemical selectivity with the cotton under the one-pass continuous dyeing process conditions.

This could be due to one of two reasons, viz either 

(i)insufficient time to convert the parent dye to its more reactive derivative. Or 

Investigation of the 1st possible cause

Fixation/Dye species

Retention time (tR) by HPLC

(Determined by prepared standards)

After 30secs Drying

After 60secs Drying

After 30secs Thermofixation

After 60secs Thermofixation

Fixation (%) 3 4 30 38

Parent (MCT) dye (%) 4.96 63 61 37 28

In-situ formed3-carboxypyridinium triazine dye (%)

2.19 20 19 15 12

Hydrolysed dye (%) 3.28 14 16 18 22

Increase in dyeing time scale

Chromatographic analysis of the dye species

Reaction involved in this system can be explained as follows.

N

NN

Cl

X

NH

DyeNR'3

NR'3N

NN

X

NH

Dye

+

N

NN

O-Cell

X

NH

Dye

Cell-O

N

NN

OH

X

NH

Dye

A

B

OH

Fast

Slow

Conversion of commercial Procion Red PX-4B to its nicotinic acid derivative

N

ONH

NH

N

NNSO3H

SO3H SO3H

Cl

NH

CH3

Procion Red PX- 4B

N

CO2

N

ONH

NH

N

NNSO3H

SO3H SO3H

NH

CH3

+

Nicotinc derivative of Procion Red PX - 4B

N

COOH

pH 6.0 - 6.580 - 85oC

Comparison of the fixation yield (and dye species) of Procion Red PX-4B and its synthesised nicotinic acid derivative

Thus, it can be concluded that

rapid hydrolysis of the in-situ formed quaternary salt was one of the reasons for the reduction in colour yield.

Comparison of colour yields at lower pH (7.0)

Conclusion

Addition of nicotinic acid to the pad liquor of the one-pass continuous dyeing process, as a catalyst, even though it resulted in ‘in-situ’ formation of the (more active) 3-carboxy pyridinium-s-triazinyl derivative, failed to give an improvement in colour yield of selected Procion PX and Levafix CA reactive dyes at pH 9.0 on unmercerised cotton.

…….THANKS…….