ASSESSMENT OF TWO LOCAL PLANT DYES AS COLOURANTS FOR PETROLEUM PRODUCTS (PETROL, KEROSENE AND DIESEL)

ABSTRACT
Dyes from Pterocarpus osun Craib and Lawsonia inermis Linn. were extracted using ethanol and methanol respectively. The extracted dyes were subsequently purified using chromatographic methods. Purified pigments were characterized using Ultra-Violet Visible Spectrophotometer, Fourtier Transform Infrared Spectrophotometer and Lovibond Tintometer. The UV spectra of the dyes in petrol, kerosene and diesel showed presence of chromophores. The FTIR spectra of the dyes showed presence of phenolic O-H stretching and C=C of aromatic functional groups. The dye from Lawsonia inermis Linn. was remarkably stable in colouring petrol for a period of twenty-eight days but not in kerosene and diesel while the dye from Pterocarpus osun Craib was not stable. Thus, dye from Lawsonia inermis Linn. can be used as alternative source of colourant for petrol while the dye can not be used for the same purpose for kerosene and diesel due to their instability. The dye from Pterocarpus osun Craib cannot be used because of their instability. They are not remarkably active in colouring any of the petroleum products (petrol, kerosene and diesel).

TABLE OF CONTENTS
Title Page i
Certification ii
Dedication iii
Acknowledgement iv
Abstract v
Table of Contents vi
List of Tables x
List of Figures xi
List of Appendices xii

CHAPTER ONE:
1.0 Introduction 1
1.1 Dyestuffs 1
1.2 Lawsonia inermis Linn. Plant 4
1.3 Pterocarpus osun Craib plant 5
1.4 Statement of the problems 5
1.5 Objectives of the study 6
1.6 Justification of the study 6
CHAPTER TWO:
2.0 Literature review 7
2.1 Historical development 7
2.2 Colour and constitution 9
2.3 Nomenclature of dyes 17
2.4 Classification of dyes 19
2.4.1 Classification according to methods of application 19
2.4.2 Classification according to chemical constitution 36
2.5 Natural dyes 51
2.5.1 Plant dyes 52
2.5.2 Animal dyes 59
2.5.3 Mineral dyes 61
2.6 Uses of dyes 62
2.7 Dyeing 65
2.7.1 Mechanism of dyeing 65
2.7.2 Natural dyeing principles 67
2.8 Fastness properties 69
2.9 Colour in textile industry 70
2.10 Colour in petroleum industry 71
CHAPTER THREE:
3.0 Materials and methods 73
3.1 Reagents 73
3.2 Equipment 73
3.3 Plant materials 74
3.4 Extraction procedure 75
3.5 Purification of the extracts 75
3.5.1 Column chromatographic purification of P.osun extract 76
3.5.2 Vacuum liquid chromatographic purification of L.inermis extract76
3.6 Solubility of the dyes in organic solvents 76
3.7 De-colourization of petroleum products 77
3.8 Spectroscopic analysis of the dyes 77
3.8.1 Ultraviolet spectroscopy 77
3.8.2 Infrared spectroscopy 77
3.9 Colour stability analysis of the dyes 78
CHAPTER FOUR:
4.0 Results and discussion 79
4.1 Physical data of the dyes 79
4.1.1 Solubility test of the dyes 80
4.1.2 P. osun dye wavelengths of maximum absorption in petroleum products 81
4.1.3 L. inermis dye wavelengths of maximum absorption in petroleum products 85
4.1.4 Colour intensity of P. osun dye in petroleum products 89
4.1.5 Colour intensity of L. inermis dye in petroleum products 93
4.1.6 Infrared spectra analysis of P. osun dye 97
4.1.7 Infrared spectra analysis of L. inermis dye 98
4.2 Discussion 98
4.3 Contributions to knowledge 101
4.4 Conclusion 102
References 103
Appendices 110

LIST OF TABLES
Table 2.1: Absorbed and complementary visible colours 11
Table 2.2: Summary of mineral dyes and sources 62
Table 4.1: Physical data of the dyes 79
Table 4.1.1: Solubility test of the dyes 80
Table 4.1.2: P. osun dye wavelengths of maximum absorption in petrol 82
Table 4.1.3: P. osun dye wavelengths of maximum absorption in kerosene 83
Table 4.1.4: P. osun dye wavelengths of maximum absorption in diesel 84
Table 4.1.5: L. inermis dye wavelengths of maximum absorption in petrol 86
Table 4.1.6: L. inermis dye wavelengths of maximum absorption in kerosene 87
Table 4.1.7: L. inermis dye wavelengths of maximum absorption in diesel 88
Table 4.1.8: Colour intensity of P.osun in petrol 90
Table 4.1.9: Colour intensity of P.osun in kerosene 91
Table 4.1.10: Colour intensity of P.osun in diesel 92
Table 4.1.11: Colour intensity of L. inermis dye in petrol 94
Table 4.1.12: Colour intensity of L. inermis dye in kerosene 95
Table 4.1.13: Colour intensity of L. inermis dye in diesel 96
Table 4.1.14: FTIR of P.osun dye 97
Table 4.1.15: FTIR of L. inermis dye 98

LIST OF FIGURES
Figure 4.1: Variation of (λmax) with time using petrol coloured with P.osun dye 82
Figure 4.1.1: Variation of (λmax) with time using kerosene coloured with P.osun dye 83
Figure 4.1.2: Variation of (λmax) with time using diesel coloured with P.osun dye 84
Figure 4.1.3: Variation of (λmax) with time using petrol coloured with L.inermis dye 86
Figure 4.1.4: Variation of (λmax) with time using kerosene coloured with L. inermis dye 87
Figure 4.1.5: Variation of (λmax) with time using diesel coloured with L. inermis dye 88
Figure 4.1.6: Variation of colour with time using petrol coloured with P.osun dye 90
Figure 4.1.7: Variation of colour with time using kerosene coloured with P.osun dye 91
Figure 4.1.8: Variation of colour with time using diesel coloured with P.osun dye 92
Figure 4.1.9: Variation of colour with time using petrol coloured with L. inermis dye 94
Figure 4.1.10: Variation of colour with time using kerosene coloured with L. inermis dye 95
Figure 4.1.11: Variation of colour with time using diesel coloured with L. inermis dye 96

LIST OF APPENDIX
APPENDIX 1
UV-Visible spectra results of P. osun extract in petrol for 28 days. 110
APPENDIX 2
UV-Visible spectra results of P. osun extract in kerosene for 28 days 118
APPENDIX 3
UV-Visible spectra results of P. osun extract in diesel for 28 days 126
APPENDIX 4
UV-Visible spectra results of L. inermis extract in petrol for 28 days 134
APPENDIX 5
UV-Visible spectra results of L. inermis extract in kerosene for 28 days 142
APPENDIX 6
UV-Visible spectra results of L. inermis extract in diesel for 28 days 150
APPENDIX 7
FTIR spectra analysis result of P.osun extract 158
APPENDIX 8
FTIR spectra analysis result of L. inermis extract 159

CHAPTER ONE
1.0 Introduction
1.1 Dyestuffs
Today, in the world of growing environmental consciousness, natural colourants have attracted the attention of everyone1,2. The alarming rate of high use of synthetic dyes which causes carcinogenicity, mutagenicity, green house effect and are very expensive have provided an urgent approach to the use of natural plant dyes in the petroleum industry3,4. Natural plant dyes have been discovered accidentally and their uses have become so much a part of man’s customs that it is difficult to imagine modern world without dyes. The art of dyeing spread widely as civilization advanced5.
A dye is an organic compound composed of chromophore (the coloured portion of the dye molecule) and auxochrome (which slightly alters the colour) .The auxochrome makes the dyes soluble and is a site for bonding material. Dyes are molecules that can be dissolved in water or some other carrier so that they will penetrate the material6.
For a dye to be usable in colouring materials, it must be highly coloured; must yield goods that are “colour fast”, or resistant to colour change or loss during use and care; and must be soluble or capable of being made soluble in water or other medium in which they are applied, or they must themselves be molecularly dispersible into the material7.
The archaeological evidences have shown that dyeing has been extensively carried out for over 5000 years, particularly in India and Phoenicia8,9. The dyes were obtained from animal, vegetable or mineral origin, with no or very little processing. They include cochineal obtained from dried cochineal insect, brazil-wood from caesalphia plant, madder from the roots of Rubia tinctoria, Tyrian purple from purple snail (Murex bandaris), and indigo from the leaves of Indigofera tinctoria and many more. The plant parts that were used are roots, bark, leaves and wood10,11. Colourant improve the appearance, culinary effect and promote acceptability of substrates12.
The colour index categorizes all colouring matters according to their application and characteristics. Dyes can also be classified according to their chemical structure, shade, fastness, etc13.
With advances in science and technology, dyes synthetically produced from coal tar and petroleum sources, and natural dyes have almost been replaced by synthetic dyes. The most significant discovery in synthetic dyes occurred in the 19th century when the first man-made dye was synthesized by a Chemist, William Henry Perkin14. He produced the first basic azine dye known as mauveine . The production of this dye opened door for the synthesis of many classes of dyes including the first azo dye, Congo Red [2].

Dyes are used to colour petrol, kerosene and diesel in order to improve their appearance, as well as for identification of grade, type of use or merely as a trademark of the manufacturer15. Solvent dyes used to colour refined petroleum products is to be able to differentiate between petrol, diesel, kerosene and jet fuels16. Petroleum dyes help in identification of fuel adulteration. They also help to create differentiation in various petroleum products such as leaded and unleaded, high and low octane gasoline, high and low sulphur diesel and aviation fuels attributes17. Other reasons for dyeing fuel, such as for aviation, supports the fuelling process itself, to ensure that the right type of fuel is used in the correct aircraft – as the consequences of getting this wrong can be disastrous18. However, solubility as well as hue and fastness are the major determinant factors for dyes used in these petroleum products.