DEVELOPMENT OF ACID-BASE INDICATOR FROM FLOWER PETALS (HIBISCUS SABDARIFFA AND ALLAMANDA) By OLA YIWOLA JACOB (2006/24200EH) DEPARTMENT OF CHEMICAL ENGINEERING FEDERAL UNIVERSITY OF TECHNOLOGY, MINNA NIGERIA NOVEMBER,2011
DEVELOPMENT OF ACID-BASE INDICATOR FROM FLOWER PETALS (HIBISCUS SABDARIFFA AND ALLAMANDA) By OLAYIWOLAJACOB (2006/24200EH),,<. " ',', ~!; A PROJECT SUBMITTED TO THE DEPARTMENT"OF CHEMICAL ENGINEERING,. " ' FEDERAL UNIVERSITY OF TECHNOLOGY, MINNA ",. '. NIGERIA ", "" { '.1 ',;.. :' ':,';'r,':;:,\; -' IN PARTIAU FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF, ""',, - BACHELOR OF ENGINEERING (B. ENG) DEGREE IN CHEMICAL " " ENGINEERING 'I' " ;.,,' NOYEMBER,2011 ""t"., ;'~,.' ~t it.}., ~
CERTIFICATION This is to certify that this project report (thesis) "DEVELOPMENT OF ACID-BASE ICATOR USING FLOWER PETALS (HIBISCUS SABDARIFF A AND ALLAMANDA)" Olayiwola Jacob meets the requirements for the partial fulfillment of the award of Bachelor of (B. Eng) degree in Chemical Engineering, Federal University of Technology, Dr. D. O. Agbajelola Name and Signature Date Dr. M. O. Edoga Name and Signature Date," External Examiner " Name and Signature Date iv
DECLARATION I declare that the work in the project report (thesis) entitled "development of acid-base indicator from flower petals (hibiscus sabdariffa and allamanda)" has been performed (carried out) by me under the supervision of Engr. Dr D.O Agbajelola. No part ofthis project report (thesis) was presented for another degree or diploma elsewhere at any institution to the best of Olayiwola Jacob c$-,.. Name of student Date iii
ACKNOWLEGDEMENT to express my profound gratitude to Almighty God for His Protection, provision and JUU.UUJU grace throughout my years in school. so want to appreciate the immense financial and moral support of my lovely mum Mrs. Alice my sisters Florence, Elizabeth, Deborah and Dorcas, my nieces and nephew Tosin, aye, Kehinde, Dami, Judah and Abigail and the families of the Makanjuola's, Aminu's and to specially appreciate my project supervisor Engr. Dr D.O. Agbajelola, for his fatherly and advice during this research work.i also want to express my gratitude to the Head of of Chemical Engineering, Federal University, Minna, in person of Dr M.O Edoga the lecturers I was opportune to learn from during my degree programme. Finally I want thank all my course mate in chemical engineering department, I love you all. v
ABSTRACT The project report highlights the development of acid-base indicator from flower petals. It aims at producing efficient indicator from flowers as substitutes or possible replacement for standard indicators in use in chemical industries, research laboratories and schools for the determination of acidity, alkalinity, humidity's, extent of reactions, etc. 20 g of various flower petals of Hibiscus sabdariffa and allamanda, were collected, dried, crushed and their pigments separately extracted in a soxhlet extractor at a temperature of 81 C using a mixture of ethanol and hydrochloric acid. The extract was then stabilized by hydrolyzing it with concentrated HCI and purified by crystallizing the hydrolyzed extract. The indicator properties of the flower pigments were tested by observing its color change in acid and base. The solution of the indicator crystals was prepared by dissolving 19 of the sample in 1000 cm 3 ethanol and used for titrating O.lm. NaOH and O.117m HCI solutions to obtain the end point. The purity of the indicator produced was tested with thin layer chromatography, which made it possible to classify the pigment produced as anthocynanin. The sharp contrast between their colors in acid and base made the I pigment suitable for use as acid-base indicators. vi
TABLE OF CONTENT Cover Page Title Page Declaration Certification Acknowledgement Abstract List of Tables List of Figures List of Appendices Nomenclature li 111 IV v VI Xli Xlll XIV xv CHAPTER ONE 1.0 Introduction 1.1 Aim and obj ectives 1.2 Justification 1.3 Scope of study 1.4 Problem statement 1 1 2 2 2 CHAPTER TWO 2.0 Literature Review 2.1 The Structure of Pigments (Acid and Base) 2.2 Properties of Good Acid-Base Indicator 2.3 Acid-base Indicator 2.4 Theories of Indicator Action 2.4.1 Chromaphore theory 3 3 5 6 6 8 vii
2.4.2 Resonance theory 2.5 Acid-Base theories 2.5.1 Theory of solvent system 2.5.2 Bronsted lowry theory 2.5.3 Lewis theory 2.5.4 Arrhenius theory 2.6 Classes of Acid-Base Indicator 2.7 Disadvantages of Acid-Base Indicator 2.8 Errors in Indicator Titration 2.9 Factors Influencing Indicator Action 2.10 Choice of Solvent for Acid-base Titration 2.11 Some Common Acid-Base indicators 2.12 Natural Indicator Ingredient 2.12.1 Occurrence of anthocyanins 2.12.2 Methods of isolating and identifying anthocyanin in plants 2.12.3 Uses of anthocyanin 2.12.4 Industrial application of anthocyanin 2.12.5 Chemistry of anthocyanin 2.12.6 Structure of anthocyanins 2.13 Identification and Characterization of Pigment 2.13.1 Chromatography identification 2.13.2 Spectral method of identification 2.14 Continuous Extraction 2.15 Solvent Recovery 2.15.1 Desirable solvent properties 2.15.2 Advantages and disadvantages of solvent extraction 2.16 General Methods of Flower Pigment Extraction 2.16.1 Mechanical pressing 8 9 9 9 10 10 10 11 11 11 12 13 14 14 15 IS 16 16 18 18 18 19 20 21 21 23 23 23 viii
2.16.2 Rendering method 2.16.3 Solvent extraction 2.17 Factors Influencing the Rate of Extraction 2.17.1 Particle size 2.17.2 Solvent 2.17.3 Temperature 2.17.4 Agitation 23 24 24 24 24 25 25 CHAPTER THREE 3.0 Methodology 3.1 Equipments and Materials used 3.1 Pretreatment and Size Reduction 3.1 Extraction Procedure 3.1 Crystallization procedure 3.1 Pigment Characterization,26 26 27 28 28 28 3.5.1 Flower extracts indicator properties 3.5.1.1 Acid-base color change 3.5.1.2 Uses as an indicator and comparative titration 3.5.1.3 ph range determination 3.5.2 Purity Test 3.5.2.1 Chromatography characterization 3.5.3 Stability Test 3.5.3.1 Volume of change with time 28 28 28 29 30 30 30 30 CHAPTER FOUR 4.0 Results and Discussion 4.1 Results lx 31 31
4.1.1 Extraction Results, 4.1.2 Indicator Properties 4.1.3 Comparative Titration Results 4.1.4 Purity Test 4.1.5 Stability Test 4.2 Discussion of Results 31 32 32 34 35 37 CHAPTER FIVE 5.0 Conclusion and Recommendation 5.1 Conclusion 5.2 Recommendation 39 39 39 REFERENCES 40 APPENDIX 42 x
LIST OF TABLES Table Page Table 2.1: Common Acid-Base Indicator 13 Table 2.2: Chlorides of Anthocyanin 17 Table 3.1: List of Apparatus Used 26 Table 3.2: List of Materials or Reagents 27 Table 4.1: Flower Pigment Extracted Using Eth@ol and HCI 31, Table 4.2: Acid-Base Color Change Results 32 Table 4.3: Strong Acid Vs Strong base Titration 32 Table 4.4: Strong Acid Vs Weak Base Titration 33 Table 4.5: Weak Acid Vs Strong Base Titration 33 Table 4.6: ph Color Change 34 Table 4.7: the R f Values in Thin Layer Chromatography Plate 34 Table 4.8: Volume of Hydrolysed pigment Indicator Required to Color NaOH 35 Table 4.9: Volume ofunhydrolysed pigment Indicator Required to Color NaOH 35 xi
LIST OF FlGURES Figu.re Page Figure 2.1: Structure of Anthocyanin 18 Figure 4.1: Hydrolysed Indicator Stability Test 36 Figure 4.2: Unhydrolysed Indicator Stability Test 36.Figure 4.3: Flow Diagram for the Industrial Prod.uctioll of Pigment (Acid.,.Base) Indi~ator 38 xii