Preparation of Azo Dyes

Powerful Essays
UNIVERSITY OF SAN CARLOS

DEPARTMENT OF CHEMISTRY

NAME: Maniwang, Ma. Aiza C. DATE: March 21, 2011

COURSE: BS Chemistry II APPROVED: ___________

PREPARATION OF AZO DYES

ABSTRACT

In this experiment, the azo dyes p-nitrobenzene azoresorcinol and methyl orange were prepared by the azo coupling reaction. The p-nitrobenzene azoresorcinol dye was prepared from p-nitroaniline and resorcinol. The diazonium salt formed was from the reaction of the cold solution of dissolved p-nitroaniline in hydrochloric acid and water with the solution of sodium nitrite. Azo coupling was then followed by letting the diazonium react with a solution of resorcinol in water and sodium hydroxide. The resulting mixture was treated with excess hydrochloric acid turning the mixture to a color red. After suction filtration and drying, a red-brown powder was obtained as a final product.

Furthermore, synthesis of methyl orange was prepared from sulfanilic acid and N,N-dimethylaniline. The sodium diazobenzenesulfonate was made by the diazotization of the sulfanilic acid and sodium hydroxide mixture with a solution of sodium nitrite which was then cooled. Coupling reaction occurred when the solution of sodium diazobenzenesulfonate was mixed with a solution of N,N-dimethylaniline in hydrochloric acid. The first product obtained from the coupling was a bright red acid form of methyl orange called helianthin. In basic medium, through the addition of a dilute solution of sodium hydroxide, helianthin is converted to the orange sodium salt known as the methyl orange.

INTRODUCTION

Para-nitrobenzeneazoresorcinol dye and methyl orange belong to a class of dyes known as “azo colors” which contain the azo group linked to two aromatic nuclei. The nature of the aromatic substituent’s on both sides of the azo group (-N=N-) controls the colors of the azo compound as well as the water- solubility of dyes and how well they bind to a particular fabric. In addition to the azo group, the dyes



References: Introduction to Organic Laboratory Techniques A Contemporary Approach (1976) by Donald L. Paris, Gary M. Lampman and George S. Kriz, Jr. Laboratory Experiments in Organic Chemistry 6th Edition (1970) by Roger Adams, John R. Johnson, Charles F. Wilcox Jr. phoenix.liu.edu/~nmatsuna/che122/exp17.pdf Date accessed: March 5, 2011 Principles of Modern Organic Chemistry by Cason, James

You May Also Find These Documents Helpful

  • Satisfactory Essays

    How to prepare azo dyes

    • 346 Words
    • 2 Pages

    Names:____________ Date Performed:_____ Experiment No:______ Score:_____________ AZO DYES PREPARATION INTRODUCTION AND OBJECTIVES The preparation of azo dyes is a standard reaction in an Organic Chemistry lab. Its adaptation to a parallel synthesis format is straightforward. Since the dyes vary widely in color, the diversity of this parallel synthesis becomes obvious. It includes techniques on diazotization and electrophilic substitiution. The experient belo is made to allow studens to…

    • 346 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    Azo Dye Lab Report

    • 607 Words
    • 3 Pages

    The purpose of this lab was to synthesize indigo and an azo dye and to determine how effective each dye was to dye different types of fabrics. 0.168g of 2-nitrobenzaldehyde was dissolved into acetone along with 25 drops of distilled water and NaOH to synthesize indigo. The solution was filtered, and the solid indigo was placed into the filter flask to reduce indigo to leucoindigo with 10mL of 3M NaOH. The flask was heated along with sodium dithionite and distilled water added to the flask. Afiber…

    • 607 Words
    • 3 Pages
    Good Essays
  • Good Essays

    AZO-STANDARD

    • 345 Words
    • 2 Pages

    AZO-STANDARD Azo-standard is a drug which is used for the treatment of urinary tract infections (UTI), Surgeries and injuries. This drug is available in tablet form 100mg and 200mg doses respectively. It contains chemical name as phenazopyridine hydrochloride. It has lot of positive results in market as well thousands of positive reviews online. This medicine is recommended by physician as no 1 drug for the treatment of urinary tract infections. There are many other drugs like it such as Baridium…

    • 345 Words
    • 2 Pages
    Good Essays
  • Good Essays

    Dye Decolorization

    • 3454 Words
    • 14 Pages

    spp and its application in dye decolorization Project supervisor: Dr. R. Masalu Lab scientist: Mr. Chuwa INTRODUCTION: Due to rapid industrialization and urbanization, a lot of chemicals including dyes are manufactured and used in day-to-day life. Dyes are synthetic and aromatic molecular structural compounds. According to their dissociation in an aqueous solution, dyes can be classified as acid, direct reactive dyes (anionic), basic dyes (cationic) and disperse dyes (nonionic). They are used…

    • 3454 Words
    • 14 Pages
    Good Essays
  • Good Essays

    The Dye

    • 448 Words
    • 2 Pages

    Tie-dye is a modern term coined in the mid-1960s in the United States for a set of ancient resist-dyeing techniques, and for the products of these processes. The process of tie-dye typically consists of folding, twisting, pleating, or crumpling fabric or a garment and binding with string or rubber bands, followed by application of dye. The manipulations of the fabric prior to application of dye are called resists, as they partially or completely prevent the applied dye from colouring the fabric.…

    • 448 Words
    • 2 Pages
    Good Essays
  • Better Essays

    Natural Dyes

    • 11215 Words
    • 45 Pages

    Natural dyes are dyes or colorants derived from plants, invertebrates,a or minerals. The majority of natural dyes are vegetable dyes from plant sources – roots, berries, bark, leaves, and wood — and other organic sources such as fungi and lichens. Archaeologists have found evidence of textile dyeing dating back to the Neolithic period. In China, dyeing with plants, barks and insects has been traced back more than 5,000 years.[1] The essential process of dyeing changed little over time. Typically…

    • 11215 Words
    • 45 Pages
    Better Essays
  • Satisfactory Essays

    Tie Dye

    • 574 Words
    • 3 Pages

    Visual Arts Topic: Textile and Design Manipulation Topic: Tie Dye Time: 4 sessions x 30 mins each General Objective To be able to use appropriate materials to create designs on fabric by various tie dyeing techniques. Specific Objectives At the end of the lesson students should be able to: ✓ 1. Define Tie Dye ✓ 2. List materials needed for tie dyeing ✓ 3. Explain Tie Dye as a resist dyeing ✓ 4. Know different techniques and explain each of…

    • 574 Words
    • 3 Pages
    Satisfactory Essays
  • Satisfactory Essays

    Dye Solution

    • 575 Words
    • 3 Pages

    answer through your investigations: 1. Which fabric (a) cotton, a natural fiber and (b) rayon, a synthetic fiber is best dyed with mayana-alum dye combination? 2. Often, mordants are added to fix the dye onto the fabrics. These are usually inorganic oxides or salts which form colored complex with the dye. Which mordant is more suited for dyeing cotton with dye extracted from eggplant skins? 3. Which mordant is more suitable for dyeing a synthetic fiber with the synthetic extract from mangosteen…

    • 575 Words
    • 3 Pages
    Satisfactory Essays
  • Good Essays

    Forming Methyl Orange an Azo Die Abstract: An synthetic azo dye was created by reaction of diazonium salt with N,N-Dimethylanaline. The final product created was 4-dimethylaminoazobenzene-4-sulfonic acid, an orange clay-like substance. Sulfanilic acid was chemically manipulated by using sodium carbonate followed by cooled sodium nitrate and hydrochloric acid to form the diazonium salt used in the reaction. The products were washed in ethanol. The product was obtained at an 84% yield and was…

    • 505 Words
    • 3 Pages
    Good Essays
  • Good Essays

    tie dye

    • 1048 Words
    • 4 Pages

    to dye 3. 1 package RIT powder dye or 1/2 bottle RIT liquid dye 4. Rubber bands, string, or 2-inch wide strips of cloth for tying Instructions: 1. Gather the shirt into accordion-like folds, then fold the gathered fabric in half. Band tightly with cloth strips every 2 or 3 inches. 2. Before starting to dye, put on rubber gloves and prepare the dye bath. Dissolve 1 package RIT powder dye or 1/2 cup RIT liquid dye in about 2 gallons very hot water. For dark or bright colors, prepare dye bath…

    • 1048 Words
    • 4 Pages
    Good Essays