1. To produce dye based to the coupling of diazonium.
2. To understand the characteristic of dye orange II.
The first dye was introduced by William Henry Perkin on 1856. It can be produced by the coupling of diazonium sulfanilic acid with nafthol in alkaline solution.. This was the common method used to produce dye nowadays. In this experiment, dye produced was the orange II. Azo compound is compound that contain azo group (-N=N-) between the conjugated aromatic ring and absorb light to show.
Azo compounds are usually intensely coloured because the azo (diazenediyl) linkage –N=N-, brings the two aromatic rings into conjugation. This gives and extended system of delocalized π electrons and allows absorption of light in the visible region. Azo compounds, because of their intense colours and because they can be synthesized from relatively inexpensive compounds, are used extensively as dyes. azo dyes almost always contain one or more –SO3- Na+ groups to confer water solubility on the dye and assist in binding the dye to the surfaces of polar fibers such as wool, cotton or nylon.many dyes are made by coupling reactions of napthyllamines and napthols. Orange II, a dye introduced in 1876, is made from 2-naphthol. The structure of dye orange II shown as below.
In this experiment, Orange II is made by coupling diazonium sulfanilic acid with 2-naphthol in alkaline solution. The main reaction is represented by the chemical equation as below:-
REACTANTS AND PRODUCTS TABLE
Substances Quantity (g)
(g/cm3) Volume (ml) Safety data
Sulfanilic acid 0.0866 173.19 0.0005 1.49 Irritant to skin, eyes, and other mucous membranes. Flush any skin surface with copious amounts of water upon exposure. Wear gloves during this procedure.