Chemistry

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  • Topic: Azo compound, Azo coupling, Sodium chloride
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  • Published : July 24, 2008
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EXPERIMENT 2: SYNTHESIS OF ORANGE II (2-NAFTHOL ORANGE
OBJECTIVE

1.To produce dye based to the coupling of diazonium.
2.To understand the characteristic of dye orange II.

INTRODUCTION

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.

REACTION SCHEME
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

SubstancesQuantity
(g)
m.w
molDensity
(g/cm3)Volume (ml)
Safety data
Sulfanilic acid0.0866173.190.00051.49Irritant to skin, eyes, and other mucous membranes. Flush any skin surface with copious amounts of water upon exposure. Wear gloves during this procedure.

Anhydrous sodium carbonate0.0266105.990.000251Wear protective gloves and clean body-covering clothing. Use chemical safety goggles and/or full face shield where dusting or splashing of solutions is possible. Maintain eye wash fountain and quick-drench facilities in work area. Anhydrous sodium nitrite0.041690.0005942.168Toxic. Causes irritation to the respiratory tract and systemic poisoning with symptoms paralleling ingestion. If contact with skin immediately flush skin with plenty of water for at least 15 minutes. if contact with eye, immediately flush eye with plenty of water for at least 15 minutes Hydrochloric acid36.461.490.1Use safety glasses, gloves. Effective ventilation. 2-nafthol0.72144.20.004991.22 2-Naphthol is highly toxic and can be readily absorbed through the skin. Contact with the skin can cause peeling and discoloration. Use gloves while handling this substance Sodium chloride258.440.0342May irritate damaged skin; absorption can occur with effects similar to those via ingestion. Causes irritation, redness, and pain. If contact with skin, wash exposed area with soap and water. Sodium hydroxide401.1114If swallowed, do not induce vomiting. Give large quantities of water. Never give anything by mouth to an unconscious person. In case of contact, immediately flush eyes or skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse. If inhaled, remove to fresh air. If not breathing give artificial respiration. If breathing is difficult, give oxygen. In all cases get medical attention immediately. Sodium sulphate0.25322.200.000776Wear protective gloves and clean body-covering clothing. Use chemical safety goggles. Maintain eye wash fountain and quick-drench facilities in work area. Sulphuric acid98.082 dropIn case of contact, immediately flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Wash...
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