WHAT IS MELAMINE?

INTRODUCTION

Melamine is an organic compound which has many industrial uses. The name ‘melamine’ is derived from the german language.it is the combination of melam and amine.This chemical substance has gained publicity due to the Chinese milk problem. Therefore general public came to know melamine.during recent time many food items were found to have melamine in large quantities which can cause toxicity.

CHEMICAL NATURE

This is an organic base consisting three cyanamide groups, with 1,3,5- triazine skeleton.According to the IUPAC nomenclature, it is known as “1,3,5-Triazine-2,4,6-triamine”.It can be combined with formaldehyde to form a resin. This resin is a synthetic polymer which is fire resistant and heat tolerant. Melamine can be combined with cyanuric acid to form melamine cyanurate, which has been the culprit of Chinese milk powder problem.

SYNTHESIS

Justus von Liebig was the person who has introduced melamine to world. He was a well known German chemist and he has synthesised melamine in 1834 by using cyanamide. But today urea is used to synthesize the melamine in chemical industry.The chemical reaction is as follows;

6 (NH₂)₂CO → C₃H₆N₆ + 6 NH₃ + 3 CO₂

There are two awys by which above reaction can be carried out;catalyzed gas-phase production and high pressure liquid-phase production.In first method, urea is used as the sugstrate to produce melamine whereas ammonia is used in the second method as the substrate.Thent the resultant effluent should be cooled.Ultimately melamine should be crystalized and washed.This last step will generate considerable amount of water, which is a pollutant if discharged directly into the environment.

APPLICATIONS

1. Thermosetting plastic; This is produced by combining melamine with formaldehyde.This product has many uses including production like countertops, dry erase boards, fabrics, glues, housewares and flame retardants.

2. Melamine can be made into a foam product. Melamine foam has a distinctive structure composed of stacked bubble shapes, which are extremely hard and therefore can easily clean a wide variety of substances.

3. superplastizcizers; The melamine formaldehyde is sulfonated to produce a polymer which is used as cement admixture.This helps to reduce the water content of the concrete and same time increase the fluidity and the workability of the mix during its handling and pouring.

4. uses as a fertilizer; since melamine contains high percentage of nitrogen it can be used as a fertilizer.

5. Arsanical drugs; These are derivatives of melamine and used to treat African trypanosomiasis.

6. Melamine was used as a non-protein nitrogen source for animals but now it is not used due to the side effects profile.

7. Melamine resin is used in Formica and similar construction products made from composite materials. Formica is made using melamine resin, which is used to coat the fibers in the upper layer of the construction product.

LABORATORY INVESTIGATIONS FOR MELAMINE

Laboratory tests are not routinely done to demonstrate melamine but due to the recent development in China, the tests are becoming more popular. These tests are very expensive therefore facilities are not freely availabl to test the presence of melamine.

There are several tests availble but two tests are frequently used; a high performance liquid chromatography and the other procedure is based on surface-enhanced Raman spectroscopy (SERS).

TOXICITY

Any chemical substance can be toxic if they are ingested in large doses. Therefore melamine is nontoxic in low doses but it is toxic in lage doses. Melamine is also toxic when it is combined with cyanurate acide.LD50 value of mealmine is 3 gram per kilogram bodyweight.The harmful effects of melamine can be acute or chronic in nature.

Acute harmfull effects are irritation of skin and eye when contact, acute renal failure with large doses and gastrintestinal effects.dose more than 4gram per kilogram body weight can result in acute renal failure where as lower doses can give rise to the skin and eye irritation.

Logstanding exposure can give rise to wide range of chronic effects.These effects include subfertility, bladder stones, kidney stones and bladder cancer.