Write short note on green chemistry. Explain with the help of example 

Asked by Shwetadhana101 | 27th Feb, 2019, 08:34: AM

Expert Answer:

Green Chemistry:

Producing chemicals for our daily needs using reactions and chemical processes which neither use toxic chemicals nor emit such chemicals into the atmosphere.

 

Techniques:

Green chemistry neither uses nor produces toxic reagents or solvents and severe conditions. 

Instead, it uses mild and environmentally friendly reagents such as sunlight, microwaves, sound waves and enzymes.

Some important techniques are described below:

(a) Use of sunlight and microwaves:

1) Photochemistry involves the use of sunlight and ultraviolet light.

The main advantage of a photochemical reaction is that the products obtained by it are unique,

i.e. these products cannot be obtained by a normal chemical method.

 

2) In microwave ovens, no toxic solvents are used.

Only the reactants in the proper ratio are mixed on solid support like alumina and exposed to microwaves.

 

3) The reaction is complete within minutes and the products obtained are higher than those obtained by using toxic solvents.

Hence, the use of microwaves reduces the time of reaction and increases the yield.

 

(b) Use of sound waves:

1) Sound waves can also be used to carry out certain reactions. This branch of chemistry is known as sonochemistry.

2) Efforts are needed to develop conditions to achieve the desired goal.

 

(c) Use of enzymes:

1) Enzymes are environmentally friendly reagents. They work in aqueous solutions and at ambient temperatures.

2) Using enzymes, many biochemical methods have been developed to prepare intermediates of certain chemicals and antibiotics.

3) For example, semi-synthetic penicillin has been prepared using these techniques.

 

Answered by Varsha | 28th Feb, 2019, 10:51: AM