GREEN CHEMISTRY

GREEN CHEMISTRY

Examples of green chemistry solvents or safer solvents 

Solvents are consumed in large quantities in many chemical syntheses as well as for cleaning and    degreasing.
Traditional solvents are often toxic or are chlorinated. Green solvents, on the other hand, are generally derived from renewable resources and biodegrade to harmless, often a naturally occurring product.

Some green solvents are, liquid carbon dioxide instead of tetra chloro ethylene, replacement of benzene with toluene, cyclo hexane instead of carbon tetra chloride, dichloro methane instead of chloroform etc.

Examples of green chemistry  

For the preparation and designing of so many chemicals by traditional route and also by greener route
are shown below.

(I) preparation of styrene using tolune and methanol is a traditional method. Replacing CFC solvents with liquid CO₂ is a greener method.

(II) preparation of butenafine by traditional and greener method are  also another example of green chemistry.

(III) Hydrazine is traditionally produced by the reaction of sodium hypocloride with ammonia is a traditional process. 

The net reaction produces one equivalent of sodium chloride for every equivalent of thetargeted product hydrazine.

In the greener Peroxide process hydrogen peroxide is employed as the oxidant and the side product is water. The net conversion follows:

(IV) The family of  polycarbonates contains very important polymers which are used where high optical
properties combined with strength are needed.

The polycarbonate most used is manufactured from bisphenol A , whose structure is,

The polycarbonate is manufactured  by a condensation reaction between bisphenol A and either carbonyl chloride or diphenyl carbonate.

Carbonyl chloride is a very poisonous gas, manufactured from other hazardous gases, carbon monoxide and chlorine.

On the other hand, diphenyl carbonate is produced from dimethyl carbonate, which is readily manufactured from methanol, carbon dioxide and oxygen in the liquid phase, in presence of copper(II) 
chloride. 

Dimethyl carbonate,when heated with phenol in the liquid phase, forms the diphenyl carbonate.

Overall, the process for the production of polycarbonate that uses diphenyl carbonate is less hazardous than that using carbonyl chloride.

(V) cleaning of cloths by chlorinating agents is a traditional method .But replacement of chlorinated solvents by liquid carbon dioxide is a greener process for cleaning.




Summary: 


What is green chemistry?
What is the significance of green chemistry?
What are the examples of green solvents?

Read more: Hydroiodicacid-formula-properties-uses with pH calculation