Green Chemistry

Ø Green chemistry is a way of thinking and is about utilising the existing knowledge and principles of chemistry and other sciences to reduce the adverse impact on environment.

Ø Green chemistry is a production process that would bring about minimum pollution or deterioration to the environment.

Ø The byproducts generated during a process, if not used gainfully, add to the environmental pollution.

Ø Such processes are not only environmental unfriendly but also cost-ineffective.

Ø The waste generation and its disposal both are economically unsound.

Ø Utilisation of existing knowledge base for reducing the chemical hazards along with the developmental activities is the foundation of green chemistry.

Green Chemistry in day-to-day Life

i) Dry Cleaning of Clothes

Tetra chlroroethene (Cl₂C=CCl₂) was earlier used as solvent for dry cleaning. The compound contaminates the ground water and is also a suspected carcinogen. The process using this compound is now being replaced by a process, where liquefied carbondioxide, with a suitable detergent is used. Replacement of halogenated solvent by liquid CO₂ will result in less harm to ground water.

These days hydrogen peroxide (H₂O₂) is used for the purpose of bleaching clothes in the process of laundary, which gives better results and makes use of lesser amount of water.

(ii) Bleaching of Paper

Chlorine gas was used earlier for bleaching paper. These days, hydrogen peroxide (H₂O₂) with suitable catalyst, which promotes the bleaching action of hydrogen peroxide, is used.

(iii) Synthesis of Chemicals

Ethanal (CH₃CHO) is now commercially prepared by one step oxidation of ethene in the presence of ionic catalyst in aqueous medium with a yield of 90%.

(iv) ‘Green Solution’ to Clean Turbid Water

Powder of kernel of tamarind seeds has been found to be an effective material to make municipal and industrial waste water clean. It is non-toxic, biodegradable and cost effective material. This powder is usually discarded as agricultural waste. The present practice is to use alum to treat such water. It has been found that alum increases toxic ions in treated water and can cause diseases.

Green chemistry, in a nutshell, is a cost effective approach which involves reduction in material, energy consumption and waste generation.