Green Chemistry in day-to-day Life

(i) Dry Cleaning of Clothes

Tetrachloroethene ($Cl_2C{=}CCl_2$) was traditionally used as the solvent for dry cleaning, but it contaminates groundwater and is a suspected carcinogen. It is being replaced by a process using liquefied carbon dioxide with a suitable detergent, which causes far less harm to groundwater. Similarly, hydrogen peroxide (H₂O₂) is now used for bleaching clothes during laundering, giving better results while using less water.

(ii) Bleaching of Paper

Paper bleaching once relied on chlorine gas. It is now commonly replaced by hydrogen peroxide (H₂O₂) combined with a suitable catalyst that promotes its bleaching action — avoiding the toxic chlorinated byproducts associated with chlorine bleaching.

(iii) Synthesis of Chemicals

Ethanal (CH₃CHO) is now manufactured commercially through a single-step oxidation of ethene, using an ionic catalyst in aqueous medium, achieving a 90% yield:

This single-step aqueous route avoids the multiple stages and harsher conditions of older synthetic methods.

(iv) A "Green Solution" for Cleaning Turbid Water

Powdered kernel of tamarind seed — normally discarded as agricultural waste — has been found to be an effective, non-toxic, biodegradable and cost-effective material for clarifying municipal and industrial wastewater. This is a notable improvement over the conventional practice of using alum, which has been found to increase toxic ion levels in treated water and can contribute to disease.

The Bigger Picture …