Green chemistry. Introduction of green chemistry. Definition of green chemistry. History and development of green chemistry. 12 principles of green chemistry. Example of green chemistry. Disinfection of water. Production of allyl alcohol. synthesis of ibuprofen. Microwave assisted reaction. Ultrasound assisted reaction.

1. Vignesh R
KMCH college of pharmacy
B.Pharm fourth semester
Medicinal Chemistry – I

2. Introduction
An ideal chemical reaction should have number of attributes such as
Safety
Simplicity
High yield
Recyclable raw materials reagent
Absence of hazardous byproduct

3. Green Chemistry is the utilization of a set of principles that reduces or eliminates
the use or generation of hazardous substances in the design, manufacture and
application of chemical products .
Green Chemistry is a recent approach to design of energy efficient processes and
the best form of waste disposal.
Green chemistry discusses the engineering concept of pollution prevention and
zero waste both at laboratory and industrial scales
Green Chemistry

4. History and development
Green chemistry emerged from a variety of existing ideas and research efforts
(such as atom economy and catalysis) in the period leading up to the 1990s, in the
context of increasing attention to problems of chemical pollution and resource
depletion.
In 1998, Paul Anastas (who then directed the Green Chemistry Program at the
US EPA) and John C. Warner (then of Polaroid Corporation) published a set of
principles to guide the practice of green chemistry. The twelve principles address
a range of ways to lower the environmental and health impacts of chemical
production,

5. 12 Principles of Green Chemistry
The principles cover such concepts as:
-The design of processes to maximize the amount of raw material that
ends up in the product.
-The use of renewable material feedstocks and energy source.
-The use of safe, environmentally benign substances, including solvents,
whenever possible.
-The design of energy efficient processes.
-Avoiding the production of waste, which is viewed as the ideal form of
waste management

6. 1) Prevention.
2) Atom economy.
3) Less hazardous chemical syntheses.
4) Designing safer chemicals.
5) Safer solvents and auxiliaries.
6) Design for energy efficiency.
7) Use of renewable feedstocks.
8) Reduce derivatives.
9) Catalysis
10)Design for degradation.
11)Real-time analysis for pollution prevention
12)Inherently safer chemistry for accident prevention.

7. Disinfection of water:
Disinfection of water by chlorination. Chlorine oxidizes the pathogens there by
killing them, but at the same time forms harmful chlorinated compounds.
A remedy is to use another oxidant, such as Ozonlysis

8. Production of allyl alcohol
Traditional route: Alkaline hydrolysis of allyl chloride, which generates the product
and hydrochloric acid as a by-product

9. Greener route, to avoid chlorine: Two-step using propylene (CH2=CHCH3), acetic
acid (CH3COOH) and oxygen (O2)
Added benefit: The acetic acid produced in the 2nd reaction can be recovered and
used again for the 1st reaction, leaving no unwanted by-product.

12. Microwave Assisted Reactions
Oxidation of Toluene
Oxidation of toluene with KMn04 under normal conditions of refluxing takes 10-12
hrs compared to reaction in microwave conditions5, which takes only 5 min and
the yield is 40%.

13. Diels Alder Reaction
The reaction involves 1,4-addition of an alkene (e.g., maleic anhydride) to a
conjugated
diene (e.g. anthracene) to form an adduct of six membered ring. Under usual condition
the reaction requires a reflux period of 90 min. However, under microwave conditions
diglyme is used as a solvent and 80% yield of the adduct is obtained in 90
sec.

14. Ultrasound Assisted Reactions
Saponification
Saponification can be carried out under milder conditions using sonification.7,8
Thus, methyl 2,4-dimethylbenzoate on saponification (20 KHz) gives the
corresponding acid in 94% yield compared to 15% yield by the usual process of
heating with aqueous alkali (90 min)

15. Thank you…