Definition Green Chemistry:

The design, development and implementation of chemical products and processes that reduces or eliminate the use and generation of hazardous substances.

12 Principles of Green Chemistry

Paul Anastas and John C. Warner developed 12 principles of green chemistry, which help to explain what the definition means in practice. The principles of green chemistry are key tools for achieving sustainability as they combine the possibility of synthesis of new products with conditions for assuring that they are degradable and non-toxic to the environment. 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 safe, environment-benign substances, including solvents, whenever possible.

• the design of energy efficient processes; and

• the best form of waste disposal: not to create it in the first place.

The 12 Principles are :

12 Principles of Green Chemistry

Green Chemistry vs Environmental Chemistry

Green chemistry is a philosophy of chemical research and engineering that encourages the design of products and processes that minimize the use and generation of hazardous substances. It is also known as sustainable chemistry.

·      Green chemistry is doing chemistry the way nature does chemistry -using renewable, biodegradable materials which do not persist in the environment.

·        It is using catalysis and bio catalysis to improve efficiency and conduct reactions at low or ambient temperature.

·        It is a proven systems approach.

·        It reduces negative human health and environmental impacts.

·        It offers strategic pathway to build a sustainable future.

·        In nature, green chemistry seeks to reduce and prevent pollution at its source. It aims to avoid problems before they happen.

Environmental chemistry is the chemistry of the natural environment and of pollutant chemicals.

              Green Chemistry

  Environmental Chemistry

The design, development and implementation of chemical products and processes that reduce or eliminate the use and generation of hazardous substances.

It is the branch of chemistry which is concerned with the chemical phenomenon occurring in the environment.

12 Principles developed by Paul C Anastas and John C warner.

No rules or Principles

Prevention approach

Treatment approach

Green chemistry focuses on the environmental impact of chemistry. It is a powerful approach to pollution prevention, waste minimization and hazard reduction.

Environmental chemistry focuses on the effects of polluting chemicals on nature.


 1. It is better to prevent waste than to treat or clean up waste after it is formed.

2. Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product. Consider atom economy and materials efficiency in the choice or design of synthetic transformations. Choosing transformations that incorporate most of the starting materials into the product is more efficient and it minimizes waste.

3. Wherever practicable, synthetic methodologies should be designed to use and generate substances that possess little or no toxicity to human health and the environment.

4. Chemical products should be designed to preserve efficacy of function while reducing toxicity.

5. The use of auxiliary substances (e.g., solvents, separation agents, etc.) should be made unnecessary wherever possible and inoffensive when used. Solvent use leads to considerable waste generation. Reduction of solvent volume or complete elimination of the solvent is often possible. In cases, where the solvent is needed, less hazardous replacements should be employed. Purification steps also generate large sums of solvent and other waste. Avoid purifications when possible and minimize the use of auxiliary substances when they are needed.

6. Energy requirements should be recognized for their environmental and economic impacts and should be minimized. Synthetic methods should be conducted at room temperature and pressure.

7. A raw material or feedstock should' be renewable rather than depleting wherever technically and economically practicable. In academic labs, this may be more of a research problem than a readily implemented in-lab solution.

8. Reduce derivatives - Unnecessary derivatization (blocking group, protection/deprotection, temporary modification) should be avoided whenever possible.

9. Catalytic reagents (as selective as possible) are used in greater proportions than stoichiometric reagents. Catalysts can serve several roles during a transformation, they can enhance the selectivity of a reaction, reduce the temperature of a transformation, enhance the extent of conversion to products and reduce reagent-based waste (since they are not consumed during the reaction). By reducing the temperature, one can save energy and potentially avoid unwanted side reactions.

10. Chemical products should be designed so that at the end of their function they do not persist in the environment and break down into innocuous degradation products.

11. Analytical methodologies need to be further developed to allow for real-time, in-process monitoring and control prior to the formation of hazardous substances. It is always important to monitor the progress of a reaction to know when the reaction is complete or to detect the emergence of any unwanted by-products.

12. Substances and the form of a substance used in a chemical process should be chosen to minimize potential for chemical accidents, including releases, explosions, and fires.

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