Green Chemistry and The 12 Principles of Green Chemistry

Question 1

What is green chemistry?

Answer 1

Green chemistry is defined as a set of principles that reduces or eliminates the use and generation of hazardous substances in the design, manufacture, disposal and use of chemical products.

Question 2

aims of green chemistry

Answer 2

It deals with ways to reduce or prevent the production of wastes that could harm the environment in any particular manufacturing process.

It seeks to reduce the wastage of chemicals and energy and to increase the
efficiency of the process.

Question 3

The main problems which can occur in the chemical industry are:

Answer 3

● The use and production of substances that are hazardous to the environment

● Inefficient use of energy – high temperatures and pressures

● Low yield of product

Question 4

Prevention-

Answer 4

it is better to reduce waste than to treat it after it has been produced.

Question 5

Atom economy-

Answer 5

the method(s) used for synthesis should make use of 100% of the raw materials. There
should be no wastage of raw materials.

Question 6

Less hazardous chemical synthesis –

Answer 6

the reactants, products and catalysts used in the manufacturing process should have little or no harmful effects on the environment.

Question 7

Safer solvents and other agents-

Answer 7

reactions used must include chemicals that are safe to the environment.

Question 7

Minimum energy requirements –

Answer 7

as little energy as possible should be used. Reactions should be carried out at room temperature where possible. If the reaction is exothermic, the energy produced must
be used to help in the process.

Question 8

Monitoring to prevent pollution –

Answer 8

each step should be monitored to ensure pollutants are not produced. Methods should be developed to ensure pollutant are not produced or released to the
environment.

Question 9

Use of catalysts –

Answer 9

This reduces the amount of energy needed (hence the energy costs) as the reaction can
be carried out at a lower temperature.

(It will also ensure that no unwanted reaction takes place as catalysts are specific to a particular reaction).

Question 10

EXAMPLES OF GREEN CHEMISTRY

Answer 10

• Treating emissions (harmful gas into the air)
  by using filters
• Using an improved catalyst
  the yield is higher, the yield being what is produced
• Using fuels from algae
  Various strains of algae produce biofuels such as methane and butanol.
  BECAUSE It does not depend on non-renewable resources (petroleum).