Chemistry - C7.5 - Green Chemsitry

Every year the chemical industry make thousands or millions of tonnes of BULK CHEMICALS. These include:

• Sulfuric Acid
• Phosphoric Acid
• Sodium Hydroxide
• Ammonia

The industry makes smaller amounts of fine chemicals, including:

• Medicinal drugs
• Food additives
• Fragrances

The industry employs chemists for research and development. They aim to discover:

• New products, to meet a new need or to meet an existing need in a new way.

• New processes, to make a product more cheaply or sustainably. This is why chemists develop new catalysts.

Government health and safety regulations control chemical processes abd the storage and transport of chemicals. The regulations protect people (for example workers at a factory) and the environment.

The production of a chemical involves these stages:

• converting raw materials into feedstock (the starting material for the proccess)

• converting the feeddtocks into products. This is synthesis. It happens in a reactor. Feedstock may be fed into the reactor at high temperature or pressure. The reactor may contain a catalyst.

• A mixture of products, by-products and waste may leave the reactor.

• The chemical plant seperates these from each other. At this stage, unreacted feedstocks return to the reacrtor.
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• Analysing the products to check their purity.
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Green Chemistry aims to make chemical processes as safe and sustainable as possible.

Chemists achieve this by...

• Using renuable feedstocks, for example, making polymer from corn starch instead of crude oil
• Making the process as efficient as possible. This is measured as the atom economy, which shows the mass of product atoms as a percentage of the mass of reactant atoms.

atom economy = mass of atoms in the product

                        mass of atoms in the reactants         x 100%