The Role Catalysts In Chemical Reactions, Their Importance In Industry

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The Role Catalysts In Chemical Reactions, Their Importance In Industry, Problems and New Developments

- Advanced Level Chemistry (Salters') - Paper 3 mock.


A Catalyst is a substance that alters the rate of a reaction. The catalyst remains unchanged at the end of the reaction. The process is called catalysis.
In this report I aim going to explain the role of catalysts in chemical reactions and their importance in industry. I will also outline the problems associated with the use of some catalysts and discuss, using appropriate examples, new developments in this area which will help reduce damage to the environment. The process of
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Zeolites are highly porous crystals with minute channels ranging from 0.3nm to 0.8nm in diameter. Due to their definite crystalline structure and the fact that their pores are too small to contain carbonaceous build-up, zeolites do not share the problems of silica- alumina gels.

Zeolites are able to exhibit shape-selective crystals i.e.. their active sites are specific to only a few product molecules (the ones that will fit into the tiny pores).

An example of this is when the zeolite ZSM-5 is used to catalyse the synthesis of 1,4-dimethylbenzine. When molecules of methylbenzene combine with methanol in the ZSM-5 catalyst, only rod-shaped molecules 1,4-dimethylbenzene are released,
(these are the commercially desirable ones). The boomerang shaped molecules are unable to pass through the catalysts pores and are therefore not released.

Until relatively recently, one of the large drawbacks with catalysts was the highly toxic by-products which they became after use. This was because the catalysts were often corrosive acids with a high toxicity level in liquid form.
Examples include hydrogen fluoride. Once these catalysts had been used this promoted great problems in terms of disposal as these acids corrode disposal containers and are highly dangerous to transport and handle.

These problems have been solved by a new type of catalyst. Solid acid catalysts, such as silica-alumina gels and zeolites, hold their acidity internally
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