Unit 9: Catalysis In general, catalysts can be divided into two categories—heterogeneous and homogeneous. In a heterogeneous reaction system, the catalyst is in a different phase than are the reactants. Consider, for example, the synthesis of isopropylbenzene, where isopropylbenzene is produced by alkylation of benzene with propylene using a crystalline zeolite (an aluminum silicate molecular sieve)as a catalyst. The reagents are in gas phase, and the reaction takes place only when these reagents are activated on the zeolite (solid) surface. In homogeneous catalysis, on the other hand, the reagents and the catalyst are in the same phase, usually dissolved in solution. Consider, for example, olefin metathesis using Grubbs’s catalyst, where both reagents and the catalyst (a ruthenium-based carbine) are dissolved in the same solution.
In this unit, you will draw upon much of the knowledge of inorganic chemistry you have accumulated thus far in your studies in order to understand catalytic cycles in industrial applications. Industrial applications studied in this unit specifically include the conversion of ammonia to nitric acid, the Haber process, and the Contact Process.
Unit 9 Time Advisory
This unit should take you approximately 4 hours to complete.
☐ Subunit 9.1: 1.5 hours
☐ Subunit 9.2: 2.5 hours
Unit9 Learning Outcomes
Upon successful completion of this unit, the student will be able to:
- Define heterogenous and homogeneous catalysts and give examples of each.
- Explain the effect of catalysts on activation energies and reaction rates.
- Discuss industrial applications of catalysts and give some specific examples.
9.1 General Principle
- Reading: Jim Clark’s Chemguide: “Types of Catalysis”
Link: Jim Clark’s Chemguide: “Types of
Instructions: Please read the entire webpage. This material explains the basic concepts of catalysis. The two major types of catalysis are homogeneous, where the reactants and catalyst are in the same phase, and heterogeneous, where the reactants and the catalyst are in different phases. Examples of each are given.
9.2 Industrial Applications of Inorganic Catalysis
- Reading: Jim Clark’s Chemguide: “Catalysts in Inorganic Industrial
Link: Jim Clark’s Chemguide: “Catalysts in Inorganic Industrial
Instructions: Please read the entire webpage. The conversion of ammonia to nitric acid is covered in detail on this page. Please follow the links to read more about the Contact Process, for the production of sulfuric acid, and the Haber Process, for the production of ammonia. Also note whether the processes involve homogeneous or heterogeneous catalysis.