Basic Building Blocks to Downstream Products by Homogeneous Catalysis

3 BASIC BUILDING BLOCKS TO DOWNSTREAM PRODUCTS BY HOMOGENEOUS CATALYSIS 

Although the fundamental processes for refining petroleum and its conversion to basic building blocks are based on heterogeneous catalysts, many important value-added products are manufactured by homogeneous catalytic processes. Some of these reactions are shown in Fig. 1.2. 

The substances within the circles are the basic building blocks obtained from petroleum refining by processes discussed in the previous section. The products within the square are manufactured from these raw materials by homogeneous catalytic pathways. Except for 1.7, all the other four processes shown in Fig. 1.2 are large-tonnage manufacturing operations. 

High octane gasoline diesel, kerosene, aviation fuel 

Propylene and a-alkenes can be reacted with synthesis gas to give -butyraldehyde and alcohols, respectively. These reactions are called hydroformylation or oxo-reactions. The reaction between butadiene and hydrocyanic acid to obtain adiponitrile is called hydrocyanation. The mechanistic details and the relevance of hydroformylation and hydrocyanation reactions for the manufacture of consumer products are discussed in Chapter 5. 

Polymerization of ethylene, propylene, and butadiene yields polyethylene, polypropylene, and polybutadiene, respectively. Although heterogeneous catalysts are mainly used in the industry, the mechanisms of these polymerization reactions are best understood by referring to well-established homogeneous catalytic systems. Selective conversions of ethylene to butene, or hexene, or a mixture of a-alkenes, are also achieved by homogeneous catalysts. Polymerization reactions are discussed in Chapter 6, while the selective conversions of ethylene to other alkenes are discussed in Chapter 7. 

Oxidation of ethylene to acetaldehyde is one of the early examples of an industrial homogeneous catalytic process. Adipic acid and terephthalic acid are required for the manufacture of nylon and polyester, respectively. All these are produced by homogeneous catalyst-based oxidation reactions. 

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Basic Building Blocks to Downstream Products by Homogeneous Catalysis 7... 

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