The chemical industry encompasses manufacturing facilities whose products result from (a) chemical reactions between organic, inorganic, or both materials; (b) extraction, separation, or purification of a natural product, with or without the aid of chemical reactions; (c) the preparation of specifically formulated mixtures of materials, whether natural or synthetic. Examples of products from the chemical industry include plastics, resins, dyes, pharmaceuticals, paints, soaps, detergents, petrochemicals, perfumes, inorganic materials, and synthetic organic materials.

Many of these processes involve a series of unit operations in chemical engineering depending on the size definition of a plant, as well as basic chemical reactions (processes) such as polymerization, oxidation, reduction, hydrogenation, among others. The global chemical industry is valued at one and a half trillion U.S. dollars today, with over 70,000 commercial products. The total global trade of chemical products has a value of 400 billion U.S. dollars, representing 10 percent of the value of global trade.

The three largest sectors within the global chemical industry are petrochemicals, pharmaceuticals, and performance chemicals. Petrochemicals dominate the global chemical industry with a 30 percent share, followed by pharmaceuticals (16.5 percent), and performance chemicals (16 percent). The European Union (EU), the United States, and Germany are the top three manufacturers, followed by Japan, France, the United Kingdom, Italy, and other Asian countries. However, there has been a significant shift in global demand for chemical products, moving from industrialized nations to developing countries, and the relocation of basic chemical manufacturing from industrialized regions to the Asia-Pacific and China.

The chemical industry as a whole contributes significantly to well-being and employment worldwide. The European Union (EU) is the largest chemical producer globally, accounting for nearly one-third of estimated global production. Throughout the EU, around 1.7 million people are employed in approximately 25,000 chemical companies, and the industry provides additional employment in a wide range of related industries [2]. The chemical, petrochemical, and pharmaceutical industries in the United States together had over 13,000 establishments, over a million employees, and a total shipment value of approximately 406.9 billion U.S. dollars [3]. Additionally, many Asian and Latin American countries have grown rapidly and become international competitors in the chemical industry. Consequently, the global chemical industry is among the most competitive industries in the world.