ABSTRACT
Petrochemicals are chemicals derived from petroleum products. Examples of petrochemicals are plastics, rubbers, fi bres, paints, solvents, and detergents. In fact, petroleum products are mixtures of hydrocarbons, whereas the raw materials for petrochemicals are pure hydrocarbons separated and converted to desirable products, such as polymers, solvents, and surfactants, usually in several stages and may be grouped as (1) feedstocks (fi rst-generation petrochemicals), (2) intermediates (second-generation petrochemicals), and (3) fi nished products (third-generation petrochemicals). Products similar to petrochemicals derived from non-petroleum sources are not strictly petrochemicals. For example, cellulose, natural rubber, natural resins, nylon 11, and ethanol of plant origin are strictly non-petrochemicals. Coal distillation is also a source of varieties of coal chemicals, e.g., benzene, toluene, xylene, and naphthalene. In fact, before petroleum sources were known, coal chemicals were used to produce a variety of products. Many of the chemicals from non-petroleum sources are co-processed with petrochemicals to the fi nished product. Non-hydrocarbons obtained from petroleum, e.g., hydrogen, carbon monoxide, carbon dioxide, sulfur, and carbon, are also loosely called petrochemicals. Hydrogen, nitrogen and oxides of carbon manufactured from steam reforming and partial oxidation of naphtha are also petrochemicals. These are used for production of ammonia, urea, melamine, fertilizer, etc.
