Petroleum benzene is generally produced through processes such as catalytic reforming, ethylene cracking, and toluene disproportionation, with high purity; Hydrogenated benzene is produced by coal coking process to produce crude benzene, which is then refined by hydrogenation. Hydrogenated benzene may contain small amounts of impurities such as sulfur and nitrogen depending on the properties of the raw materials and the depth of hydrogenation; Coking benzene is a general term for acid washed benzene, hydrogenated benzene, and refined benzene. The types and levels of impurities are related to coal raw materials and their processing technology.
1, Upstream of benzene
(1). Preparation of naphtha through catalytic reforming.
(2). Toluene is prepared by toluene disproportionation, and can also produce xylene as a byproduct, which extends downwards as part of the PX-PTA-PET industry chain.
(3). Naphtha is prepared by ethylene cracking. 4. Crude benzene is produced by coal coking and refined by hydrogenation of crude benzene.
2, Downstream of benzene
(1). Styrene SM: Benzene and ethylene are reacted in two steps to prepare styrene (benzene ethylbenzene styrene), which can be further developed into polystyrene PS, HIPS, EPS, ABS resin, ASA resin.
(2). Caprolactam: Caprolactam can be developed downstream to prepare nylon 6, and nylon 6 and nylon 66 are two commonly used nylon varieties.
(3). Phenol: Benzene and propylene react in two steps to prepare phenol (benzene isopropylbenzene phenol), which can be further developed towards resins or reacted with acetone to prepare bisphenol A. Bisphenol A is an important intermediate in the production of epoxy resins and polycarbonate.
(4). Nitrobenzene: Nitrobenzene is prepared by nitration reaction between benzene and mixed acid, followed by hydrogenation reduction to produce aniline. Aniline is an important raw material for MDI.
(5). Adipic acid: Benzene is hydrogenated to produce cyclohexane, which is then oxidized with air to produce KA oil (a mixture of cyclohexanol and cyclohexanone), and finally oxidized with nitric acid to produce adipic acid. Adipic acid is an important monomer for the production of nylon 66 (reacting with hexamethylenediamine, the other monomer being adiponitrile).
