Naphthalene in tar processing

Industrial naphthalene holds an extremely important position in the chemical industry; it is a basic raw material for the dye, plastic, and pharmaceutical industries. It is widely used in the production of synthetic fibers, rubber, resins, dyes, etc., and is primarily used to produce phthalic anhydride, which is then used to manufacture resins, engineering plastics, dyes, paints, and pharmaceuticals； It can also be used in the production of pesticides, **, plant growth hormones, as well as antioxidants for rubber and plastics. Substances such as 1-naphthol, 2-naphthol, H-acid, J-cyanic acid, and Klevic acid can be obtained from it, and pure naphthalene can be synthesized as well.

The main users of 95-naphthalene in our factory are those who produce alkaline water agents (cement additives), accounting for about 60% of the raw material usage.

Naphthalene can be used to produce phthalic anhydride, naphthalenesulfonates, **naphthochemicals, plasticizers, water reducers, anti-aging agents, and more. It is a very important basic organic chemical raw material that is widely used in the production of dyes, pigments, rubber additives, as well as intermediates or products in the fields of construction, medicine, and pesticides.

It is used as a solvent and analytical reagent, as well as in organic synthesis. It is employed in the production of pharmaceuticals, pesticides, fragrances, dyes, and rubber antioxidants. It is mainly used to produce phthalic anhydride, and it also serves as a raw material for the manufacture of dyes and pharmaceuticals. Naphthalene is a raw material in pesticide production; it can be converted into naphthol and phenylnaphthol, oxidized to phthalic anhydride from which phthalimide can be produced, or combined with chloroacetic acid to form naphthaleneacetic acid. It can serve as an intermediate for insecticides such as imidacloprid and methomyl, herbicides such as mesotrione and diuron, and plant growth regulators such as naphthaleneacetic acid and naphthoxyacetic acid. Use: Used for preventing mold and corrosion in leather. Uses: It is mainly used in the production of phthalic anhydride, and it also serves as a basic raw material for the manufacture of dyes, pharmaceuticals, plastics, etc. It can be used to produce dye intermediates, dispersants, water reducers, and other products. Crude naphthalene is refined into refined naphthalene using clay. Production method: The preparation method involves using high-temperature coal tar (with naphthalene accounting for about 8%–12%). After distilling the tar to remove the light oil fraction and the phenol oil fraction, the fraction at 210–230°C is collected, thereby obtaining the naphthalene oil fraction. By using the cooling crystallization method on naphthalene oil fractions, crude naphthalene with a naphthalene content of 75% can be obtained. This crude naphthalene is then filtered, dried, and pressed to yield compressed blocks with a naphthalene content of 96%–98%. The compressed naphthalene is melted, washed with sulfuric acid for purification, neutralized with 10% sodium hydroxide to remove phenols, and then distilled to remove water; the fraction obtained at 100–130°C is collected, and finally the product is formed through crystallization. If it is produced from petroleum hydrocarbons, its raw materials come from catalytically reformed heavy oil, catalytic cracking recycle oil, and the tar by-product of ethylene production.

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