| EPA chemical substance information | information provided by: ofmpeb.epa.gov (external link) |
| Overview | tar is a solid phase generated when the internal components of a cigarette are cracked and cooled. The cigarette is smoked at a standard rate of two seconds per minute, and the particulate matter contained in the smoke is filtered by a fiber filter, the tar content of each cigarette is obtained by further subtracting the weight of the aqueous particulate matter and nicotine. It was determined that 99.4 of the tar was non-toxic, 0.2 was a cancer inducer, and 0.4 was a cancer promoter. Therefore, all countries in the world have set the maximum tar content of cigarettes, and the content of each cigarette under 15 mg is called safe. At present, the tar content of domestic cigarettes is about 28.2 mg per cigarette. |
| components of coal tar | Coal tar is a complex mixture of hydrocarbons with high aromaticity, most of them are polycyclic and fused ring compounds with or without side chains and heterocyclic compounds containing oxygen, sulfur and nitrogen, and contain a small amount of aliphatic hydrocarbons, cycloalkanes and unsaturated hydrocarbons, and also entrained with coal dust, coke dust and pyrolytic carbon. The coal tar just recovered also contains about 5% of water dissolved in a variety of inorganic salts and other impurities. Due to the presence of very fine pyrolytic carbon, water tends to form a stable emulsion with oil. Most of the components of coal tar have a high melting point, but because a large number of monomer compounds dissolve each other to form a low co-soluble mixture, the coal tar is still in a liquid state at room temperature. High temperature coal tar contains more than 10000 compounds, according to the chemical nature can be divided into neutral hydrocarbons, acidic phenols and alkaline pyridine, Quinoline compounds. By, 480 compounds had been identified in coal tar, accounting for 55% of the total mass of coal tar, including 174 neutral compounds, 63 acidic compounds, and 113 basic compounds, the remainder are fused rings and heterocyclic compounds containing oxygen and sulfur. |
| Properties and composition | the composition and properties of low-temperature coal tar are quite different from those of high-temperature coal tar, low-temperature coal tar contains more oxygen-containing compounds and chain hydrocarbons, in which the content of phenol and its derivatives is 10% ~ 30%, and the content of alkane is about 20%, and the heavy oil (tar pitch) it is suitable for the production of vehicle engine fuel oil and chemicals by hydrogenation technology. The composition and properties of coal tar produced by different raw materials and different pyrolysis processes are quite different. Table is a typical low temperature coal tar properties and composition data, wherein the density value is measured at 20 °c. |
| coal tar and psoriasis | coal tar was first discovered and described by Becher and Serie in 1681. Coal tar is a classic preparation for the treatment of skin diseases. It is an important topical drug in dermatology and an indispensable "weapon" in dermatology. In foreign countries, tar products are used to treat psoriasis, atopic dermatitis, seborrheic dermatitis and prurigo. Coal tar, also known as coal distillate oil, coal tar solution, has the effect of inhibiting the mitotic activity of epidermal cells to synthesize DNA, and returning the proliferation rate to normal. In the past, most of the coal tar products were rough, bad smell, and many patients gave up. With the progress of modern chemical synthesis process, coal tar through scouring, made of medical odor-free, milky white cream or yellow brown lotion, liniment. |
| Application of coal tar processing products | the phenolic compounds in medium and low temperature coal tar are mainly low-grade phenols, the chemical extraction method can be used to extract the lower phenol as a chemical raw material, and the fraction after the extraction of the lower phenol will be an excellent raw material for the preparation of high ten Alkane number diesel oil by hydrogenation. Medium and low temperature coal tar can be used to produce diesel oil, gasoline and other vehicle engine fuel oil and chemicals by hydrotreating. Hydrogenation of high-temperature coal tar to fuel oil is more difficult than hydrogenation of medium-and low-temperature coal tar. According to the traditional processing technology, the fractions of high-temperature coal tar can be further processed to separate a variety of chemical products, the main products and uses of extraction and processing are: phenol oil fraction phenol: phenolic resin, synthetic fiber, medicine; Cresol: fungicides, plasticizers, mineral processing agents, herbicides, spices, flame retardants; Xylenol: pesticides, engineering Plastics; Pyridine base: Medicine; Coumarone resin, asphalt paint. Naphthalene oil fraction naphthalene: Dyes, plastics, pharmaceuticals, surfactants, plasticizers, sanitary spheres. Washing oil fraction methyl naphthalene: solvent, polynaphthyl Ester plastic, MF type auxiliary agent, cement water reducing agent, feed additive; Indole: perfume; Biphenyl: insulating oil, heat carrier; Dimethyl naphthalene: polynaphthyl Ester plastic, insulating material;: Dye Poly (naphthyl ester) plastic; Oxyfluorene: Insect repellent; Fluorene: plastic; Quinolines: pharmaceuticals, pesticides, dyes, chromogenic agents. Anthracene oil fraction anthracene: Dye, pulp digestion aid, Emulsifier; Phenanthrene: pesticide; Carbazole: Dye; Carbon Black: tire manufacturing, other rubber, plastic additives, dyes, printing ink and other industries; anti-corrosion oil. Two anthracene oil fraction fluoranthene: inspection agent; Pyrene: Dyes, engineering plastics; Carbon black. Coal tar pitch pitch Coke; Carbon product Binder, molding fuel binder, magnesia carbon brick, needle coke, carbon fiber; Anti-corrosion and waterproof material, asphalt paint, asphalt for road construction, etc. |
| Use | used as an intermediate of antivirals famciclovir and penciclovir |
