Coal tar

Alias COALTARCRUDE;CoalTarPitchVolatiles(BenzeneSolubleFraction);Pitch,coaltar,high-temp.;DChemicalbookistillates(coaltar);FluxolST. CoalTarPitch;Pitch,coaltar,hightemperature;Coaltardistillates.

Coal tar is a complex mixture of highly aromatic hydrocarbons, the vast majority of which are polycyclic, thick cyclic compounds with or without side chains and heterocyclic compounds containing oxygen, sulfur and nitrogen, and contain a small amount of aliphatic hydrocarbons, naphthenic hydrocarbons and unsaturated hydrocarbons, and also entrained coal dust, coke dust and pyrolysis carbon. Freshly recovered coal tar also contains about 5% Chemicalbook of water dissolved in a variety of inorganic salts and other impurities. The water tends to form stable emulsions with the oil due to the presence of very fine particles of pyrolytic carbon. The vast majority of the components of coal tar have high melting points, but due to a large number of monomer compounds dissolve each other to form a low co-soluble mixture, so that the coal tar is still liquid at room temperature.

High-temperature coal tar contains more than 10,000 compounds, which can be categorized by chemical properties into neutral hydrocarbons, acidic phenols and basic pyridine and quinoline compounds. By 1972, 480 compounds had been identified in coal tar, the content of which totaled 55% of the mass of coal tar, including 174 neutral compounds, 63 acidic compounds, 113 alkaline compounds, and the rest are thick rings and heterocyclic compounds containing oxygen and sulfur.

Properties and Composition

The composition and properties of low-temperature coal tar and high-temperature coal tar have a large difference Chemicalbook difference, low-temperature coal tar contains more oxygenated compounds and chain hydrocarbons, of which the content of phenol and its derivatives amounted to 10% to 30%, alkane hydrocarbons about 20%, while the content of heavy oil (tar pitch) is relatively small, more suitable for the use of hydrogen technology to produce automotive engine fuel oil and chemicals. The composition and properties of the coal tar produced vary greatly with different raw coal types and different pyrolysis processes. The table shows the properties and composition data of a typical medium-low temperature coal tar, in which the density value is measured at 20℃.

Uses of coal tar processed products

The phenolic compounds in the medium-low temperature coal tar are mainly low-grade phenol, which can be extracted by chemical extraction method as chemical raw material, and the fraction after extraction of low-grade phenol will be an excellent raw material for hydrogenation to produce high cetane diesel. Low and medium temperature coal tar can be hydrotreated to produce diesel, gasoline and other automotive engine fuel oil and chemicals. High-temperature coal tar hydrotreating fuel oil is more difficult than medium-low temperature coal tar hydrotreating, according to the traditional processing technology, high-temperature coal tar fractions can be further processed, can be separated from a variety of chemical products, extraction and processing of the main products and uses are: phenol oil fractions Phenol: phenolic resins, synthetic fibers, pharmaceuticals; cresols: fungicides, plasticizers, mineral processing agents, herbicides, fragrances, flame retardants; dicresyl: insecticides, engineering plastics; pyridine base: medicine; Gumarone resin, asphalt paint. Naphthalene oil fraction naphthalene: dyestuffs, plastics, pharmaceuticals, surface-active Chemicalbook agents, plasticizers, sanitary balls. Wash oil fraction methyl naphthalene: solvents, poly naphthalene ester plastics, MF-type additives, cement water reducing agent, feed additives; indole: spices; biphenyl: insulating oil, heat carrier; dimethyl naphthalene: poly naphthalene ester plastics, insulating materials; acenaphthene: dyes poly naphthalene ester plastics; oxyfluorene: insect repellents; fluorene: plastics; quinolines: pharmaceuticals, pesticides, dyestuffs, color rendering agent. Anthracene oil fraction anthracene: dyestuffs, pulp evaporation aids, emulsifiers; phenanthrene: pesticides; carbazole: dyestuffs; carbon black: tire manufacturing, other rubber, plastic additives, dyestuffs, printing inks, and other industries; anticorrosive oils. Dithracene Oil Fraction fluoranthene: detection agents; pyrene: dyes, engineering plastics; carbon black, etc. Coal tar pitch pitch coke; carbon products binder, molding fuel binder, magnesium-carbon bricks, needle coke, carbon fiber; anticorrosive and waterproof materials, asphalt paint, tar for road construction, etc..

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