Improvements in the recovery or production of unitary cyclic compounds form the products obtained by the pressure extraction or destructive hydrogenation of carbonaceousmaterials

摘要

Products obtained from solid carbonaceous materials by extraction under pressure or mild destructive hydrogenation are separated from solid constituents and then extracted with an aliphatic hydrocarbon containing 4-9 carbon atoms. The portion soluble in the extracting agent is fractionated, and the heavy oils so obtained, or fractions thereof, are treated to recover unitary cyclic compounds therefrom by the methods described in Specification 435,254 or by the methods ordinarily used in recovering polynuclear compounds from coal tar. The preliminary extraction or destructive hydrogenation of the solid carbonaceous material may be effected by pasting the material with a middle oil and asphalt, obtained in the process, and subjecting the mixture for 1-3 hours or more to a temperature of 300-480 DEG C. in one or more stages, preferably at increasing temperatures, and a pressure of 50 atm. or more, e.g. 100-300 atm., in the presence or absence of hydrogen and optionally in the presence of a catalyst; the latter may be an oxide, sulphide, oxalate or halide of tin, molybdenum, tungsten, zinc, manganese or iron, with or without a halogen or a hydrogen halide or an organic halogen compound, or a mixture of iron or an iron compound with an alkaline substance. If brown coal is treated, it may first be freed from bitumen in known manner, e.g. by extraction with a mixture of benzene and alcohol. The destructive-hydrogenation or pressure-extraction products are preferably freed from benzine before they are extracted with the aliphatic hydrocarbons of 4-9 carbon atoms; this extraction may be effected under pressure at 20-200 DEG C., preferably at a temperature near the critical temperature of the extracting agent. The extract is then freed from the extracting agent and separated into middle and heavy oils; the middle oil, which may have a maximum boiling point of 325 DEG C., may be used for pasting fresh carbonaceous material, while the heavy oil is treated for the recovery of cyclic compounds, as indicated above. The extraction with aliphatic hydrocarbons containing 4-9 carbon atoms may be preceded by an extraction with liquefied hydrocarbons containing 1-3 carbon atoms, which may contain hydrogen in solution; in this extraction, which is preferably effected at a raised temperature and pressure, the middle oil passes into solution and the asphalts and heavy oil remain undissolved, the undissolved portion being then extracted with aliphatic hydrocarbons containing 4-9 carbon atoms to separate the heavy oil. The recovery of the cyclic compounds from the heavy oil or its fractions may be preceded by a dehydrogention treatment. This may be effected at 400-700 DEG C. or, if side chains are to be split off, at 500-1000 DEG C., preferably in the presence of a catalyst; the latter may be magnesium, zinc, aluminium, silicon, titanium, tin, vanadium, chromium, molybdenum, tungsten, uranium, manganese, iron, nickel, cobalt or a rare-earth metal, or an oxide, sulphide, halide or phosphate thereof, with or without a halogen, a hydrogen halide, or an organic halogen compound. The catalysts may be applied to carriers, e.g. lignite coke which has been activated and preferably neutralized with acid, active silicic acid, or a bleaching earth, which may advantageously be treated with hydrogen p fluoride. The dehydrogenation may be effected under pressure in the presence of hydrogen, a total pressure of 200 atm. and a hydrogen partial pressure of 50 atm. being suitable. Other gases or vapours, e.g. steam, nitrogen, methane, water gas, air, or oxides of carbon, may also be present. In the example, coal is pasted with a mixture of middle oil and asphalt obtained in the process, and small proportions of tin oxalate and ammonium chloride are added; the paste is heated with hydrogen to 470 DEG C. under a pressure of 300 atm., and the products are passed to a separator kept at 230 DEG C., from which hydrogen and vaporized benzine are withdrawn; the liquid products from the separator are centrifuged to remove solids and then heated in an autoclave with pentane to 180-190 DEG C.; the extract is separated from undissolved asphalts, and distilled to yield middle and heavy oils; the latter is heated with hydrogen to 550 DEG C. in the presence of nickel sulphide and tungsten sulphide, and the product is separated into fractions from which carbazole, pyrene, chrysene, fluorene and pyrene homologues are isolated; other products stated to be obtainable are anthracene, benzoperylene and coronene.ALSO:Products obtained from solid carbonaceous materials by extraction under pressure or mild destructive hydrogenation are separated from solid constituents and then extracted with an aliphatic hydrocarbon containing 4-9 carbon atoms. The portion soluble in the extracting agent is fractionated, and the heavy oils so obtained, or fractions thereof, are treated to recover unitary cyclic compounds therefrom by the methods described in Specification 435,254 or by the methods ordinarily used in recovering polynuclear compounds from coal tar. The destructive-hydrogenation or pressure-extraction products are preferably freed from benzine before they are extracted with the aliphatic hydrocarbons of 4-9 carbon atoms; this extraction may be effected under pressure at 20-200 DEG C. preferably at a temperature near the critical temperature of the extracting agent. The extract is then freed from the extracting agent and separated into middle and heavy oils; the middle oils, which may have a maximum boiling point of 325 DEG C., may be used for pasting fresh carbonaceous material, while the heavy oil is treated for the recovery of cyclic compounds, as indicated above. The extraction with aliphatic hydrocarbons containing 4-9 carbon atoms may be preceded by an extraction with liquefied hydrocarbons containing 1-3 carbon atoms, which may contain hydrogen in solution; in this extraction, which is preferably effected at a raised temperature and pressure, the middle oil passes into solution and the asphalts and heavy oil remain undissolved, the undissolved portion being then extracted with aliphatic hydrocarbons containing 4-9 carbon atoms to separate the heavy oil. The recovery of the cyclic compounds from the heavy oil or its fractions may be preceded by a dehydrogenation treatment. This may be effected at 400-700 DEG C. or, if side chains are to be split off, at 500-1000 DEG C., preferably in the presence of a catalyst; the latter may be magnesium, zinc, aluminium, silicon, titanium, tin, vanadium, chromium molybdenum, tungsten, uranium, manganese, iron, nickel, cobalt or a rare-earth metal, or an oxide, sulphide, halide or phosphate thereof, with or without a halogen, a hydrogen halide, or an organic halogen compound. The catalysts may be applied to carriers, e.g. lignite coke which has been activated and preferably neutralized with acid, active silicic acid, or a bleaching earth, which may advantageously be treated with hydrogen fluoride. The dehydrogenation may be effected under pressure in the presence of hydrogen, a total pressure of 200 atm. and a hydrogen partial pressure of 50 atm. being suitable. Other gases or vapours, e.g. steam, nitrogen, methane, water gas, air, or oxides of carbon, may also be present. In the example, coal is pasted with a mixture of middle oil and asphalt obtained in the process, and small proportions of tin oxalate and ammonium chloride are added; the paste is heated with hydrogen to 470 DEG C. under a pressure of 300 atm., and the products are passed to a separator kept at 230 DEG C., from which hydrogen and vaporized benzine are withdrawn; the liquid products from the separator are centrifuged to remove solids and then heated in an autoclave with pentane to 180-190 DEG C.; the extract is separated from undissolved asphalts, and distilled to yield middle and heavy oils; the latter is heated with hydrogen to 550 DEG C. in the presence of nickel sulphide and tungsten sulphide, and the product is separated into fractions from which carbazole, pyrene, chrysene, fluorene and pyrene homologues are isolated; other products stated to be obtainable are anthracene, benzoperylene and coronene.