Patent GB-493508-A (GB)
Title: Improvements in the recovery or production of unitary cyclic compounds from the products obtained in the pressure extraction of solid carbonaceous materials
IPC: C10G47/00
Filed: 1937-04-06
Abstract: In the recovery of unitary cyclic compounds from the products obtained by the extraction of carbonaceous materials with solvents, the extracts are separated by means of selective solvents into fractions rich and poor in hydrogen respectively, the fraction poor in hydrogen is subjected to destructive hydrogenation and/or dehydrogenation and the products are treated to recover unitary cyclic products by physical or chemical means. The extraction of the solid carbonaceous materials is carried out under pressures of 20-1000 atmos. and at temperatures of 200-500 DEG  C. in presence of solvents comprising middle oil, phenols, wholly or partially hydrogenated naphthalene, anthracene, phenanthrene or other polynuclear compounds, and in presence of hydrogen in small amounts. The initial materials may be pretreated with acids or gases or by spraying and/or heating with catalytic substances.  The separation of the extract may be carried out with two groups of solvents: (1) those which dissolve the constituents poor in hydrogen, e.g. sulphur dioxide, aniline, methyl aniline, toluidine, furfurol, acetonitrile, dichlorethylether, triethylene glycol, phenylhydrazine, and keto acids; (2) those which precipitate high-molecular-weight fractions poor in hydrogen comprising asphalts and resins, e.g. ethane, propane, pentane, &c.  Mixtures of the two groups may be used. The fraction poor in hydrogen is then subjected to destructive hydrogenation under known conditions or to dehydrogenation (a) by heating to 400-700 DEG  C., in presence of catalysts on carriers, if desired in presence of hydrogen having a partial pressure up to 50 atmos. or in presence of other gases, (b) by treatment in stages at different temperatures and in presence of different catalysts, (c) in presence of metals of the platinum group, (d) by heating in presence of air and copper at 350 DEG  C., (e) by heating in presence of sulphur, selenium, tellurium, oxides of nitrogen, dilute nitric acid, (f) in presence of halogens.  The individual cyclic compounds may be recovered by fractional distillation and/or crystallization, centrifuging, filtration or precipitation, phenanthrene being obtained from the fraction boiling between 325 and 345 DEG  C., fluorene from the 295-320 DEG  C. fraction, and pyrene and chrysene from the fraction boiling above 390 DEG  C.  The fraction rich in hydrogen may be further treated by destructive hydrogenation to obtain lubricating and Diesel oils.  Example: brown coal is extracted with tetrahydronaphthalene; the extract is freed from solvent and treated at 400 DEG  C. with a benzine boiling at 70-100 DEG  C.; the layers formed are separated by centrifuging; the fraction rich in hydrogen is freed from benzine by distillation and treated with hydrogen at 380 DEG  C. and 250 atmos. in presence of tungsten sulphide; the fraction poor in hydrogen is hydrogenated at 470 DEG C., and 250 atmos. in presence of molybdenum on granular lignite coke; the fraction boiling between 340 and 420 DEG  C. is heated with flowers of sulphur for 2 hours at 300 DEG  C. and pyrene, methylated pyrenes, chrysene and anthracene are recovered from the products. Specifications 333,550, [Class 32], 435,254, and 493,447 are referred to.ALSO:In the recovery of unitary cyclic compounds from the products obtained by the extraction of carbonaceous materials with solvents, the extracts are separated by means of selective solvents into fractions rich and poor in hydrogen respectively, the fraction poor in hydrogen is subjected to destructive hydrogenation and/or dehydrogenation, and the products are treated to recover unitary cyclic products by physical or chemical means.  The extraction of the solid carbonaceous materials is carried out under pressures of 20-1000 atmos. and at temperatures of 200-500 DEG  C. in presence of solvents comprising middle oil, phenols, wholly or partially hydrogenated naphthalene, anthracene, phenanthrene or other polynuclear compounds, and in presence of hydrogen in small amounts. The initial materials may be pretreated with acids or gases or by spraying and/or heating with catalytic substances.  The separation of the extract may be carried out with two groups of solvents; (1) those which dissolve the constituents poor in hydrogen, e.g. sulphur dioxide, aniline, methyl aniline, toluidine, furfurol, acetonitrile, dichlorethylether, triethyleneglycol, phenylhydrazine and keto-acids; (2) those which precipitate high molecular weight fractions poor in hydrogen comprising asphalts and resins, e.g. ethane, propane, pentane, &c.  Mixtures of the two groups may be used.  The fraction poor in hydrogen is then subjected to destructive dehydrogenation, (a) by heating to 400-700 DEG  C. in presence of catalysts on carriers, if desired in presence of hydrogen having a partial pressure up to 50 atmos. or in presence of other gases, (b) by treatment in stages at different temperatures and in presence of different catalysts, (c) in presence of metals of the platinum group, (d) by heating in presence of air and copper at 350 DEG  C., (e) by heating in presence of sulphur, selenium, tellurium, oxides of nitrogen, dilute nitric acid, (f) in presence of halogens.  The individual cyclic compounds may be recovered by fractional distillation and/or crystallization, centrifuging, filtration or precipitation, phenanthrene being obtained from the fraction boiling between 325 and 345 DEG  C., fluorene from the 295-320 DEG  C. fraction, and pyrene and chrysene from the fraction boiling above 390 DEG  C.  The fraction rich in hydrogen may be further treated by destructive hydrogenation to obtain lubricating and Diesel oils. Example: brown coal is extracted with tetrahydronaphthalene; the extract is freed from solvent and treated at 400 DEG  C. with a benzene boiling at 70-100 DEG  C.; the layers formed are separated by centrifuging; the fraction rich in hydrogen is freed from benzine by distillation and treated with hydrogen at 380 DEG  C. and 250 atmos. in presence of tungsten sulphide; the fraction poor in hydrogen is hydrogenated at 470 DEG  C. and 250 atmos. in presence of molybdenum on granular lignite coke; the fraction boiling between 340 and 420 DEG  C. is heated with flowers of sulphur for 2 hours at 300 DEG  C. and pyrene, methylated pyrenes, chrysene and anthracene are recovered from the products.  Specifications 333,550, [Class 32], 435,254, and 493,447 are referred to.