Patent GB-409770-A (GB)
Title: Improvements in the manufacture and production of benzanthrene
IPC: C07C5/41
Filed: 1932-11-10
Abstract: Benzanthrene and dihydrobenzanthrene are produced by passing a  - benzylnaphthalene through a reaction space of volume Vcc. at a temperature t DEG C. between about 650 DEG  C. and 800 DEG  C., the flow of the a -benzylnaphthalene in grams per hour being maintained at from 1 to 4 times a minimum value Dmin such that <FORM:0409770/III/1> Known dehydrogenation catalysts may be present, such as oxides or other compounds of the alkaline earth metals or of magnesium, zinc or aluminium and non-volatile oxides or other compounds, which are not reducible to metals under the reaction conditions, of elements exhibiting more than one valency, e.g. molybdenum trioxide, tungsten trioxide, chromium trioxide or vanadium pentoxide. Non-reactive diluent gases such as nitrogen, carbon dioxide, water vapour or methane may be present and the reaction may be effected under ordinary or reduced pressure.  The reaction vessel may be made of or lined with porcelain, quartz, or metals or alloys which cause no deposition of carbon, e.g. copper, brass, manganese-copper, or chromium-nickel steels.  Such metals or alloys are preferably first provided with a thin layer of sulphide by treatment with hydrocarbons containing sulphur or are provided with a protective coating of enamel.  Alternatively, the reaction vessel may be provided with fillers of quartz, coke or graphite or with rings of the above metals or alloys which cause no deposition of carbon.  The following examples are specified.  (1) Vaporized a -benzylnaphthalene diluted with nitrogen is passed through a manganese-copper tube at 720 DEG  C., the number of grams of a -benzylnaphthalene passed per hour being equal to the volume of the tube in cc.; the vapours are condensed and the condensate subjected to fractional distillation to obtain a 69 per cent yield of benzanthrene.  (2) Vaporized a -benzylnaphthalene diluted with carbon dioxide is passed over a magnesia catalyst which has been coated with lustrous carbon by treatment with ethylene at 700 DEG  C. and which is contained in a manganese-copper tube at 725 DEG  C., the number of grams of a -benzylnaphthalene passed per hour being twice the volume of the tube in cc.; the vapours are condensed and subjected to fractional distillation to obtain a yield of benzanthrene and dihydrobenzanthrene of 71 per cent.  (3) A mixture of vaporized a -benzylnaphthalene and water vapour is passed over a catalyst comprising zinc oxide, alumina and lime contained in a porcelain tube at 650 DEG  C., the number of grams of a -benzylnaphthalene passed per hour being one-eighth of the volume of the tube in cc.; the vapours are condensed and after separating the water, the condensate is further treated as in (1).ALSO:Benzanthrene and dihydrobenzanthrene are produced by passing a -benzylnaphthalene through a reaction space of volume V cc. at a temperature t DEG  C. between about 650 DEG  C. and 800 DEG  C., the flow of the a -benzylnaphthalene in grams per hour being maintained at from 1 to 4 times a minimum value Dmin such that <FORM:0409770/IV/1> Known dehydrogenation catalysts may be present, such as oxides or other compounds of the alkaline earth metals or of magnesium, zinc or aluminium and non-volatile oxides or other compounds, which are not reducible to metals under the reaction conditions, of elements exhibiting more than one valency, e.g. molybdenum trioxide, tungsten trioxide, chromium trioxide or vanadium pentoxide. Non-reactive diluent gases such as nitrogen, carbon dioxide, water vapour or methane may be present and the reaction may be effected under ordinary or reduced pressure.  The reaction vessel may be made of or lined with porcelain, quartz, or metals or alloys which cause no deposition of carbon, e.g. copper, brass, manganese-copper, or chromium-nickel steels.  Such metals or alloys are preferably first provided with a thin layer of sulphide by treatment with hydrocarbons containing sulphur or are provided with a protective coating of enamel.  Alternatively, the reaction vessel may be provided with fillers of quartz, coke or graphite or with rings of the above metals or alloys which cause no deposition of carbon.  The following examples are specified: (1) Vaporized a -benzylnaphthalene diluted with nitrogen is passed through a manganese-copper tube at 720 DEG C., the number of grams of a -benzylnaphthalene passed per hour being equal to the volume of the tube in cc.; the vapours are condensed and the condensate subjected to fractional distillation to obtain a 69 per cent yield of benzanthrene.  (2) Vaporized a -benzylnaphthalene diluted with carbon dioxide is passed over a magnesia catalyst which has been coated with lustrous carbon by treatment with ethylene at 700 DEG  C. and which is contained in a manganese-copper tube at 725 DEG  C., the number of grams of a -benzylnaphthalene passed per hour being twice the volume of the tube in cc.; the vapours are condensed and subjected to fractional distillation to obtain a yield of benzanthrene and dihydrobenzanthrene of 71 per cent.  (3) A mixture of vaporized a -benzylnaphthalene and water vapour is passed over a catalyst comprising zinc oxide, alumina and lime contained in a porcelain tube at 650 DEG  C., the number of grams of a -benzylnaphthalene passed per hour being one-eighth of the volume of the tube in cc.; the vapours are condensed and after separating the water, the condensate is further treated as in (1).