Patent GB-355192-A (GB)
IPC: C07B35/04
Filed: 1930-02-13
Abstract: In the catalytic vapour-phase oxidation of organic compounds, excessive oxidation is avoided by adding a difficultly oxidizable vapour to the reaction mixture.  Vaporized carbon tetrachloride and other chlorinated organic compounds, anthraquinone, and difficultly oxidizable hydrocarbons are suitable additions.  The preparation of suitable catalysts is described in the examples. In example 1, a catalyst is prepared by coating aluminium granules with ammonium metavanadate and calcining in air at 450 DEG  C.  The vanadium pentoxide in the contact mass may be replaced wholly or in part by other metal oxides of the fifth or sixth periodic group, or by suitable salts of aluminium, titanium, iron, cobalt, or zirconium. In example 2, a catalyst is prepared by coating pumice with a caustic-potash suspension of ferric and titanium hydrates, and calcining at 400-500 DEG  C.  The ferric oxide in the catalyst may be replaced by an oxide of cobalt, copper, or nickel, the titanium oxide by another dehydrogenating or dehydrating catalyst, and the caustic potash by other alkali or alkaline-earth hydroxides, or potassium nitrate or nitrate.  In example 3, the catalyst used is a silver vanadyl vanadate, prepared by melting vanadium pentoxide with silver nitrate, or a similarly prepared alkali vanadyl vanadate, in which part of the alkali is replaced by base-exchange by aluminium, copper, or iron.  The catalyst may be used alone or diluted or supported on carriers, a number of which are specified; in the last event cementing agents, e.g. potassium sulphate or nitrate, may be included.  Stabilizer promoters (cf. Specification 291,419, [Class 1 (i), Chemical processes &c.],) e.g. oxides of aluminium, titanium, and thorium may also be present.  The application of the process to the purification of coal-tar ammonia is referred to.ALSO:In the catalytic vapour-phase oxidation of organic compounds, excessive oxidation is avoided by adding a difficultly oxidizable vapour to the reaction mixture.  Vaporized carbon tetrachloride and other chlorinated organic compounds, anthraquinone, and difficultly oxidizable hydrocarbons are suitable additions.  The method may be applied to reactions in which oxygenated organic compounds are obtained from other organic compounds by oxidation, or to reactions in which organic impurities are removed from a compound by total combustion, or to reactions in which both these effects are obtained. The catalysts used may be those described in Specifications 281,307, 291,419, 295,270, 296,071, and 315,854, [all in Class 2 (iii), Dyes &c.], and the processes may be circulatory.  In example 1, a catalyst prepared by coating aluminium granules with ammonium metavanadate and calcining in air at 450 DEG  C., is used for the manufacture of maleic or mesotartaric acid by the vapour-phase oxidation of benzene, phenol, tar phenols, furfurol or phthalic anhydride in the presence of a difficultly oxidizable vapour.  The vanadium pentoxide in the contact mass may be replaced wholly or in part by other metal oxides of the fifth or sixth periodic group, or by suitable salts of aluminium, titanium, iron, cobalt or zirconium. In example 2, a catalyst is prepared by coating pumice with a caustic-potash suspension of ferric and titanium hydrates and calcining at 400-500 DEG  C.  This catalyst is used in purifying phenanthrene containing carbazole and dead oils, by total combustion of the impurities in the vapour phase in the presence of anthracene as a protective agent. The resulting mixture of anthracene and phenanthrene may be separated by means of a solvent for phenanthrene, such as benzene, toluene, solvent naphtha, furfural, acetone, cyclohexane, and o-dichlorbenzene.  Ammonia may be used as the protective agent, instead of anthracene.  The ferric oxide in the catalyst may be replaced by an oxide of cobalt, copper, or nickel, the titanium oxide by another dehydrogenating or dehydrating catalyst, and the caustic potash by other alkali or alkaline-earth hydroxides, or potassium nitrite or nitrate.  In example 3, the catalyst used is a silver vanadyl vanadate, prepared by melting vanadium pentoxide with silver nitrate, or a similarly prepared alkali vanadyl vanadate, in which part of the alkali is replaced by base-exchange by aluminium, copper or iron.  The catalyst may be used alone or diluted or supported on carriers, a number of which are specified; in the last event cementing agents, e.g. potassium sulphate or nitrate, may be included.  "Stabilizer promoters," e.g. oxides of aluminium, titanium, and thorium, may also be present.  Toluene, air and anthraquinone or a chlorinated aromatic or aliphatic hydrocarbon, e.g. dichlorethane, are passed over the catalyst, benzaldehyde and benzoic acid being obtained.  In like manner there may be obtained salicyl aldehyde and salicylic acid from cresol; halogen- and nitrobenzaldehydes and -benzoic acids from the corresponding toluenes; aldehydes and acids from xylene, pseudocumene, mesitylene, and p-cymene; a -naphthoquinone from naphthalene; naphthalic anhydride from acenaphthene; and fluorenone from fluorene.  Mention is made also of the manufacture of fumaric acid from the initial materials of example 1; phthalic anhydride and maleic acid from naphthalene; anthraquinone from anthracene; phenanthraquinone, diphenic acid, phthalic anhydride and maleic acid from phenanthrene; acenaphthylene, acenaphthoquinone, bisacenaphthylidenedione, naphthaldehydic acid and hemimellitic acid from acenaphthene; vanillin and vanillic acid from eugenol and isoeugenol; formaldehyde from methanol or methane; acetic acid from ethanol; and chloracetic acid from ethylene chlorhydrin.  The purification of anthracene, naphthalene, benzene and coal-tar ammonia by total combustion of the impurities is mentioned also.