Production of phthalic anhydride by catalytic oxidation and a catalyst therefor

    公开(公告)号:GB941293A

    公开(公告)日:1963-11-06

    申请号:GB1569062

    申请日:1962-04-25

    Applicant: BASF AG

    Abstract: A catalyst including V2O5, Na2S2O7\t and K2S2O7 on a carrier having special physical properties e.g. SiO2 is used as a fluidised bed in the oxidation of naphthalene or o-xylene to phthalic anhydride. Examples describe the formation also of maleic anhydride and naphthaquinone as by-products. The reaction is carried out at 250-420 DEG C.ALSO:In a process for the production of phthalic anhydride from o-xylene or from naphthalene by oxidation with gases containing oxygen in molecular form, at a temperature of 250 DEG C.-420 DEG C. by the use of V2O5-alkali pyrosulphate catalysts on carrier material in a fluidized bed there is used a catalyst which comprises V2 O5, Na2 S2 O7 and K2 S2 O7, the melting point of the mixture being lower than that of K2 S2 O7, and a highly porous carrier material, especially silica gel, aluminium phosphate, synthetic or natural silicates and active carbon, having an inner surface of 200-400 sq. metres/gm. and a grain size of 10-3000 microns, the active substance being contained in the pores of the carrier in fused form under the reaction conditions. Optional catalyst constituents include H2 MoO4, P2 O5 and H2 Wo4. Examples are given.

    Production of pure phthalic anhydride from o-xylene

    公开(公告)号:GB1094750A

    公开(公告)日:1967-12-13

    申请号:GB1381565

    申请日:1965-04-01

    Applicant: BASF AG

    Abstract: In a process for the production of high-purity non-yellowing phthalic anhydride by oxidation of o-xylene with oxygen or gases containing oxygen in molecular form in the gas phase at 250 DEG to 600 DEG C. and with residence times of 0.5 to 50 seconds, with or without the co-employment of bromine or a volatile bromine compound, in contact with a catalyst containing vanadium oxide, followed by purification by crystallization and distillation the crude phthalic anhydride is first recrystallized from o-xylene and then fractionally distilled and the mother liquor obtained in the recrystallization is used for the oxidation. Preferably, the recrystallized phthalic anhydride is washed with 500 to 1200 grms. of pure xylene per kilogramme phthalic anhydride and the washing solution obtained may be used for next recrystallization. The fractional distillation is preferably carried out at 10 to 400 mm. Hg at temperatures of from 134 DEG to 257 DEG C. using columns having 5 to 30 theoretical trays.

    Production of phthalic anhydride by catalytic oxidation of o-xylene

    公开(公告)号:GB961470A

    公开(公告)日:1964-06-24

    申请号:GB1569262

    申请日:1962-04-25

    Applicant: BASF AG

    Abstract: A process for the vapour phase oxidation of o-xylene to phthalic anhydride using oxygen or an inert gas containing molecular oxygen comprises contacting the o-xylene and the oxidising gas with bromine or a bromine-containing compound which is gaseous or vaporous under the reaction conditions, in a weight percentage of bromine supplied (based on xylene) of 0.001 to 2%, with a residue time of 5 to 50 seconds and at a temperature of 250 to 380 DEG C., in a fluidised bed of a catalyst comprising a porous carrier containing in the pores thereof a liquid comprising vanadium pentoxide and either potassium pyrosulphate or a mixture of potassium pyrosulphate and sodium pyrosulphate, with or without other additives, the liquid advantageously containing 5 to 30% by wt. of vanadium pentoxide and not less than 60% by wt. of pyrosulphate. Bromine-containing compounds specified are hydrogen bromide, ammonium bromide, nitrosyl bromide, thionyl bromide, alkyl bromides having 1 to 10 carbon atoms, cycloalkyl bromide having 1 to 12 carbon atoms, aryl bromides having 6 to 10 carbon atoms, aralkyl bromides having 7 to 10 carbon atoms, and carboxylic acid bromides of aliphatic acids having 2 to 10 carbon atoms, of aryl monocarboxylic or dicarboxylic acids having 7 to 10 carbon atoms, or of aralkyl carboxylic acids having 8 to 10 carbon atoms. The porous carrier of the catalyst may be silicic acid, preferably in the form of silica gel, active carbon, aluminium phosphate, or synthetic or natural zeolites. In preparation of the catalyst (see Division B1), in place of vanadium pentoxide, vanadium compounds which under oxidising conditions are converted at the reaction temperature to vanadium pentoxide may be used, e.g. ammonium vanadate, vanadium trichloride, vanadium trioxide, vanadium tetroxide, or vanadyl sulphate. Metal activators which accelerate oxidation of hydrogen bromide to bromine may be added, e.g. ceric oxide, manganese dioxide, ferric oxide, cupric oxide, cobaltous oxide and nickelous oxide, preferably in up to 5% by wt. of the liquid. There may also be added (a) phosphoric acid as such or as phosphorus pentoxide or as compounds which yield phosphorus pentoxide, e.g. phosphorus pentasulphide, ammonium phosphate, or sodium and potassium phosphates and hydrogen phosphates, in a maximum of 4% by wt. in the liquid, (b) molybdic acid, molybdenum oxide, molybdenum sulphide, ammonium molybdate, sodium molybdate, potassium molybdate or phosphomolybdic acid, up to 6% by wt. in the liquid, (c) tungstic acid, tungsten oxides, tungsten sulphides, ammonium tungstate or phosphotungstic acid, or mixtures thereof with the above mentioned molybdenum compounds, in up to 6% by wt. of the liquid, and (d) silver oxide in up to 3% by wt. of the liquid; where alkali metal phosphates are used an equivalent amount of sulphuric acid is added and regarded as pyrosulphate, and this is preferably done in the case of alkali metal molybdates. The catalyst preferably contains 10-60% by wt. of the liquid component. The oxidation is preferably effected in the presence of small amounts of sulphur trioxide at the catalyst, and accordingly sulphur trioxide, sulphur dioxide, or other sulphur compounds oxidisable to sulphur trioxide, e.g. thiophene, carbon disulphide and thionaphthene, may be added. Specifications 906,311, 908,823 and 941,293 are referred to.ALSO:A catalyst used in the vapour phase oxidation of #s-xylene to phthalic anhydride (see Division C2) in the presence of bromine or a bromine compound consists of a highly porous carrier in the pores of which is a liquid comprising vanadium pentoxide and either potassium pyrosulphate or a mixture of potassium pyrosulphate and sodium pyrosulphate, with, if desired, other additives, the liquid advantageously containing 5-30% by weight of vanadium pentoxide and not less than 60% by weight of pyrosulphate. The porous carrier may be silicic acid, preferably in the form of silica gel, active carbon, aluminium phosphate or synthetic or natural zeolites. The liquid may be prepared by heating potassium pyrosulphate or potassium hydrogen sulphate or a mixture of potassium and sodium pyrosulphates or hydrogen sulphates, fusing till all water has evaporated, and adding at 300-450 DEG C. vanadium pentoxide or a compound oxidizable thereto under the reaction conditions, e.g. ammonium vanadate, vanadium trichloride, vanadium trioxide, vanadium tetroxide or vanadyl sulphate. Metal activators which accelerate the oxidation of hydrogen bromide to bromine may be added, e.g. ceric oxide, manganese dioxide, ferric oxide, cupric oxide, cobaltous oxide p and nickelous oxide, preferably in up to 5% by weight of the liquid. There may also be added (a) phosphoric acid as such or as phosphorus pentoxide or compounds which yield phosphorus pentoxide, e.g. phosphorus pentasulphide, ammonium phosphate, and sodium and potassium phosphates and hydrogen phosphates in up to 4% by weight of the liquid, (b) molybdic acid, molybdenum oxide, molybdenum sulphide, amonium molybdate, sodium molybdate, potassium molybdate or phosphomolybdic acid, in up to 6% by weight of the liquid, (c) tungstic acid, tungsten oxides, tungsten sulphides, ammonium tungstate, phosphotungstic acid, or mixtures thereof with the abovementioned molybdenum compounds, in up to 6% by weight of the liquid, and (d) silver oxide in up to 3% by weight of the liquid; where alkali metal phosphates are used an equivalent amount of sulphuric acid is added and regarded as pyrosulphate, and this is preferably done in the case of alkali metal molybdates. The liquid melt may be applied to the carrier by (a) mixing the carrier and the solidified melt and heating the mixture for several hours above the melting temperature of the liquid, (b) allowing the powdered solidified melt to trickle into a carrier bed fluidized by air or an inert gas, e.g. nitrogen or carbon dioxide, and maintaining the bed for some hours above the solid melting-point, or (c) soaking silica gel in aqueous solutions of the components of the liquid, followed by drying and heating to 200-600 DEG C.; in this case alkali sulphates may be used instead of alkali pyrosulphates, in which case it is necessary to supply during the heating a gas containing sulphur trioxide, sulphur dioxide, or sulphur compounds which give sulphur dioxide at the catalyst, together with an oxygen-containing gas. The catalyst preferably contains 10-60% by weight of the liquid component. Specifications 906,311, 908,823 and 941,293 are referred to.

    Production of phthalic anhydride by catalytic oxidation

    公开(公告)号:GB959511A

    公开(公告)日:1964-06-03

    申请号:GB1569362

    申请日:1962-04-25

    Applicant: BASF AG

    Abstract: Phthalic anhydride is made by treating o-xylene together with chlorine, or a chlorine compound which is vaporous under the reaction conditions, the weight ratio of chlorine, or chlorine compound, to o-xylene being from 2:100 to 1:100,000, with oxygen, or an inert gas containing free oxygen, for 5 to 50 seconds in the presence of a fluidized catalyst, at 250 to 380 DEG C., which comprises a porous carrier whose pores contain a mixture which is liquid during the reaction and which comprises vanadium pentoxide and potassium pyrosulphate or vanadium pentoxide, potassium pyrosulphate and sodium pyrosulphate with, or without, other additives; the weight ratio of vanadium pentoxide and optional additives to vanadium pentoxide being below 2:3, and the weight ratio of vanadium pentoxide to alkali metal pyrosulphate being 1:20 to 3:10. Specified carriers are aluminium phosphate, silicates, silicic acid, especially silica gel, which is preferred, and active carbon. The preferred silica gel has a grain size of 20 to 300 microns, an internal surface of 300 to 360 sq. metres per gram and a mean pore radius of 50 to 80 rA. With active carbon of grain size 20 to 600 microns the temperature should not exceed 300 DEG to 340 DEG C. Preferably, in the preparation of the catalyst, a mixture of sodium and potassium pyrosulphates, containing 10 to 50% by weight of the sodium compound is used. Vanadium compounds may be used which are convertible to the pentoxide under the reaction conditions e.g. the trichloride, tri- and tetra-oxide and sulphate. Preferably the melt contains 10 to 20% by weight of vanadium pentoxide. Activators which aid in the oxidation of hydrogen chloride to chlorine are advantageously used in quantities of up to 5% by weight of the melt. Indicated activators are compounds, especially oxides, of iron, nickel and cobalt and particularly of cerium, copper and manganese. Phosphoric acid, molybdenium trioxide and/or tungsten trioxide may also be present or formed in situ. Silver oxide may be present. Advantageously sulphur trioxide is present. The sulphur trioxide may be generated in situ e.g. from thiophene or carbon disulphide. Preferably 25 to 50% by weight of melt is used in the catalyst. The preferred temperature is 270 to 350 DEG C. A residence time of 8 to 30 seconds is preferred. Indicated chlorine compounds are hydrogen chloride, ammonium chloride, nitrosyl chloride, thionyl chloride, alkyl chlorides, aryl chlorides, aralkyl chlorides and carboxylic acid chlorides of fatty acids or of aryl mono- or dicarboxylic acids or aralkyl-carboxylic acids, preferred being o-xylyl chloride, o-xylylene dichloride or o-xylylidene dichloride. Pressures of up to 25 atmospheres may be used. Chlorine may be introduced in an inert gas e.g. nitrogen. Examples are provided. Specifications 906,311, 908,823 and 941,293 are referred to.

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