United States Patent (19) 11 4,298,533 Moriya et al. 45 Nov. 3, 1981

54). PRODUCTION OF MALEICANHYDRIDE 56) References Cited U.S. PATENT DOCUMENTS (75 Inventors: Koji Moriya; Itsuo Furuoya, both of 3,856,824 12/1974 Raffelson et al...... 260/346.75 Osaka, Japan 3,899,516 8/1975 Dickason...... 260/346.75 73) Assignee: Takeda Chemical Industries, Ltd., 4,220,595 9/1980 Dickason et al...... 260/346.75 Osaka, Japan FOREIGN PATENT DOCUMENTS 2255394 8/1973 Fed. Rep. of 21 Appl. No.: 915,301 Germany ...... 260/346.75 1368168 9/1974 United Kingdom . 22 Filed: Jun. 13, 1978 Primary Examiner-Henry R. Jiles Assistant Examiner-Bernard Dentz Related U.S. Application Data Attorney, Agent, or Firm-Wenderoth, Lind & Pomack 62) Division of Ser. No. 560,802, Mar. 21, 1975, Pat. No. 57 ABSTRACT 4,108,874. Maleic anhydride is obtained in a high yield as well as in a high purity by oxidation of a hydrocarbon of not less 30 Foreign Application Priority Data than four carbon atoms in gaseous phase in the presence Apr. 9, 1974 JP Japan ...... 49-40566 of a catalyst comprising (a) vanadium oxide, (b) phos May 22, 1974 JP Japan ...... 49-58117 phorus oxide, (c) thallium oxide and/or alkaline earth metal oxide, and if necessary, further containing (d) iron 51) Int. Cl...... CO7D 307/60 oxide. 52 U.S. Cl...... 260/346.75 58) Field of Search ...... 260/346.75 5 Claims, No Drawings 4,298,533 1. 2 known perse for the manufacture of solid catalysts, one PRODUCTION OF MALEIC ANHYDRIDE of which, for example, may be as follows. Thus, a vanadium-containing compound, a phos This is a division of application Ser. No. 560,802, filed phorus-containing compound, a thallium-containing Mar. 21, 1975, now U.S. Pat. No. 4,108,874. 5 compound and/or an alkaline earth metal-containing The present invention relates to a method for the compound, and, if required, an iron-containing com production of maleic anhydride. More specifically, the pound, each of which can be converted to the corre invention relates to a method for the production of sponding oxide by heating or through a chemical reac maleic anhydride by oxidation of a hydrocarbon of not tion, are dissolved, as required, in a suitable solvent such less than four carbon atoms in gaseous phase in the 10 as water or alcohol, and a carrier is impregnated with presence of a catalyst comprising (a) vanadium oxide, the resulting solution or solutions. The impregnated (b) phosphorus oxide, (c) thallium oxide and/or alkaline carrier (catalyst intermediate) is then calcined at 300 to earth metal oxide, and if necessary, further containing 800° C., preferably at 400 to 600 C., for 1 to 20 hours, (d) iron oxide. preferably 2 to 10 hours. Heretofore, in the production of maleic anhydride by 15 As the aforementioned vanadium-containing com catalytic oxidation of hydrocarbons of not less than four pound, there may be mentioned vanadium oxides carbon atoms such as butane, butene-1, butene-2, butadi (V2O5, V2O4, V2O3, etc.), vanadates (NH4VO3, vana ene, cyclopentadiene, benzene and hydrocarbon materi dyl oxalate, vanadyl sulfate, vanadyl chloride, etc.) and als containing them (e.g. BB fraction, spent BB fraction, so on. As said phosphorus-containing compound, there etc.), it was known to employ a catalyst composed of may be mentioned phosphorus oxides (P2O5, P2O3, vanadium oxide and phosphorus oxide or a catalyst etc.), phosphoric acids (HPO3, H3PO4, H4P2O7, comprising, in addition to vanadium and phosphorus H3PO3, etc.), phosphates ((NH4)3PO4, (NH4)2HPO4, components, a third component such as lithium oxide, (NH4)H2PO4, etc.), phosphorus halides (PCl3, PCls, iron oxide, copper oxide or chromium oxide. However, PBr3, etc.) and so on. As the thallium-containing com with these catalysts, the yields and purities of the prod 25 pound, there may be mentioned thallium oxides (Tl2O, uct have not been fully satisfactory, especially when a Tl2O3), thallium nitrates, thallium halides (TiCl, hydrocarbon material including butane, for example, TlCl3.4H2O, TIF3, TlBr, TIBr3.4H2O, TII, TI3, etc.), thallium sulfates (Tl2SO4, Tl2(SO4)3.7H2O), thallium spent BB fraction, spent-spent BB fraction, etc. is used. carbonate, organic acid thallium salts (e.g., Tl(HCOO), To obviate these disadvantages we conducted inten 30 Tl(CH3COO), CH2(COOTf)2) and so on. The afore sive research, and have found that the above disadvan mentioned alkaline earth metal-containing compound is tages are removed by employing thallium oxide and/or exemplified by alkaline earth metal salts (nitrates, e.g. alkaline earth metal oxide as a third component in addi beryllium nitrate, magnesium nitrate, calcium nitrate, tion to vanadium oxide and phosphorus oxide, that is by strontium nitrate, barium nitrate, radium nitrate; ha employing a catalyst which comprises vanadium oxide, 35 lides, e.g. magnesium chloride, calcium chloride, bar phosphorus oxide, thallium oxide and/or alkaline earth ium chloride carbonates, e.g. magnesium carbonate, metal oxide, and if necessary further containing iron strontium carbonate, barium carbonate; sulfates, e.g. oxide. The present invention is accomplished on the calcium sulfate, barium sulfate; organic acid salts, e.g. basis of these new findings, magnesium acetate, calcium acetate; and so on), alkaline It is an object of the present invention to provide an 40 earth metal hydroxides (e.g. magnesium hydroxide, industrially feasible method for the production of ma calcium hydroxide, strontium hydroxide, barium hy leic anhydride in a high yield as well as in a high purity droxide), alkaline earth metal oxides (e.g. beryllium by oxidation of a hydrocarbon of not less than four oxide, magnesium oxide, calcium oxide, strontium ox carbon atoms in gaseous phase. ide, barium oxide, radium oxide) and so on. Another object of the present invention is to provide 45 As the aforementioned iron-containing compound, a novel, highly active and long-life catalyst useful for there may be mentioned iron oxides (Fe2O3, Fe3O4), the production of maleic anhydride in a high yield as iron hydroxides (Fe(OH)3, Fe(OH)2), iron nitrates (Fe(- well as in a high purity by oxidation of a hydrocarbon of NO3)2.9H2O, Fe(NO3)2.6H2O), iron chlorides (e.g. not less than four carbon atoms in gaseous phase. FeCl3.6H2O, FeCl2.nH2O), iron alums, iron sulfates Other objects will be apparent hereinafter. 50 (e.g. Fe2(SO4)3.nH2O), organic acid iron salts (e.g. The catalyst used according to the present invention FeC4H2O4, FeC2O4.2H2O), iron phosphates (FePO4.n- comprises, as active ingredients, any of a compound H2O, Fe3(PO4)2.8H2O) and so on. Thus, in each in oxide or a mixture of vanadium oxide, alkaline earth stance, oxides or compounds which can be easily con metal oxide and phosphorus oxide; a compound oxide verted to oxides are employed. or mixture of vanadium oxide, thallium oxide and phos 55 In the manufacture of the catalyst to be employed in phorus oxide; a compound oxide or mixture of vana the practice of the present invention, the proportions of dium oxide, alkaline earth metal oxide, phosphorus said vanadium-containing compound, phosphorus-con oxide and thallium oxide; a compound oxide or mixture taining compound, thallium-containing compound and of vanadium oxide, alkaline earth metal oxide, phospho alkaline earth metal-containing compound may be var rus oxide and iron oxide; a compound oxide or mixture 60 ied, although the atomic ratio of vanadium to phospho of vanadium oxide, phosphorus oxide, thallium oxide rus is preferably 2:1 to 1:10 and, for still better results, and iron oxide; or a compound oxide or mixture of 1:1 to 1:5, and the atomic ratio of vanadium to thallium vanadium oxide, alkaline earth metal oxide, phosphorus is preferably 1:5 to 100:1 and, for still better results, 1:2 oxide, thallium oxide and iron oxide; and usually, each to 20:1. The atomic ratio of vanadium to alkaline earth of these compound oxides or mixtures is used as sup 65 metal is 1:10 to 40:1 and, for still better results, 1:5 to ported on a carrier. 15:1. When the catalyst contains iron as well, the atomic The catalyst to be employed in the practice of the ratio of vanadium to iron is preferably 1:5 to 100:1 and, present invention can be prepared by procedures for still better results, 1:2 to 20:1. 4,298,533 3 4. As for the carrier material, heat-resistant inorganic (4) a high yield even when a hydrocarbon material compounds such as, alumina, silicon carbide, titanium including butane is used as a starting material; and also oxide, silica, magnesia, diatomaceous earth, pumice, enables an increase in the space-time yield (STY) more Zirconia, cerium oxide, titanium phosphate, aluminum easily than has been possible with the prior art method, phosphate, silicon phosphate, gypsum and their mix in addition to the increased amenability to purification tures may be desirably employed. While the amount of which provides for a more economical production of catalytically active components to be supported de maleic anhydride in high purity. pends upon the particular type of carrier material and The following examples, are intended to further de the method of preparing the catalyst, among other con scribe the present invention. It should, however, be ditions, it is usually not less than 3 percent by weight 10 understood that the available methods for manufactur and, preferably, not less than 10 percent by weight. . ing the catalyst are not limited to those set forth in the The method for manufacturing the catalyst to be examples but any suitable method may be adopted employed for the purposes of the present invention will within the framework of the invention thus far de be further described in detail. Thus, for example, to scribed. finely divided ammonium metavanadate is added water 15 In the examples, "part(s)' means "weight part(s)', and, then, oxalic acid is further added to the mixture to unless otherwise specified. prepare a homogeneous solution. Then, an aqueous EXAMPLE 1 solution of phosphoric acid and an aqueous solution of In 500 parts of water was suspended 14.6 parts of thallium nitrate and/or an alkaline earth metal hydrox 20 ammonium metavanadate, followed by the addition of ide are added. 23.6 parts of oxalic acid to prepare a homogeneous ... If necessary, an aqueous solution of ferric nitrate is solution. To this solution were added 36.0 parts of an further added. The above procedure is followed by the aqueous solution(85%) of orthophosphoric acid and addition of a carrier material as suitably molded or in 13.2 parts of strontium nitrate. After dissolution, the powdery form. The moisture is expelled on a hot water 25 solution was used to impregnate 300 parts of a molded bath and, after evaporation to dryness, the mixture is a-alumina carrier. Under stirring on a hot-water bath, calcined at a temperature of about 500 C. the catalyst solution was evaporated to dryness on the As the hydrocarbon containing four or more carbon carrier material. atoms which is employed in the production of maleic The resulting composition was dried at 100 C. over anhydride, there may be mentioned such materials as 30 night and then calcined in the air at 500 C. for 4 hours butane, butene-1, butene-2, butadiene, BB fraction, to prepare a catalyst. spent BB fraction, spent-spent BB fraction, cyclopenta The above catalyst was packed into a conventional diene, benzene and so on. Among the above, the hydro continuous fixed-bed reactor and a mixed gas ofbutene carbon consisting essentially of four carbon atoms such 1 and air(butene-1:1 mole %) was introduced at atmo as butane, butene-1, butene-2, butadiene, BB fraction, 35 spheric pressure, a constant reactor bath temperature of spent BB fraction, and spent-spent BB fraction is partic 390° C. and a space velocity (SV) of 5000(hr-1). ularly preferable. As the oxidizing agent to be used for The conversion of butene-1 was 99 mole % and the oxidizing such a starting material hydrocarbon, any yield of maleic anhydride was 56 mole %, while the oxygen-containing gas may be employed, and prefera yield of monocarboxylic acid was 1.7 mole %. bly air is usually employed as such an oxygen-contain 40 ing gas, although oxygen itself or a mixture of air and EXAMPLE.2 oxygen, for instance, may also be employed, In the manufacture of a catalyst according to Exam The reaction temperature varies with the composi ple 1, 19.7 parts of barium hydroxide was used in place tion of the catalyst, the type of carrier material and of 13.2 parts of strontium nitrate. other conditions, but usually the range of 250' to 650' 45 Using the resulting catalyst, the reaction was carried C., or particularly the range of 300' to 550° C., is pre out under the same conditions as set forth in Example 1. ferred. The mixing ratio of said starting material hydro The conversion of butene-1 was 100 mole %; yield of carbon to air or oxygen is of course preferably outside maleic anhydride was 58 mole %; and yield of monocar the explosion limits. More particularly, when air is used boxylic acid was 1.3 mole %. as a source of oxygen, 0.5 to 1.5 mole percent of hydro 50 carbon is preferably employed per mole of air. The EXAMPLE 3 material gas is contacted with the catalyst usually at a In the manufacture of a catalyst according to Exam space velocity (converted to normal temperature and ple 1, 9.2 parts of calcium chloride (dihydrate) was used pressure) of 500 to 30,000 (hr-1) and, preferably, at a in place of 13.2 parts of strontium nitrate. Using the space velocity of 1,000 to 10,000(hr-1). Under certain 55 catalyst thus obtained, the reaction was carried out circumstances, the unreacted hydrocarbon may be re under the same conditions as set forth in Example 1. In cycled. this instance, the conversion of butene-1 was 100 mole The product maleic anhydride is first trapped with a %; yield of maleic anhydride was 53 mole %; and yield solvent such as, for example, water, and then can be of monocarboxylic acid was 2.7 mole %. purified by dehydration, distillation or other procedure. 60 In this manner, a high purity grade of maleic anhydride EXAMPLES 4 AND 5 can be obtained. In the manufacture of a catalyst according to Exam The present invention provides the advantages of: ple 1, one of the alkaline earth metal salts mentioned in (1) a high reaction yield; the following table was used in place of 13.2 parts of (2) a minimum amount of byproduct monocarboxylic 65 strontium nitrate. Using such catalysts, reactions were acid; carried out in the same manner as Example 1. The re (3) a high yield even when the concentration of hy sults are set out in the extreme right column of the drocarbon in air is high; and following table. 4,298,533 5 6 TABLE added 66.7 parts of barium hydroxide and while the The alkaline earth Ineta Yield of maleic entire mixture was stirred, 500 parts of titanium oxide Example salt used and its amount anhydride powder was immersed therein. The moisture was ex 4. 16.0 parts of Inagnesium 5 mole % pelled on a hot-water bath until a paste was obtained. nitrate 5 The paste was extruded and granuated to spheres about 5 10.0 parts of 50 wt.% 56 mole % 4 mm in diameter. After drying, the spherical granules aqueous solution of were calcined at 500° C. for 4 hours to prepare a cata beryllium nitrate lyst. Using this catalyst, the reaction was carried out under the same conditions as Example 1 except that the 10 EXAMPLES 6 TO 8 reactor bath temperature was 380° C. The conversion of butene-1 was 100 mole %; yield of maleic anhydride In Examples 6 to 8, an evaluation was made of the was 58 mole %; and yield of monocarboxylic acid was catalyst characteristics obtainable when the amount of BaO relative to the vanadium oxide-phosphorus oxide 1.6 mole %. system was varied. 15 EXAMPLE. 13 The procedure of Example 1 was repeated except that barium hydroxide, instead of strontium nitrate, was In 245 parts of a 20% aqueous solution of phosphoric used in the amounts indicated in the following table to acid was dissolved 14.6 parts of ammonium metavana prepare catalysts. Using each of these catalysts, the date, followed by the addition of 240 parts of a 10% reaction was carried out under the same conditions as 20 aqueous solution of oxalic acid. set forth in Example 1. The results are shown in the The above procedure was further followed by the extreme right column of the same table. The result addition of 33.2 parts of strontium hydroxide. Then, 400 obtained using a barium oxide-free catalyst is also parts of a-alumina powder, about lu, in diameter, was shown as a control. immersed in the resulting mixture. 25 The composition was then treated on a hot-water TABLE 2 bath to prepare a paste. Result of reaction Yield of Yield of Following the addition of 40 parts of starch, the paste Amount of BaO maleic monocarboxylic was extruded and then granulated to spheres about 4 V:P:Ba anhydride acid mm in diameter. After drying, the granules were cal Example (atomic ratio) (mole %) (mole %) 30 cined at 550 C. for 3 hours to prepare a catalyst. Using 6 1:25:0.1 59 1.3 this catalyst, the reaction was carried out under the 7 1:25:0.2 58 1.2 8 :2.5:1.0 53 1.5 same conditions as Example 1. The conversion of bu (1) 12.5:0.5 56 1.7 tene-1 was 97 mole %; yield of maleic anhydride was 55 Control 1:2.5:0 48 4.5 mole %; and yield of monocarboxylic acid was 3.4 mole 35 %. EXAMPLES 9 TO 11 EXAMPLES 14 THROUGH2O In 236.0 parts of a 10% aqueous solution of oxalic Using the catalyst prepared in Example 2, the hydro acid was dissolved 14.6 parts of ammonium metavana carbon materials indicated in the following table were date, followed by the addition of 36.0 parts of aqueous 40 reacted in the same manner as Example 1. The results orthophosphoric acid (85%) and 16.3 parts of barium are set forth in the extreme right column of the same nitrate. table. In the mixture was immersed 400 parts of a molded TABLE 4 a-alumina carrier, about 5 mm by 5 mm, and under occasional stirring on a hot-water bath, the catalyst 45 Yield of maleic solution was evaporated to dryness on the carrier. After Example Hydrocarbon material anhydride (mole %) 14 cis-Butene-2 57 drying at 100 C., the catalyst intermediate was calcined 15 trans-Butene-2 58 at 450° C. for 5 hours to prepare a catalyst. Using this 6 Butadiene 66 catalyst, the reaction was carried out under the same 17 Cyclopentadiene 55 conditions as Example 1 except that the mixing ratio of 8 Benzene 55 butene-1 with air was varied as shown in the following 9 Spent BB fraction* 26 table. 20 Spent-spent BB fraction* 50 The results are set forth in the extreme right column *Butene 39%, isobutene 52%, butanes, etc.9% of the same table. *Butene 81%, butanes, etc. 19% 55 TABLE 3 Concentration of butene-1, Yield of maleic EXAMPLES 21 AND 22 Example mole % relative to air anhydride (mole %) Using the catalyst according to Example 12, mixed 9 O.5 58 gases of butane and air (butane: 1 mole % and 1.5 mole 10 10 57 60 %, respectively) were reacted at atmospheric pressure, 11 1.5 58 a constant reactor bath temperature of 480 C. and a space velocity (SV) of 2000 (hr). The results are set EXAMPLE 12 forth in the following table. In 360 parts of a 20% aqueous solution of phosphoric 65 TABLE 5 acid was dissolved 24.3 parts of ammonium metavana Concentration of butane Yield of maleic date, followed by the addition of 400 parts of a 10% Example (mole % relative to air) anhydride (mole %) aqueous solution of oxalic acid. To the mixture was 2 38 4,298,533 7 8 TABLE 5-continued 3.3 parts of thallium nitrate and 10.1 parts of ferric ni trate. Concentration of butane. Yield of maleic Example (mole % relative to air) anhydride (mole %) Thereafter, the procedure of Example 23 was fol 22 lowed to prepare a catalyst. Using this catalyst, the 15 39 reaction was carried out under the same conditions as Example 23. The yield of maleic anhydride was 42 mole EXAMPLE.23 %. In 480 parts of a 5% aqueous solution of oxalic acid EXAMPLE 29 was dissolved 14.6 parts of ammonium metavanadate, 10 In 500 parts of water was suspended 14.6 parts of followed by the addition of 43.2 parts of aqueous ortho ammonium metavanadate, followed by the addition of phosphoric acid (85%), 13.2 parts of strontium nitrate 23.6 parts of oxalic acid to prepare a homogeneous and 10.1 parts of ferric nitrate. To this mixed solution solution. To this solution were added 36.0 parts of an was added 300 parts of titanium oxide powder and a aqueous solution (85%) of orthophosphoric acid and portion of the water was expelled on a hot water bath 15 19.7 parts of barium hydroxide. After dissolution, the until a paste was obtained. The paste was extruded into solution was used to impregnate 300 parts of titanium cylinders, about 2 mm by 5mm. After drying, the cylin phosphate powder (TiO2/P2O5 mole ratio=5:2). Under ders were calcined at 500° C. for 4 hours to prepare a stirring on a hot-water bath, the catalyst solution was catalyst. Using this catalyst, a mixed gas of butane and evaporated to prepare a paste. air (butane: 1 mole %) was reacted at atmospheric pres 20 The paste was extruded into cylinders about 2 mm by sure, a constant reaction bath temperature of 470 C. 5 mm. After drying, the cylinders were calcined at 500 and a space velocity (SV) of 3000 (hr-1). The yield of C. for 5 hours to prepare a catalyst. Using this catalyst, maleic anhydride was 38 mole %. the reaction was carried out under the same conditions as Example 1. EXAMPLE.24 25 The conversion ofbutene-1 was 100 mole %; yield of In the preparation of the catalyst according to Exam maleic anhydride was 58 mole %; and yield of monocar ple 23, 8.85 parts of calcium nitrate was used in place of boxylic acid was 2.1 mole %. 13.2 parts of strontium nitrate. Using this catalyst, the reaction was carried out under the same conditions as EXAMPLE 30, Example 23. 30 In 500 parts of water was suspended 14.6 parts of The yield of maleic anhydride was 35 mole %. ammonium metavanadate, followed by the addition of 23.6 parts of oxalic acid to prepare a homogeneous EXAMPLE 25 solution. To this solution were added 16.7 parts of thal In the preparation of a catalyst according to Example lium nitrate and 36.0 parts of aqueous orthophosphoric 23, 16.3 parts of barium nitrate was used in place of 13.2 35 acid (85%). After dissolution, 300 parts of molded al parts of strontium nitrate. Using the resulting catalyst, alumina was immersed in the solution and, under occa the reaction was carried out under the same conditions sional stirring on a hot-water bath, the catalyst-solution as Example 23. The yield of maleic anhydride was 40 was evaporated to dryness on the a-alumina carrier. mole %. After drying at 100°C, overnight, the composition was 40 calcined in the air at 450° C. for 4 hours to prepare a EXAMPLE 26 catalyst. In 500 parts of a 5% aqueous solution of oxalic acid This catalyst was packed into a conventional continu was dissolved 14.6 parts of ammonium metavanadate, ous fixed-bed reactor, in which a mixed gas ofbutene-1 followed by the addition of 36.0 parts of aqueous ortho and air (butene-1: 1 mole %) was reacted at atmospheric phosphoric acid (85%), 15.8 parts of barium hydroxide 45 pressure, a reactor bath temperature of 400 C. and a and 6.6 parts of thallium nitrate. Thereafter, the proce space velocity (SV) of 5000 (hr-1). The conversion of dure of Example 23 was followed to prepare a catalyst. butene-1 was 98% and the yield of maleic anhydride Using this catalyst, the reaction was carried out under was 58 mole %, while the yield of monocarboxylic acid was 1.3 mole %. the same conditions as Example 1. The conversion of 50 butene-1 was 100 mole %; yield of maleic anhydride EXAMPLES 31 THROUGH 33 was 62 mole %; and yield of monocarboxylic acid was 0.9 mole %, Using the catalyst according to Example 30, the reac tion was carried out under the same conditions as Ex EXAMPLE 27 55 ample 30 except that the concentration of hydrocarbon In the preparation of a catalyst according to Example in air was varied as shown in the following table. The 26, 10.0 parts of strontium hydroxide was used in place results are set forth in the same table. of 15.8 parts of barium hydroxide. Using the resulting TABLE 6 catalyst, the reaction was carried out under the same Yield of maleic conditions as Example 1. The conversion ofbutene was 60 Example Butene-l/air (mole %) anhydride (mole %) 100 mole %; yield of maleic anhydride was 61 mole %; 31 0.5 59 and yield of monocarboxylic acid was 1.1 mole %. 32 1.2 58 33 1.5 56 EXAMPLE 28 In 500 parts of a 5% aqueous solution of oxalic acid 65 was dissolved 14.6 parts of ammonium metavanadate, EXAMPLE 34 followed by the addition of 43.2 parts of aqueous ortho In 800 parts of water was suspended 21.9 parts of phosphoric acid (85%), 19.7 parts of barium hydroxide, ammonium metavanadate, followed by the addition of 4,298,533 10 35.4 parts of oxalic acid to prepare a homogeneous solution. In this solution were dissolved 64.8 parts of EXAMPLE 44 phosphoric acid (85% aqueous solution) and 10.1 parts In 500 parts of a 10% aqueous solution of oxalic acid of thallium nitrate. The resultant solution was used to was dissolved 30 parts of ammonium metavanadate, impregnate titanium oxide granules, 7 to 10 meshes, and followed by the addition of 70 parts of aqueous ortho under occasional stirring on a hot-water bath, the cata phosphoric acid and 13 parts of thallium nitrate. To the lyst-solution was evaporated to dryness on the carrier. resulting homogeneous solution was added 400 parts of After drying at 100 C., the composition was calcined at finely divided titanium oxide and the water was evapo 450° C. for 5 hours. Using this catalyst, the reaction was rated off on a hot-water bath. When the system had carried out under the same conditions as Example 30. In O become viscous, a small amount of water was added. this example, the conversion ofbutene-1 was 100% and The composition was placed on a flat plate where it was the yield of maleic anhydride was 60 mole %. The yield dried. The dried composition was crushed and sieved to of monocarboxylic acid was less than 1 mole %. 7-10 meshes, after which it was heattreated in the air at 550 C. for 3 hours to prepare a catalyst. EXAMPLES 35 THROUGH 41 15 This catalyst was packed into the same reactor as that Using the catalyst according to Example 34, the reac used in Example 30 and a mixed gas of n-butane and air tion was carried out in the same manner as Example 30 (butane: 1 mole %) was reacted at atmospheric pres except that the hydrocarbons indicated in the following sure, a space velocity(SV) of 2000 (hr) and a reaction table were used in place ofbutene-1. The results are set 20 temperature of 515 C. forth in the same table. The conversion of butane was 72 mole %; yield of maleic anhydride was 35 mole %; and yield of monocar TABLE 7 boxylic acid was 1.4 mole %. Yield of maleic Example Raw material anhydride (mole %) 25 EXAMPLE 45 35 cis-Butene-2 60 Using the catalyst of Example 44, the reaction was 36 trans-Butene-2 59 carried out with a mixing ratio of n-butane to air of 1.5 37 Butadiene 65 38 Spent BB fraction* 27 mole % at a reaction temperature of 525 C. and a space 39 Spent-spent BB fraction"? 51 velocity (SV) of 3000 (hr-1). In this example, the con 40 Cyclopentadiene 58 30 version of butane was 83 mole %; yield of maleic anhy 41 Benzene 58 dride was 34 mole %; and yield of monocarboxylic acid "Butene 39%; isobutene 52%; butane, etc.9% was 0.8 mole %. *Butene 81%; butane, etc., 19% EXAMPLE 46 35 In 1000 parts of water was suspended 30 parts of EXAMPLE 42 ammonium metavanadate, followed by the addition of In 500 parts of a 5% aqueous solution of oxalic acid 50 parts of oxalic acid and 90 parts of aqueous phos was dissolved 14.6 parts of ammonium metavanadate, phoric acid (85%). After a homogeneous solution was followed by the addition of 22.2 parts of phosphorus prepared, 13 parts of thallium nitrate and 20 parts of pentoxide, 16.7 parts of thallium nitrate, and 5.1 parts of 40 ferric nitrate were added. To this solution containing ferric nitrate. The resulting mixed solution was used to catalyst-active components was added 400 parts of tita impregnate 300 parts of a-alumina powder and a por nium oxide powder in the size range of 10 to 20 meshes tion of the water was evaporated off to leave a paste, and the composition was evaporated to dryness on a The paste was extruded and sphered about 4 mm in hot-water bath. After drying, the composition was cal diameter. After drying, the spheres were calcined in the 45 cined at 500 C. for 5 hours to prepare a catalyst. air at 500 C. for 4 hours to prepare a catalyst. Using this Using this catalyst, a mixed material gas of n-butane catalyst, the reaction was carried out under the same and air (n-butane: 1.2 mole %) was reacted at a space conditions as Example 30 except that the reaction tem velocity (SV) of 2000 (hr) and a reaction temperature perature was 460° C. The conversion of butene-1 was of 510 C. The conversion of butane was 81 mole %; 100%; yield of maleic anhydride was 56 mole %; and 50 yield of maleic anhydride was 37 mole %; yield of yield of monocarboxylic acid was 3 mole %. monocarboxylic acid was 1.1 mole %. EXAMPLE 43 EXAMPLE 47 In 600 parts of a 5% solution of oxalic acid was dis Using the same catalyst as that used in Example 46, solved 17.5 parts of ammonium metavanadate, followed 55 air containing 1.2 mole % of n-butane was reacted at a by the addition of 79.3 parts of diammonium phosphate space velocity (SV) of 3000 (hr-1) and a reaction tem and 20.0 parts of thallium nitrate. To this solution was perature of 506 C. added 350 parts of finely divided titanium oxide (rea The conversion of butane was 51 mole %: yield of gent grade #1), and the water was evaporated off to maleic anhydride was 27 mole %; and yield of monocar prepare a paste, which was then wet-granulated. After 60 boxylic acid was 0.6%. drying, the granules were calcined in the air at 500 C. EXAMPLE 48 for 3 hours. In 500 parts of a 10% aqueous solution of oxalic acid The reaction was carried out under the same condi was dissolved 30 parts of ammonium metavanadate, tions as Example 30, 65 followed by the addition of 70 parts of aqueous ortho The conversion of butene-1 was 100%; yield of ma phosphoric acid (85%) and 13 parts of thallium nitrate. leic anhydride was 58 mole %; and yield of monocar To this solution was added 400 parts of titanium phos boxylic acid was 2 mole %. phate powder (TiO2/P2O5 mole ratio = 1:1). 4,298,533 11 12 Under stirring on a hot-water bath, the catalyst solu relative to iron oxide, when used, being from about 1:2 tion was evaporated to prepare a paste. The paste was to about 20:1 based on the atomic ratio of vanadium to extruded into cylinders about 2 mm by 5 mm. After iron. drying, the cylinders were calcined at 500 C. for 5 2. A method as claimed in claim 1, wherein the cata hours to prepare a catalyst. Using this catalyst, the reac lyst comprises vanadium oxide and, alkaline earth metal tion was carried out under the same conditions as Ex oxide, thallium oxide and phosphorus oxide. ample 30. 3. A method as claimed in claim 1, wherein the cata The conversion ofbutene-1 was 100 mole %; yield of lyst comprises vanadium oxide and, alkaline earth metal maleic anhydride was 60 mole %; and yield of monocar oxide, phosphorus oxide, thallium oxide and iron oxide. boxylic acid was 2.6 mole %. 10 4. A method as claimed in claim 1 or 2, wherein the What is claimed is: hydrocarbon consists essentially of four carbon atoms, 1. In a method for producing maleic anhydride by 5. In a method for producing maleic anhydride by oxidation of a hydrocarbon having not less than four oxidation of a hydrocarbon having not less than four carbon atoms in gaseous phase in the presence of a carbon atoms in gaseous phase in the presence of a catalyst, the improvement wherein the catalyst com 15 prises (a) vanadium oxide, (b) phosphorus oxide, (c) an catalyst, the improvement wherein the catalyst consists alkaline earth metal oxide selected from the group con essentially of (a) Vanadium oxide, (b) phosphorus oxide, sisting of beryllium oxide, strontium oxide and barium (c) an alkaline earth metal oxide selected from the group oxide, and (d) thallium oxide, said catalyst optionally consisting of beryllium oxide, strontium oxide and bar further containing (e) iron oxide, the amount of vana 20 ium oxide, and (d) iron oxide, the amount of vanadium dium oxide relative to phosphorus oxide being from oxide relative to phosphorus oxide being from about 1:1 about 1:1 to about 1:5 based on the atomic ratio of vana to about 1:5 based on the atomic ratio of vandium to dium to phosphorus, the amount of vanadium oxide phosphorus, the amount of vanadium oxide relative to relative to said alkaline earth metal oxide being from said alkaline earth metal oxide being from about 1:5 to about 1:5 to about 15:1 based on the atomic ratio of 25 about 15:1 based on the atomic ratio of vanadium to the vandium to the alkaline earth metal, the amount of alkaline earth metal, the amount of vanadium oxide vanadium oxide relative to thallium oxide being from relative to iron oxide being from about 1:2 to about 20:1 about 1:2 to about 20:1 based on the atomic ratio of based on the atomic ratio of vanadium to iron. vanadium to thallium, the amount of vanadium oxide ck sk k *k sk 30

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