3,535,346 United States Patent Office Patented Oct. 20, 1970

1. 2 pecially maleic anhydride, in a high yield by oxidation of 3,535,346 organic compounds, e.g. benzene, toluene, o-Xylene, naph CATALYST FOR THE PRODUCTION OF CARBOXYLIC ACED ANHYDRDE thalene, etc. under rather mild conditions. Kyohei Sudo and Susumu. Sato, Hikari, Japan, assignors Other objects will be apparent to those skilled in the to Takeda Chemical Industries, Ltd., Osaka, Japan art upon reading the following description. No Drawing. Filed Sept. 13, 1967, Ser. No. 667,349 This invention in one aspect concerns novel and highly Claims priority, application Japan, Sept. 14, 1966, activated catalyst compositions for the production of di 41/60,978 carboxylic acid anhydride by oxidation of organic com Int, Cl. B01j 11/82, C07c57/14 pounds, which compositions consist substantially of 1 U.S. C. 260-346.8 6 Claims O mol part of V2O5, about 0.2 to about 0.7 mol part of MoO3, about 0.01 to about 0.1 mol part of PO, about 0.01 to about 0.05 mol part, more desirably about 0.015 ABSTRACT OF THE DISCLOSURE to about 0.03 mol part of AgO, and about 0.01 to about The incorporation of specified amounts of silver oxide 0.3 mol part, more desirably about 0.05 to about 0.2 and Sodium oxide into otherwise conventional vanadium 15 mol part of Na2O, all these ingredients being supported Oxide-molybdenum oxide catalyst compositions for the on a carrier. The activity of the catalyst is further height oxidative production of dicarboxylic acid anhydrides from ened by including about 0.01 to about 0.03, more desir organic compounds, such as benzene, xylene and naph ably about 0.01 to about 0.02 mol part of BOs with the thalene, enhances the catalytic activity of such composi above components supported on a carrier. tions, and makes it possible to obtain high yields while 20 The catalyst compositions of the present invention can carrying out the oxidation under mild conditions. The life be prepared by homogeneously mixing a carrier with the of the catalyst is also considerably lengthened. Further precursors of each of the active ingredients, followed enhancement of the catalytic activity is obtained by ad by subjecting the mixture to a heat treatment, whereby the ditionally incorporating a small amount of BO there precursors are converted into the corresponding oxides. into. 25 The carrier can e.g. be carborundum (silicon carbide), aluminum oxide, pumice and the like, carborundum be ing optimal. The amount of the carrier used is about 100 This invention relates to catalyst compositions for the volume parts relative to about 10 to 30 weight parts of production of dicarboxylic acid anhydride and, more par the active ingredients. ticularly, to improved vanadium oxide-molybdenum oxide The precursors are exemplified by e.g.: type catalyst compositions which are modified by the in corporation of silver oxide and sodium oxide. NHVO3, HVO4, HVO, HVO for VO5; Vanadium oxide-molybdenum oxide compositions have (NH4)MorO24.4H2O, HMOO HMo(OHO for ben used as catalysts in the preparation of dicarboxylic MoO; acid anhydride by oxidation of an organic compound, 35 HPO, (NH4)HPO, HPO for PO5; for example benzene, Xylene, naphthalene, etc. Since AgNO3 for AgO; such catalysts have only a short useful life, especially NaCl, NaHCO3, NaCO, (COONa) for NaO; when employed at high temperature, many attempts have HBO, HBO for B2O3. been made to overcome this defect. However, the use of Each of these precursors is used in the ratio (chem Such catalysts has heretofore given rather low yields of 40 ical equivalent) corresponding to that of the components the desired dicarboxylic acid anhydride, especially when of the desired catalytic composition. Practically, at first, used under mild conditions (e.g. at rather low tempera an aqueous solution containing all the precursors is pre ture). Therefore, such catalysts are not very satisfactory pared by admixing these precursors in water sufficient to for the production of dicarboxylic acid anhydride on a dissolve them. In this admixing process, oxalic acid can commercial scale. 45 be used as dissolving agent together with water, if neces The present invention is directed to the provision of Sary. The amount of Oxalic acid is selected from a range more highly activated catalysts for the production of di of about 0.4 mol to about 1.5 mol relative to 1 mol of carboxylic acid anhydride by oxidation of organic com the precursor for VO5. Thus-prepared solution is homo pounds, which catalysts are capable of producing the geneously admixed with the carrier. Then, water is re desired compounds in high yield even under rather mild 50 moved by evaporation from the mixture, and finally, the conditions. This objective has now been achieved by thus-treated mixture is activated by heating at about 380° incorporating silver oxide (AgO) and sodium oxide to about 460 C., more desirably at about 400 to about (Na2O) in specified amounts into the known vanadium 440 C. under contacting with air for about 3 to about oxide-molybdenum oxide type catalysts, whereby cata 55 15 hours, more desirably for about 7 to about 10 hours. lysts of remarkably enhanced catalytic activity result. In order to obtain the desired dicarboxylic acid an It is thus an object of this invention to provide novel, hydride by using the catalyst of this invention, the organic highly activated and long-life catalysts useful for the compound (benzene, toluene, o-xylene, naphthaleno, etc.), production of dicarboxylic acid anhydride, especially is contacted with oxygen or oxygen-containing gas such maleic anhydride and/or phthalic anhydride, in a high 60 as air in the presence of the catalyst at an elevated tem yield by oxidation of organic compounds, e.g. benzene, perature. toluene, o-xylene, naphthalene, etc. Practically, a gaseous mixture of the organic compound Another object of this invention is to provide a process and the oxygen or oxygen-containing gas is, underheat for the production of dicarboxylic acid anhydride, es ing, Subjected to contact with the catalyst by, for example, 3,535,346 3 4. passing through a column packed with the catalyst. The to keep the internal temperature of the reactor at the amount of the organic compound is about 0.3 to about desired magnitude. 1.2 mol percent relative to the oxygen or oxygen-con A gaseous mixture of benzene and air is fed into the taining gas. reactor for 30 hours under various conditions; cf. Table 1. In case of passing the gaseous mixture through a The exit gases are led to a water scrubber, wherein the column packed with the catalyst, the mixture is fed there 5 maleic anhydride is converted into maleic acid. The con through at a space velocity (hr.) of about 3000 to tent of the maleic acid in the scrubbings is determined about 6000: and yield in calculated. The results are shown in Table 1: Volume of gas fed (l/hr.) O Space Welocity (hr.) = Wolume of catalyst used (.) TABLE 1. Condition Result, (Calculated under one atmosphere at 20° C.) Reaction Concentation Space of benzelle Maloic acid temperature is about 370° C. to about 480 C. calculated velocity in mixed gas Reaction yield 2 (wl. as an average value during the period of contacting with No. (hr.-1) (nol percent) temperature (rc(int) the catalyst. 5,000 . 40 429 112 By the use of a catalyst composition of this invention, 4,000 0.95 422 1G the desired dicarboxylic acid anhydride can be produced 3,000 0.95 4. 11: in remarkably high yield in comparison with prior pro 1 Average temperature of catalyst. cesses. For example, the yield of maleic anhydride from 2 Relative to the weight of benzene fed. 100 parts by weight of benzene, when using the present catalyst composition is more than 112 parts by weight, EXAMPLE 2. Calculated as maleic acid. Moreover, the catalyst can 26.7 parts of oxalic acid and 0.395 part of sodium chlo be effectively employed for more than one year without ride and then 31 parts of NHVO and 9 parts of degradation of the catalytic acitvity, because use of the (NH4)MoO2.4H2O are dissolved in 120 parts by volume novel catalysts of this invention in the process for the of distilled water. oxidation of organic compounds, makes it possible to To the thus-prepared solution, there is added 10 parts lower the reaction temperature in such process by about by volume of an aqueous solution containing 0.28 part of 50° to about 100° C. in comparison with the tempera phosphoric acid, and then 10 parts by volume of an aque ture required in the prior art, and consequently the Vola ous solution containing 1.98 parts of AgNO3 is stirred tilization of sensitive components of the catalyst can ef thereinto. fectively be prevented during the reaction. To the thus-obtained solution, there is added 145 parts Further, the present method requires relatively small of Carborundum (particle size 3.8 to 4.3 millimeters in amounts of oxygen or oxygen-containing gas for the oxi diameter), and the water is slowly removed by evapora dation process of the organic compound. Therefore, the tion, whereby the solutes are supported on the Carborun use of the present catalyst in the production of dicarbox dum. ylic acid anhydride from the corresponding organic com Then, after the manner set forth in Example 1, the pound is advantageous from an industrial standpoint. above-treated Carborundum is heated at 400 C. for 8 In the following examples, part(s) are on a weight hours to produce 155 parts of desired catalyst, wherein: basis, unless otherwise stated. Parts by weight bear the 40 same relation to parts by volume as do grams to milli Mo Part liters. V2O5 ------1.0 EXAMPLE 1. Moos ------'------war - we -- w ------as 0.386 534 parts of oxalic acid and 15.8 parts of sodium chlo POs ------0.014 ride and then 620 parts of NHVO and 180 parts of Nago ------0.025 (NH4)MoO2.4H2O are dissolved in 2400 parts by vol Ag2O ------'------was aw ------0.042 ume of distilled water. To the thus-prepared Solution, are supported on the Carborundum, the total quantity there is added 100 parts by volume of an aqueous Solu of active ingredients amounting to about 22% (w./v.) tion containing 7.2 parts of H3PO and 5.6 parts of relative to the carrier. HBO, and then 100 parts by volume of an aqueous Solu 50 In manner similar to that set forth in Example 1, maleic tion containing 25.2 parts of AgNO3 is stirred thereinto. anhydride is produced from benzene under various con To the solution thus obtained, there is added 2600 ditions (cf. Table 2), and the results are shown in the said parts of Carborundum, the particle size of which is 3.8 table: to 4.3 millimeters in diameter, after which the water is TABLE 2 slowly removed by evaporation, whereby the Solutes are supported on the Carborundum particles. Condition Result Concentration The above-treated Carborundum particles supporting Space of benzene Malcic acid the solutes thereon are heated at 400 C. for 8 hours, velocity in nixed gas Reaction yield 2 (wt. under air-blowing, in an activator which is equipped with No. (hr.-1) (mol percent) temperature 1 percent) external electric heaters. Thus 3100 parts of the desired 60 1------4,000 0.95 4.38 14. catalyst is obtained, wherein: 2------3,000 0.95 432 7.5 Mol part 1 Average temperature of catalyst. V2O5 ------1.O 2 Relative to the weight of benzene fed. MoC3 ------a ar are a 0.386 EXAMPLE 3 65 POs ------0.04 After the manner set forth in Example 2, a catalyst Na2O ------0.050 is prepared, using the following Substances: Ag2O ------0.028 Distilled acid------parts by volume.-- 360 B2O3 ------0.017 Oxalic acid------parts---- 78 are supported on the Carborundum, the total amount of 70 NaCl ------do---- 4.74 active ingredients amounting to about 22% (w./V.) re NHAVO3 ------do---- 93 lative to the carrier. The catalyst is charged into a stain (NH4)MoO2.4H2O w - a al- are r(do---- 27 less steel tube reactor which is equipped with a jacket HsPO4------do---- 1.44 and external electric heaters. The reactor is heated by AgNO3 ------do---- 2.4 th? heaters, while molten salts are circulated in the jacket 75 Carborundum ------do---- 390 3,535,346 5 6 Thus 465 parts of the catalyst is obtained, wherein: 0.05 mol part of AgO and about 0.01 to about 0.3 mol part of Na2O, all being supported on a carrier. Mol part 2. A catalyst composition for the production of di V20s ------1.0 carboxylic acid anhydride by oxidation of an organic Moos ------0.386 compound, which composition consists of 1 mol part of P20s ------0.04 5 VO5, about 0.2 to about 0.7 mol part of MoC), about Na2O ------0.10 0.01 to about 0.1 mol part of POs, about 0.01 to about Ag2O ------0.021 0.05 mol part of AgO, about 0.01 to about 0.3 mol part BaOs ------0.017 cf Na2O and about 0.01 to about 0.03 mol part of B2O3, are supported on Carborundum, the total amount of the all being supported on a carrier. active ingredients amounting to about 22% (w.v.) rela 10 3. A catalyst composition for the production of di tive to the carrier. By the use of the catalyst, maleic acid carboxylic acid anhydrie by oxidation of an organic is produced from benzene after the maner set forth in compound, which composition consists of 1 mol part of Example 1, and the following results are obtained: V2O5, about 0.2 to about 0.7 mol part of MoC) about TABLE 3 5 0.01 to about 0.1 mol part of POs, about 0.02 to about 0.04 mol part of AgO and about 0.025 to about 0.1 mol Condition Result part of Na2O, all being supported on a carrier. Concentration Space of benzene Maleic acid 4. A catalyst composition for the production of di velocity in mixed gas Reaction yield 2 (wt. carboxylic acid anhydride by oxidation of an organic No. (hr.-1) (mol percent) temperature I percent) 20 compound, which composition consists of 1 mol part of

4,000 0.95 393 12 VO5, about 0.2 to about 0.7 mol part of MoC), about 3,000 0.95 395 114 0.01 to about 0.1 mol part of POs, about 0.02 to about 1 Average temperature of catalyst. 0.04 mol part of AgaO, about 0.025 to about 0.1 mol 2 Relative to benzene fed. part of Na2O and about 0.01 to about 0.02 mol part of It is clear from the foregoing that catalyst according to 25 B2O3, all being supported on a carrier. this invention is also effective, even at rather low reaction 5. A catalyst composition according to claim 1, wherein temperatures. the carrier is a silicon carbide. EXAMPLE 4 6. In a process for the production of maleic anhydride by oxidation of benzene, toluene or o-xylene in the pres The same procedure is in Example 1 is carried out, 30 ence of an oxidation catalyst under heating, the improve except that ortho-Xylene is used as the starting material ment wherein the oxidation catalyst consists of 1 mol part in place of benezene, whereby the following results are of V2O5, about 0.2 to about 0.7 mol part of MoO, about contained: 0.01 to about 0.1 mol part of PO5, about 0.01 to about TABLE 4 0.05 mol part of AgaO and about 0.01 to about 0.3 mol 35 part of Na2O, all being supported on a carrier. Condition Result, Yield relative to References (Cited o-xylene fed Concentration (wt. percent) UNITED STATES PATENTS Space of o-xylene Reaction velocity in mixed gas tempera- Phthalic Maleic 40 2,625,519 1/1953 Hartig ------252-437 XR No. (hr.-) (mol percent) ture (C.) acid acid 2,777,860 1/1857 Egbert et al. ------260-346.8 1----- 5,000 0, 60 450 19.1 9, 5 3,086,026 4/1963 Wiebusch 252- .437 XR 3,211,671 10/1965 Egbert ------252-437 What is claimed is: 3,277,017 10/1966 Stefaniak ------252-437 1. A catalyst composition for the production of di carboxlyic acid anhydride by oxidation of an organic PATRICK P. GARVIN, Primary Examiner compound, which composition consists of 1 mol part of V2O5, about 0.2 to about 0.7 mol part of MoO, about U.S. Cl. X.R. 0.01 to about 0.1 mol part of POs, about 0.01 to about 252-432, 437, 435; 260-346.4