Co-MoOx-Al2O3 catalyst for hydrodeoxidation

386 Maleic Anhydride During the last few years, sales of maleic anhydride have been in the doldrums: demand has been much less than industry's capacity to produce. However, industry has now geared up to meet an expected upturn in demand: new capacity has been installed, some plants have received a retrofit to enable them to use more effective feedstock and improved catalysts and technology are being developed. Maleic anhydride has traditionally been produced by the heterogeneously catalysed highly exothermic oxidation of benzene using multitubular reactors with molten salt coolant. The use of benzene is clearly wasteful on feedstock and in recent years considerable effort has been devoted to the development of catalysts capable of operating satisfactorily and giving good yields of maleic anhydride from n-butane. Judging from publications, these catalysts are based on V2OS/P2OS, which may contain a range of oromoters. Relative to benzene, nbutane has the advantages of lower price, higher theoretical weight yield and lower requirements from the health hazard viewpoints. At least four companies have independently developed catalysts for this purpose, and several plants now utilize the feedstock. A few months ago, Monsanto commenced production from a new large (ca 60,000 te pa) plant in Florida, (see Appl.Catal., 7, (1983), No.l), using a proprietary catalyst. This company also plans to convert some of its benzene-based capacity to n-butane. Halcon (New York) has developed for sale a catalyst for n-butane oxidation. For many years Halcon has been a major supplier of technology, including catalysts, for the route from benzene, and will doubtless be interested in the modification of benzene plants to enable operation with n-butane. Denka (Texas) has developed a catalyst for the oxidation of the latter hydrocarbon: this catalyst is used in its own plant and is also available for use by other producers, either for plants designed specifically for n-butane, or for modified benzene-based plants. Finally, a catalyst which is believed to have a particularly high selectivity has been developed by ICI. Meanwhile, there has been much activity on the development of a new generation of processes for future investment. The common theme is the

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Volume 7, No. 3 - September 1983

application of fluidised bed reactors, rather than multitubular designs. The fluidised bed approach is potentially capable of a significantly lower capita investment requirement and a lower net consumption of utilities. This arises partly from the possibility of using a higher ratio of hydrocarbon to oxidant gas, since gas mixing may be within the bed, avoiding the need to maintain the mixture below the lower flammability limit. The catalysts for the new react0 type must have high attrition resistant as well as high selectivities, activities and chemical life. At least three companies have developed (or are developing) catalysts of this type and process technology to which they could be applied. Badqer offers a process for licence based on catalyst'know-how oriainallv acauired from Mobil. backedup by fur'ther'extensive laboratory and pilot plant work and culminating in a demonstration plant constructed at Denka's Texas plant. Badger point out that their technology may be used advantageously in a retrofit mode, usins the recovery and purification systems of an existing fixed bed plant. Secondl) the Ftalital Division of Alusuisse Itali is said to have tentative plans to built in Italy a fluidised-bed n-butane-based slant with a caoacitv of 30-40,000 te pa utilising technology-being developed jointly with C-E Lummus. At present a 3,000 te pa demonstration plant is beinq constructed. C-E Lummus will offer the _ orocess for license. Thirdlv, Sohio and DCB have indicated they have-reached the pilot-plant stage in the development of a fluidised-bed process using n-butane as feedstock. This process is also available for license. There can be little doubt that the catalyst developments of thelast few years, together with the process develop ment opportunities which promoted them, will continue to bring substantial changes to maleic anhydride production technology. Co-MOO,-A1203 Catalyst Hydrodeoxidxtion

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It has been found (H. Weigold; Fuel 61 (19821 1021) that a Co-Max-Al203'catalyst (Harshaw HT-400 R) can be used successfully for the conversion of various phenols to aromatic hydrocarbons at 3OOo-4000C with hydrogen at a pressure of 76 bar.