SAVA Process

In this process,an air-benzene mixture (3-wt. % benzene) is fed to a tubular reactor (see Fig. 2-4). The tubes are loaded with a vanadium complex catalyst on extruded cylinders or spheres of alumina. Molten salt bath is used to maintain the temperature of 355-375°C. The recovery system is quite similar to the SD process. Very high yields and long catalyst life have been claimed. 

In addition to these, there are processes such as the Alusuisse/UCB process,developed by the two firms with claims of higher yields (86% overall). Other variations of benzene oxidation utilized by various firms are similar to the SD process, the main difference being in the recovery and purification steps. 

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In the almost 60 years since the first patent on MA production by Weiss and Downs/ a flood of patent and nonpatent literature has been published. In the benzene oxidation route, vanadium oxide stands out to be the most common feature of all the catalysts. It appears that in the commercial production of MA from benzene, vanadium oxide or cocatalyst promoted vanadium oxide over a support is used (except SAVA process). Typical promoters used are oxides or salts of the following elements Mo, W, Bi, Sn, P, Ag, Cu, Na, B, Ti, and Ni. The V + Mo is most common. Other elements may also act as modifiers (see Ref. 15). 

Savas, E. S., Computer Control of Industrial Processes, McGraw-Hill Book Company, New York/Toronto/London 1965... 

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