Published December 1998
Solutia (formerly the chemical division of Monsanto) and the Boreskov Institute of Catalysis (Russia) have developed a new technology, AlphOx, to produce phenol from benzene in a single step. The process, which eliminates cumene as an intermediate and acetone as a by-product, is based on the gas-phase reaction of benzene with nitrous oxide (N2O) over a zeolite catalyst. Solutia is planning to commercialize the process, using an oftgas stream from its adipic acid plant as the nitrous oxide source. A pilot plant employing AlphOx has been in operation since 1996, and the first commercial AlphOx facility is scheduled for start-up by 2000.
Our technical and economic evaluation of a plant using an off-gas stream from adipic acid production indicates that the total fixed capital investment for AlphOx is lower than that for a comparable cumene-based phenol process. The net production cost for AlphOx is also competitive and is not affected by fluctuations in the acetone market. However, the phenol plant capacity is limited by the availability of N2O recovered from the adipic acid process. A relatively small phenol plant requires a world-scale adipic acid plant for its N2O supply. Therefore, the AlphOx technology would seem to appeal to producers looking for small phenol capacities, which may not be economical with the conventional cumene-based process.
Solutia and the Boreskov Institute of Catalysis are also jointly developing a technology for N2O production. The process is based on the oxidation of ammonia with air, but further details have not yet been disclosed. Large-scale, on-purpose generation of N2O, if commercially viable, would solve the capacity limitation problem of the AlphOx plant.