Sumitomo to commercialize new caprolactam process
Conventional routes to caprolactam involve a liquid-phase Beckmann rearrangement of cyclohexanone oxime produced by reacting hydroxylamine and cyclohexanone (obtained by benzene hydrogenation followed by oxidation).
The chief drawback of the process is that it also yields 1.6-4.0 mt of ammonium sulfate per metric ton of caprolactam. This requires additional facilities to produce sulfuric acid, which acts as a catalyst, and to recover the ammonium sulfate. While caprolactam producers sell ammonium sulfate as fertilizer, they rarely make a good return on it.
Sumitomo's new process uses a proprietary, high performance catalyst to carry out the Beckmann rearrangement in a gas phase without coproducing ammonium sulfate. Sumitomo has already demonstrated the approach in a 5000 mt/yr demonstration plant.
In has also worked with EniChem, which has developed a low-cost route to cyclohexanone. The EniChem process uses a proprietary catalyst (TS-1) to produce cyclohexanone by direct ammoximation from ammonia and hydrogen peroxide. EniChem has demonstrated the route at its 12,000 mt/yr semiworks plant in Porto Marghera, Italy.
Sumitomo and EniChem say they have jointly studied a new process that combines Sumitomo's gas-phase Beckmann rearrangement with EniChem's direct ammoximation. Having confirmed that the new process achieves significant cost advantage over other processes, the companies plan to implement the newly-developed process commercially.
Sumitomo will build the first new commercial plant in Japan. It says it will be the world's first facility capable of producing caprolactam without coproducing ammonium sulfate.
Caprolactam is a key raw material for nylon-6, which is widely used in fibers (apparel, carpet), automotive and electric appliance parts (resins), and food packaging films. Sumitomo expects Asian demand for nylon-6 engineering plastics to rise 7% annually, and film, 4% per year.
Sumitomo Chemical currently produces 93,000 mt/yr of caprolactam at its plant in Ehime, Japan. It plans to use its new technology to "vigorously" seek caprolactam business opportunities both in Japan and abroad.
The company recently announced plans to commercialize its new, low-cost propylene oxide process. It says the process yields no coproducts and has lower capital costs than competing technologies.
Edited by Alan S. Brown
Managing Editor, Chemical Online
abrown@vertical.net
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