Update of Caprolactam via Liquid Phase Ammoximation and Vapor Phase Rearrangement

Published December 2004

In PEP Report 7C the liquid phase ammoximation process based on Enichem technology was evaluated, while PEP Review 1998-15 examined a vapor phase rearrangement process based on Sumitomo technology. The review used the economics from the report for the cyclohexanone oxime. The original intent of the review was to reevaluate the ammoximation process by incorporating a simulation model of the process. However, that proved infeasible because of a number of physical property issues that prevented appropriate simulation results. Subsequent reviews (2001-2, 2004-1, and 2004-6) examined the major property problems encountered during the original simulation effort. Therefore, this review reexamines the results of the original report and the first review to update the economics of the combined process.

While the physical properties generated by the intervening reviews resolved the simulation problems, the simulation cannot be considered highly accurate because some of the physical property parameters were regressed from very limited data or even contrived data that matched behavior based on anecdotal information. More rigorous property parameters would be needed to improve the results, which requires property estimation experts that are generally not available in smaller organizations, such as consulting groups. Thus further refinements of the properties and simulation model may yet add economic improvements to the process technology. However, the general conclusion from PEP Review 1998-15 appears to hold, namely that the technology combination represented by the referenced patents does not appear to be economical compared to existing technology.