Published August 2019
Most cyclohexanol/cyclohexanone is prepared as a mixture by the catalytic oxidation of cyclohexane. Liquid0phase oxidation is the preferred route. Vapor0phase oxidation is commercially feasible, but is not believed to be currently used in the United States. Reportedly, the reaction must take place at a low conversion rate per pass (usually below 5%) in order for the yield on cyclohexane feedstock to reach 70%. The ratio of cyclohexanol to cyclohexanone will vary depending on the production parameters; high cyclohexanol content is preferred for adipic acid production, while high cyclohexanone content is preferred for caprolactam production. Both compounds may be separated by fractional distillation. Essentially, pure cyclohexanone can be attained via the dehydrogenation of cyclohexanol/cyclohexanone mixture while using a catalyst such as nickel. If cyclohexanol is the most desired product, a catalyst such as boric acid is used during the oxidation of cyclohexane. Use of this catalyst can result in as high as a 10:1 alcohol0to0ketone mixture that is used in the production of adipic acid.
The following pie chart shows world consumption of uncoupled cyclohexanol and cyclohexanone:
The top 15 producers of uncoupled cyclohexanol/cyclohexanone accounted for about 75% of global capacity. In 2018, Shandong Haili 2a subsidiary of Shandong Bohui3 and Luxi Chemical controlled 22% of global capacity.
The expansive growth of nylon products in Northeast Asia is the driving factor for cyclohexanol/cyclohexanone consumption in the world. China continues to expand, while Japan and Taiwan are not expected to add or reduce capacity for KA oil in the region. South Korea has no domestic production of uncoupled cyclohexanol/cyclohexanone and imports from Japan and Taiwan. Moreover, cyclohexene as a feedstock is relatively more cost0competitive compared with cyclohexane as a feedstock and, thus, there is a rising trend among caprolactam producers to use cyclohexene as feedstock.
Strong caprolactam demand abroad shifted China into a net export position for cyclohexanol/cylcohexanone in 2011. In 2017:, China shifted to a net import position to help satisfy demand. In the next five years, China will likely remain a small net importer.
Global trade in uncoupled cyclohexanol/cyclohexanone represented about 8% of consumption in 2018, with Japan being the largest exporter, followed by Taiwan and Western Europe. Over the next five years, trade volumes are expected to decline. Overall, the market for uncoupled cyclohexanol/cyclohexanone was tight, as a result of global consumption growing at a faster rate than capacity over the last five years, leading to greater availability in the market. In the next five years, the tightness in the market is expected to ease. China will continue to shape the global market for uncoupled cyclohexanol/cyclohexanone.