The ammoximation route produces cyclohexanone oxime directly from cyclohexanone using hydrogen peroxide and ammonia over a titanosilicate catalyst, in a single step. The older hydroxylamine route requires a separately manufactured hydroxylamine intermediate, which adds process steps and byproduct streams. This dataset shows ammoximation-related claims sitting inside the dominant C07D and B01J classes, reflecting its status as the more heavily patented modern route, while hydroxylamine-route filings are a smaller, older slice of the same corpus.

The classical Beckmann rearrangement and older oxime-production routes generate large volumes of ammonium sulfate as a low-value byproduct, and its disposal or valorisation has a direct effect on process economics. Despite that centrality, byproduct-handling classes such as C01C (ammonia, cyanides and nitrogen compounds) account for only 1.7% of the 691 records in scope, which is thin relative to the core reaction chemistry. That gap is one of the clearer under-claimed branches in this landscape.

Filing in this space is concentrated: the five most active assignees together account for 398 of 691 records (57.6%), and the ten most active account for 519 (75.1%). The leading assignee alone holds 206 records, several times the count of the fifth-place holder at 39. Major chemical producers with long-running caprolactam and nylon 6 operations dominate the ranking, alongside dedicated research institutes affiliated with large petrochemical groups.

The filing trend suggests maturity rather than growth: annual filings rose from 14 in 2017 to a peak of 19 in 2021, then held around 18 by the 2022 midpoint without further increase. Recent-year momentum data shows even the largest assignees recording zero filings in the latest year, though the roughly 18-month publication lag means the most recent year understates true activity. Taken together, this looks like a settled technology space where innovation is incremental rather than a rapidly expanding one.

The thinnest IPC classes relative to the core chemistry are separation processes (B01D, 2.7% of records) and nitrogen-compound handling (C01C, 1.7%), both of which sit downstream of the main reaction steps rather than inside them. Mixing and reactor design (B01F, 5.1%) is similarly under-represented given how sensitive ammoximation yield is to reactor conditions. These branches are candidates for narrowly scoped claims, but any claim there should be checked against the specific process language of existing filings, not just against IPC class counts.