One assignee leads clearly with 58 of the 92 records in scope for this search, and the top five assignees combined account for 91.3% of all records. This is a highly concentrated field rather than one with many comparably sized players. The remaining seven ranked assignees in the twelve-company list hold small, single-digit counts each, down to one record at tenth place.

Filing activity peaked in 2021 at 53 records and had fallen to 6 by the 2022 midpoint, suggesting a flat-to-declining trend rather than continued growth. Because publication lags filing by roughly 18 months, the most recent one to two years on any chart will always look thinner than they eventually turn out to be, so some caution is warranted before calling the field in decline outright. Even accounting for that lag, the drop from the 2021 peak is steep enough to suggest consolidation around existing claims rather than a slowdown purely from publication timing.

Separation processes are the biggest co-claimed category: B01D appears in 54.3% of the 92 records in scope, meaning more than half of filings pair the cracking reaction with a purification step such as pressure swing purification. Catalysis (B01J, 14.1%) and refrigeration/heat integration (F25B, 16.3%) follow at lower shares. Since a single record can carry multiple IPC classes, these shares add up to more than 100% and should be read as overlapping coverage, not a breakdown of distinct segments.

The thinnest-claimed IPC classes in this dataset are B23K (welding, soldering and brazing, 2.2% of records), C23C (coatings and surface deposition, 2.2%) and B60K (vehicle propulsion and drive, 1.1%). These point toward under-claimed sub-areas such as brazed heat-exchanger construction inside the reactor, anti-coking catalyst coatings, and vehicle-mounted cracking modules. A low share does not guarantee an easy filing path — it can also mean lower commercial interest so far — so any white-space claim should be checked against the leading assignees' broader portfolios before drafting.

In this dataset, the top ten assignees account for 100% of the 92 records in scope, and the top five alone cover 91.3% — there is essentially no long tail of unranked filers beyond the twelve companies the ranking captures. That is a tight structure: a new entrant is very likely to encounter prior art from one of a small handful of established filers regardless of which sub-claim they pursue. Co-filing is also rare, with only two co-assignee pairs identified, so most of this concentration comes from individual companies building their own portfolios rather than joint ventures.