The MTO patent record is concentrated at the top: a single assignee holds 57 of the 120 records in scope, and the top five assignees together hold 104 records, or 86.7% of the field. This means the practical freedom-to-operate question in MTO is really about clearing prior art from a handful of large integrated chemical and research organisations, not navigating a fragmented field of many small filers. Beyond the top ten assignees, who together account for all 120 records, there is effectively no further tail to consider in this dataset.

No — filing activity peaked at 19 records in 2020 and had fallen to 5 by the 2022 midpoint, indicating the field has cooled from its high point rather than continuing to expand. The most recent year in the dataset should be read cautiously, since patent publication typically lags the actual filing date by around 18 months, so recent-year counts always understate real activity. Taken together, the pattern looks like a technology whose foundational claims were staked out earlier in the period, with later activity being incremental rather than expansive.

Catalysis-related claims under IPC class B01J appear on 63 of the 120 records in scope, or 52.5%, meaning just over half of all filings claim catalyst system elements alongside the core methanol-conversion chemistry. Every record in the dataset carries a C07C classification covering the conversion chemistry itself, so the meaningful differentiator between filings is often whether they also stake a claim on the catalyst side. A design-around strategy focused purely on process conditions without touching catalyst composition claims may still need careful review against this B01J-classified group.

This 2023 filing from China Petroleum & Chemical Corporation covers a fluidized-bed MTO process where methanol contacts catalyst to produce olefins, the catalyst is progressively deactivated and sent to a regenerator, and regenerated catalyst returns to the reactor through a dedicated line. The claim specifically turns on controlling the oxygen content by volume in the gas phase on that regenerated-catalyst return line, which narrows its practical reach to processes managing oxygen levels at that particular point in the reactor-regeneration loop. Processes that manage regeneration differently, or that don't route regenerated catalyst through a comparable dedicated line, sit outside this specific claim scope.

The IPC composition shows a sharp drop-off outside the core C07C and B01J classes: furnace and kiln integration for catalyst regeneration (F27B) appears on only 6.7% of the 120 records, and separation processes (B01D) on just 2.5%. These narrower branches — along with catalyst attrition resistance treated independently of SAPO-34 composition, and ethylene/propylene downstream separation — carry far fewer claims than the core reactor and catalyst-composition space. That makes them a reasonable starting point for new claim drafting, though a proper clearance search against the specific assignees active in those classes is still necessary before filing.