Acetic Acid Carbonylation Patents: Who Leads, Filing Trends 2026
- One filer dominates the ranking. the leading assignee holds 226 of the 283 families tracked, with a steep drop to single digits by fifth place.
- Filing has cooled since its 2021 peak. activity hit 17 filings that year before falling toward the flat-to-declining pattern seen at the 2022 midpoint.
- Separation and catalysis claims trail the core reaction. B01D separation processes appear in 18.4% of records and B01J catalysis in 16.6%, well behind the 99.6% carrying C07C core-chemistry classes.
What this landscape covers
Methanol carbonylation is the dominant industrial route to acetic acid, and the patent record around it concentrates on a narrow set of engineering problems: catalyst stability (rhodium and iridium systems), water content control in the reactor, iodide promoter chemistry, corrosion resistance of reactor materials, and the purification train that separates product from catalyst and byproducts. This dataset pulls 283 published records dated between 2015 and the 2026-07-31 cut-off, filtered to IPC classes C07C51, C07C53 and B01J31.
Because publication typically lags filing by around 18 months, the most recent filing years in this set are undercounted and should be read as a floor, not a ceiling, on actual activity.
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Filing trend and technology composition
Two views of the same 283-record dataset: how filing activity has moved year over year, and which IPC subclasses the records fall into.
Filing trend, 2017–2026
Filings rose from 6 in 2017 to a peak of 17 in 2021, then slowed; by the 2022 midpoint the count was down to 1, and the trend since reads flat to declining. The 2026 figure is partial because the data cut-off is 2026-07-31 and recent filings have not all published yet.
IPC subclass composition
C07C (acyclic and carbocyclic compounds) appears in 99.6% of the 283 records, confirming the corpus is anchored on the core carbonylation chemistry. B01D separation processes (18.4%) and B01J catalysis (16.6%) are the next most common, followed by smaller shares in C07B general organic methods, G01N analysis, and C02F water treatment. Since a record can carry multiple classes, these shares sum to more than 100%.
Shares are the percentage of the 283 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Acetic Acid via Methanol Carbonylation with Eureka
This page is one run against one query. Ask Eureka your own question about acetic acid via methanol carbonylation and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records and a representative filing
EP2327474B1 — Methanol carbonylation system with multi-solvent absorber
Filed by Celanese International Corporation and granted with an effective date of 2018-01-10, this record addresses the absorber stage of the purification train — the equipment that recovers light ends and controls solvent handling downstream of the carbonylation reactor.Original title filed in German; abstract summarised from the record.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US5001259A | Methanol carbonylation process | 1,134 |
| 2 | US5144068A | Methanol carbonylation process | 1,117 |
| 3 | US5026908A | Methanol carbonylation process | 996 |
| 4 | US7223886B2 | Removal of permanganate reducing compounds from methanol carbonylation process stream | 249 |
| 5 | EP0161874A1 | Methanol carbonylation process | 193 |
| 6 | US20090270651A1 | Methanol carbonylation system having absorber with multiple solvent options | 146 |
| 7 | US20080293966A1 | Control of impurities in reaction product of rhodium-catalyzed methanol carbonylation | 107 |
| 8 | US7223883B2 | Removal of permanganate reducing compounds from methanol carbonylation process stream | 98 |
| 9 | US7884237B2 | Methanol carbonylation with improved aldehyde removal | 67 |
| 10 | US8318977B2 | Methanol carbonylation system having absorber with multiple solvent options | 66 |
Citation counts favour older records simply because they have had more time to be cited; treat them as a signal of influence within this corpus, not of current technical importance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Browse MCP servers →What the numbers say about this field
Three patterns stand out once the ranking, the trend and the IPC composition are read together.
One filer holds most of the ranked families
The leading assignee accounts for 226 of the 283 families in the ranking, with fifth place down to 7 and tenth place down to 3. That is a steep drop-off rather than a gradual one, which means most of the ranked companies hold only a handful of families each.
Activity has cooled since 2021
Filings climbed from 6 in 2017 to a peak of 17 in 2021, then dropped sharply — the 2022 midpoint shows just 1 filing. Recent-year momentum data shows the major named assignees all at 0 in the latest tracked year, though the 2026 count is partial given publication lag.
Separation and catalysis trail the core reaction claims
Almost every record touches core C07C chemistry, but only about a fifth of records address separation processes and roughly a sixth address catalysis specifically, despite these being cited as major technical challenges in the field's own search terms — reactor corrosion, water content, iodide promoters and purification.
Filing is spread across several major offices
The United States receives the most filings at 67, followed by the EPO at 37, then Singapore, WIPO/PCT, Malaysia and India. That spread across both mature and Asia-Pacific offices suggests filers are protecting commercial acetic acid production and licensing routes in multiple manufacturing regions rather than concentrating on a single jurisdiction.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to acetic acid via methanol carbonylation, with the prior art for and against each one.
Who is filing, and where the claim space is still open
The ranked list is short — 26 companies — and dominated by one filer, with named individual inventors and a handful of corporate assignees making up the rest.
The dominant filer
One assignee holds the large majority of the ranked families in this dataset, spanning core carbonylation chemistry through to purification-train equipment such as the absorber system in EP2327474B1.
A thin second tier
Past the leader, family counts fall quickly — fifth place holds 7 families and tenth place holds only 3. These are mostly named individual inventors and smaller corporate assignees rather than large chemical majors.
Individual inventors tied to the leader
The strongest co-assignee pairs link named individuals to the dominant corporate filer, each appearing together on multiple families. This pattern is typical of inventor-assignee filing structures inside a single corporate research programme rather than genuine joint ventures.
| Assignee | Recent year | YoY |
|---|---|---|
| Celanese International Corporation | 0 | — |
| LyondellBasell Acetyls LLC | 0 | — |
| Celanese Corp | 0 | — |
| SCATES MARK O | 0 | — |
| TORRENCE G PAULL | 0 | — |
| INEOS Acetyls UK Ltd | 0 | — |
| SHAVER RONALD D | 0 | — |
| BP Chemicals Ltd | 0 | — |
Where to take this next
The dataset points to a mature, concentrated field with specific pockets still open for differentiated claims.
Check freedom-to-operate around the purification train
Separation and catalysis claims are less dense than core reaction claims, but the highest-cited records include purification-stream patents that are worth checking before filing in that space.
Run a freedom-to-operate check →Track the dominant filer's recent activity
With the leading assignee at 0 filings in the latest tracked year and overall activity down from its 2021 peak, a fresh pull closer to the current date would clarify whether this is a genuine slowdown or a publication-lag artefact.
Set up a monitoring alert →Common questions about this landscape
One assignee holds the large majority of the 283 ranked families in this dataset, at 226, with the next closest filers holding single-digit counts by fifth place. This is a heavily concentrated field rather than one with several comparably sized competitors. Smaller assignees and named individual inventors make up the rest of the 26 companies in the ranking, often tied to the leading filer through co-assignee filings.
Filing activity peaked at 17 records in 2021 after rising from 6 in 2017, then declined sharply — the 2022 midpoint shows only 1 filing, and the pattern since reads flat to declining. Recent years should be read cautiously because patent publication typically lags filing by about 18 months, so the last one to two years in any dataset understate true activity. Even accounting for that lag, the overall trajectory points to a mature technology rather than one seeing accelerating investment.
The search terms behind this dataset target rhodium and iridium catalyst systems, water content control in the reactor, iodide promoter chemistry, corrosion of reactor materials, and the purification train. Nearly all records (99.6%) carry core C07C carbonylation chemistry classes, while separation processes and catalysis-specific classes appear in smaller shares of records. That gap suggests the core reaction is heavily claimed while supporting process equipment has comparatively more room.
Based on IPC composition, separation processes (B01D, 18.4% of records) and catalysis-specific claims (B01J, 16.6%) trail far behind the near-universal core reaction chemistry classes (C07C, 99.6%). Specific sub-areas worth examining include corrosion-resistant reactor materials, iodide promoter recovery, and real-time water content control — these support the reaction but are not the reaction claim itself, and filing density there is comparatively thinner. A first claim in these areas would likely need to focus on a specific equipment configuration or control method rather than the reaction chemistry.
EP2327474B1, assigned to Celanese International Corporation with an effective date of 2018-01-10, covers a methanol carbonylation system using a multi-solvent absorber in the purification stage. It sits within the broader purification-train claim space rather than the core reaction, so it is most relevant to anyone designing absorber or solvent-recovery equipment downstream of the carbonylation reactor. Whether it blocks a specific new filing depends on the exact absorber configuration and solvent-handling method claimed, which requires a direct claim-by-claim comparison rather than a landscape-level read.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.