US 2271214

I'll run targeted searches for this specific patent number and any litigation involving it.

Let me search specifically for litigation and any 2026 CAFC activity regarding this patent.

US Patent 2,271,214 — Analyst Summary

Source of authority: Google Patents full text, https://patents.google.com/patent/[US2271214](/patent/US2271214)/en (fetched 2026-09-26). Where the OCR text is garbled, I flag it rather than silently "fixing" the identifiers.

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1. Bibliographic data (as recorded)

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2. Abstract

⚠️ Important caveat: This is a 1942 patent. It has no formal, applicant-supplied abstract — abstracts were not required on US patents of that era. The Google Patents page presents an excerpted passage from the specification in its "Definitions" slot, which functions as a de facto abstract:

"This invention relates to a method for separating free hydrogen from gaseous hydrocarbons containing the same and is of particular application in increasing the hydrogen content of recycle gases in processes for treating hydrocarbons with hydrogen."

I am treating that quoted sentence as the patent's own summary language, not as an official abstract of record.

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3. Technology context (from the specification)

The patent sits inside the 1930s–40s hydrotreating/reforming art. Welty catalogs the relevant refinery processes — destructive hydrogenation (coal or heavy oil, 3000–10,000 cu ft H₂/bbl, 20–200 atm, 500–900 °F), hydrofining (900–1100 °F), and hydroforming (750–850 °F, Mo/Cr/W oxide or sulfide catalysts) — and then focuses on the then-newer catalytic reforming with hydrogen present at 850–1050 °F (pref. 900–1000 °F), 100–1000 psig (pref. 200–400 psig), 1000–6000 cu ft H₂/bbl (pref. 2000–3000), space velocity 0.1–4 (pref. 0.5–1.5). Under those conditions there may be no net hydrogen consumption, or even net hydrogen production, so concentrating and recycling the free hydrogen in the uncondensable gas is economically valuable. Welty notes numerous prior proposals to concentrate H₂ in recycle gas by eliminating gaseous hydrocarbons; his invention is offered as a new route.

Core technical insight: gaseous hydrocarbon hydrates can be formed by contacting the gas with water (or another aqueous medium) under pressure and at low temperature. Because the hydrocarbon hydrates are solid, free hydrogen — which does not form such a hydrate — can be separated from them. Key operating guidance:

• Water as medium: temperature as close to 32 °F as possible; between 32–40 °F may be satisfactory at higher pressures.
• Water is preferably pre-saturated with the hydrocarbon constituents of the gas; in continuous operation it self-saturates.
• Very small water quantity relative to gas — about 100 cc water per cubic foot of gas.
• Alternative aqueous media are expressly contemplated: water solutions of sodium, calcium or potassium chlorides, sulfates or nitrates, and water solutions of ethyl, isopropyl or butyl alcohol, glycerine, or ethylene glycol. With these, freezing point is well below 32 °F, so hydrate formation may occur "at any point above the freezing point of the particular solution or aqueous medium selected."
• Contacting may be by sparging/bubbling through a chilled water body (as drawn) or by fine spray or other mixing means.
• Accumulated hydrates are decomposed periodically by warming the water slightly to release the hydrocarbon gases.

The single figure is a diagrammatic sectional elevation of a hydrotreating unit: oil line 1 → heater 2 → reactor 4 with catalyst; H₂ via line 6/9; effluent through cooler 11 → separator 13; gas through scrubber 16 → one or more hydrate chambers 18 with chilled water lines 20 and cooling coils 21; hydrogen exits via lines 22/23 for recycle, hydrocarbon gases released via 19/17/24. The drawing text on the Google Patents page is badly OCR-garbled (e.g., "Yictor l whTch'corTt'ains a catalyst," "gas-will-befermett," "hydrocar b ons forrn").

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4. Plain-language overview of the independent claims

All four claims are independent; there are no dependent claims. All are directed to the same inventive step: form solid hydrocarbon hydrates with water, then separate the hydrogen-rich remaining gas from the solid.

Claim 1 — Broadest claim.
A process for increasing the free-hydrogen concentration in a gas that contains substantial quantities of free hydrogen plus C₁–C₃ hydrocarbons. Steps: (a) expose the gas to water under superatmospheric pressure and at a low temperature above the freezing point of water; (b) the conditions must be such that solid hydrates of the hydrocarbons may form; (c) separate the remaining gas from the solid hydrates. In plain terms: chill wet, compressed refinery gas so the light hydrocarbons freeze out as a solid hydrate cage, and draw off the hydrogen-rich gas. (Note: OCR renders "substantial quam'itie's'of'l'fe hydrogen" and "superatmosplig liapressure" — garbled encodings of "substantial quantities of free hydrogen" and "superatmospheric pressure.")

Claim 2 — Pressure/temperature-narrowed version of Claim 1.
Same C₁–C₃ + free H₂ feed and same hydrate/separate steps, but expressly limited to pressure in excess of 100 pounds per square inch and a temperature close to but above 32 °F. This adds the numerical operating window that the specification ties to hydrate formation.

Claim 3 — Process-integration claim.
Directs the process at recycle gas obtained from treating hydrocarbon oils with hydrogen at pressures in excess of ___ pounds per square inch (⚠️ the numeral is missing in the OCR text of the granted patent — the line reads "under pressures in excess of pounds per square inch"; I cannot state the value with confidence). The gas contains substantial free H₂ and C₁–C₃ hydrocarbons. Steps: expose the gas to water at substantially the same pressure at which the gas was obtained (i.e., no need to let down the reactor pressure), at a temperature close to but above 32 °F, with temperature, pressure, and water quantity correlated with one another so solid hydrocarbon hydrates form; then separate the remaining gas from the hydrates. The distinctive limitation is keeping the gas at reaction pressure during the hydrate step — an energy-saving integration with the hydrotreating loop.

Claim 4 — Water-ratio claim.
Same feed and same hydrate/separate steps, but recites a specific water dosage: about 100 cubic centimeters of water per cubic foot of gas, under superatmospheric pressure and a low temperature above 32 °F, with temperature and pressure adjusted relative to the quantity of water and the composition of the gas so that solid hydrocarbon hydrates form. This is the "starved-water" operating regime Welty emphasizes (small water volume relative to gas), claimed as a numerical process parameter.

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5. Practical significance

The patent is an early, explicit recognition that gas hydrates can be used as a separation tool rather than merely treated as a flow-assurance nuisance (the specification's era coincides with Bureau of Mines work on hydrate formation in gas transmission lines). It claims a hydrate-based route to hydrogen enrichment of recycle gas — conceptually an ancestor of modern hydrate-based gas-separation ideas, though the specific "form solid hydrate, then separate" approach is distinct from the later mainstream cryogenic, PSA, and membrane routes.

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6. Litigation / CAFC 2026 docket search — result: none found

I searched for infringement litigation, CAFC activity, and case law referencing this specific number (including "2,271,214," "2271214" combined with litigation / Federal Circuit / Standard Oil Development terms). I found no litigation, no CAFC docket, and no 2026 case activity involving US 2,271,214. The conclusive reason is legal, not merely evidentiary:

• The patent's term ran from the 1942 issue date and expired January 27, 1959 (17-year term then in force; Google Patents lists "Anticipated expiration 1959-01-27" and status "Expired – Lifetime"). An expired patent cannot be asserted in an infringement action, so there is no plausible 2026 CAFC docket for this number absent some procedural relic (e.g., a long-running damages accounting), which I found no trace of.
• My searches for the bare identifier produced false-positive hits on unrelated identifiers, which I am explicitly not treating as this patent:
  • EP 2271214 — "Pharmaceutical solutions and method for solubilizing therapeutic agents," Particle Sciences, Inc. (Gwozdz, Loxley, Mitchnick), filed 2009-03-27 — a different office and a different invention. (EP register)
  • A Brazilian STJ internal appeal (AgInt no AREsp 2271214) and a CA 2271214 C Canadian patent — coincidental numbering.
  • A 2024 journal article numbered 2271214 in PPAR Research — coincidental.

Uncertainty disclosure: I did not have direct live access to PACER, the USPTO PatentCenter assignment/transaction record, or a CAFC docket database in this session; my litigation conclusion rests on targeted web searches plus the controlling fact of the 1959 expiration. If you need a negative-litigation assertion fit for a filing, it should be confirmed against Docket Navigator or PACER directly.

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7. Bottom line

US 2,271,214 is a 1942 Standard Oil Development Co. process patent by Albert B. Welty, Jr., filed February 15, 1939, claiming a hydrate-based method of enriching the free-hydrogen content of hydrotreater recycle gas by contacting a high-pressure gas containing H₂ and C₁–C₃ hydrocarbons with chilled water (or a salt/alcohol/glycol/ethylene-glycol solution) so that the hydrocarbons form solid hydrates, which are then separated from the hydrogen-rich gas — optionally at full reaction pressure and with only about 100 cc of water per cubic foot of gas. It is expired (1959) and, so far as the available evidence shows, has never been the subject of litigation, including any 2026 CAFC docket.

I'll search for litigation involving US patent 2271214 across patent litigation sources.

Initial searches returned only unrelated identifiers (EP 2271214, RU 2271214 C1, CN 2271214 Y, a UK trademark). Let me search more specifically for the US patent.

Let me check Unified Patents and litigation databases directly, plus any interference/historical litigation.

Summary of Search Results

Bottom line: I found no litigation — no district court case, ITC action, CAFC appeal, PTAB/post-grant proceeding, or arbitration — involving U.S. Patent No. 2,271,214. I report this as "none found," not as "none exists," for the reasons in the caveats below.

Patent identification (literal interpretation of the number)

U.S. Patent No. 2,271,214

• Title: "Separating hydrogen from gaseous hydrocarbons"
• Inventor: Albert B. Welty, Jr. (Elizabeth, N.J.)
• Original assignee: Standard Oil Development Company (Delaware)
• Application No.: 256,415 · Filed: February 15, 1939 · Granted/Published: January 27, 1942
• Claims: 4 (all process claims for concentrating free hydrogen in a gas by forming solid hydrocarbon hydrates)
• Google Patents legal status field: "Expired – Lifetime"; the page lists an anticipated expiration of January 27, 1959 (17-year term under pre-1956 law)
• Source: https://patents.google.com/patent/[US2271214](/patent/US2271214)/en

Search results for litigation

Important warning: unrelated "2271214" hits (do NOT confuse these)

Every non-U.S. hit using this digit string is a different patent or mark, and I flag them because a naive search will conflate them:

• EP 2271214 — Particle Sciences, Inc., "Pharmaceutical solutions and method for solubilizing therapeutic agents" (EP app. 09724079.0, filed 2009-03-27, granted 2017-05-03, lapsed ~2018). This is the source of the Belgian, Irish, and Lithuanian register hits.
• RU 2271214 C1 — Russian patent on complex correction of hypermetabolic disturbance in patients.
• CN 2271214 Y — Chinese utility model, "Information card with hidden magnetic hole."
• U.K. Trademark 2271214 — AMT Coffee Limited (classes 29–32, 43).

None of these is U.S. Patent No. 2,271,214.

Why no litigation is plausible/expected

1. The patent is long expired. Its term ended in 1959 — roughly 67 years before the current date. An expired patent cannot support an infringement action.
2. Modern litigation databases do not reach it. The Unified Patents portal, PTAB records, and PACER effectively cover the 1980s onward. Any federal suit over a patent that expired in 1959 would have to have been filed between 1939 and 1959, and such records are largely not indexed in the databases available to me.
3. The "Cited By" list on Google Patents is not litigation. The six documents citing the patent (e.g., US 2415700, US 2432423, US 2898288, US 2904511, US 3288646, US 5660603) are later patents citing it as prior art — not lawsuits. Likewise the "Similar Documents" list is prior-art similarity, not litigation.
4. Standard Oil Development Company's known 1930s–1950s petroleum patent litigation (e.g., Standard Oil Co. v. United States, 283 U.S. 163 (1931); Alamo Refining Co. v. Shell Development Co.; Standard Oil Development Co. v. Marzall, 181 F.2d 280 (D.C. Cir. 1950)) concerns cracking/reforming patents, and my searches surfaced no pleading specifically naming 2271214.

Caveats and confidence

• High confidence that there is no litigation involving US 2,271,214 in the modern, searchable corpora (district courts post-1980s, CAFC, PTAB, ITC, Unified Patents).
• Low confidence / cannot exclude any pre-1959 infringement or interference proceeding. A full answer would require pre-1988 federal court records, the USPTO's historical interference records, and judicial digests of that era — none of which are reachable through the tools used here. If a pre-1959 suit exists, it would be in paper archives, not online dockets.
• I have not fabricated case names, numbers, jurisdictions, or dates. Where the record is empty, I have said so rather than supplying an inference.

If you want to close the historical gap, the next steps would be: a manual search of the United States Patent Quarterly / Decisions of the Commissioner of Patents digests for 1942–1959, and a check of the 2nd/3rd Circuit and D.N.J. archived case files (Standard Oil Development Co.'s home jurisdiction) for that window. I can't verify those from here.

I'll verify the ODP-derived "no proceedings" baseline with targeted searches before writing this up.

One more verification pass — checking for numbering confusion and any related AIA-trial records.

Proceedings overview

Total AIA trial proceedings on US 2,271,214 ("Separating hydrogen from gaseous hydrocarbons," Welty/Standard Oil Development Co., filed 1939-02-15, granted 1942-01-27): zero. Breakdown: 0 active, 0 claims invalidated, 0 claims sustained, 0 settled, 0 institution denials — no IPR, PGR, or CBM has ever been filed against this patent. The defensive posture is not "hardened patent" and not "dead claims"; it is "expired patent outside the AIA trial system entirely." The patent's ODP/Google record shows an anticipated expiration of 1959-01-27 (the pre-1995 seventeen-year term running from the 1942 grant), roughly 53 years before the first AIA petition could be filed on 2012-09-16. Any demand letter citing this number is citing a patent that has been in the public domain for over six decades — the practical defense is expiration and the 35 U.S.C. § 286 six-year damages window, not an IPR.

No proceedings to report

There is no proceeding number to populate here, and I will not manufacture one. For completeness on why the count is zero:

• PGR is statutorily unavailable. 35 U.S.C. § 321(c) limits post-grant review to patents with an effective filing date on or after 2013-03-16. This patent's effective filing date is 1939-02-15.
• CBM is unavailable on two independent grounds. The transitional CBM program reached only "covered business method" patents (financial-services technique), and it sunset on 2020-09-16. A 1942 catalytic hydroforming / gas-hydrate separation patent is neither.
• IPR was the only theoretically available vehicle. The Board has historically been willing to institute IPR on expired patents, so nothing categorically foreclosed a petition. But an expired patent offers only pre-expiration back damages, and here the § 286 six-year lookback closed around 1965. There was never an economic reason for any petitioner to spend IPR fees on this number.
• No reexamination history surfaced either. The full text at https://patents.google.com/patent/US2271214/en shows the original four claims exactly as granted, with no reexamination certificate, amended claim set, or cancellation. (I checked the record as reproduced; I did not separately pull the paper file at https://patentcenter.uspto.gov/ — worth a five-minute confirmatory pull if you actually need to certify the claim set.)

Search corroboration. Targeted searches for this patent number in the PTAB context returned nothing on-point. Every hit was a different patent whose number merely ends in "214" — e.g., Xilinx v. Arbor Global Strategies, IPR2020-01567 (US 7,126,214, final decision 2022-03-02, all claims unpatentable); the Collins reference US 5,505,214; and the unrelated European publication EP 2,271,214 (Particle Sciences, "Pharmaceutical solutions and method for solubilizing therapeutic agents," granted 2017-05-03, since lapsed) and Chinese utility model CN 2271214 Y. Those are not proceedings on this patent and should not be confused with it.

Strategic summary

Claim status: 1, 2, 3, and 4 are UNTESTED — and that distinction is meaningless here. No claim of 2,271,214 has been canceled, narrowed, or sustained by the Board, because no claim of it has ever been challenged in an AIA trial. What is documented is that the patent expired on 1959-01-27 and lapsed into the public domain. All four claims are method claims drawn to contacting a hydrogen-plus-C₁–C₃-hydrocarbon gas with water under superatmospheric pressure at low temperature to form solid hydrocarbon hydrates, then separating the hydrogen-rich gas — claim 1 is the broad genus; claim 2 adds a >100 psi and near-32 °F limitation; claim 3 ties the pressure to the pressure of the hydrogen-treatment process that generated the gas; claim 4 specifies roughly 100 cc of water per cubic foot of gas.

Estoppel landscape is empty — and irrelevant. 35 U.S.C. § 315(e)(2) estoppel only attaches to parties who actually petitioned. No one petitioned, so no petitioner or privy is estopped, and no ground is foreclosed to anyone. But that is a hollow advantage: there is no infringement defendant to be estoppel-constrained, because there is no enforceable right. If you are being threatened under this number, do not spend money on an invalidity case. Spend it on a one-page chronology showing grant on 1942-01-27, expiration on 1959-01-27, and the resulting unenforceability of any infringement theory — plus the § 286 bar on any pre-1965 damages.

Pattern signals: none, and none possible. There is no repeat-petitioner pattern, no serial-IPR dynamic, no defensive aggregator (no Unified Patents, RPX, or similar) in any chain, and no Federal Circuit appeal, because there is no proceeding to appeal. For context, this patent's continuing relevance is as prior art, not as a weapon: it sits in the backward-citation trail of later hydrate-based gas-separation patents such as US 5,660,603 (International Process Services, 1997) and US 2,898,288 (Socony Mobil, 1959), so it is far more useful to someone attacking a modern hydrate-separation claim than to anyone asserting it.

One practical caveat. A "no PTAB activity" finding for a 1942 patent is a function of age, not of market testing. A well-asserted modern patent almost always attracts IPRs. This one never could. The absence of PTAB activity here therefore tells you nothing about whether the patent is strong — it tells you the patent is old enough that AIA trials were legislated into existence long after it died.

Recommended next steps

1. Treat the patent as expired and unenforceable, and say so in writing. Cite the ODP/Google record: filed 1939-02-15, granted 1942-01-27, anticipated expiration 1959-01-27 (https://patents.google.com/patent/US2271214/en). There is no PTAB record to link because none exists; if you want a citable negative, run the number through PTAB E2E (https://ptacts.uspto.gov/ptacts/) and the Patent Trial and Appeal Board decisions search, and preserve the null result in your file.
2. Check for a number-transcription error before assuming bad faith. If a demand letter cites "2271214," verify whether the sender meant a modern US patent ending in 214, the European EP 2,271,214 (Particle Sciences — pharma solubilization, unrelated field), or the Chinese CN 2271214 Y. Asserting a number that resolves to an expired 1942 petrochemical patent in an unrelated technology is a strong indicator of a copy-paste or lookup error rather than a real campaign.
3. If the sender insists, escalate on the record. A demand premised on a patent that expired in 1959 — with the § 286 damages window closed by roughly 1965 — is not a close validity question. Consider a declaratory judgment action for non-infringement/expiration, and evaluate Rule 11 exposure under the pre-suit investigation duty to the extent the letter advances a knowingly time-barred claim.
4. Don't waste the position on an IPR. There is nothing to institute. Save the AIA-trial budget; the winning paper here is a three-date chronology and the expiration statute.
5. Separately, verify the paper file at PatentCenter (https://patentcenter.uspto.gov/) for any reexamination certificate or disclaimer that the reproduction might have dropped. I saw no such certificate, but confirming the claim set on the face of the file costs little and forecloses the argument that an amended claim somehow survives.

Confidence and limits: I am highly confident there are no AIA trial proceedings on US 2,271,214 — the structured ODP block says so, and targeted searches found only number-similar unrelated patents. I did not independently audit the pre-AIA reexamination files at the USPTO, and I did not find (and have not assumed) any US patent numbered 11,271,214; if a directory check turns one up, treat it as a separate patent requiring separate analysis.

I'll search for the assignment record for this patent before writing anything.

Nothing on assignment records yet. Let me query the USPTO assignment API endpoints and Google Patents legal events directly.

Let me check what date coverage the USPTO assignment database has, and try to reach the assignment API directly.

Access limitation — read this first

I must be straight with you: I was unable to retrieve a single verified reel/frame record for US 2,271,214 in this session. My calls to the USPTO assignment API/lookup path did not return assignment JSON, and I exhausted my search budget before I could pull the Assignment Center result set directly. I did not have live, page-level access to https://assignmentcenter.uspto.gov/ or https://assignment.uspto.gov/patent/index.html.

Two distinct findings, which must not be conflated:

1. What I can state with confidence: There is one assignment of record documented on the face of the patent itself — the front page reads "Albert B. Welty, Jr., Elizabeth, N. J., assignor to Standard Oil Development Company, a corporation of Delaware" (US2271214A, issued 1942-01-27). That is an inventor→corporate pre-issue assignment. I have no reel/frame number for it and am not going to invent one.
2. What I cannot state: I cannot confirm whether the Assignment Center shows additional post-issuance links, nor can I certify a "no records" result. Note also that Google Patents' legal-events feed for this patent shows only "Application granted" (1942-01-27) and "Anticipated expiration" (1959-01-27) — no recorded reassignments appear in the indexed data, which is consistent with (but not proof of) a chain that never left the original assignee's corporate family.

Where I say "unverified" below, treat it as a genuine open item requiring a direct Assignment Center query, not as a soft finding.

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Inventors

Single-inventor patent — no co-inventors, so there is no multi-inventor assignment-splitting issue to trace.

Departure pattern: not present. This is a positive finding against the "inventors bolt within 12 months" tell. Welty stayed with the same corporate family for at least another decade and a half: he appears as a co-inventor on US 2,694,623, "Process for the Enrichment of Water Gas" (filed 1949, issued 1954-11-16), inventors Albert Welty and Sumner Sweetser, assignee Standard Oil Development Co. Same assignee, ~15 years later. That is the profile of a career refinery-process chemist inside a major oil company's R&D arm — the opposite of a portfolio about to be fire-sold.

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Original assignee

Standard Oil Development Company, a Delaware corporation (per the patent face), with its laboratories at Linden, New Jersey.

• Primary line of business: the centralized research, development and patent-holding arm of Standard Oil Company (New Jersey) — the entity created in the 1927 Jersey Standard reorganisation to consolidate petroleum process R&D and patent prosecution. It was an operating R&D organization, not a licensing shell: it ran pilot plants and process-development laboratories and was a prolific filer in hydrogenation/hydroforming chemistry (see e.g. US 2,241,500, US 2,248,869 filed out of the same organization).
• Did it ship a product embodying the claims? Yes, in the relevant sense — the patent is a process patent for a step inside Jersey Standard's own catalytic hydrotreating/reforming refinery flow (the specification expressly targets "recycle gases in processes for treating hydrocarbons with hydrogen"). The assignee was itself building and practising those hydrotreating processes; the claimed hydrate step was an internally-practised process improvement, not a licensed abstraction.
• Current status / corporate lineage: Standard Oil Development Company → renamed Esso Research and Engineering Company in 1955 → renamed Exxon Research and Engineering Company in 1974 (Library of Congress name-authority record, https://id.loc.gov/authorities/names/n79066875.html, noting "In 1955 the Standard Oil Development Company became the Esso Research and Engineering Company. The name was changed in 1974 to Exxon Research and Engineering Company."). Not dissolved, not bankrupt — it sits inside today's ExxonMobil. That lineage matters: any 1955 or 1974 "change of name" filings for patents still in force would have run through Exxon's IP counsel, not through any licensing vehicle.

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Assignment timeline

Verified entries: none with a reel/frame I could confirm.

Assignment documented but not reel/frame-verified:

• Execution date not verified (necessarily on or before the 1942-01-27 issue date; typically executed proximate to the 1939-02-15 filing) / recording date not verified — Reel not retrieved
  • Conveyance: Assignment (pre-issue, inventor to company)
  • Assignor: Albert B. Welty, Jr.
  • Assignee: Standard Oil Development Company (Delaware)
  • Correspondent: not retrieved — I will not guess at the attorney of record. For this era the recording correspondent would most likely have been in-house Patent Division counsel at Standard Oil Development Co., but that is inference, not evidence, and the Assignment Center record is the only thing that settles it.
  • Context: original corporate assignment — the inventor vested his rights in his employer's R&D subsidiary as a condition of employment; the standard 1930s–40s oil-industry practice, no third party involved.

Additional entries: undetermined. Whether the Assignment Center shows later links (a 1955 "Change of Name" to Esso Research and Engineering, a 1974 Change of Name to Exxon Research and Engineering, or a transfer on the 1959/1960s patent-plasticisation side) is unclear. Note the term mechanics: the patent expired 1959-01-27, before the 1974 Exxon renaming, so no Change of Name recording would have been needed for the 1974 renaming as to this patent. A 1955 Esso-name-change recording is chronologically possible but I found no trace of one.

⚠️ Two search-result artifacts I encountered and am explicitly not treating as this patent: EP 2271214 ("Pharmaceutical solutions and method for solubilizing therapeutic agents," Particle Sciences, Inc., filed 2009-03-27) and CA 2271214 (an NCR/Diebold-style automated banking machine patent). Coincidental numbering, different offices, different decades.

Verification link (please run this yourself to close the gap): https://assignmentcenter.uspto.gov/ — search by patent number 2271214; the parallel index is https://assignment.uspto.gov/patent/index.html.

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Timeline diagram

timeline
    title Ownership of US 2271214
    1939 : Filed by Albert B Welty Jr
         : Rights assigned to Standard Oil Development
    1942 : Patent issued to Standard Oil Development
    1955 : Assignee renamed Esso Research and Engineering
    1959 : Patent term expired
    1974 : Renamed Exxon Research and Engineering

Event text kept to simple year labels and short strings; no parentheses, slashes or commas. The 1974 and 1955 renames are shown as corporate milestones of the original assignee — they are not verified as recorded assignments against this patent number.

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NPE / troll-pattern signals

The framing caveat first: this patent's enforceable life ended 1959-01-27. The entire modern NPE playbook — 1980s onward — post-dates it by decades. So most signals below are "not present" for a structural reason rather than for want of evidence, and I say which is which.

1. Shell-entity transfer — not present. No evidence of any transfer out of the Standard Oil/Esso/Exxon corporate family. The only assignee ever documented is an operating R&D subsidiary of a major integrated oil company. No "IP / Holdings / Licensing / Ventures" successor appears anywhere in the record I could reach. (If the Assignment Center query shows a link I could not retrieve, this call would need revisiting — that is the one place a surprise could hide.)

2. Known asserter in the chain — not present. No assignee in the documented chain matches any public NPE list — not Acacia, Marathon, IV, Wi-LAN/Conversant, Round Rock, Pendrell, or any Unified Patents/RPX high-frequency plaintiff. Assignee is Standard Oil Development Co.; corporate successor is ExxonMobil, an operating company.

3. Repeat correspondent across the chain — unclear. I could not retrieve a single recorded correspondent for this patent, so I cannot test recurrence. I am deliberately recording this as unclear rather than absent — "no correspondent found because I couldn't open the records" is not the same as "no recurring correspondent." Do not treat this row as cleared.

4. Cascading transfers — not present. No chained LLC assignments within any 24-month window. There are no LLC assignees at all in the documented chain.

5. Pre-litigation transfer — not present. No infringement suit naming this patent exists (consistent with the 1959 expiration), so there is no suit to have been preceded by an arranged transfer. Signal is inapplicable.

6. Bankruptcy fire-sale — not present. Neither Standard Oil Development Company nor Jersey Standard/Exxon ever filed Chapter 7 or 11. Distinguish the 1911 Standard Oil antitrust dissolution — a Sherman Act decree breaking up the trust 28 years before this application was filed. It is not a bankruptcy, did not touch this patent, and is a common misreading of "Standard Oil" hits.

7. Privateering — not present. No evidence the original assignee pushed this patent to an NPE to assert against competitors. Standard Oil Development's practice in this era was internal practice plus cross-licensing (e.g. its 1930s Italian-registry transfers to International Hydrogenation Patents Co. Ltd., Vaduz, for carbonaceous-material hydrogenation — a pooling arrangement among majors, not privateering). I found no comparable transfer for US 2,271,214.

8. Defensive aggregator (anti-NPE) — not present. Chain does not terminate at RPX, AST, LOT, Unified Patents, or OIN. Note the inverse observation: by 1959 this patent was already in the public domain and unassertable, so it was never a candidate for defensive aggregation — its neutralization happened by expiration, not by acquisition.

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Verdict

Insufficient data — specifically, the "only the original assignment" branch of that category.

Justification: The sole ownership fact I can ground is the assignment recited on the patent face — Albert B. Welty, Jr. of Elizabeth, N.J. → Standard Oil Development Company, a Delaware corporation — with no reel/frame retrieved, and no post-issuance assignment traceable anywhere (Google Patents legal events, 1942–1959, show only grant and expiration). No NPE signal is present, and the strongest negative evidence is structural: the term expired 1959-01-27, roughly two decades before the modern assertion industry existed. I am not upgrading this to a confident "operating-company / non-asserting" verdict because I never actually opened the Assignment Center record for this number, and I will not infer absence of records from absence of access.

To close this out, run the search here: https://assignmentcenter.uspto.gov/ (patent number 2271214), and capture the correspondent of record for any entry — that single field is the one item in this report I could not obtain and the one I would most want before signing off.

I'll search for the specific patent number and its citation/prior-art record before analyzing.

Now let me pull the actual patent document/front page and probe the field's prior art (gas hydrate formation, hydrogen separation) contemporaneous with the 1939 filing.

I hit the tool-call ceiling while chasing two follow-up queries (the patent's own examiner-citation block and the 1934 Hammerschmidt hydrate paper), so I'll flag what I could and could not verify. Everything below builds on the prior sections rather than restating them.

1. Identifier confirmation (no substitution)

Patent number searched: 2,271,214 / US2271214A. The record returned is the same document analyzed earlier — Separating hydrogen from gaseous hydrocarbons, Albert B. Welty, Jr., Standard Oil Development Co., filed 1939‑02‑15, issued 1942‑01‑27. I did not accept any near-miss identifier (e.g., EP 2271214, Brazilian AgInt no AREsp 2271214, CA 2271214 C, PPAR Research article no. 2271214), consistent with the earlier "false positive" note.

2. Critical framing: the fetched record contains no backward citations

This is the single most important finding for your question, and it does not match the premise "look at each patent citation for 2271214":

• The Google Patents record for US2271214A as fetched contains only a "Cited By (6)" block — i.e., forward citations (later documents that cite this patent).
• It contains no "Citations" / "References Cited in the file of this patent" block — i.e., the examiner/applicant prior-art list that would be the §102 prior art.
• The only other lists on the page ("Similar Documents," "Family Applications") are not citations to this patent's prior art.

Consequence: On the record available to me, there is no cited prior art of record for US 2,271,214. I cannot produce a "cite and analyze each reference" list for §102 because the source contains no such list. I am explicitly declining to manufacture one. (Caveat: Google Patents' machine-readable text sometimes omits the 1930s-era "References Cited in the file of this patent" block that appears on the printed face of the patent. I could not open the PDF or the PatentCenter file wrapper in this session to confirm whether such a block exists — see §5.)

3. The six forward citations ("Cited By"), with §102 verdicts

These are cited by later patents against, or as background relative to, this patent — they are not prior art against it. Dates are the priority/filing and publication dates as given in the record.

Corroboration of the citation direction: the examiner citation block of US 3,288,646 lists "2,271,214 1/1942 Welty 23‑210," and US 2,898,288's "References Cited in the file of this patent" lists "Welty Jan. 27, 1942" among its references. Both confirm the '214 patent flows outward as a cited reference — it is the cited art, not the citing art. (The same US 2,898,288 block also lists Pyzel July 29, 1941; Layng et al. Dec. 5, 1944; Danner et al. Dec. 30, 1947; Cardwell et al. Dec. 22, 1953; Kirshenbaum June 5, 1956; Guernsey July 17, 1956 — but those are references in another patent's file, not US 2,271,214's. I did not verify their patent numbers and will not supply them.)

4. §102 analysis — why none of the six can anticipate

Because the application was filed February 15, 1939, pre‑AIA 35 U.S.C. §102 governs (the AIA §102 regime, effective 2013, is inapplicable to this filing). The controlling cutoffs:

• §102(b) statutory bar: a US or foreign patent or a printed publication dated more than one year before the US filing date, i.e., before February 15, 1938.
• §102(a): knowledge/use by others in the US, or patenting/publication anywhere, before the invention date (here, no later than February 15, 1939).
• §102(e): a US patent granted on an application filed before the invention date.
• §102(g): prior invention by another.

Applying these:

• Every one of the six references has a filing/priority date of 1942 or later. Not one predates February 15, 1938 (§102(b)), and not one predates the February 15, 1939 filing (§102(a), (e)). Therefore none of the six is available as §102 prior art at all, and none can anticipate claim 1, claim 2, claim 3, or claim 4 — the verdict for each is No, on date grounds alone, independent of subject matter.
• Independently, the subject matter also fails to meet the claims' core limitation (form solid hydrocarbon hydrates with water/aqueous medium and separate the H₂-rich gas). US 2,415,700 is a hydrotreating process; US 2,432,423 is ethylene purification/compression; US 2,898,288 is refrigerated recycle in reforming; US 2,904,511 uses hydrates but to desalinate water; US 3,288,646 is a fuel-cell method; US 5,660,603 is a hydrate-based natural-gas separation (but post-dates by 56 years). Substantive overlap with the hydrate concept appears only in the later documents, which is why they cite '214 rather than anticipate it.
• Practical note: the patent expired January 27, 1959, so no §102 analysis of it has operative legal consequence today. This is a validity/priority-date exercise, not an enforcement question.

5. Genuine prior art landscape (what would have been §102 art) — and its limits

Since the record supplies no cited references, the relevant question becomes: what art pre-dating 1938/1939 existed on gas-hydrate formation, and could it anticipate? From what I could ground:

• Hammerschmidt, E. G., "Formation of Gas Hydrates in Natural Gas Transmission Lines," Industrial & Engineering Chemistry, 1934, 26, 851 — the foundational paper establishing that light hydrocarbons (methane, ethane, propane, etc.) form solid hydrates in pressurized, chilled gas systems. Its citation appeared in a retrieved reference list (the Canadian Journal of Chemical Engineering hydrate-desalination review surfaced in my searches) and it is a pre‑1938 printed publication for §102(b) purposes. However, it addresses hydrate plugging as a flow-assurance problem; it does not disclose separating free hydrogen from C₁–C₃ hydrocarbons by hydrate formation. It is therefore enabling background/§103 material on the hydrate phenomenon, not an anticipation of claims 1–4.
• The 1930s Bureau of Mines/gas-transmission hydrate work sits in the same category.
• Flag: my two follow-up searches (the 1934 Hammerschmidt full text and a search for 1938–1939 patents on hydrogen/hydrocarbon separation by hydrates) timed out at the step limit. I could not complete a systematic pre‑1938 patent sweep. I am stating the Hammerschmidt citation from a secondary reference list, not from direct examination of the paper.

Also relevant to your framing: this extends the earlier observation that the patent's term expired in 1959 — a 1939 filing also means the §102 window closes in February 1938, which is why the substantive prior art (if any) would have to be found in 1920s–1930s gas-processing and hydrate literature, not in the patent's own citation record.

6. Contradictions / corrections to the earlier sections

• No contradiction in substance, but one framing correction: the earlier section's "Cited by (6, later documents)" should not be read as "prior art." Your current task's premise ("look at each patent citation for 2271214") implicitly treats the Cited‑By list as prior art. It is not, and per §3–§4 it cannot be.
• The earlier section's flags all carry forward and matter here: (a) claim 3's missing pressure numeral in the OCR ("under pressures in excess of ___ pounds per square inch") means I cannot fully characterize claim 3's scope; (b) claim 1's garbled OCR ("substantial quam'itie's'of'l'fe hydrogen," "superatmosplig liapressure"); (c) claim 3's garbled hydrate phrase ("solid 'iiydratesmLthemdmcarbons").

7. Bottom line

• US 2,271,214 was searched and confirmed as a distinct document; no similar-number substitution was made.
• The patent's citation record contains no prior-art citations — only 6 forward citations. On this record, there is no cited §102 prior art to analyze, and I will not invent one.
• All 6 forward citations postdate the 1939 filing (1942–1995), so none anticipates claims 1, 2, 3, or 4 under §102(a), (b), (e), or (g). Verdict for each: No.
• The most relevant genuine prior art in the field is the pre-1938 hydrate literature (Hammerschmidt 1934 and related gas-industry work), which anticipates none of the claims: it discloses hydrate formation as a nuisance, not hydrate-based hydrogen/hydrocarbon separation.
• Uncertainty disclosure: I could not access the USPTO PatentCenter file wrapper or the printed face/PDF of US 2,271,214, nor complete a pre‑1938 patent sweep, in this session. If the printed patent carries a "References Cited in the file of this patent" block that Google omits, that block — not the Cited‑By list — would be the definitive §102 art list and should be pulled from the PatentCenter file wrapper or the PDF before any filing-grade negative assertion is made.

I'll ground this §103 analysis in the actual prior-art record before building the combinations.

Excellent — that surfaced a directly-on-point hydrate-separation patent I need to pin down. Let me date the key references.

I hit the step ceiling mid-verification, so I'll flag exactly which reference dates I confirmed and which I could not. This builds on the earlier Prior Art section (which established that US 2,271,214 has no cited prior art of record — only six forward citations, all post-1939) and on the claim-construction caveats already flagged (claim 3's missing pressure numeral; OCR corruption in claims 1 and 3).

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§103 Obviousness Analysis — US 2,271,214 (Welty, filed 1939-02-15)

0. Three framing points that constrain everything below

(a) §103 itself did not exist when this patent was granted. 35 U.S.C. §103 was enacted by the Patent Act of 1952 and applied only to applications filed on or after January 1, 1953. US 2,271,214 was filed in 1939 and granted in 1942. In its own era it could only have been attacked for lack of "invention" under R.S. §4886 as construed in Cuno Engineering Corp. v. Automatic Devices Corp., 314 U.S. 84 (1941) ("flash of genius") and A&P Tea Co. v. Supermarket Equipment Corp., 340 U.S. 147 (1950). Those cases cut toward validity. I therefore analyze under modern pre-AIA §103(a) (Graham v. John Deere, 383 U.S. 1 (1966); KSR Int'l v. Teleflex, 550 U.S. 398 (2007)) as instructed, while noting the result would have been harder to reach in 1942.

(b) The prior art set must be built from outside the patent's own record. Because the record contains no "References Cited in the file of this patent" block, there is no examiner-constructed §102 list to test for §103. Every combination below is constructed from art independently verified to predate the critical dates. I could not pull the paper file wrapper (PatentCenter), so there may be art of record I have not seen.

(c) The exercise is academic. Term expired 1959-01-27. No §103 holding here has any operative defensive value.

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1. Person having ordinary skill in the art (PHOSITA), as of February 1939

A refinery chemical engineer holding a B.S. in chemical engineering plus roughly 2–5 years in petroleum refining gas handling / low-temperature gas processing. Such a person would be familiar with: (i) the Bureau of Mines and Industrial & Engineering Chemistry gas-hydrate literature (then ~5 years mature); (ii) refinery recycle-gas loops and the economics of hydrogen partial pressure; (iii) dew-point/cold-separation practice for removing light ends from gas; (iv) the cost of recompression in a recycle circuit. Critically, this PHOSITA would not need to discover that light hydrocarbons form solid hydrates — that was established, published art by 1934.

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2. The properly available §103 reference set (dates confirmed unless noted)

What R1 actually discloses (verified abstract): solid compounds "resembling snow or ice" formed with CH₄, C₂H₆, C₃H₈ and iso-C₄H₁₀ in the presence of water at elevated pressures and temperatures; formation depends on pressure, temperature and gas–water-vapor composition; melting point of the mixed hydrates in a natural-gas mixture runs from ~34 °F at 110 lb./sq. in. abs. to ~60 °F at 800 lb.; a pressure–melting point relation Y = 8.9X^0.285; hydrates contain 6–7 mols H₂O; formation accelerated by high gas velocity, pressure pulsation, or inoculation.

Note what is absent from Hammerschmidt's hydrate-former list: hydrogen. That omission is the fulcrum of the whole obviousness question.

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3. Claim element chart against the available art

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4. The combinations that would render the claims obvious — and the motivation

Combination A — R1 (Hammerschmidt 1934) + R6 (admitted art: recycle-gas H₂ enrichment) → claims 1 and 2

Rationale: (i) combining prior art elements according to known methods to yield a predictable result; (ii) use of a known technique (chilling a wet, pressurized light-hydrocarbon gas) to improve a similar process in the same way.

Motivation to combine: R6 establishes the unmet need — raising H₂ concentration in hydrotreater recycle gas by eliminating gaseous hydrocarbons — and R1 supplies a known, published, quantitative means of converting exactly those hydrocarbons (C₁–C₃) into a solid phase at a specified pressure/temperature window. A PHOSITA seeking an alternative to scrubbing/condensation for light-end removal would find in R1 a method that removes light ends as a solid, which is separation-trivial by gravitational settling or filtration. The selectivity is supplied by the art itself: R1 enumerated the hydrate formers as methane, ethane, propane and isobutane and did not include hydrogen.

Why the result is predictable rather than inventive: the separation outcome follows directly from known physical chemistry — the guest molecules that occupy the water cages are the C₁–C₃ hydrocarbons, hydrogen does not (a fact confirmed by later literature: hydrogen clathrate hydrate required the extreme-pressure work of Dyadin et al., Mendeleev Commun. 9(5):209 (1999) and Mao et al., Science 297:2247 (2002), i.e., ~200 MPa-regime conditions unknown in 1939). The PHOSITA would have a reasonable expectation of success (In re O'Farrell, 853 F.2d 894 (Fed. Cir. 1988)).

Claim 2 in particular is the weakest claim in the patent. Its numerical window is not merely suggested by R1 — it is read off R1's table (34 °F at 110 psia) and R1's equation Y = 8.9X^0.285. Under In re Aller, 220 F.2d 454 (CCPA 1955), and KSR, optimizing a recognized, result-effective process parameter within a range disclosed by the art is obvious absent a showing of criticality. The specification offers no criticality data. I would expect claim 2 to fall on this combination.

Combination B — R1 + R4 (Schuftan) → claim 1, and R4's salt/alcohol teaching → the specification's alternative aqueous media

R4 is the closest available patent art and the most useful single reference, because it (a) is a US patent granted on a 1937-12-02 application, making it pre-AIA §102(e) art as of a date before Welty's filing; (b) describes hydrate formation in the same refinery gas milieu ("cracked gases, hydrogenation gases, etc.… as is done, for example, in the production of motor fuels"); (c) confirms the pressure/temperature regime (cooling to about 0 °C; hydrate formation "only at temperatures below 7° C." absent inhibition); and (d) discloses that alcohol, salt solutions (e.g., ammonium nitrite) and the lowering of partial pressures control hydrate formation — i.e., the very media Welty claims as alternatives.

Motivation to combine R1 + R4: both references address the same physical phenomenon in the same industrial setting. A PHOSITA reading R4's statement that hydrate formation occurs in hydrogenation gases during low-temperature separation, alongside R1's quantitative formation conditions, would have both the system and the conditions. R4's disclosure of salt/alcohol media also expressly teaches the freezing-point-depression route that Welty presents as an alternative embodiment — meaning those embodiments attract an even stronger §103 case than the water-only claims.

However — see §5. R4 points the opposite direction from Welty on the key step.

Combination C — R1 + R6 + R5 → claim 3 (pressure-retention)

The distinctive limitation of claim 3 is doing the hydrate step at substantially the gas's original pressure. The motivation is purely economic and well known: recompression dominates the cost of a refinery recycle loop, so one keeps the stream at pressure across intermediate treatment steps. R5 expressly recites maintaining initial pressure through successive cooling steps specifically because depressurizing would re-evaporate condensed water and increase downstream drying burden, and because the retained pressure "permits economical recompression thereof." A PHOSITA would therefore have been motivated to site a chilling/hydrate step downstream of the reactor without a let-down, exactly as claim 3 requires — and the specification itself concedes this by noting the scrubbed gas is "still under reaction pressure."

Caveat that materially weakens this analysis: the OCR of claim 3 reads "under pressures in excess of ___ pounds per square inch" — the numeral is missing in the granted text as fetched. I cannot verify whether claim 3's pressure limitation is coextensive with claim 1's "superatmospheric" or adds a distinct threshold. Claim 3's obviousness verdict is therefore qualified, not definitive.

Combination D — R1 + R4 → claim 4 (≈100 cc water/ft³ of gas)

Once the hydrate-separation step is chosen, the water dosage is a result-effective variable optimized by routine calculation: R1 gives the hydrate stoichiometry (6–7 mol H₂O per mol of guest), from which the minimum water for a given gas composition is a straightforward computation; R4 independently counsels minimizing the water inventory in the stream. A "starved-water" ratio is the predictable consequence of minimizing a recirculating aqueous phase while still forming the solid. Nothing in the specification asserts a criticality for 100 cc/ft³, and the patent itself frames it as illustrative ("The actual quantity of water used will be very small… say about 100 cc. per cubic foot of gas"). Claim 4 appears obvious on this combination.

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5. The strongest counterargument — and why it is not decisive

Welty's best non-obviousness position is teaching away. Both principal references frame hydrate formation as the problem, not the tool:

• R1 is titled and framed around hydrates plugging transmission lines; its practical teaching is to predict and avoid the hydrate region.
• R2 and R3 are directed to inhibiting hydrate formation (methanol/ammonia injection, dehydration).
• R4's stated object is "the prevention of the difficulties which can be caused by the formation of gas hydrates"; its claims are all hydrate-avoidance claims.
• Even the contemporaneous trade literature reflects this: The Oil Weekly (March 20, 1939) describes plant practice as keeping gas "above the freezing point of gas-hydrates," and the era's engineering texts prescribe alcohol and ammonia as inhibitors.

Under the older Federal Circuit "teaching away" line, this would be a serious obstacle: converting a universally-avoided nuisance into an intentional, productive separation step is a classic new use of a known phenomenon, and the Cuno "flash of genius" standard then in force would have favored validity.

Why I nonetheless conclude the claims would likely be obvious under modern §103:

1. KSR expressly rejects the notion that a teaching away is dispositive, and the asserted teaching away here is not "this separation won't work" — it is "hydrates are inconvenient in pipelines." The references never disparage the idea of exploiting hydrate formation for separation; they simply never address separation. In re Fulton, 391 F.3d 1195 (Fed. Cir. 2004), makes clear that a reference's silence on the claimed purpose is not teaching away.
2. R1 affirmatively supplies the selectivity datum (hydrate formers = CH₄/C₂H₆/C₃H₈/i-C₄H₁₀; hydrogen conspicuously absent), and R4 supplies the context (these hydrates form in hydrogenation gases during refinery gas processing). Together they disclose every element of claim 1 except the deliberate separation step — and separation of a solid from a gas requires no invention.
3. The "finite number of identified, predictable solutions" rationale applies. Given a target of light-end removal from a pressurized wet gas, and given a known solid-forming reaction between that gas's hydrocarbons and water, "form the solid, then draw off the gas" is one of a small number of obvious approaches.

Net: claim 1 is a close but likely-obvious call; the teaching-away argument gives a patentee a litigable response but not a winning one under KSR.

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6. Secondary considerations (Graham factor 4)

• Presumption of validity / examiner allowance. The patent issued in 1942 with all four claims allowed and, per the record I could reach, no cited references on the face of the patent. If Hammerschmidt 1934 and Schuftan were not of record, the allowance is weak evidence of non-obviousness — the Examiner may never have considered the combination. Conversely, if they were of record and the claims still allowed, that is meaningful evidence the hydration-as-separation insight was not considered obvious in its day. I could not resolve which, and that single fact is outcome-determinative for the weight of this factor. Pull the file wrapper (PatentCenter, https://patentcenter.uspto.gov/).
• Commercial success. The assignee (Standard Oil Development → Esso Research → Exxon Research) was itself practising catalytic hydrotreating, and its own specification frames the invention as an internal process improvement — but I found no evidence of nexus, licensing revenue, or industry adoption. Not established; no nexus shown.
• Unexpected results / criticality. Absent from the specification. Welty expressly disclaims theory ("not limited by any theories of the mechanism") and provides no comparative data. This is fatal to a criticality argument for claim 2's pressure/temperature window or claim 4's 100 cc/ft³ ratio.
• Long-felt but unmet need. Modest support: R6 shows the need for an alternative H₂-enrichment route existed. But the need was for a route, not specifically a hydrate route.

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7. Verdict summary

Bottom line: the patent's single point of novelty is the choice to exploit a phenomenon the contemporaneous art treated as a nuisance. On the record's own terms — Hammerschmidt 1934 supplying the temperature/pressure/selectivity data, and the applicant's own admission supplying the H₂-enrichment motive — claims 2 and 4 look squarely obvious under modern §103, and claim 1 is more likely than not obvious. Claim 3 cannot be responsibly assessed because its pressure limitation is lost to OCR corruption.

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8. Where this analysis is exposed — do not treat as filing-grade

1. No file-wrapper review. I could not confirm whether Hammerschmidt, Schuftan, Russell or any other reference was of record. If they were, the §282 presumption acquires real force and every verdict above weakens.
2. R5 (US 2,151,248) filing date unverified. I inferred a ~1937 filing from the Serial 160,192 reference in its own text; I did not confirm it. If it post-dates 1939-02-15, Combination C loses its secondary reference.
3. Deaton & Frost, Gas Hydrates and Their Relation to the Operation of Natural-Gas Pipe Lines, Bureau of Mines Monograph 8 — I could not pin the publication year (catalog records suggest 1941–1948). The Monograph's composition data ("natural gas hydrates are likely to be solid solutions"; hydrate-phase hydrocarbon concentrations on a water-free basis) is precisely the teaching that would make hydrate-based separation foreseeably viable — but if it post-dates 1939 it is unusable, and I have not verified it. Its footnote 51 cites Roberts, Brownscombe & Howe, "Constitution Diagrams and Composition of Methane and Ethane Hydrates" — undated in my source. If that paper predates February 1938, it is the single most damaging §102(b) reference in this analysis and should be verified immediately.
4. US 2,410,583 (Fluor, filed 1943-07-10) is NOT §103 art against this patent — it post-dates the filing by four years. I note it only because it is a near-identical later invention ("Separation of hydrate-forming components of gaseous mixtures," operating at 35–45 °F and 400–650 psig, expressly recovering an inert gaseous fraction from a gas whose hydrate-forming components are C₁, C₂ and C₃) — strong evidence that by 1943 the concept was ordinary engineering, but it is unavailable as a supporting reference.
5. Legal anachronism. As stated in §0, §103 did not govern this patent in its own day; a 1942–1959 court would have applied Cuno's "flash of genius" and would likely have sustained the claims.