Catalysis & Process Chemistry
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Homogeneous Hydroformylation Catalysis
Hydroformylation Catalyst
How much of the spread in linear:branched selectivity on 1-octene at 20 bar and 110 C is set by rhodium resting-state populations across six benchmark ligands?
THE QUESTION
Which ligand-catalyst pair pushes linear:branched hydroformylation selectivity past [threshold] at industrially relevant syngas pressure while holding TON above [threshold]? Verifier: parallel pressure-reactor HTE with GC. [baseline: to verify]
WORK ORDER
Attribution of linear:branched hydroformylation selectivity to rhodium resting-state populations at 20 bar
BACKGROUND
What this Apodex Lab is
Industrial hydroformylation converts alkenes and synthesis gas into aldehydes used to manufacture plasticisers, detergents, and chemical coatings. Modern processes aim for a linear-to-branched product ratio above roughly 30:1 at 10–30 bar total pressure with a CO:H2 ratio near 1:1, while maintaining turnover numbers exceeding 10,000 per rhodium atom. Because rhodium is priced around a thousandfold above cobalt, catalyst longevity and active-metal inventory dominate the economics of every production plant.
Published research treats regioselectivity as a direct property of ligand geometry, using fresh-catalyst batch screenings on clean 1-alkenes to rank wide-bite-angle diphosphines such as the Xantphos family. However, commercial operation focuses on catalyst conditioning, degradation products, water content, and shifting gas compositions. Operando high-pressure spectroscopy reveals that the dominant catalytic species during turnover differs from the initial precatalyst. Because resting-state populations and chromatographic product distributions have never been measured simultaneously on the same pressurised charge across a benchmark panel, existing compilations cannot separate the selectivity contribution of ligand structure from shifts in the active rhodium population.
The Hydroformylation Catalyst Apodex Lab resolves this attribution by pairing high-pressure infrared spectroscopy directly with inline gas chromatography on 1-octene in toluene at 110 C and 20 bar total pressure across six benchmark phosphorus ligands. By tracking the bis-phosphine monocarbonyl hydride resting-state population before and after an imposed step change in the CO:H2 ratio from 1:1 to 2:1 at 4 h, the measurement isolates the variance in selectivity explained by catalyst speciation under operating pressure. If speciation governs selectivity, operando tracking becomes a mandatory screen for subsequent catalyst evaluation rounds; if not, operando spectroscopy is eliminated from future screening protocols to focus resources on feed composition and isomerisation.
WHY NOW
Why the field is spending on an assumption
Operando high-pressure spectroscopy now detects working rhodium speciation under syngas, but existing records lack paired chromatographic selectivity and turnover numbers from the same pressurised charge. Current screening treats linear:branched regioselectivity as an intrinsic ligand property based on fresh-catalyst batch runs. Consequently, published rankings cannot separate ligand geometry from shifts in the rhodium resting-state population driven by pressure, gas ratios, or operating conditions.
WHAT WE’D BUY
What we would ask a laboratory to run
We are not buying the answer. We are buying a measurement with an interval — and the bars it will be compared against.
Measurements across six phosphorus ligands hydroformylating 1-octene in toluene at 110 C and 20 bar in a stirred autoclave. Liquid sampling to gas chromatography and operando high-pressure infrared spectroscopy record linear:branched aldehyde ratios, 12 h turnover numbers, and rhodium resting-state mole fractions on the same charges. Carbon monoxide and hydrogen ratios step from 1:1 to 2:1 at 4 h. High-pressure NMR checks infrared speciation on two charges. The test returns the fraction of selectivity variance explained by resting-state populations with a 95 percent interval bounded to 0.30 absolute units, pooled and per-ligand selectivity slopes against resting-state fraction, and 12 h turnover numbers per rhodium with 95 percent intervals.
SCOPE & LIMITS
The measurements use only fresh catalyst on pure 1-octene and do not capture performance on aged catalyst, recycle streams, or mixed olefin feeds.
WHO EXECUTES
The kind of lab that can run this
A high-pressure catalysis contract laboratory or university core facility running parallel pressure-reactor high-throughput screening with online GC and an operando high-pressure infrared/NMR spectroscopy cell for rhodium speciation.
EXECUTOR KIND
wet-lab
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