Catalysis & Process Chemistry
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Plastic Depolymerisation Catalysis
Plastic Upcycling Catalyst
How do chloride, dye, and adhesive contaminants alter product slate and turnover rate during zinc-catalysed PET glycolysis pinned at conversion 0.60 ± 0.05?
THE QUESTION
Which catalyst depolymerises a specified post-consumer PET or PE stream to a defined monomer or high-value product at yield above [threshold] below 350 C — and does yield hold on real contaminated feed rather than virgin polymer? Verifier: bench batch or flow reactor with GC-MS and quantitative NMR. [baseline: to verify]
WORK ORDER
Contaminant-resolved selectivity and rate coefficients for continuous-flow zinc-catalysed PET glycolysis
BACKGROUND
What this Apodex Lab is
Recycling post-consumer plastic back into virgin-grade monomers requires catalysts that survive the impurities in real waste streams. Published data show zinc-catalysed glycolysis depolymerising clean polyethylene terephthalate to monomer yields above 90 percent in 20 to 60 minutes. On real baled waste, however, yields frequently drop towards 60 percent. Plant developers planning 30–50 kt/y commercial recycling lines cannot determine whether this yield deficit stems from a poisoned catalyst slowing the reaction rate or from unwanted side-reactions producing coloured oligomers that foul downstream crystallisation.
Existing evidence fails to resolve the problem because high-temperature batch runs destroy polymer additives, catalysts, and chemical evidence in one pot. Measuring an endpoint yield algebraically fuses reaction rate with product selectivity. Polyvinyl chloride, masterbatch pigments, disperse dyes, and hot-melt label adhesives all enter the feed simultaneously, yet published studies rely on virgin or lightly washed flake. When roughly 70 percent of scientists struggle to reproduce published homogeneous catalysis outcomes, unquantified claims of contaminant tolerance leave plant designers without empirical deactivation rates for real feed streams.
The Plastic Upcycling Catalyst Apodex Lab isolates these chemical mechanisms by running post-consumer polyester in ethylene glycol through a continuous-flow fixed bed below 250 C with conversion pinned to 0.60 ± 0.05. Operating below 350 C keeps both catalyst and contaminants intact while flow control separates residence-time shifts from product-slate changes. By dosing polyvinyl chloride, pigments, and label adhesives individually, the measurement uses quantitative nuclear magnetic resonance and gas chromatography-mass spectrometry to establish deactivation and selectivity coefficients per weight percent of contaminant. These coefficients tell plant developers whether to invest in larger reactor volume, negotiate catalyst leasing terms, or install pre-wash delabelling equipment.
WHY NOW
Why the field is spending on an assumption
Published plastic depolymerisation reports focus on first-pass monomer yields from clean polymer in small batch runs. These high-temperature batch systems confound catalyst deactivation with thermal degradation, destroying contaminants, catalysts, and reaction intermediates simultaneously. When monomer yield drops on real post-consumer waste, researchers cannot attribute the loss between slowed reaction rates and degraded product slates. Commercially available continuous-flow reactors operating below 250 C now enable independent control of residence time and temperature. By holding conversion constant while dosing individual contaminants, operators can separate deactivation rates from selectivity changes for the first time.
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.
This work order measures the effect of three dosed contaminant classes (PVC-derived chloride, pigments and dyes, and hot-melt adhesive) on post-consumer PET depolymerisation in a continuous-flow zinc-catalysed reactor. Operation holds conversion pinned to 0.60 ± 0.05 at temperatures below 250 C in ethylene glycol. For each contaminant class, the measurement delivers a rate coefficient for fractional turnover loss and a selectivity coefficient for changes in monomer fraction, both with 90 percent confidence intervals designed to achieve a half-width of about 3 percentage points per weight percent contaminant. Mass balances close within 95 ± 5 percent using quantitative nuclear magnetic resonance, gas chromatography-mass spectrometry, and solids recovery, alongside a single-stage crystallisation test that records crude product recovery and purity.
SCOPE & LIMITS
The results apply to one post-consumer PET bale lot with contaminants dosed individually at conversion pinned to 0.60 ± 0.05, providing an upper bound on deactivation rather than accounting for interacting contaminants in mixed feeds.
WHO EXECUTES
The kind of lab that can run this
A university catalysis core facility or contract chemistry CRO able to run a continuous bench flow reactor below 350 C on solid plastic feed, with GC-MS and quantitative NMR product accounting plus ICP-OES and XPS for spent-catalyst analysis.
EXECUTOR KIND
wet-lab
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