Published 2026-06-24 · Updated 2026-08-26 · Prepared and reviewed by the Demeto Technical & Quality Team. Final acceptance must follow the agreed test methods, commercial-lot evidence and written technical agreement.
Begin with feedstock variability
Colorants, additives, adhesives, multilayer components and non-PET contamination determine the impurity challenge before reaction conditions are considered.
Design purification around the impurity map
Crystallization, washing, filtration, distillation and polishing steps should address the actual volatile, insoluble, colored and metal-containing species.
Measure the relevant quality dimensions
Use purity together with color, acid value, moisture, ash, metals and targeted organic impurities. Traceability and recycled-content evidence may also be required.
Close the loop with repolymerization
Polymerization behavior, color build, molecular-weight development and final material properties reveal whether purification was sufficient.
Stabilize the commercial process
Define feedstock controls, operating windows, batch release criteria and corrective actions before scaling recurring output.
Build an impurity map before selecting equipment
Separate likely contaminants into volatile, insoluble, colored, metal-containing and structurally similar organic groups. Then link each group to a removal mechanism and an analytical check. This avoids adding purification steps that improve headline assay while leaving the application-critical impurity unchanged.
Track mass balance and yield
Record PET input, methanol, catalyst, recovered crude DMT, purified DMT, side streams and residues. A quality result without mass balance can conceal unstable conversion or excessive product loss. Commercial assessment should combine purity, recovery yield, energy, solvent recovery, waste handling and final application value.
Make repolymerization part of release
Use a controlled protocol to compare reaction behavior, color growth, molecular-weight or viscosity development and final material properties. The release decision should link feedstock lot, purification batch, DMT test data and polymer result so that a downstream failure can be traced back through the recycling process.
Sources and use boundary
- ACS IECR — Efficient Methanolysis of PET (2024)
- Polymer Degradation and Stability — PET methanolysis to DMT and EG
- PubMed — Targeted conversion of waste PET (2025)
This article combines public references with a procurement and qualification framework. It does not replace the current SDS from the actual source, the written product specification, agreed test methods or evidence for the commercial lot.