Published 2026-07-15 · Updated 2026-07-15 · Demeto Technical Team
The reaction in brief
PET depolymerizes in excess methanol with a catalyst through transesterification, yielding DMT and ethylene glycol. Unlike glycolysis or hydrolysis products, DMT is a crystallizable solid — which is exactly what makes deep purification practical.
Feedstock pre-treatment sets the difficulty
Dyes, additives, adhesives, multilayer structures and non-PET contamination in bottle flake, fiber or film waste determine the downstream purification load. Better sorting, washing and melt filtration widen the operating window of everything that follows.
From crude product to recycled DMT
Crude DMT passes through crystallization, washing and filtration, supplemented where needed by distillation and polishing to strip colored bodies, ash, metals and organic traces. Purification depth decides whether the product fits general polyester or film and specialty applications.
Two evidence sets define quality
Purification indicators — purity, color, acid value, moisture, ash and targeted impurities — form one set. Application evidence from repolymerization trials — reaction rate, color build and molecular-weight development — forms the other. Recovered monomer is only truly usable when both pass.
What commercial operation requires
A stable waste supply, fixed operating windows, explicit batch release criteria and recycled-content plus traceability documentation turn a laboratory route into a dependable recycled DMT product.