Related Experiment Video
Updated: Jul 27, 2025

Synthesis of Soft Polysiloxane-urea Elastomers for Intraocular Lens Application
Published on: March 8, 2019
Polyurethane Recycling: Thermal Decomposition of 1,3-Diphenyl Urea to Isocyanates
Shahab Zamani1, Sterre H E van der Voort1, Jean-Paul Lange1,2
1Sustainable Process Technology, Faculty of Science and Technology, University of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands.
Abstract:
Substituted urea linkages are formed during the production of polyurethane foam. To chemically recycle polyurethane toward its key monomers via depolymerization (i.e., isocyanate), it is essential to break the urea linkages to form the corresponding monomers, namely, an isocyanate and an amine. This work reports the thermal cracking of a model urea compound (1,3-diphenyl urea, DPU) into phenyl isocyanate and aniline in a flow reactor at different temperatures. Experiments were performed at 350-450 °C, with a continuous feed of a solution of 1 wt.% DPU in GVL. In the temperature range studied, high conversion levels of DPU are achieved (70-90 mol%), with high selectivity towards the desired products (close to 100 mol%) and high average mole balance (∼95 mol%) in all cases.
Related Concept Videos
Free-Radical Chain Reaction and Polymerization of Alkenes
Types of Step-Growth Polymers: Polyesters
Polyesters are commonly prepared from terephthalic acid and ethylene glycol; the crude product is known as poly(ethylene terephthalate) or PET. However, polyesters are synthesized industrially by transesterification of dimethyl terephthalate with ethylene glycol at 150 °C. The two reactants and the...
Olefin Metathesis Polymerization: Acyclic Diene Metathesis (ADMET)
Similar to cross-metathesis, ADMET also involves the formation of metallacyclobutane intermediate by [2+2] cycloaddition of one of the double bonds of a terminal diene with...
Radical Chain-Growth Polymerization: Mechanism
Polymer Classification: Architecture
Olefin Metathesis Polymerization: Overview
Ruthenium-based Grubbs catalyst is the most commonly used catalyst for olefin metathesis polymerization. Grubbs catalyst consists...

