Polyurethane Recycling: Thermal Decomposition of 1,3-Diphenyl Urea to Isocyanates

Shahab Zamani; Sterre H.E. van der Voort; Jean-Paul Lange; Sascha R.A. Kersten; M. Pilar Ruiz

doi:10.3390/polym15112522

Polyurethane Recycling: Thermal Decomposition of 1,3-Diphenyl Urea to Isocyanates

Shahab Zamani, Sterre H.E. van der Voort, Jean-Paul Lange, Sascha R.A. Kersten, M. Pilar Ruiz^*

^*Corresponding author for this work

Sustainable Process Technology

Research output: Contribution to journal › Article › Academic › peer-review

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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.

Original language	English
Article number	2522
Number of pages	12
Journal	Polymers
Volume	15
Issue number	11
DOIs	https://doi.org/10.3390/polym15112522
Publication status	Published - 30 May 2023

Keywords

Isocyanates
Polyurethanes
Recycling
Urea

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10.3390/polym15112522Licence: CC BY

ArticleFinal published version, 1.11 MBLicence: CC BY

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title = "Polyurethane Recycling: Thermal Decomposition of 1,3-Diphenyl Urea to Isocyanates",

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.",

keywords = "Isocyanates, Polyurethanes, Recycling, Urea",

author = "Shahab Zamani and {van der Voort}, {Sterre H.E.} and Jean-Paul Lange and Kersten, {Sascha R.A.} and Ruiz, {M. Pilar}",

note = "Funding Information: The authors thank Shell Global Solutions International B.V. for funding this research and Benno Knaken, Johan Agterhorst, Ronald Borst, Raymond Spanjer, and Erna Fr{\"a}nzel-Luiten for their technical support. Publisher Copyright: {\textcopyright} 2023 by the authors. Financial transaction number: 6100017269",

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T2 - Thermal Decomposition of 1,3-Diphenyl Urea to Isocyanates

AU - Zamani, Shahab

AU - van der Voort, Sterre H.E.

AU - Lange, Jean-Paul

AU - Kersten, Sascha R.A.

AU - Ruiz, M. Pilar

N1 - Funding Information: The authors thank Shell Global Solutions International B.V. for funding this research and Benno Knaken, Johan Agterhorst, Ronald Borst, Raymond Spanjer, and Erna Fränzel-Luiten for their technical support. Publisher Copyright: © 2023 by the authors. Financial transaction number: 6100017269

PY - 2023/5/30

Y1 - 2023/5/30

N2 - 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.

AB - 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.

KW - Isocyanates

KW - Polyurethanes

KW - Recycling

KW - Urea

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VL - 15

JO - Polymers

JF - Polymers

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M1 - 2522

ER -

Polyurethane Recycling: Thermal Decomposition of 1,3-Diphenyl Urea to Isocyanates

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Keywords

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