Skip to content
DraconiticResearch
Search Sources API
197,768 studies31 sourcesUpdated 53 min ago
PreprintCC BYChemRxiv

Bottom-up design of the operating window for direct urea synthesis from first-principles molecular thermodynamics

  • Minwoo Kim1,2
  • Seungtae Kim1,2
  • Ji Woong Yu3,4,5
  • Won Bo Lee1,2,6
6 affiliations
  1. 1Department of Chemical and Biological Engineering
  2. 2Seoul National University
  3. 3School of Frontier Sciences
  4. 4Ajou University
  5. 5Department of Chemistry
  6. 6School of Transdisciplinary Innovations
Open at sourcePDFDOICite

Abstract

Urea, among the most widely utilized foods for crops, is mass-produced via the carbon-and energy-intensive Bosch–Meiser process. However, its operating condition is settled empirically, vulnerable to undersampling and suboptimal production, and its molecular mechanism is not well understood. Here we present a bottom-up design of the operating condition driven by first-principles molecular modeling. Using a machine learning force field trained on first-principles calculations of urea and relevant species, we explored the free energy surface of the reaction space from reactant to product across temperatures. We found a strong thermodynamic preference for acyl substitution over competing pathways, with a free energy minimum around 420 K arising from the balance between carbamic acid’s protonation ratio and solvation number, which respectively increase and decrease with temperature. And we confirmed that the optimal condition originates from near-critical behavior, showing a fixed ratio to the critical temperature below unity. The maximum-yield temperatures of simulation and experiment correspond when scaled to their critical temperatures, suggesting this combined approach for engineering the operating condition.

Related

  1. Operating conditions redefine the governing principles of catalyst-layer fabrication
    Sven Nösberger, Ahmad Tirmidzi, Gustav K.H. Wiberg +1
    ChemRxivPreprintCC BYFull textGeneral chemistryChemRxiv
  2. Lithium Polysulfide Speciation in Lithium–Sulfur Batteries: A First-Principles Benchmark of Thermodynamics, Bonding, and Solvent Control
    Rafael Ferreira Ferreira de Menezes, Tiago Cassiano, Lydia Meyer +10
    ChemRxivPreprintCC BYGeneral chemistryChemRxiv
  3. Deciphering the Active Phase Evolution of Co-W-Based Catalysts during Carbon Nanotube Growth by First-Principles Thermodynamics.
    Ran Sun, Ting Cheng, Feng Ding +1
    ACS nanoPeer-reviewedCC BYFull textMaterials & polymersEurope PMC
  4. Advancements in bottom-up synthesis routes for monolayer graphene: a review
    Muhammad A. Awan, Szymon Abrahamczyk, Maria Hasan +4
    Royal Society Open SciencePeer-reviewedCC BY 4.0Full textMaterials & polymersCrossrefEurope PMC
  5. Physics-Guided Learning with Calibrated Uncertainty for Molecular Thermodynamics Beyond Observed Chemical Space
    Yi-Cheng Shen, Shu Wang, Shiang-Tai Lin
    ChemRxivPreprintLicence not statedGeneral chemistryChemRxiv

Cite

BibTeXRIS
BibTeX
@misc{kim2026bottomup,
  title = {{Bottom-up design of the operating window for direct urea synthesis from first-principles molecular thermodynamics}},
  author = {Minwoo Kim and Seungtae Kim and Ji Woong Yu and Won Bo Lee},
  howpublished = {ChemRxiv},
  year = {2026},
  month = sep,
  doi = {10.26434/chemrxiv.15008967/v1},
  url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008967/v1},
  note = {CC BY},
}
RIS
TY  - UNPB
TI  - Bottom-up design of the operating window for direct urea synthesis from first-principles molecular thermodynamics
AU  - Minwoo Kim
AU  - Seungtae Kim
AU  - Ji Woong Yu
AU  - Won Bo Lee
PY  - 2026
DA  - 2026/09/17
PB  - ChemRxiv
DO  - 10.26434/chemrxiv.15008967/v1
UR  - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008967/v1
AB  - Urea, among the most widely utilized foods for crops, is mass-produced via the carbon-and energy-intensive Bosch–Meiser process. However, its operating condition is settled empirically, vulnerable to undersampling and suboptimal production, and its molecular mechanism is not well understood. Here we present a bottom-up design of the operating condition driven by first-principles molecular modeling. Using a machine learning force field trained on first-principles calculations of urea and relevant species, we explored the free energy surface of the reaction space from reactant to product across temperatures. We found a strong thermodynamic preference for acyl substitution over competing pathways, with a free energy minimum around 420 K arising from the balance between carbamic acid’s protonation ratio and solvation number, which respectively increase and decrease with temperature. And we confirmed that the optimal condition originates from near-critical behavior, showing a fixed ratio to the critical temperature below unity. The maximum-yield temperatures of simulation and experiment correspond when scaled to their critical temperatures, suggesting this combined approach for engineering the operating condition.
ER  -