Spontaneous formation of urea from carbon dioxide and ammonia in aqueous droplets

• 成果类型: Article
• 署名作者: Mohajer, Mercede Azizbaig; Basuri, Pallab; Evdokimov, Andrei; David, Gregory; Zindel, Daniel; Miliordos, Evangelos; Signorell, Ruth
• 署名单位: Swiss Federal Institutes of Technology Domain; ETH Zurich; Auburn University System; Auburn University
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-12368
• DOI: 10.1126/science.adv2362
• 发表日期: 2025-06-26
• 页码: 1426-1430
• 关键词: proton affinity; basis-sets; water; bicarbonate; carbamate; chemistry; kinetics; nh3; ph

摘要

Urea is a key molecule in the search for the origin of life and a basic chemical produced in large quantities by industry. Its formation from ammonia and carbon dioxide requires either high pressures and temperatures or, under milder conditions, catalysts or additional reagents. In this study, we observed the spontaneous formation of urea under ambient conditions from ammonia and carbon dioxide in the surface layer of aqueous droplets. Single, optically trapped droplets were probed by using Raman bands as markers. We found the surface layer to act like a microscopic flow reactor, with chemical gradients providing access to unconventional reaction pathways. This observation revealed a general mechanistic scheme for distinctive droplet chemistry. Interfacial chemistry is a possible nonenergetic route for urea formation under prebiotic conditions.