Potential Application of Machine-Learning-Based Quantum Chemical Methods in Environmental Chemistry

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 56(4), P. 2115 - 2123

Published: Jan. 27, 2022

It is an important topic in environmental sciences to understand the behavior and toxicology of chemical pollutants. Quantum methodologies have served as useful tools for probing pollutants recent decades. In years, machine learning (ML) techniques brought revolutionary developments field quantum chemistry, which may be beneficial investigating However, ML-based methods (ML-QCMs) only scarcely been used studies so far. To promote applications promising methods, this Perspective summarizes progress ML-QCMs focuses on their potential that could hardly achieved by conventional methods. Potential challenges predicting degradation networks pollutants, searching global minima atmospheric nanoclusters, discovering heterogeneous or photochemical transformation pathways well environmentally relevant end points with wave functions descriptors are introduced discussed.

Language: Английский

---

Enhancement of Atmospheric Nucleation Precursors on Iodic Acid-Induced Nucleation: Predictive Model and Mechanism

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(17), P. 6944 - 6954

Published: April 21, 2023

Iodic acid (IA) has recently been recognized as a key driver for new particle formation (NPF) in marine atmospheres. However, the knowledge of which atmospheric vapors can enhance IA-induced NPF remains limited. The unique halogen bond (XB)-forming capacity IA makes it difficult to evaluate enhancing potential (EP) target compounds on based widely studied sulfuric systems. Herein, we employed three-step procedure EP nucleation precursors NPF. First, evaluated 63 by simulating free energies (ΔG) IA-containing dimer clusters. Among all clusters, 44 contained XBs, demonstrating that XBs are frequently formed. Based calculated ΔG values, quantitative structure–activity relationship model was developed evaluating other precursors. Second, amines and O/S-atom-containing acids were found have high EP, with diethylamine (DEA) yielding highest combining both concentration considered Finally, studying larger (IA)1–3(DEA)1–3 IA-DEA system merely 0.1 ppt (2.5×106 cm–3) DEA yields comparable rates IA–iodous system.

Language: Английский

---

Counterintuitive Oxidation of Alcohols at Air–Water Interfaces

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(8), P. 4791 - 4799

Published: Feb. 16, 2023

This study shows that the oxidation of alcohols can rapidly occur at air-water interfaces. It was found methanediols (HOCH2OH) orient interfaces with a H atom -CH2- group pointing toward gaseous phase. Counterintuitively, hydroxyl radicals do not prefer to attack exposed but -OH forms hydrogen bonds water molecules surface via water-promoted mechanism, leading formation formic acids. Compared oxidation, mechanism interface significantly lowers free-energy barriers from ∼10.7 ∼4.3 kcal·mol-1 and therefore accelerates The unveils previously overlooked source environmental organic acids are bound up aerosol acidity.

Language: Английский

---

Computational Chemistry as Applied in Environmental Research: Opportunities and Challenges

ACS ES&T Engineering, Journal Year: 2023, Volume and Issue: 4(1), P. 66 - 95

Published: Oct. 12, 2023

The constant development of computer systems and infrastructure has allowed computational chemistry to become an important component environmental research. In the past decade, application quantum classical mechanical calculations model understand increased exponentially. this review, we highlight various applications techniques in areas research (e.g., wastewater/air treatment, sensing, biodegradation). We briefly describe each approach, starting with principle methods followed by molecular mechanics (MM), dynamics (MD), hybrid QM/MM methods. recent introduction artificial intelligence machine learning their potential disrupt field are also discussed. Challenges current future directions address them presented.

Language: Английский

---

Atmospheric Autoxidation of Organophosphate Esters

Environmental Science & Technology, Journal Year: 2021, Volume and Issue: 56(11), P. 6944 - 6955

Published: Nov. 18, 2021

Organophosphate esters (OPEs), widely used as flame retardants and plasticizers, have frequently been identified in the atmosphere. However, their atmospheric fate toxicity associated with transformations are unclear. Here, we performed quantum chemical calculations computational toxicology to investigate reaction mechanism of peroxy radicals OPEs (OPEs-RO2•), key intermediates determining chemistry OPEs, products. TMP-RO2• (R1) TCPP-RO2• (R2) derived from trimethyl phosphate tris(2-chloroisopropyl) phosphate, respectively, selected model systems. The results indicate that R1 R2 can follow an H-shift-driven autoxidation under low NO concentration ([NO]) conditions, clarifying RO2• mechanism. unexpected be attributed distinct role ─(O)3P(═O) phosphate-ester group facilitating H-shift OPEs-RO2• commonly encountered ─OC(═O)─ ─ONO2 ester groups Under high [NO] mediate form organonitrates alkoxy radical-related products volatility aquatic compared corresponding parent compounds. proposed advances our current understanding environmental risk OPEs.

Language: Английский

---

A structure activity relationship for ring closure reactions in unsaturated alkylperoxy radicals

Physical Chemistry Chemical Physics, Journal Year: 2021, Volume and Issue: 23(31), P. 16564 - 16576

Published: Jan. 1, 2021

The ring closure in unsaturated alkyl peroxy radicals can be a competitive process the atmospheric oxidation of biogenic organic compounds.

Language: Английский

---

Poly (vinyl ethers) based on the biomass-derived compound, eugenol, and their one-component, ambient-cured surface coatings

Progress in Organic Coatings, Journal Year: 2022, Volume and Issue: 170, P. 106996 - 106996

Published: June 28, 2022

Language: Английский

---

Atmospheric oxidation mechanism and kinetics of indole initiated by ●OH and ●Cl: a computational study

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(17), P. 11543 - 11555

Published: Sept. 7, 2022

Abstract. The atmospheric chemistry of organic nitrogen compounds (ONCs) is great importance for understanding the formation carcinogenic nitrosamines, and ONC oxidation products might influence aerosol particle growth. Indole a polyfunctional heterocyclic secondary amine with global emission quantity almost equivalent to that trimethylamine, highest emission. However, indole remains unclear. Herein, reactions ⚫OH ⚫Cl, subsequent resulting radicals O2 under 200 ppt NO 50 HO2⚫ conditions, were investigated by combination quantum chemical calculations kinetics modeling. results indicate addition dominant pathway reaction indole. both ⚫Cl H abstraction are feasible corresponding ⚫Cl. All favorably formed further react produce peroxy radicals, which mainly form organonitrates, alkoxy hydroperoxide products. Therefore, mechanism distinct from previously reported amines, primarily highly oxidized multifunctional compounds, imines or nitrosamines. In addition, can N-(2-formylphenyl)formamide (C8H7NO2), first time providing evidence identity C8H7NO2 mass peak observed in + experiments. More importantly, this study demonstrate despite forming abstracting an atom at N site, nitrosamines not produced reaction.

Language: Английский

---

Rate Coefficient Measurements for the CH₃SCH₂OO Radical + NO Reaction Between 313 and 413 K

International Journal of Chemical Kinetics, Journal Year: 2025, Volume and Issue: unknown

Published: March 20, 2025

ABSTRACT The CH 3 SCH 2 OO radical is a key intermediate formed in the gas‐phase oxidation of dimethyl sulfide (CH , DMS). In this study, rate coefficient, k 1 ( T ), for + NO reaction was measured using pulsed laser photolysis–iodide chemical ionization mass spectrometry (CIMS) detection competitive method over temperature range 313–413 K. Hydroperoxymethyl thioformate (HOOCH SCHO, HPMTF) following H‐shift monitored CIMS as function added concentration. ) results are described by Arrhenius expression (313–413 K) = (1.43 ± 0.29) × 10 −12 exp((510 160)/ cm molecule −1 s where quoted uncertainties σ and pre‐exponential coefficient uncertainty includes estimated systematic errors. An extrapolation to room yields (298 7.9 . Results from study compared with previous dependent (261–400 studies. obtained work recommended use atmospheric chemistry climate models.

Language: Английский

---

Characterization and Seasonal Variation of PM_2.5 Composition in Xi’an, Northwest China: Oxygenated and Nitrogenous Organic Aerosol

ACS Earth and Space Chemistry, Journal Year: 2024, Volume and Issue: 8(7), P. 1370 - 1384

Published: June 20, 2024

Oxygenated (CHO) and nitrogenous (CHON) organic aerosols (OA) are important components of fine particulate matter (PM2.5) in urban environments. To achieve a molecular-level understanding the seasonal variation OA fraction, ambient PM2.5 samples collected from April 2018 to March 2019 Xi'an, Northwest China, were analyzed using an iodide Chemical Ionization Mass Spectrometer combined with Filter Inlet for Gases AEROsols (FIGAERO–CIMS). The set compounds identified by FIGAERO–CIMS was estimated represent 28.6% PM2.5. Evaporation temperatures measured indicated that semivolatile (SVOCs) dominant among analytes. Concentrations CHO (6.01 ± 4.24 μg m–3) CHON (3.17 2.34 increased winter, especially during severe haze episode January 2019. comprised up 75.3 3.2% total detected compounds. average carbon oxidation state (OSC¯) slightly elevated summer samples. mainly nitro-aromatics their abundance substantially which attributed extensive biomass burning demonstrated high levels levoglucosan. Biomass-burning related sources accounted 61.0 19.6% 68.3 21.9% concentration autumn respectively, while secondary formation source species spring (70.1 11.6%) (79.8 7.0%). These results emphasize importance as reveal clear need control used heating Xi'an its surroundings.

Language: Английский

---