Methylamine Research Articles

Enhanced Homogeneity in Perovskite Photovoltaic Films via Antisolvent Extraction of a Methylamine-Based Gel Precursor.

Solution-processed perovskite solar cells (PSCs) are at the forefront of next-generation photovoltaics, exhibiting outstanding photoelectric performance and cost-effective manufacturing. However, the prevalent use of polar aprotic solvents such as N,N-dimethylformamide and dimethyl sulfoxide in the preparation of perovskite precursor solution hinders complete solvent removal during film formation. Their high boiling points and strong coordinating abilities lead to solvated intermediates and heterogeneous perovskite crystal nucleation, particularly in the absence of the antisolvent-assisted crystallization. To address this, we developed a methylamine (MA)-based gel dispersion system that significantly improves the uniformity of perovskite films. By employing ethyl acetate (EA) antisolvent extraction, the gel precursor is extracted from a solution of MAI and PbI2 in MA ethanol, which is then diluted in pure acetonitrile (ACN) solvent to form a clear perovskite precursor solution. Benefiting from the highly volatile nature of the ACN-based gel perovskite precursor solution and its rich concentration of high-valent PbIn2-n coordination compounds, this approach enables the fabrication of high-quality MAPbI3 perovskite films, yielding PCEs of 21.34% for PSC and 19.77% for a 5 × 5 cm2 mini-module. This MA-based gel perovskite precursor strategy offers a promising avenue for potential applications in the scalable manufacture of PSCs.

Ratiometric Imaging Detection of Amyloid-β Fibrils by a Dual-Emissive Tris-Heteroleptic Ruthenium Complex.

Two dual fluorescent/phosphorescent tris-heteroleptic mononuclear Ru(ΙΙ) complexes (2 and 3) were designed and applied in amyloid-β (Aβ) sensing. These complexes have a general formula of [Ru(phen)(dppz)(L)](PF6)2, where L is (2-pyrazinyl)(2-pyridyl)(methyl)amine (H-L) with different substituents (-OMe for 2, -H for 3), phen is 1,10-phenanthroline, and dppz is dipyridophenazine, respectively. Compared with the previously reported ratiometric probe 1 with a di(pyrid-2-yl)(methyl)amine ligand, complex 2 can be employed for not only ratiometric emissive detection of Aβ aggregation but also ratiometric imaging detection of Aβ fibrils. In ratiometric emissive detection, as the incubation time of the Aβ sample (Aβ40 and Aβ42) was prolonged, a new phosphorescence emission band appeared with gradual enhancement of the emission intensity, while the fluorescence emission was basically unchanged, which could be treated as an intrinsic internal reference signal. In comparison, a larger ratiometric photoluminescence enhancement (I640/I440) was observed for Aβ40 aggregation with respect to Aβ42. In ratiometric imaging detection, the imaging signals obtained from the phosphorescence emission are much brighter than the fluorescence emission in both Aβ40 and Aβ42 fibrils. As indicated by molecular docking results, stronger interactions were found between complex 2 with Aβ40 fibrils, which included π/π, π/C-H, and π/H interactions between bidentate ligands dppz and phen with amino acid residues. Moreover, computational calculations were carried out to assist the interpretation of these experimental findings.

Cation Engineering for Efficient and Stable Wide‐Bandgap Perovskite Solar Cells

Large voltage deficit and photoinduced halide segregation are the two primary challenges that hinder the advancement of wide‐bandgap (WBG) (Eg ≥ 1.65 eV) perovskite solar cells (PSCs). Herein, a cation engineering approach to enhance the optoelectronic properties of formamidine–cesium (FA‐Cs) WBG perovskites by incorporating methylamine (MA) as the third cation is presented. Three perovskite species with a bandgap of 1.68 eV, abbreviated as Cs0.05, Cs0.15, and Cs0.25, are systematically studied by optimizing the MA content. The incorporation of MA is found to effectively enhance the crystallinity and improve the carrier lifetimes of the three perovskite species. Moreover, the microstrain in the FA‐MA‐Cs perovskite films is significantly reduced due to the buffer effect of MA between the size‐mismatched FA and Cs, a benefit derived from the cascade cation design. The optimized compositions for the three species are Cs0.05MA0.2FA0.75PbI2.58Br0.42, Cs0.15MA0.1FA0.75PbI2.68Br0.32, and Cs0.25MA0.03FA0.72PbI2.73Br0.27, respectively. Among these, Cs0.25MA0.03FA0.72PbI2.73Br0.27 perovskite stands out due to its high crystallinity, low microstrain, and low trap density, giving rise to the highest efficiency of 20.64% with the lowest voltage loss. This perovskite also exhibits superior air, light, and thermal stability. These findings underscore the importance of rational cation design in achieving efficient and photostable WBG PSCs.

Treatment of brominated epoxy resin waste in subcritical dimethylformamide wastewater: Upcycling of brominated epoxy resin and dimethylformamide degradation

The debromination and upcycling of brominated epoxy resin (BER) waste is important for the e-waste treatment, while the degradation and removal of N, N-dimethylformamide (DMF) is the critical step for the DMF wastewater treatment. In this study, a co-treatment strategy was proposed for the BER waste and DMF wastewater by the subcritical water process. The co-treatment was carried out using subcritical DMF wastewater (SDW) as the reaction medium. The results showed a significantly synergistic effect between the BER conversion and DMF degradation in the SDW process. The optimal reaction conditions were as follows: reaction temperature of 300 °C, solid-to-liquid ratio of 1:15 g/mL, DMF wastewater of 30000 mg/L and reaction time of 60 min. Under the optimal reaction conditions, the debromination ratio of the BER was 98.57 %, the degradation ratio of the DMF reached 99.59 %, and phenolic substances with a purity of 86.61 % were recovered. The formation of HBr from the debromination of the BER was the most significant factor affecting the pH of the system, which had a noticeable impact on the degradation of the DMF. The main degradation products of the DMF were dimethylamine (DMA), methylamine (MA), NH3, NH4+, and CO2. The products degraded from the DMF could significantly promote the debromination and conversion of the BER. Life cycle assessment (LCA) analysis showed that the SDW process had low CO2 emissions. It is believed that the SDW process proposed in this study is an efficient technology for the synergistic treatment of the BER waste and DMF wastewater.

Low-Energy Electron Scattering from Ethyl Amine and Propyl Amine: A Comparative Study.

In this study, we investigate the low-energy electron (<20 eV) scattering cross sections for the linear ethyl amine and propyl amine using the R-matrix approach. A theoretical study is conducted, covering various cross sections such as elastic, symmetry-wise elastic, differential, momentum transfer, and electronic excitation. We obtained the ionization cross section using the CSP-ic and BEB methodologies. We unveil the intricate electron-amine interactions within these molecular systems. Additionally, our work extends to a comparative analysis among ethyl amine, propyl amine, and previously studied methyl amine systems. By comparing the obtained results, we discern subtle differences and similarities in the electron scattering behaviors across these structurally related amines. The findings presented herein shed light on fundamental electron-amine interactions, offering valuable insights for diverse fields ranging from chemical kinetics to astrophysics.

Quantum study of the competition and interplay between complexes resulting from the interaction of methylamine and halogen cyanides

In this study, quantum calculations were conducted to investigate the nature, formation mechanism, and properties of complexes resulting from the interaction between methylamine (MA) and halogen cyanide molecules (XCN, X = F, Cl, Br, and I). Three types of complexes were formed from the interaction of MA with XCN, characterized as Tetrel bond-hydrogen bond (TB-HB), Tetrel bond (TB), and Halogen bond (XB), denoted by symbols A, B, and C, respectively. The data obtained from the interaction energy indicated that complexes with structure C are significantly more stable compared to the other two structures. Molecular electrostatic potential map (MEP) analysis revealed that the size of the σ-hole of the halogen atom ligand plays a crucial role in the stability of structure C complexes. To further evaluate the properties of the resulting complexes, various analyses were conducted, including Molecular electrostatic potential map (MEP), Geometry optimization, Spectroscopy, Interaction energy (SE), Natural bond orbital (NBO), Atoms in molecules (AIM), Non-covalent interaction index (NCI), and Energy decomposition analysis (EDA).

Synthesis and anticancer evaluation of new lupane triterpenoid derivatives containing various substituent at the 2 or 3 position

Betulonic acid benzyl ester 1 has been subjected to a series of structural modifications for the purpose of new triterpenoid synthesis and evaluating for anticancer activity. The one-pot two step synthesis of 2α-(aminomethyl)betulinic acid benzyl ester derivatives 3a–f (yield 46–69 %) was achieved by the Mannich reaction of compound 1 with methyleneiminium salts, generated in situ from N,N-disubstituted bis(amino)methanes 2a–f by the action of acetyl chloride in dichloromethane, and subsequent reduction of aminomethylation products with sodium borohydride. Minor 2β-(aminomethyl) triterpenoids 4c,d,f were also isolated (yield 6–15 %). We found, that the stereoselective reaction of triterpenoid 1 with acetylides, generated at –78 °C from alkynes in the presence of n-BuLi, has been useful and noteworthy as the key step in providing of new alkyne substituted triterpenoids – benzyl 3-alkynyl-3-deoxy-2(3),20(29)-lupadiene-28-oates or 3-deoxy-2(3)-dehydro-28-oxoallobetulin derivative. The new compounds were examined for anticancer activity against the human cell lines (MTT assay). All tested derivatives were non-toxic on human fibroblasts. The 3‐(phenylethynyl)lupa-2(3),20(29)-diene 9 showed selective cytotoxicity on cervical cancer cell lines. Tumor cells death trigged by the most active compound 4f resulted from apoptotic processes. These data make the series of synthesized 2 or 3 substituted lupane derivatives as promising compounds with anticancer potential.

Highly sensitive QCM gas sensor based on ZIF-8-derived porous carbon and multi-walled carbon nanotubes decorated nanocomposite for salmon meat freshness detection

The concentration of amine gases are often used as an indicator of the freshness of seafood. However, currently used detection methods are usually complex to operate, have excessive time periods. Therefore, it is necessary to design and develop a sensor that can quickly and accurately detect a wide range of target amine gases with ease of operation and excellent performance. This paper demonstrated a quartz crystal microbalance (QCM) gas sensor based on ZIF-8-derived porous carbon and multi-walled carbon nanotubes decorated nanocomposite (ZIF-C/MWCNTs). The ZIF-C/MWCNTs composite was successfully prepared by high temperature carbonization of ZIFs templates and room temperature diffusion method. Our prepared sensor was operated at room temperature (25℃) and relative humidity (35 %), the results indicated that the limit of detections (LODs) of the QCM sensor for methylamine (MA), trimethylamine (TMA), ammonia (NH3) and dimethylamine (DMA) were 3.12 μmoL·L−1, 1.44 μmoL·L−1, 1.97 μmoL·L−1 and 2.81 μmoL·L−1, respectively. Finally, the improved QCM sensor was used to detect salmon meat stored at 4℃ and these results of these assays were juxtaposed with those obtained through Microdiffusion as an indicator of salmon meat freshness. The sensor was expected to be a potential device to detect the freshness of instant seafood quickly and accurately.

Diverse avenues of research support the transmethylation theory of psychosis: implications for neuroprotection

Transmethylation in the context of psychiatry has historically referred to the enzymatic transfer of a methyl group from one biochemical to another, whose resulting function can change so dramatically that a biochemical like tryptamine, for example, is converted into the hallucinogen dimethyltryptamine. Central to endogenous methylation activity is the folate cycle, which generates the primary transferable methyl groups in mammalian biochemistry. The relevance of this cycle to mental health becomes clear when the cycle is dysregulated, often leading to a buildup of both homocysteine and S-adenosylhomocysteine (SAH), while accompanied by a transient reduction in the intended physiologic target, S-adenosylmethionine (SAM). This paper includes an in-depth review of the causes of folate cycle perturbations associated with psychotic symptoms, expounding on alternative downstream pathways which are activated and pointing toward potential etiologic agents of the associated psychosis, the methylated tertiary amines N-methyl-salsolinol, N-methyl-norsalsolinol, and adrenochrome, which appear in scientific reports concerning their association with hallucinogenic and/or neurotoxic outcomes. Electrotopological state (E-state) data has been generated for these compounds, illustrating a strong similarity with hallucinogens, particularly in terms of the E-state of the nitrogen in their tertiary amine moieties. In light of the role the folate cycle plays in transmethylation, neuroprotective strategies to prevent the transition to psychosis are suggested, including the advisory that folate supplementation can be harmful depending on the status of other relevant biochemicals.

Interface Engineering of Substrate-Integrated Single-Crystal Perovskite Wafers for Sensitive X-Ray Detection.

Metal halide perovskite single crystals are emerging candidates for X-ray detection, however, it is challenging for growth of thickness-controlled single-crystal wafer on commercial backplanes, limiting their practical imaging application. Herein, integration of micrometer-thick methylammonium lead triiodide (MAPbI3) single-crystal wafer on indium tin oxide (ITO) substrates by methylamine (MA)-induced interface recrystallization is reported. Through selection of hole transport material with rich functional group, intimate interface contact with low trap density can be achieved, leading to superior carrier transport properties and homogeneous photoresponse. The as-fabricated X-ray detectors exhibit high sensitivity of 1.4×104 µC Gyair -1 cm-2 and low detection limit of 177 nGyair s-1, which are comparable to previous reports based on free-standing MAPbI3 bulk crystals. This work provides a feasible strategy for constructing substrate-integrated single-crystal perovskite wafers with controlled thickness, which may promote practical imaging application of perovskite X-ray detectors.

A Surprisingly High Enhancing Potential of Nitric Acid in Sulfuric Acid–Methylamine Nucleation

Nitric acid (NA) has recently been found to enhance sulfuric acid (SA)-driven new particle formation (NPF) at low temperatures (≤240 K). However, studies on the role of NA in atmospheric NPF remain limited. Herein, we explored the enhancement effect of NA on binary SA–methylamine (MA) nucleation by investigating the mechanism and kinetics of (NA)x(SA)y(MA)z (0 ≤ x, 0 ≤ y, x + y ≤ 3, 0 ≤ z ≤ 3) clusters using quantum chemical calculations and cluster dynamics simulations. We found that the mixed ternary NA-SA-MA clusters have lower evaporation rates compared to the corresponding NA-SA–dimethylamine (DMA) and NA-SA–ammonia (A) clusters, indicating the stronger binding ability of NA with respect to SA-MA clusters. At atmospheric conditions (T ≥ 278.15 K), NA can enhance the cluster formation rate of SA-MA by about six orders of magnitude, demonstrating a surprisingly high enhancing potential. Moreover, NA acts as an important participant in the cluster growth pathways of the NA-SA-MA system, as opposed to the “bridging” role of NA in the previously studied NA-SA-A system. This study proposes the first case of NA efficiently enhancing SA–amine nucleation at ambient temperature, suggesting a larger impact of NA in atmospheric NPF than previously expected.

Impact of the structural interplay between methyl amine cation and inorganic lead-halide cage of organic perovskites on the optoelectronic properties

Energy harvesting systems using organic–inorganic metal perovskite materials are the subject of active research and development. The synthesis protocols as well as the composition, structure, and stability of these materials are still up for dispute. There are relatively few studies available correlating the relation between the optical band gap and the composition of bulk perovskite materials. Given this, the primary goal of this work is to investigate the influence of structural interplay between methyl amine cation and an inorganic lead-halide cage of organic perovskites by varying the halide functionality of lead halide. Three different products have been synthesised, namely: Methyl ammonium lead iodide-chloride (CH3NH3PbICl2), methyl ammonium lead iodide-bromide (CH3NH3PbIBr2) and methyl ammonium lead iodide (CH3NH3PbI3). This work is a first-hand report that sheds light on the importance of the interplay between the electrostatic forces generated by the methyl ammonium group and the metal halide framework of organic perovskite on its optoelectronic properties.

In situ preparation of oriented microbial consortium-based compound enzyme strengthens food waste disintegration and anaerobic digestion: Performance, mechanism, microbial communities and global metabolic pathways

This study used food waste (FW) as the substrate, under the co-culture system, innovatively developed the oriented and high matching degree microbial consortium-based compound enzyme (MCE) used for promoting FW hydrolysis and anaerobic digestion (AD). It was found that the highest hydrolysis efficiency and substrate biodegradability could be obtained after 1:100 MCE (i.e. the inoculation ratio of Aspergillus oryzae CICC 40214 as protease generator and Aspergillus niger CICC 40294 as amylase generator was 1:100) pretreatment, thereby harvesting the highest biomethane yield of 522.61 mL/g VS. The dissection of FTIR results indicated that the structure of main components of starch, protein and lipid in FW was destructed after MCE pretreatment, of which the protein was more susceptible to MCE and disintegrated first, while its structure also became looser. XPS C1s spectra and N1s spectra showed that the C-(C/H) and protein-N of the enzyme pretreated solid were respectively decreased from 77.82 % to 69.19 % and 69.43 % to 40.07 %, which further implied that more carbohydrates and proteins were released from solid phase to liquid phase after MCE pretreatment. The microbial community and metagenome analysis illustrated that MCE pretreatment regulated the microbial communities lead to a shift in the favorable direction of biomethane production. While based on the changes in gene abundance, the deciphering of global metabolic pathways revealed that the 80 %, 60 %, 75 % and 86 % of the functional genes related to glycolysis, amino acid metabolism, TCA cycle and methane metabolism were respectively intensified after 1:100 MCE pretreatment, thereby achieving the maximized biomethane yield.

Amine-releasable Mediator In situ Repair Perovskites for Efficient and Stable Perovskite Solar Cells.

Residual lead iodide (PbI2) is deemed to a double-edged sword in perovskite film as small amounts of PbI2 are beneficial to the photovoltaic performance, but excessive will cause degradation of photovoltaic performance and stability. Herein, an in situ repair strategy has been developed by introducing amine-releasable mediator (methylammonium pyridine-2-carboxylic, MAPyA) to eliminate over-residual PbI2 and regulate the crystal quality of perovskite film. Notably, MAPyA can be partially decomposed into methylamine (MA) gas and pyridine-2-carboxylic (PyA) during high temperature annealing. The released MA can locally form liquid intermediate phase, facilitating the reconstruction of perovskite microcrystals and residual PbI2. Moreover, the leftover PyA is confirmed to effectively passivate the uncoordinated lead ions in final perovskite film. Based upon this, superior perovskite film with optimized crystal structure and holistic negligible PbI2 is acquired. The assembled device realizes outstanding efficiency of 24.06 %, and exhibits a remarkable operational stability that maintaining 87 % of its origin efficiency after continuous illumination for 1480 h. And the unencapsulated MAPyA-treated devices present significant uplift in humidity stability (maintaining ~93 % of the initial efficiency over 1500 h, 50-60 % relative humidity). Furthermore, the further optimization of this strategy with nanoimprint technology proves its superiority in the amplificative preparation for perovskite films.

Amine‐releasable Mediator In situ Repair Perovskites for Efficient and Stable Perovskite Solar Cells

AbstractResidual lead iodide (PbI2) is deemed to a double‐edged sword in perovskite film as small amounts of PbI2 are beneficial to the photovoltaic performance, but excessive will cause degradation of photovoltaic performance and stability. Herein, an in situ repair strategy has been developed by introducing amine‐releasable mediator (methylammonium pyridine‐2‐carboxylic, MAPyA) to eliminate over‐residual PbI2 and regulate the crystal quality of perovskite film. Notably, MAPyA can be partially decomposed into methylamine (MA) gas and pyridine‐2‐carboxylic (PyA) during high temperature annealing. The released MA can locally form liquid intermediate phase, facilitating the reconstruction of perovskite microcrystals and residual PbI2. Moreover, the leftover PyA is confirmed to effectively passivate the uncoordinated lead ions in final perovskite film. Based upon this, superior perovskite film with optimized crystal structure and holistic negligible PbI2 is acquired. The assembled device realizes outstanding efficiency of 24.06 %, and exhibits a remarkable operational stability that maintaining 87 % of its origin efficiency after continuous illumination for 1480 h. And the unencapsulated MAPyA‐treated devices present significant uplift in humidity stability (maintaining ~93 % of the initial efficiency over 1500 h, 50–60 % relative humidity). Furthermore, the further optimization of this strategy with nanoimprint technology proves its superiority in the amplificative preparation for perovskite films.

MnN4 embedded zeolite-templated carbon for methylamine and trimethylamine sensing: Insights from DFT study

From the perspective of raw material losses and human health, monitoring fish-based food quality has become more prominent. As a nondestructive technology, gas sensors have received extensive attention for evaluating the freshness of fish. In this study, the sensing and electronic properties of methylamine (MA) and trimethylamine (TMA) molecule adsorption on MnN4 embedded zeolite templated carbon (MnN4-C) were studied by density functional theory (DFT) method. The results show that the MnN4-C exhibits good structural stability, and displays high sensitivity toward MA and TMA gases by analysis of the interaction distance, adsorption energy, charge transfer and sensing response. It is worth noting that the ambient humidity has demonstrated no effect on the gas-sensing properties of MnN4-C for the studied gases. Meanwhile, applying a positive electric field can increase the adsorption energy and charge transfer, which enhances the MA and TMA gas sensitivity of MnN4-C. The recovery time reveals that MnN4-C can be an excellent reusability sensor for MA and TMA gases. This study provides theoretical direction for exploring the sensing application of MnN4-C in evaluating freshness of fish.

Formation of perovskite by solid-gas reaction through low-temperature carbon counter electrode in hole-conductor-free perovskite solar cells

Recently, hole-conductor-free perovskite solar cells (PSCs) with carbon counter electrode (CCE) have attracted great attention for its high stability and low fabrication cost. Furthermore, it would lower the cost and simplify the manufacturing process of PSCs by low temperature processing instead of high temperature sintering for fabrication. In this case, however, it is very important to improve the interfacial contact between perovskite layer and CCE. In this work, we for the first time introduce solid-gas reaction between dimethylammonium lead iodide (DMAPbI3) in solid state under carbon layer and methylamine (MA) gas passed through CCE which is formed at low temperature of 120 ℃. Based on Brunauer-Emmett-Teller (BET) measurement and XRD analysis, it is found that MA gas can pass through our low-temperature CCE and perovskite crystals could be successfully formed by the reaction with DMAPbI3. In this case, due to the existence of liquid crystal intermediate state and volume expansion, interfacial contact would become better and the charge transfer and recombination characteristics have improved considerably. The best performance devices based on optimized MA gas treatment time exhibit higher efficiency of 12.4% than that of PSCs fabricated by conventional ways with low-temperature processed CCE (9.6%).

Selective N-monomethylation of amines using CO2/H2 catalyzed by high-activity Cu–ZrOx interface on SBA-15

N-methylation of amines using CO2 and H2 addresses the problems of expensive raw materials and harsh reaction conditions. However, designing a high-active and stable interface for the efficient preparation of monomethyl amine compounds in this tandem reaction remains a challenge to be overcome. Here, Cu–ZrOx composites are dispersed on SBA-15, silicalite-1, and ZSM-5 through the oxalic acid precipitation method for the N-methylation of amines using CO2 and H2. Results show that the dispersion of Cu–ZrOx on the surface of SBA-15 is superior to the other two molecular sieves and effectively prevents the sintering of active metals. A 20 wt% Cu–ZrOx/SBA-15 catalyst proves to be optimal for the N-methylation of aniline (AN) using CO2 and H2 to methylaniline (MA) and the catalyst performance remains stable after 5 cycle runs. The optimal catalyst exhibits an AN conversion of 97.6% and a selectivity of 96.5% for MA under the conditions of 180 °C, 4.0 MPa (H2/CO2/N2 = 72/24/4, molar ratio), and 8 h. Spectroscopic investigation and controlled experiments indicated that the preferential adsorbed AN on the catalyst surface reacts with CO2 to generate C–N bond, thereby avoiding the self-coupling side reaction of AN and achieving a high yield of 94.2% for MA.

Oligomerization Mechanism of Methylglyoxal Regulated by the Methyl Groups in Reduced Nitrogen Species: Implications for Brown Carbon Formation.

Uncertain chemical mechanisms leading to brown carbon (BrC) formation affect the drivers of the radiative effects of aerosols in current climate predictions. Herein, the aqueous-phase reactions of methylglyoxal (MG) and typical reduced nitrogen species (RNSs) are systematically investigated by using combined quantum chemical calculations and laboratory experiments. Imines and diimines are identified from the mixtures of methylamine (MA) and ammonia (AM) with MG, but not from dimethylamine (DA) with the MG mixture under acidic conditions, because deprotonation of DA cationic intermediates is hindered by the amino groups occupied by two methyl groups. It leads to N-heterocycle (NHC) formation in the MG + MA (MGM) and MG + AM (MGA) reaction systems but to N-containing chain oligomer formation in the MG + DA (MGD) reaction system. Distinct product formation is attributed to electrostatic attraction and steric hindrance, which are regulated by the methyl groups of RNSs. The light absorption and adverse effects of NHCs are also strongly related to the methyl groups of RNSs. Our finding reveals that BrC formation is mainly contributed from MG reaction with RNSs with less methyl groups, which have more abundant and broad sources in the urban environments.

A possible unaccounted source of nitrogen-containing compound formation in aerosols: amines reacting with secondary ozonides

Abstract. Nitrogen (N)-containing compounds have a significant impact on the optical and toxicological properties of aerosols. 1,2,4-Trioxolanes, known as secondary ozonides (SOZs), i.e., key products from the ozonolysis of biogenic terpenoids, are readily taken up into atmospheric aerosols and act as oxidants, potentially interacting with amines in the atmosphere. In the present work, we carefully investigated the component of the particles produced by the ozonolysis of β-caryophyllene (β-C) in the presence of ethylamine (EA), methylamine (MA), dimethylamine (DMA), or ammonia. The mass spectrometric results show that SOZ is the dominant product from the ozonolysis of β-C. It readily reacts with EA and MA but has inert reactivities toward DMA and ammonia. Similar experimental results were achieved with α-humulene (α-H), an isomer of β-C, was used in place of β-C. Additionally, D2O and H218O solvents were used for the characterization of products. The results revealed an intriguing phenomenon where the products from β-C SOZ and α-H SOZ reacting with the same amine (EA or MA) possessed different functional groups, despite the fact that they are isomerized species with identical chemical structure (1,2,4-trioxolane). This indicates that the chemical conformation of SOZs has a strong influence on how they react with amines. For the first time, SOZs derived from β-C and α-H reacting with amines are reported in this study; this may represent a hitherto unrecognized source of N-containing compound production in atmospheric aerosols.