scholarly journals The ozonolysis of primary aliphatic amines in fine particles

2008 ◽  
Vol 8 (5) ◽  
pp. 1181-1194 ◽  
Author(s):  
J. Zahardis ◽  
S. Geddes ◽  
G. A. Petrucci
Keyword(s):  
Fine Particles ◽  
Reaction System ◽  
Tropospheric Chemistry ◽  
Ozone Exposure ◽  
Surface Barrier ◽  
Secondary Amide ◽  
Tertiary Amide ◽  
Aerosol Mass ◽  
Criegee Intermediates ◽  
Species Specific

Abstract. The oxidative processing by ozone of the particulate amines octadecylamine (ODA) and hexadecylamine (HDA) is reported. Ozonolysis of these amines resulted in strong NO2– and NO3– ion signals that increased with ozone exposure as monitored by photoelectron resonance capture ionization aerosol mass spectrometry. These products suggest a mechanism of progressive oxidation of the particulate amines to nitroalkanes. Additionally, a strong ion signal at 125 m/z is assigned to the ion NO3– (HNO3). For ozonized mixed particles containing ODA or HDA + oleic acid (OL), with pO3≥3×10–7 atm, imine, secondary amide, and tertiary amide products were measured. These products most likely arise from reactions of amines with aldehydes (for imines) and stabilized Criegee intermediates (SCI) or secondary ozonides (for amides) from the fatty acid. The routes to amides via SCI and/or secondary ozonides were shown to be more important than comparable amide forming reactions between amines and organic acids, using azelaic acid as a test compound. Finally, direct evidence is provided for the formation of a surface barrier in the ODA + OL reaction system that resulted in the retention of OL at high ozone exposures (up to 10−3 atm for 17 s). This effect was not observed in HDA + OL or single component OL particles, suggesting that it may be a species-specific surfactant effect from an in situ generated amide or imine. Implications to tropospheric chemistry, including particle bound amines as sources of oxidized gas phase nitrogen species (e.g.~NO2, NO3), formation of nitrogen enriched HULIS via ozonolysis of amines and source apportionment are discussed.

scholarly journals The ozonolysis of primary aliphatic amines in single and multicomponent fine particles

2007 ◽  
Vol 7 (5) ◽  
pp. 14603-14638 ◽  
Author(s):  
J. Zahardis ◽  
S. Geddes ◽  
G. A. Petrucci
Keyword(s):  
Fine Particles ◽  
Reaction System ◽  
Tropospheric Chemistry ◽  
Ozone Exposure ◽  
Surface Barrier ◽  
Secondary Amide ◽  
Tertiary Amide ◽  
Aerosol Mass ◽  
Criegee Intermediates ◽  
Species Specific

Abstract. The oxidative processing by ozone of the particulate amines octadecylamine (ODA) and hexadecylamine (HDA) is reported. Ozonolysis of these amines resulted in strong NO2− and NO3− ion signals that increased with ozone exposure as monitored by photoelectron resonance capture ionization aerosol mass spectrometry. These products suggest a mechanism of progressive oxidation of the particulate amines to nitro alkanes. Additionally, a strong ion signal at 125 m/z is assigned to the ion NO3−(HNO3). For ozonized mixed particles containing ODA or HDA + oleic acid (OL), with pO3≥3×10−7 atm, imine, secondary amide, and tertiary amide products were measured. These products most likely arise from reactions of amines with aldehydes (for imines) and stabilized Criegee intermediates (SCI) or secondary ozonides (for amides) from the fatty acid. The routes to amides via SCI and/or secondary ozonides was shown to be more important than comparable amide forming reactions between amines and organic acids, using azelaic acid as a test compound. Finally, direct evidence is provided for the formation of a surface barrier in the ODA + OL reaction system that resulted in the retention of OL at high ozone exposures (up to 10−3 atm for 17 s). This effect was not observed in HDA + OL or single component OL particles, suggesting that it may be a species-specific surfactant effect from an in situ generated amide or imine. Implications to tropospheric chemistry, including particle bound amines as sources of oxidized gas phase nitrogen species (e.g. NO2, NO3), formation of nitrogen enriched HULIS via ozonolysis of amines and source apportionment are discussed.

scholarly journals Quantification of the role of stabilized Criegee intermediates in the formation of aerosols in limonene ozonolysis

2021 ◽  
Vol 21 (2) ◽  
pp. 813-829
Author(s):  
Yiwei Gong ◽  
Zhongming Chen
Keyword(s):  
Second Generation ◽  
Reaction System ◽  
Tropospheric Chemistry ◽  
Formation Mechanisms ◽  
High Humidity ◽  
Effect Of Water ◽  
Criegee Intermediates ◽  
Low Humidity ◽  
First And Second Generation ◽  
Stabilized Criegee Intermediates

Abstract. Stabilized Criegee intermediates (SCIs) have the potential to oxidize trace species and to produce secondary organic aerosols (SOAs), making them important factors in tropospheric chemistry. This study quantitatively investigates the performance of SCIs in SOA formation at different relative humidity (RH) levels, and the first- and second-generation oxidations of endo- and exocyclic double bonds ozonated in limonene ozonolysis are studied separately. Through regulating SCI scavengers, the yields and rate constants of SCIs in a reaction system were derived, and the quantities of SCIs were calculated. The quantity of SOAs decreased by more than 20 % under low-humidity conditions (10 % RH–50 % RH), compared to that under dry conditions, due to the reactions of SCIs with water, while the inhibitory effect of water on SOA formation was not observed under high-humidity conditions (60 % RH–90 % RH). When using excessive SCI scavengers to exclude SCI reactions, it was found that the effect of water on SOA formation with the presence of SCIs was different from that without the presence of SCIs, suggesting that SCI reactions were relevant to the non-monotonic impact of water. The fractions of the SCI contribution to SOAs were similar between dry and high-humidity conditions, where the SCI reactions accounted for ∼ 63 % and ∼ 73 % in SOA formation in the first- and second-generation oxidation; however, marked differences in SOA formation mechanisms were observed. SOA formation showed a positive correlation with the quantity of SCIs, and the SOA formation potential of SCIs under high-humidity conditions was more significant than that under dry and low-humidity conditions. It was estimated that 20 %–30 % of SCIs could be converted into SOAs under high-humidity conditions, while this value decreased by nearly half under dry and low-humidity conditions. The typical contribution of limonene-derived SCIs to SOA formation is calculated to be (8.21 ± 0.15) × 10−2 µg m−3 h−1 in forest, (4.26 ± 0.46) × 10−2 µg m−3 h−1 in urban areas, and (2.52 ± 0.28) × 10−1 µg m−3 h−1 in indoor areas. Water is an uncertainty in the role SCIs play in SOA formation, and the contribution of SCIs to SOA formation needs consideration even under high RH in the atmosphere.

scholarly journals Selective Extraction of Platinum(IV) from the Simulated Secondary Resources Using Simple Secondary Amide and Urea Extractants

Separations ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 139
Author(s):  
Yuki Ueda ◽  
Shintaro Morisada ◽  
Hidetaka Kawakita ◽  
Keisuke Ohto
Keyword(s):  
Electrical Equipment ◽  
Selective Extraction ◽  
Extraction Process ◽  
Secondary Amide ◽  
Separation And Purification ◽  
Secondary Resources ◽  
Tertiary Amide ◽  
Third Phase ◽  
Simulated Effluent ◽  
Secondary Amides

The recycling of rare metals such as platinum (Pt) from secondary resources, such as waste electronic and electrical equipment and automotive catalysts, is an urgent global issue. In this study, simple secondary amides and urea, N-(2-ethylhexyl)acetamide, N-(2-ethylhexyl)octanamide, and 1-butyl-3-(2-ethylhexyl)urea, which selectively extract Pt(IV) from a simulated effluent containing numerous metal ions, such as in an actual hydrometallurgical process, were synthesized and achieved efficient Pt(IV) stripping using only water. Comparison of Pt(IV) extraction behavior with a tertiary amide without N–H moieties suggests that the secondary amides and urea extractants effectively use hydrogen bonding to the hexachloroplatinate anion by N–H moieties. Examining the conditions for the third phase formation revealed that the secondary amide extractant with the longest alkyl chain can be used in the extraction process for a long time without forming any third phase, despite its lower Pt(IV) extraction capacity. The practical trial with simple compounds developed in this study should contribute to the development of Pt separation and purification processes.

scholarly journals Density changes of aerosol particles as a result of chemical reaction

2004 ◽  
Vol 4 (5) ◽  
pp. 6431-6472 ◽  
Author(s):  
Y. Katrib ◽  
S. T. Martin ◽  
Y. Rudich ◽  
P. Davidovits ◽  
J. T. Jayne ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Oxygen Content ◽  
Chemical Reactions ◽  
Aerosol Particles ◽  
Ozone Exposure ◽  
Spherical Particles ◽  
Aerodynamic Diameter ◽  
Layer Density ◽  
Aerosol Mass ◽  
Mobility Diameter

Abstract. This paper introduces the capability to study simultaneously changes in the density, the chemical composition, the mobility diameter, the aerodynamic diameter, and the layer thickness of multi-layered aerosol particles as they are being altered by heterogeneous chemical reactions. A vaporization-condensation method is used to generate aerosol particles composed of oleic acid outer layers of 2 to 30 nm on 101-nm polystyrene latex cores. The layer density is modified by reaction of oleic acid with ozone for variable exposure times. For increasing ozone exposure, the mobility diameter decreases while the vacuum aerodynamic diameter increases, which, for spherical particles, implies that particle density increases. The aerosol particles are confirmed as spherical based upon the small divergence of the particle beam in the aerosol mass spectrometer. The particle and layer densities are calculated by two independent methods, namely one based on the measured aerodynamic and mobility diameters and the other based on the measured mobility diameter and particle mass. The uncertainty estimates for density calculated by the second method are two to three times greater than those of the first method. Both methods indicate that the layer density increases from 0.89 to 1.12 g·cm−3 with increasing ozone exposure. Aerosol mass spectrometry shows that, concomitant with the increase in the layer density, the oxygen content of the reacted layer increases. Even after all of the oleic acid has reacted, the layer density and the oxygen content continue to increase slowly with prolonged ozone exposure, a finding which indicates continued chemical reactions of the organic products either with ozone or with themselves. The results of this paper provide new insights into the complex changes occurring for atmospheric particles during the aging processes caused by gas-phase oxidants.

Hydride Reductions of 1H-Pyrrolo[2,1-c][1,4]-benzodiazepine-5,11-diones: Selective Reduction of Secondary Amides to Carbinolamines

1998 ◽  
Vol 51 (12) ◽  
pp. 1121 ◽  
Author(s):  
Andrew G. Katsifis ◽  
Meredith E. McPhee ◽  
Damon D. Ridley
Keyword(s):  
Selective Reduction ◽  
Secondary Amide ◽  
Tertiary Amide ◽  
Secondary Amides

For the syntheses of radiolabelled pyrrolo[1,4]benzodiazepine antitumour antibiotics we required a method in which the unstable carbinolamine functionality was introduced prior to the radiolabel. In turn this required the selective reduction of a secondary amide in the presence of, inter alia, a tertiary amide. We report methods which can be used to achieve this outcome in a series of 1H-pyrrolo[2,1-c][1,4]benzodiazepine-5,11-diones.

scholarly journals Description and evaluation of aerosol in UKESM1 and HadGEM3-GC3.1 CMIP6 historical simulations

2020 ◽  
Vol 13 (12) ◽  
pp. 6383-6423
Author(s):  
Jane P. Mulcahy ◽  
Colin Johnson ◽  
Colin G. Jones ◽  
Adam C. Povey ◽  
Catherine E. Scott ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Dimethyl Sulfide ◽  
Cloud Droplet ◽  
Organic Aerosol ◽  
Tropospheric Chemistry ◽  
Earth System ◽  
Aerosol Mass ◽  
The Impact ◽  
Aerosol Source

Abstract. We document and evaluate the aerosol schemes as implemented in the physical and Earth system models, the Global Coupled 3.1 configuration of the Hadley Centre Global Environment Model version 3 (HadGEM3-GC3.1) and the United Kingdom Earth System Model (UKESM1), which are contributing to the sixth Coupled Model Intercomparison Project (CMIP6). The simulation of aerosols in the present-day period of the historical ensemble of these models is evaluated against a range of observations. Updates to the aerosol microphysics scheme are documented as well as differences in the aerosol representation between the physical and Earth system configurations. The additional Earth system interactions included in UKESM1 lead to differences in the emissions of natural aerosol sources such as dimethyl sulfide, mineral dust and organic aerosol and subsequent evolution of these species in the model. UKESM1 also includes a stratospheric–tropospheric chemistry scheme which is fully coupled to the aerosol scheme, while GC3.1 employs a simplified aerosol chemistry mechanism driven by prescribed monthly climatologies of the relevant oxidants. Overall, the simulated speciated aerosol mass concentrations compare reasonably well with observations. Both models capture the negative trend in sulfate aerosol concentrations over Europe and the eastern United States of America (US) although the models tend to underestimate sulfate concentrations in both regions. Interactive emissions of biogenic volatile organic compounds in UKESM1 lead to an improved agreement of organic aerosol over the US. Simulated dust burdens are similar in both models despite a 2-fold difference in dust emissions. Aerosol optical depth is biased low in dust source and outflow regions but performs well in other regions compared to a number of satellite and ground-based retrievals of aerosol optical depth. Simulated aerosol number concentrations are generally within a factor of 2 of the observations, with both models tending to overestimate number concentrations over remote ocean regions, apart from at high latitudes, and underestimate over Northern Hemisphere continents. Finally, a new primary marine organic aerosol source is implemented in UKESM1 for the first time. The impact of this new aerosol source is evaluated. Over the pristine Southern Ocean, it is found to improve the seasonal cycle of organic aerosol mass and cloud droplet number concentrations relative to GC3.1 although underestimations in cloud droplet number concentrations remain. This paper provides a useful characterisation of the aerosol climatology in both models and will facilitate understanding in the numerous aerosol–climate interaction studies that will be conducted as part of CMIP6 and beyond.

Factors Influencing the Ozone Resistance of Neoprene Vulcanizates under Flexure

1959 ◽  
Vol 32 (4) ◽  
pp. 1117-1133 ◽  
Author(s):  
R. M. Murray
Keyword(s):  
Dynamic Testing ◽  
Constant Stress ◽  
Ozone Exposure ◽  
Surface Barrier ◽  
Limiting Factor ◽  
Surface Films ◽  
Protective Film ◽  
Dynamic Conditions ◽  
Static Conditions ◽  
Ozone Resistance

Abstract The need for dynamic testing conditions, such as mild flexing, to study the attack of ozone on elastomeric vulcanizates, has become increasingly apparent. Many rubber goods, such as belts, tire sidewalls, and hose, are subjected to intermittent or continuously fluctuating strains in service and to evaluate their ozone resistance under constant stress or strain conditions is unrealistic and often leads to entirely erroneous conclusions. For example, it is well known that under static strain a vulcanizate's ozone resistance is enhanced by compounding with a wax which migrates to its surface and forms a protective film. However, numerous investigators have reported that when a wax film is continuously ruptured by dynamic testing, the vulcanizate is even more vulnerable to ozone attack than if no wax were present. Other surface films also may act detrimentally under dynamic conditions. One such film may form under static exposure by the migration of antiozonants to the surface of a sample where they or their ozone reaction products provide a shield against ozone. Also, diene elastomers, even when not under stress, react with ozone without cracking and it has been postulated that the thin films formed as a result of this reaction are less extensible and consequently more subject to rupture on flexing than the unreacted rubber beneath them. It may well be found that the resistance of any surface barrier to dynamic stresses is the limiting factor for many products in service. Consequently, techniques for testing under dynamic conditions are needed at least to supplement testing under constant stress or strain in ozone. Ozone exposure under dynamic conditions may prove to have analytical advantages over the static method. First, because dynamic tests accelerate ozone attack over that obtained statically even though no increased strain is impressed. This permits the more ozone resistant elastomers to be tested at lower concentrations of ozone than would be possible statically. By testing in more dilute ozone, the correlation between results obtained under atmospheric exposure and the ozone cabinet should be better. Also, it seems likely that compounding ingredients which improve ozone resistance under dynamic conditions should provide improvement under static conditions as well, even though the converse is not necessarily true.

scholarly journals The 2005 Study of Organic Aerosols at Riverside (SOAR-1): instrumental intercomparisons and fine particle composition

2011 ◽  
Vol 11 (23) ◽  
pp. 12387-12420 ◽  
Author(s):  
K. S. Docherty ◽  
A. C. Aiken ◽  
J. A. Huffman ◽  
I. M. Ulbrich ◽  
P. F. DeCarlo ◽  
...  
Keyword(s):  
Gas Phase ◽  
Fine Particles ◽  
Organic Aerosols ◽  
Diurnal Cycles ◽  
Aerosol Mass ◽  
High Volatility ◽  
Multiple State ◽  
Highly Correlated ◽  
Primary Emissions ◽  
A Minor

Abstract. Multiple state-of-the-art instruments sampled ambient aerosol in Riverside, California during the 2005 Study of Organic Aerosols at Riverside (SOAR) to investigate the chemical composition and potential sources of fine particles (PMf) in the inland region of Southern California. In this paper, we briefly summarize the spatial, meteorological and gas-phase conditions during SOAR-1 (15 July–15 August), provide detailed intercomparisons of high-resolution aerosol mass spectrometer (HR-AMS) measurements against complementary measurements, and report the average composition of PMf including the composition of the organic fraction measured by the HR-AMS. Daily meteorology and gas-phase species concentrations were highly consistent, displaying clear diurnal cycles and weekday/weekend contrast. HR-AMS measurements of non-refractory submicron (NR-PM1) mass are consistent and highly correlated with those from a filter dynamics measurement system tapered-element oscillating microbalance (TEOM), while the correlation between HR-AMS and heated TEOM measurements is lower due to loss of high volatility species including ammonium nitrate from the heated TEOM. Speciated HR-AMS measurements are also consistent with complementary measurements as well as with measurements from a collocated compact AMS while HR-AMS OC is similar to standard semi-continuous Sunset measurements within the combined uncertainties of both instruments. A correction intended to account for the loss of semi-volatile OC from the Sunset, however, yields measurements ~30% higher than either HR-AMS or standard Sunset measurements. On average, organic aerosol (OA) was the single largest component of PMf. OA composition was investigated using both elemental analysis and positive matrix factorization (PMF) of HR-AMS OA spectra. Oxygen is the main heteroatom during SOAR-1, with O/C exhibiting a diurnal minimum of 0.28 during the morning rush hour and maximum of 0.42 during the afternoon. O/C is broadly anti-correlated with H/C, while N/C and S/C (excluding organonitrate (ON) and organosulfate (OS) functionalities) are far lower than O/C at about 0.015 and ~0.001, respectively. When ON and OS estimates are included O/C, N/C, and S/C increase by factors of 1.21, 2, and 30, respectively, while H/C changes are insignificant. The increase in these ratios implies that ON accounts for ~1/2 of the organic nitrogen while OS dominate organic sulfur at this location. Accounting for the estimated ON and OS also improves the agreement between anions and cations measured by HR-AMS by ~8%, while amines have only a very small impact (1%) on this balance. Finally, a number of primary and secondary OA components were resolved by PMF. Among these a hydrocarbon-like OA and two minor, local OA components, one of which was associated with amines, were attributed to primary emissions and contributed a minor fraction (~20%) of OA mass. The remaining OA mass was attributed to a number of secondary oxidized OA (OOA) components including the previously-identified low-volatility and semi-volatile OOA components. In addition, we also report for the first time the presence of two additional OOA components.

scholarly journals Reverse Polarity Reductive Functionalization of Tertiary Amides via a Dual Iridium Catalyzed Hydrosilylation & SET Strategy

2020 ◽  
Author(s):  
Tatiana Rogova ◽  
Pablo Gabriel ◽  
Stamatia Zavitsanou ◽  
Jamie Leitch ◽  
Fernanda Duarte ◽  
...  
Keyword(s):  
Active Pharmaceutical Ingredient ◽  
Building Blocks ◽  
Chemical System ◽  
Secondary Amide ◽  
Reductive Activation ◽  
Tertiary Amide ◽  
New Strategy ◽  
Tandem Process ◽  
Electron Reduction ◽  
Tertiary Amides

A new strategy for the mild generation of synthetically valuable α-amino radicals from robust tertiary amide building blocks has been developed. By combining Vaska’s complex-catalyzed tertiary amide reductive activation and photochemical single electron reduction into a streamlined tandem process, metastable hemiaminal intermediates were successfully transformed into nucleophilic α-amino free radical species. This umpolung approach to such reactive intermediates was exemplified through coupling with an electrophilic dehydroalanine acceptor, resulting in the synthesis of an array of α-functionalized tertiary amine derivatives, previously inaccessible from the amide starting materials. The utility of the strategy was expanded to include secondary amide substrates, intramolecular variants and late stage functionalization of an active pharmaceutical ingredient. DFT analyses were used to establish the reaction mechanism and elements of the chemical system that were responsible for the reaction’s efficiency.

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