In Situ Direct Measurement of Vapor Pressures and Thermodynamic Parameters of Volatile Organic Materials in the Vapor Phase: Benzoic Acid, Ferrocene, and Naphthalene

ChemPhysChem ◽  
2013 ◽  
Vol 14 (9) ◽  
pp. 1920-1925 ◽  
Author(s):  
Walid M. Hikal ◽  
Brandon L. Weeks
Keyword(s):  
Benzoic Acid ◽  
Thermodynamic Parameters ◽  
Direct Measurement ◽  
Vapor Phase ◽  
Organic Materials ◽  
Vapor Pressures ◽  
Volatile Organic

scholarly journals Water-Enhanced Flux Changes under Dynamic Temperatures in the Vertical Vapor-Phase Diffusive Transport of Volatile Organic Compounds in Near-Surface Soil Environments

2021 ◽  
Vol 13 (12) ◽  
pp. 6570
Author(s):  
Asma Akter Parlin ◽  
Monami Kondo ◽  
Noriaki Watanabe ◽  
Kengo Nakamura ◽  
Mizuki Yamada ◽  
...  
Keyword(s):  
Air Quality ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Vapor Phase ◽  
Inverse Correlation ◽  
Diffusive Transport ◽  
Near Surface ◽  
Voc Emissions ◽  
Transport Behavior ◽  
Volatile Organic

The quantitative understanding of the transport behavior of volatile organic compounds (VOCs) in near-surface soils is highly important in light of the potential impacts of soil VOC emissions on the air quality and climate. Previous studies have suggested that temperature changes affect the transport behavior; however, the effects are not well understood. Indeed, much larger changes in the VOC flux under in situ dynamic temperatures than those expected from the temperature dependence of the diffusion coefficients of VOCs in the air have been suggested but rarely investigated experimentally. Here, we present the results of a set of experiments on the upward vertical vapor-phase diffusive transport of benzene and trichloroethylene (TCE) in sandy soils with water contents ranging from an air-dried value to 10 wt% during sinusoidal temperature variation between 20 and 30 °C. In all experiments, the flux from the soil surface was correlated with the temperature, as expected. However, the changes in flux under wet conditions were unexpectedly large and increased with increasing water content; they were also larger for TCE, the volatility of which depended more strongly on the temperature. Additionally, the larger flux changes were accompanied by a recently discovered water-induced inverse correlation between temperature and flux into the overlying soil. These results demonstrated that the flux changes of VOCs under dynamic temperatures could be increased by volatilization-dissolution interactions of VOCs with water. Future extensive studies on this newly discovered phenomenon would contribute to a better understanding of the impacts of soil VOC emissions on the air quality and climate.

scholarly journals Anthropogenic enhancements to production of highly oxygenated molecules from autoxidation

2019 ◽  
Vol 116 (14) ◽  
pp. 6641-6646 ◽  
Author(s):  
Havala O. T. Pye ◽  
Emma L. D’Ambro ◽  
Ben H. Lee ◽  
Siegfried Schobesberger ◽  
Masayuki Takeuchi ◽  
...  
Keyword(s):  
Fine Particulate Matter ◽  
Peroxy Radicals ◽  
Dominant Component ◽  
Fine Particulate ◽  
Biogenic Voc ◽  
Aircraft Observations ◽  
Volatile Organic ◽  
Climate Interactions ◽  
Urban Plume

Atmospheric oxidation of natural and anthropogenic volatile organic compounds (VOCs) leads to secondary organic aerosol (SOA), which constitutes a major and often dominant component of atmospheric fine particulate matter (PM2.5). Recent work demonstrates that rapid autoxidation of organic peroxy radicals (RO2) formed during VOC oxidation results in highly oxygenated organic molecules (HOM) that efficiently form SOA. As NOxemissions decrease, the chemical regime of the atmosphere changes to one in which RO2autoxidation becomes increasingly important, potentially increasing PM2.5, while oxidant availability driving RO2formation rates simultaneously declines, possibly slowing regional PM2.5formation. Using a suite of in situ aircraft observations and laboratory studies of HOM, together with a detailed molecular mechanism, we show that although autoxidation in an archetypal biogenic VOC system becomes more competitive as NOxdecreases, absolute HOM production rates decrease due to oxidant reductions, leading to an overall positive coupling between anthropogenic NOxand localized biogenic SOA from autoxidation. This effect is observed in the Atlanta, Georgia, urban plume where HOM is enhanced in the presence of elevated NO, and predictions for Guangzhou, China, where increasing HOM-RO2production coincides with increases in NO from 1990 to 2010. These results suggest added benefits to PM2.5abatement strategies come with NOxemission reductions and have implications for aerosol–climate interactions due to changes in global SOA resulting from NOxinteractions since the preindustrial era.

Synthesis of 1-acyl- and 1-(thioacyl)-4-benzylpiperazines as potential antidepressants

1990 ◽  
Vol 55 (7) ◽  
pp. 1817-1827 ◽  
Author(s):  
Vojtěch Kmoníček ◽  
Emil Svátek ◽  
Jiří Holubek ◽  
Miroslav Ryska ◽  
Martin Valchář ◽  
...  
Keyword(s):  
Benzoic Acid ◽  
Thionyl Chloride ◽  
Antidepressant Activity ◽  
Acid Chlorides ◽  
Phosphorus Pentasulfide ◽  
Antidepressant Agent ◽  
Dimethylaminobenzoic Acid ◽  
Amino Amides

2-Nitro, 3-nitro- and 4-nitrobenzoyl chloride were reacted with 1-benzylpiperazine in benzene in the presence of triethylamine and gave the amides IV-VI, the first of which is considered a bioisostere of the antidepressant agent piberaline (I). 2-Dimethylamino-, 3-dimethylamino- and 4-dimethylaminobenzoic acid were treated with thionyl chloride in benzene in the presence of triethylamine or pyridine, and the acid chlorides formed were reacted in situ with 1-benzylpiperazine affording the amides VII-IX. The amides I and IV-VI were transformed by treatment with phosphorus pentasulfide in pyridine to the thioamides X-XIII. 4-(Dimethylaminomethyl)benzoic acid was reacted with 1-benzylpiperazine in dimethylformamide in the presence of N,N'-carbonyldiimidazole and afforded the amide XIV. Heating of ethyl 5-methylimidazole-4-carboxylate with 1-benzylpiperazine to 200-210 °C gave the amide XV together with the unexpected 1-benzyl-4-ethylpiperazine (XVI). The oily or crystalline bases of the amino amides or thioamides were mostly transformed to crystalline salts and characterized by spectra. Out of the compounds prepared only X (V⁄FB-17 070) and XIV (V⁄FB-17 114) showed indications of efficacy in tests which are considered indicative of antidepressant activity. Compounds VII, VIII, and X appeared to be mildly antidopaminergic - similarly like piberaline (I), and compounds IV, V, XI, XIV, and XV on the contrary showed signs of dopaminominetic activity.

Warming up for mechanosynthesis – temperature development in ball mills during synthesis

2017 ◽  
Vol 53 (10) ◽  
pp. 1664-1667 ◽  
Author(s):  
Hannes Kulla ◽  
Manuel Wilke ◽  
Franziska Fischer ◽  
Mathias Röllig ◽  
Christiane Maierhofer ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Direct Measurement ◽  
Ball Mills ◽  
Temperature Development

We present a first direct measurement of the temperature during milling combined with in situ Raman spectroscopy monitoring.

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