Article

1999 ◽  
Vol 77 (5-6) ◽  
pp. 647-653
Author(s):  
Robert P Claridge ◽  
Ross W Millar ◽  
John H Ridd
Keyword(s):  
Nitrogen Dioxide ◽  
Nuclear Polarization ◽  
Straight Chain ◽  
Absorption Signal ◽  
Emission Signal ◽  
Enhanced Absorption ◽  
Reverse Mode ◽  
Diallyl Ether ◽  
Cyclic Compounds ◽  
Cis And Trans

The reaction of diallyl ether with nitrogen dioxide in organic solvents yields a mixture of cis and trans 2,3-bis(nitromethyl)tetrahydrofurans, cis and trans 2-nitratomethyl-3-nitromethyltetrahydrofurans and a number of straight-chain compounds with one to four nitro groups. Under the conditions used, the cyclic compounds form the main products when the solution of nitrogen dioxide is slowly added to the solution of diallyl ether but not when the reverse mode of addition is used. When 15N-nitrogen dioxide is used, the products show strong 15N nuclear polarization: the 2,3-di(nitromethyl)tetrahydrofurans give an emission signal, and one straight-chain product with two nonequivalent nitro groups shows both an emission signal and an enhanced absorption signal. For both the cyclic and straight-chain products, the nuclear polarization is consistent with the successive reactions of diallyl ether with two nitrogen dioxide radicals with uncorrelated spins.Key words: diallyl ether, nitrogen dioxide, 15N nuclear polarization, CIDNP.

15N nuclear polarization in the reactions of diallyl ether with nitrogen dioxide

1999 ◽  
Vol 77 (5-6) ◽  
pp. 647-653
Author(s):  
Robert P. Claridge ◽  
Ross W. Millar ◽  
John H. Ridd
Keyword(s):  
Nitrogen Dioxide ◽  
Nuclear Polarization ◽  
Diallyl Ether

scholarly journals A broadband cavity enhanced absorption spectrometer for aircraft measurements of glyoxal, methylglyoxal, nitrous acid, nitrogen dioxide, and water vapor

2016 ◽  
Vol 9 (2) ◽  
pp. 423-440 ◽  
Author(s):  
K.-E. Min ◽  
R. A. Washenfelder ◽  
W. P. Dubé ◽  
A. O. Langford ◽  
P. M. Edwards ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Cross Sections ◽  
Nitrous Acid ◽  
Aircraft Measurements ◽  
Charge Coupled Device ◽  
Light Emitting ◽  
Enhanced Absorption ◽  
Field Campaigns ◽  
A Charge ◽  
Absorption Spectrometer

Abstract. We describe a two-channel broadband cavity enhanced absorption spectrometer (BBCEAS) for aircraft measurements of glyoxal (CHOCHO), methylglyoxal (CH3COCHO), nitrous acid (HONO), nitrogen dioxide (NO2), and water (H2O). The instrument spans 361–389 and 438–468 nm, using two light-emitting diodes (LEDs) and a single grating spectrometer with a charge-coupled device (CCD) detector. Robust performance is achieved using a custom optical mounting system, high-power LEDs with electronic on/off modulation, high-reflectivity cavity mirrors, and materials that minimize analyte surface losses. We have successfully deployed this instrument during two aircraft and two ground-based field campaigns to date. The demonstrated precision (2σ) for retrievals of CHOCHO, HONO and NO2 are 34, 350, and 80 parts per trillion (pptv) in 5 s. The accuracy is 5.8, 9.0, and 5.0 %, limited mainly by the available absorption cross sections.

Phase-shift off-axis cavity-enhanced absorption detector of nitrogen dioxide

2006 ◽  
Vol 17 (4) ◽  
pp. 923-931 ◽  
Author(s):  
Vasili L Kasyutich ◽  
Philip A Martin ◽  
Robert J Holdsworth
Keyword(s):  
Phase Shift ◽  
Nitrogen Dioxide ◽  
Enhanced Absorption

scholarly journals Inherent calibration of a blue LED-CE-DOAS instrument to measure iodine oxide, glyoxal, methyl glyoxal, nitrogen dioxide, water vapour and aerosol extinction in open cavity mode

2010 ◽  
Vol 3 (6) ◽  
pp. 1797-1814 ◽  
Author(s):  
R. Thalman ◽  
R. Volkamer
Keyword(s):  
Nitrogen Dioxide ◽  
Water Vapour ◽  
Absorption Spectroscopy ◽  
Cavity Mode ◽  
Trace Gases ◽  
Broad Band ◽  
Open Cavity ◽  
Aerosol Extinction ◽  
Methyl Glyoxal ◽  
Enhanced Absorption

Abstract. The combination of Cavity Enhanced Absorption Spectroscopy (CEAS) with broad-band light sources (e.g. Light-Emitting Diodes, LEDs) lends itself to the application of cavity enhanced Differential Optical Absorption Spectroscopy (CE-DOAS) to perform sensitive and selective point measurements of multiple trace gases and aerosol extinction with a single instrument. In contrast to other broad-band CEAS techniques, CE-DOAS relies only on the measurement of relative intensity changes, i.e. does not require knowledge of the light intensity in the absence of trace gases and aerosols (I0). We have built a prototype LED-CE-DOAS instrument in the blue spectral range (420–490 nm) to measure nitrogen dioxide (NO2), glyoxal (CHOCHO), methyl glyoxal (CH3COCHO), iodine oxide (IO), water vapour (H2O) and oxygen dimers (O4). We demonstrate the first direct detection of methyl glyoxal, and the first CE-DOAS detection of CHOCHO and IO. The instrument is further inherently calibrated for light extinction from the cavity by observing O4 or H2O (at 477 nm and 443 nm) and measuring the pressure, relative humidity and temperature independently. This approach is demonstrated by experiments where laboratory aerosols of known size and refractive index were generated and their extinction measured. The measured extinctions were then compared to the theoretical extinctions calculated using Mie theory (3–7 × 10−7cm−1). Excellent agreement is found from both the O4 and H2O retrievals. This enables the first inherently calibrated CEAS measurement at blue wavelengths in open cavity mode, and eliminates the need for sampling lines to supply air to the cavity, i.e., keep the cavity enclosed and/or aerosol free. Measurements in open cavity mode are demonstrated for CHOCHO, CH3COCHO, NO2, H2O and aerosol extinction. Our prototype LED-CE-DOAS provides a low cost, yet research grade innovative instrument for applications in simulation chambers and in the open atmosphere.

scholarly journals Broadband cavity-enhanced absorption spectroscopy in the ultraviolet spectral region for measurements of nitrogen dioxide and formaldehyde

2016 ◽  
Vol 9 (1) ◽  
pp. 41-52 ◽  
Author(s):  
R. A. Washenfelder ◽  
A. R. Attwood ◽  
J. M. Flores ◽  
K. J. Zarzana ◽  
Y. Rudich ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Absorption Spectroscopy ◽  
Spectral Region ◽  
Trace Gases ◽  
Ambient Air ◽  
Array Detector ◽  
Enhanced Absorption ◽  
Cavity Enhanced Absorption Spectroscopy ◽  
Ultraviolet Spectral Region ◽  
Standard Additions

Abstract. Formaldehyde (CH2O) is the most abundant aldehyde in the atmosphere, and it strongly affects photochemistry through its photolysis. We describe simultaneous measurements of CH2O and nitrogen dioxide (NO2) using broadband cavity-enhanced absorption spectroscopy in the ultraviolet spectral region. The light source consists of a continuous-wave diode laser focused into a Xenon bulb to produce a plasma that emits high-intensity, broadband light. The plasma discharge is optically filtered and coupled into a 1 m optical cavity. The reflectivity of the cavity mirrors is 0.99930 ± 0.00003 (1− reflectivity  =  700 ppm loss) at 338 nm, as determined from the known Rayleigh scattering of He and zero air. This mirror reflectivity corresponds to an effective path length of 1.43 km within the 1 m cell. We measure the cavity output over the 315–350 nm spectral region using a grating monochromator and charge-coupled device array detector. We use published reference spectra with spectral fitting software to simultaneously retrieve CH2O and NO2 concentrations. Independent measurements of NO2 standard additions by broadband cavity-enhanced absorption spectroscopy and cavity ring-down spectroscopy agree within 2 % (slope for linear fit  = 1.02 ± 0.03 with r2 = 0.998). Standard additions of CH2O measured by broadband cavity-enhanced absorption spectroscopy and calculated based on flow dilution are also well correlated, with r2 = 0.9998. During constant mixed additions of NO2 and CH2O, the 30 s measurement precisions (1σ) of the current configuration were 140 and 210 pptv, respectively. The current 1 min detection limit for extinction measurements at 315–350 nm provides sufficient sensitivity for measurement of trace gases in laboratory experiments and ground-based field experiments. Additionally, the instrument provides highly accurate, spectroscopically based trace gas detection that may complement higher precision techniques based on non-absolute detection methods. In addition to trace gases, this approach will be appropriate for measurements of aerosol extinction in ambient air, and this spectral region is important for characterizing the strong ultraviolet absorption by brown carbon aerosol.

Cavity-enhanced absorption: detection of nitrogen dioxide and iodine monoxide using a violet laser diode

2003 ◽  
Vol 76 (6) ◽  
pp. 691-697 ◽  
Author(s):  
V.L. Kasyutich ◽  
C.S.E. Bale ◽  
C.E. Canosa-Mas ◽  
C. Pfrang ◽  
S. Vaughan ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Laser Diode ◽  
Enhanced Absorption ◽  
Iodine Monoxide

Stereochemistry of Disilanylene-Containing Cyclic Compounds. Palladium-Catalyzed Reactions of cis- and trans-3,4-Benzo-1,2-diisopropyl-1,2-dimethyl-1,2-disilacyclobut-3-ene with Ethylene

2012 ◽  
Vol 31 (9) ◽  
pp. 3492-3498 ◽  
Author(s):  
Akinobu Naka ◽  
Joji Ohshita ◽  
Eigo Miyazaki ◽  
Toshiko Miura ◽  
Hisayoshi Kobayashi ◽  
...  
Keyword(s):  
Palladium Catalyzed ◽  
Catalyzed Reactions ◽  
Cyclic Compounds ◽  
Cis And Trans

Stereochemistry of Disilanylene-containing Cyclic Compounds – Synthesis and Palladium-catalyzed Reactions of cis- and trans-3,4- Benzo-1,2-diisopropyl-1,2-dimethyl-1,2-disilacyclobut-3-ene

2009 ◽  
Vol 64 (11-12) ◽  
pp. 1580-1590 ◽  
Author(s):  
Akinobu Naka ◽  
Jun Sakata ◽  
Junnai Ikadai ◽  
Hiroyuki Kawasaki ◽  
Joji Ohshita ◽  
...  
Keyword(s):  
Catalytic Amount ◽  
Similar Reaction ◽  
Single Isomer ◽  
Palladium Catalyzed ◽  
Catalyzed Reactions ◽  
Cyclic Compounds ◽  
Cis And Trans

The synthesis and palladium-catalyzed reactions of cis- and trans-3,4-benzo-1,2-diisopropyl- 1,2-dimethyl-1,2-disilacyclobut-3-ene (1a and 1b) are reported. Their reactions with diphenylacetylene in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium(0) proceeded with high stereospecificity to give cis- and trans-5,6-benzo-1,4-diisopropyl-1,4-dimethyl- 2,3-diphenyl-1,4-disilacyclohexa-2,5-diene, 2a and 2b, in 95% and 93% yield, respectively. Similar palladium-catalyzed reactions of 1a and 1b with monosubstituted acetylenes, such as 1-hexyne, tert-butylacetylene, phenylacetylene, and trimethylsilylacetylene, also proceeded stereospecifically to afford the respective cis- and trans-5,6-benzo-1,4-disilacyclohexa-2,5-dienes, 3a - 6a and 3b - 6b, in excellent yields and as the sole products. The palladium-catalyzed reaction of 1a with styrene gave a mixture consisting of two stereoisomers, cis-2- and trans-2-phenyl-substituted 5,6- benzo-(r-1),cis-4-diisopropyl-1,4-disilacyclohex-5-ene 7a and 8a in a ratio of 5 : 3 in 72% combined yield, while the reaction of styrene with 1b afforded two stereoisomers, 7b and 8b, in a ratio of 2 : 1 in 80% combined yield. With 1-hexene, 1a gave two stereoisomers, 5,6-benzo-cis-2-(nbutyl)-( r-1),cis-4-diisopropyl- and 5,6-benzo-trans-2-(n-butyl)-(r-1),cis-4-diisopropyl-1,4-dimethyl- 1,4-disilacyclohex-5-ene, 9a and 10a, in a ratio of 1 : 1 in 70% combined yield. A similar reaction of 1b with 1-hexene produced 5,6-benzo-cis-2-(n-butyl)-(r-1),trans-4-diisopropyl-1,4-dimethyl-1,4- disilacyclohex-5-ene in 81% yield and as a single isomer

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