Open Access. Powered by Scholars. Published by Universities.®
- Publication
- Publication Type
Articles 1 - 7 of 7
Full-Text Articles in Entire DC Network
Recent Trends In Stratospheric Chlorine From Very Short‐Lived Substances, Ryan Hossaini, Elliot Atlas, Sandip S. Dhomse, Martyn P. Chipperfield, Peter F. Bernath, Anton M. Fernando, Jens Mühle, Amber A. Leeson, Stephen A. Montzka, Wuhu Feng
Recent Trends In Stratospheric Chlorine From Very Short‐Lived Substances, Ryan Hossaini, Elliot Atlas, Sandip S. Dhomse, Martyn P. Chipperfield, Peter F. Bernath, Anton M. Fernando, Jens Mühle, Amber A. Leeson, Stephen A. Montzka, Wuhu Feng
Chemistry & Biochemistry Faculty Publications
Very short‐lived substances (VSLS), including dichloromethane (CH2Cl2), chloroform (CHCl3), perchloroethylene (C2Cl4), and 1,2‐dichloroethane (C2H4Cl2), are a stratospheric chlorine source and therefore contribute to ozone depletion. We quantify stratospheric chlorine trends from these VSLS (VSLCltot) using a chemical transport model and atmospheric measurements, including novel high‐altitude aircraft data from the NASA VIRGAS (2015) and POSIDON (2016) missions. We estimate VSLCltot increased from 69 (±14) parts per trillion (ppt) Cl in 2000 to 111 (±22) ppt Cl in 2017, with >80% delivered to …
Phosgene In The Upper Troposphere And Lower Stratosphere: A Marker For Product Gas Injection Due To Chlorine-Containing Very Short Lived Substances, Jeremy J. Harrison, Martyn P. Chipperfield, Ryan Hossaini, Christopher D. Boone, Sandip Dhomse, Wuhu Feng, Peter F. Bernath
Phosgene In The Upper Troposphere And Lower Stratosphere: A Marker For Product Gas Injection Due To Chlorine-Containing Very Short Lived Substances, Jeremy J. Harrison, Martyn P. Chipperfield, Ryan Hossaini, Christopher D. Boone, Sandip Dhomse, Wuhu Feng, Peter F. Bernath
Chemistry & Biochemistry Faculty Publications
Abstract: Phosgene in the atmosphere is produced via the degradation of carbon tetrachloride, methyl chloroform, and a number of chlorine‐containing very short lived substances (VSLS). These VSLS are not regulated by the Montreal Protocol even though they contribute to stratospheric ozone depletion. While observations of VSLS can quantify direct stratospheric source gas injection, observations of phosgene in the upper troposphere/lower stratosphere can be used as a marker of product gas injection of chlorine‐containing VSLS. In this work we report upper troposphere/lower stratosphere measurements of phosgene made by the ACE‐FTS (Atmospheric Chemistry Experiment Fourier Transform Spectrometer) instrument and compare with results …
Spectrometric Monitoring Of Atmospheric Carbon Tetrafluoride (Cf4) Above The Jungfraujoch Station Since 1989: Evidence Of Continued Increase But At A Slowing Rate, E. Mahieu, R. Zander, G. C. Toon, M. K. Vollmer, S. Reimann, J. Muhle, W. Bader, B. Bovy, B. Lejune, C. Servais, P. F. Bernath
Spectrometric Monitoring Of Atmospheric Carbon Tetrafluoride (Cf4) Above The Jungfraujoch Station Since 1989: Evidence Of Continued Increase But At A Slowing Rate, E. Mahieu, R. Zander, G. C. Toon, M. K. Vollmer, S. Reimann, J. Muhle, W. Bader, B. Bovy, B. Lejune, C. Servais, P. F. Bernath
Chemistry & Biochemistry Faculty Publications
The long-term evolution of the vertical column abundance of carbon tetrafluoride (CF4) above the high-altitude Jungfraujoch station (Swiss Alps, 46.5 ° N, 8.0 ° E, 3580 ma.s.l.) has been derived from the spectrometric analysis of Fourier transform infrared solar spectra recorded at that site between 1989 and 2012. The investigation is based on a multi-microwindow approach, two encompassing pairs of absorption lines belonging to the R-branch of the strong ν3 band of CF4 centered at 1283 cm-1, and two additional ones to optimally account for weak but overlapping HNO3 interferences. The analysis reveals …
Interferences Of N-Chloroorganic Compounds In Free Chlorine Determination, Sushma H. Gandhi
Interferences Of N-Chloroorganic Compounds In Free Chlorine Determination, Sushma H. Gandhi
Chemistry & Biochemistry Theses & Dissertations
Various N-chlorinated organic compounds give positive responses to the analytical methods used to determine free chlorine. The present work quantifies interferences due to N-chloroisoleucine, N-chloropiperidine and N-chloro-2-methylbutyraldiminein the free chlorine determination by amperometry. These N-chloroorganic compounds were also studied for the recovery in response by the indicator electrode in amperometric titrimetry. The total chlorine content of the chloroaldimines derived from the chlorination of the amino acids, alanine, glutamic acid, glycine, isoleucine, leucine, phenylalanine, serine, valine, and those of dipeptides, alanylvaline and glycylleucine, was determined by amperometry and DPD-FAS titrimetry. The two methods were compared and evaluated with respect to recovery …
Reactions Of Aqueous Chlorine With Valine In Model Solutions And In Wastewater, Erika Forrer Mccormick
Reactions Of Aqueous Chlorine With Valine In Model Solutions And In Wastewater, Erika Forrer Mccormick
Chemistry & Biochemistry Theses & Dissertations
Solutions of the amino acid valine were chlorinated to seven chlorine-to-nitrogen mole (Cl/N) ratios and analyzed by high performance liquid chromatography, gas chromatography/mass spectroscopy, infrared spectroscopy, and nuclear magnetic resonance spectroscopy. The chlorination products found were N-chlorovaline, isobutyraldehyde, isobutyronitrile, and N-chloroisobutyraldimine. Their product distribution depends on the level of chlorination and pH. The main products identified at the lower CI/N mole ratios were N-chlorovaline and isobutyraldehyde, whereas at the higher CI/N mole ratios isobutyronitrile and N-chloroisobutyraldimine were identified as the main products. The concentration and the chlorination products of valine in municipal wastewater were also determined. The chlorination products of …
Reactions Of Organic N-Chloramines In The Gastric Fluid Of The Rat, Kathryn E. Mazina
Reactions Of Organic N-Chloramines In The Gastric Fluid Of The Rat, Kathryn E. Mazina
Chemistry & Biochemistry Theses & Dissertations
Using chlorine as a drinking water disinfectant may have potential health effects due to its reactivity with organic amino nitrogen compounds found in the stomach. Organic N-chloramines have been shown to form in the stomachs of laboratory rats. The possible reactions of N-chloramines in the stomach fluid were examined in this study using a model radiolabeled N-chloramine. 36Cl-N-Chloropiperidine, was synthesized and purified to remove 36Cl-chloride. Stomach fluid was obtained from Sprague-Dawley rats which had been first fasted for 24 or 48 hours and then administered 3 mL of deionized water. Different concentrations of radiolabeled chloramine were reacted with …
Analysis Of Organic N-Chloramines In Chlorinated Drinking Water, John Po Wen Yang
Analysis Of Organic N-Chloramines In Chlorinated Drinking Water, John Po Wen Yang
Chemistry & Biochemistry Theses & Dissertations
This thesis describes the development of a sensitive method for the separation and quantitation of organic N-chloramines in chlorinated tap water. 5-Dimethylaminonaphthalene- l-sulfinic acid has been synthesized and characterized. It yields highly fluorescent dansyl derivatives on reaction with N-chloramines. Conditions of the derivatization were optimized for the detection of N-chloropiperidine at concentrations in aqueous solution of 10-7 M. The technique gives a quantity of derivative which is proportional to the concentration of chloramine present over the range examined (10-7 M to 10-4 M). High pressure liquid chromatographic separation of dansyl derivatives of amines and amino acids has …