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The published version of this manuscript contains an error in affiliation for Theis I. Sølling. The correct affiliation details are as shown here, with the affiliation for Theis I. Sølling as: Center for Integrative Petroleum Research (CIPR), College of Petroleum Engineering and Geoscience, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.

The published version of this manuscript contains some missing information in affiliation ‘‘c’’. The correct affiliation ‘‘c’’ is Center for Integrative Petroleum Research (CIPR), College of Petroleum Engineering and Geoscience, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers..

Long path length FTIR-smog chamber techniques were used to study the title reactions in 700 Torr of N2, oxygen or air diluent at 296 ± 2 K. Values of k(Cl + CF3CN) = (2.43 ± 0.33) × 10-15 and k(OH + CF3CN) = (4.61 ± 0.34) × 10-15 cm3 molecule-1 s-1 were measured. There was no discernible reaction of CF3CN with O3 and an upper limit of k(O3 + CF3CN) ≤ 7.9 × 10-24 cm3 molecule-1 s-1 was established. The IR spectra of CF3CN and CF3CF2CN are reported. The atmospheric lifetime of CF3CN is determined by the reaction with OH and is approximately 6.9 years. Reaction of CF3CN with Cl atoms in a chamber study gives (Z-) and/or (E-) CF3CClNCl and CF3C(O)Cl as major primary products. Under environmental conditions, the OH radical initiated oxidation gives COF2 in a yield of (96 ± 8)%. The global warming potential for CF3CN is estimated as 1030 for a 100 year time horizon.

Smog chambers interfaced with in situ FT-IR detection were used to investigate the kinetics and mechanisms of the Cl atom, OH radical, and O3 initiated oxidation of (Z)- and (E)-1,2-dichloroethene (CHCl=CHCl) under atmospheric conditions. Relative and absolute rate methods were used to measure k(Cl + (Z)-CHClCHCl) = (8.80 ± 1.75) × 10-11, k(Cl + (E)-CHClCHCl) = (8.51 ± 1.69) × 10-11, k(OH + (Z)-CHClCHCl) = (2.02 ± 0.43) × 10-12, k(OH + (E)-CHClCHCl) = (1.94 ± 0.43) × 10-12, k(O3 + (Z)-CHClCHCl) = (4.50 ± 0.45) × 10-21, and k(O3 + (E)-CHClCHCl) = (1.02 ± 0.10) × 10-19 cm3 molecule-1 s-1 in 700 Torr of N2/air diluent at 298 ± 2 K. Pressure dependencies for the Cl atom reaction kinetics were observed for both isomers, consistent with isomerization occurring via Cl atom elimination from the chemically activated CHCl-CHCl-Cl adduct. The observed products from Cl initiated oxidation were HC(O)Cl (117-133%), CHCl2CHO (29-30%), and the corresponding CHClCHCl isomer (11-20%). OH radical initiated oxidation gives HC(O)Cl as a major product. For reaction of OH with (E)-CHClCHCl, (Z)-CHClCHCl was also observed as a product. A significant chlorine atom elimination channel was observed experimentally (HCl yield) and supported by computational results. Photochemical ozone creation potentials of 12 and 11 were estimated for (Z)- and (E)-CHClCHCl, respectively. Finally, an empirical kinetic relationship is explored for the addition of OH radicals or Cl atoms to small alkenes. The results are discussed in the context of the atmospheric chemistry of (Z)- and (E)-CHClCHCl.

Long path length FTIR-smog chamber techniques were used to study the title reactions in 700 Torr of N2, oxygen or air diluent at 296 ± 2 K. Values of k(Cl + CF3CN) = (2.43 ± 0.33) × 10−15 and k(OH + CF3CN) = (4.61 ± 0.34) × 10−15 cm3 molecule−1 s−1 were measured. There was no discernible reaction of CF3CN with O3 and an upper limit of k(O3 + CF3CN) ≤ 7.9 × 10−24 cm3 molecule−1 s−1 was established. The IR spectra of CF3CN and CF3CF2CN are reported. The atmospheric lifetime of CF3CN is determined by the reaction with OH and is approximately 6.9 years. Reaction of CF3CN with Cl atoms in a chamber study gives (Z-) and/or (E-) CF3CCl[double bond, length as m-dash]NCl and CF3C(O)Cl as major primary products. Under environmental conditions, the OH radical initiated oxidation gives COF2 in a yield of (96 ± 8)%. The global warming potential for CF3CN is estimated as 1030 for a 100 year time horizon.

Photolabile protecting groups offer synthetic routes with facile deprotection by photolysis, providing higher yields with less workup. Protecting groups producing only gaseous byproducts upon removal are particularly desirable as sustainable reagents. Cheletropic reactions provide just this combination of photocleavable groups with gaseous byproducts. However, only few protecting groups for cheletropic reactions have been described and little is known about their photochemistry and associated stereochemistry. Here we show that the sulfolene protecting group, used for diene protection and functionalization, can be photochemically removed. First, using TD-DFT, we conclude that the photochemical ring-opening occurs conrotatorily in a concerted process, consistent with the Woodward-Hoffmann rules. Experimentally, we demonstrate that this process can be photoinitiated by radiation between 180 and 300 nm and confirm the proposed stereochemistry in solution. Using time-resolved photoelectron spectroscopy, we determine that the first steps in the photochemical ring-opening of sulfolene occur on ultrafast timescales (≤84 fs), consistent with a fully concerted process. Our findings expand applications of the sulfolene protecting group and promise an easy strategy for control of cis-trans isomerization.

The ability to understand and possibly even predict the productivity of wells across a field is an important accomplishment in a production setting. In the tight Lower Cretaceous chalk field Valdemar, 5 wells have been observed to produce significantly larger oil volumes compared to nearby wells. This study was conducted to map the inter-well differences in the oil composition to better understand the productivity differences. This was done by analyzing any chemical differences of 21 samples from 16 different wells by GC-MS and principal component analysis of summed extracted ion chromatograms (SICs) using the chemometric analysis of selected ion chromatograms (CHEMSIC) method. The sterane (m/z 217 and m/z 218) and C4 (m/z 234) biomarker SICs were found to have chemically meaningful features described by principal component 1 (PC1). The association between these markers and the relative production was modeled to provide a better understanding of the productivity of the different wells. A correlation between oil saturation and productivity was established in the sense that the more mature and thus less viscous oil seem to have charged certain favorably placed reservoir sections first; these locations coincide with the location of the 5 wells in question.

The ability to understand and possibly even predict the productivity of wells across a field is an important accomplishment in a production setting. In the tight Lower Cretaceous chalk field Valdemar, 5 wells have been observed to produce significantly larger oil volumes compared to nearby wells. This study was conducted to map the inter-well differences in the oil composition to better understand the productivity differences. This was done by analyzing any chemical differences of 21 samples from 16 different wells by GC-MS and principal component analysis of summed extracted ion chromatograms (SICs) using the chemometric analysis of selected ion chromatograms (CHEMSIC) method. The sterane (m/z 217 and m/z 218) and C4 (m/z 234) biomarker SICs were found to have chemically meaningful features described by principal component 1 (PC1). The association between these markers and the relative production was modeled to provide a better understanding of the productivity of the different wells. A correlation between oil saturation and productivity was established in the sense that the more mature and thus less viscous oil seem to have charged certain favorably placed reservoir sections first; these locations coincide with the location of the 5 wells in question.

We have characterized the various pathways for OH radical (OH˙) induced decomposition of tert-butyl methyl ether (MTBE) and found an oxidative pathway that leads to complete degradation under the prerequisite that OH radicals are present in excess. A simple polarizable continuum model is used to predict the behavior in an aqueous medium and the behavior is unchanged compared to that in the gas phase. The computational study has also revealed some of the fundamental aspects of hydrogen transfer from asymmetric ethers; the ˙OH assisted hydrogen abstraction has a barrier when the reaction takes place at a distance from the heteroatom, that is, at the tert-butyl group, whereas hydrogen abstraction from the methyl group proceeds without a barrier. The addition of ˙OH to (CH3)3COCH2˙ also proceeds without a barrier, and so does hydrogen abstraction from the resulting adduct ((CH3)3COCH2OH) to form (CH3)3COCH(OH)˙. However, a barrier is yet again found in the hydrogen abstraction from the latter to form (CH3)3COCH[double bond, length as m-dash]O and yet again in the formation of the formyl radical (CH3)3COC[double bond, length as m-dash]O˙ by hydrogen abstraction. The latter is the last step before the final stage of complete oxidation of MTBE to form CO2.

The interfacial tension of systems containing water, n-decane, and model naphthenic acids were investigated using a predictive model based on COSMO-RS theory and experimental pendant drop measurements. Five naphthenic acid homologues that are considered to be representative of surfactants inherent to crude oil were dissolved in n-decane at equal concentrations. The interfacial tensions of the five systems at an acid concentration of 1.66 mol% relative to n-decane were experimentally determined to be 27–30 mN/m. The interfacial tensions of the five different acid-decane phases against water were also predicted using density functional theory (DFT) calculations and COSMO-RS theory. The accuracy of the predictions was very good as confirmed through pendant drop measurements of the interfacial tension. The mean-absolute-deviation between experimental and predicted values was 2.6 mN/m thus demonstrating the high predictive power of COSMO-RS theory for calculating the interfacial tension at oil–water interfaces in the presence of surface-active compounds.