Gas phase bond dissociation enthalpies and enthalpies of isomerization/reaction for small hydrocarbon combustion related compounds between 300 and 1500 K: A comparison of Gaussian-4 (G4) theoretical values against experimental data

Gas phase calculations at 1 atmosphere pressure between 300 and 1500 K at 200 K intervals were conducted using the Gaussian-4 (G4) composite method level of theory on a representative set of reactions having broad relevance in hydrocarbon combustion chemistry. Reasonable agreement between the experimental and theoretical data was obtained across the temperature range under consideration for all bond dissociation enthalpies, isomerization enthalpies, and enthalpies of reaction. For some reaction schemes, chemical accuracy for the theoretical method was maintained over the complete temperature range, whereas other systems displayed up to several kcal mol^-1^ deviations from experimental data. The direction of signed errors generally increased as the temperature was raised, and no general error trends were related to molecular size or reaction class

Projected Climate Change Impacts on Grape Growing in the Okanagan Valley, British Columbia, Canada

A statistical analysis was conducted on long-term climate records in the Okanagan Valley wine grape growing region of British Columbia, Canada. No observable trends for average annual temperatures were found in the region. Analyses of monthly mean and extreme temperatures show wide spatial and temporal heterogeneity, indicating that future studies using downscaling of global climate models for this region will require resolutions on the order of several kilometers. Mean winter temperatures are increasing throughout the valley, and extreme minimum temperatures are also increasing during the winter at the central and northern sites which have historically presented the most risk of winter damage to grapevines. Only the most southern and northern sub-regions are expected to see significant changes in their heat unit accumulations during the growing season. Over the coming century, the southern end of the valley will likely move from Winkler heat unit region 1 to 2. All regions of the Okanagan will continue to have latitude-temperature indices among the lowest of the world's fine table wine producing regions over the coming century. Growing season and dormant season average temperatures are expected to change by only a modest amount by 2100. Current climate maturity groupings for ripening grape varieties will likely stay constant at cool (central and southern areas) and intermediate (south-central) for all sites except Osoyoos (south). The climate trendings at Osoyoos suggest it will transition from an intermediate to a warm grouping by about 2050. The early to mid-season ripening capacity of the region may improve due to climate changes, but there is a risk of the asymmetric late season increases in minimum daily temperatures lowering the daily temperature range at some sites, possibly leading to difficulties in maintaining a balanced between sugar and sensory profiles as wine grapes approach maturity. The projected warming at the southern end of the valley should favor improved and increased Merlot production, will require Chardonnay production to shift northwards, and will allow growing of warmer climate wine grape varieties currently inaccessible because of low winter temperatures and a lack of growing season heat units. Increasing winter temperatures throughout the region are expected to result in increased risk of pests such as Pierce’s disease

Review of the Carbon Dioxide Splitting Patent Literature

Increasing concentrations of carbon dioxide in the atmosphere have stimulated significant global research and development efforts regarding the reduction in emissions from all point and non-point sources. In addition to technologies that do not use carbon feedstocks or which capture and "permanently" store carbon dioxide (i.e., sequestration), there is considerable worldwide interest for dissociating waste stream carbon dioxide molecules into their constituent carbon and oxygen atoms ("CO2 splitting") as a final "end-of-pipe" treatment option. This document presents a review of on-point issued and applied for patents in the field of carbon dioxide splitting. The findings suggest patents in this area appear to be subject to a higher standard because of the global importance of the carbon dioxide issue. Authorities may be hesitant, on policy grounds, to issue broad-ranging patents for carbon dioxide splitting in order to prevent a worldwide reluctance towards adopting feasible treatment methods because of the high patent licensing costs that may accrue

Congener-Specific Numbering Systems for the Environmentally Relevant C4 through C8 Perfluorinated Homologue Groups of Alkyl Sulfonates, Carboxylates, Telomer Alcohols and Acids, and Their Derivatives

We introduce a congener-specific numbering system for the C4 through C8 perfluorinated homologue groups of alkyl sulfonates, carboxylates, telomer alcohols and acids, and their derivatives. Increasing length of the carbon chain beyond C3 leads to a corresponding rapid increase in the number of potential isomers (C4 =4, C5 =8, C6 =17, C7 =39, and C8 =89 congeners). There is a need for clear and unambiguous chemical shorthand to ensure accuracy and consistency in the future perfluorinated alkyl substance (PFA) literature, and to correct previous misconceptions that may have restricted research efforts into developing full-congener PFA analysis. If adopted by the research community, introduction of a numbering system at this relatively early stage of investigations into the congener-specific analysis, environmental behavior, and toxicology of PFAs would not require an arduous and difficult reassignment of historical structures and naming conventions presented in the prior art. Many PFA congeners are chiral, necessitating a consideration of their enantiospecific environmental behavior and toxicology

Biological Activities of Extracts from Sumac (Rhus spp.): A Review

Sumac is the common name for a genus (Rhus) that contains over 250 individual species of flowering plants in the family Anacardiaceae. These plants are found in temperate and tropical regions worldwide, often grow in areas of marginal agricultural capacity, and have a long history of use by indigenous peoples for medicinal and other uses. The research efforts on sumac extracts to date indicate a promising potential for this plant family to provide renewable bioproducts with the following reported desirable bioactivities: antifibrogenic, antifungal, antiinflammatory, antimalarial, antimicrobial, antimutagenic, antioxidant, antithrombin, antitumorigenic, antiviral, cytotoxic, hypoglycaemic, and leukopenic. As well, the bioactive components can be extracted from the plant material using environmentally benign solvents that allow for both food and industrial end-uses. The favorable worldwide distribution of sumac also suggests that desirable bioproducts may be obtained at source, with minimal transportation requirements from the source through processing to end consumer. However, previous work has focussed on only a few members of this large plant family. In addition, not all of the species studied to date have been fully characterized for potential bioactive components and bioactivities. Thus, there remains a significant research gap spanning the range from lead chemical discovery through process development and optimization in order to better understand the full potential of the Rhus genus as part of global green technology based bioproduct and bioprocess research programs

Historical Trends in Annual Water Yields for the Okanagan Basin, British Columbia, Canada

The Okanagan Basin in south-central British Columbia, Canada, includes the Okanagan River watershed upstream from the outlet of Osoyoos Lake, with a total area of 8,046 km^2^. Over the past century, the population of the Basin has grown rapidly, and this trend is expected to continue. Water management issues attract significant attention in the region, given projected declines in supply and increases in demand. Historical streamflow data was obtained for three hydrometric stations on the Okanagan River between the outlet of Okanagan Lake at Penticton and near the U.S. border at Oliver. Collectively, the historical data series indicate no temporal changes in regional annual water yields for the Okanagan Basin over the past century, despite large increases in population and agricultural activity over this time. Although rapid and extensive human settlement and development of the region, along with possible climate change signatures during the 20th century, has potentially altered the inflow hydrographs to tributary streams in the Basin, the overall water yield of the region appears to be stable and possibly increasing

Gas phase enthalpies of formation, isomerization, and disproportionation of mono- through tetra-substituted tetrahedranes: A G4MP2/G4 theoretical study

Gas phase (298.15 K, 1 atm) enthalpies of formation (Δ~f~H°~(g)~), enthalpies of disproportionation to two corresponding acetylene molecules (Δ~rxn~H°~(g),Td→acet~), and enthalpies of isomerization from a tetrahedrane geometry to a 1,3-cyclobutadiene structure (Δ~isom~H°~(g),Td→CBD~) were calculated for the mono- through tetra-substituted hydro, fluoro, chloro, bromo, methyl, ethynyl, and cyano carbon tetrahedrane derivatives at the G4MP2 and G4 levels of theory. All derivatives have endothermic Δ~f~H°~(g)~ indicative of the cage strain in these systems. In all cases, Δ~rxn~H°~(g),Td→acet~ and Δ~isom~H°~(g),Td→CBD~ are predicted to be substantially exothermic. High quality linear regression fits within a homologous series were obtained between the number of substituents and the G4MP2/G4 estimated Δ~f~H°~(g)~. Via calculations on lower homolog members, this strategy was employed to allow extrapolated G4 and/or G4MP2 Δ~f~H°~(g)~ (as well as some Δ~rxn~H°~(g),Td→acet~ and Δ~isom~H°~(g),Td→CBD~) to be obtained for the mono- through tetra-substituted t-butyl, trifluoromethyl, and trimethylsilyl carbon tetrahedrane derivatives

Octanol/water distribution coefficients of the C~1~ through C~7~ perfluoro-n-alkyl sulfonates: Comparison of the IEFPCM-UFF, CPCM, and SMD solvation models

The octanol/water distribution coefficients (log D~ow~) of the C~1~ through C~7~ perfluoro-n-alkyl sulfonates (PFSAs) were calculated using the M062X/6-311++G(d,p) and MP2/6-311++G(d,p)//M062X/6-311++G(d,p) levels of theory and the IEFPCM-UFF, CPCM, and SMD solvation models. At both levels of theory with all solvation models, absolute log D~ow~ calculated for the straight chain C~1~ through C~7~ PFSAs display a substantial negative bias against available experimental data and expected trends by several log units. However, the SMD solvation model achieves accurate relative log D~ow~ accuracy, yielding fragmental contributions of a -CF~2~- group towards the log D~ow~ of 0.51+/-0.02 to 0.54+/-0.01 units (-3.0+/-0.1 to -3.1+/-0.1 kJ/mol), in good agreement with the experimental value of 0.61 units (-3.4+/-0.1 kJ/mol). In contrast, the IEFPCM-UFF and CPCM solvation models exhibit either invariant log D~ow~ with increasing perfluoro-n-alkyl chain length (CPCM) or a modestly decreasing trend (IEFPCM-UFF)

Theoretical studies in the molecular Platonic solids: Pure and mixed carbon, nitrogen, phosphorus, and silicon tetrahedranes

Calculations were conducted at the G4MP2 and G4 composite method levels of theory on the 35 potential carbon, nitrogen, silicon, and phosphorus tetrahedrane derivatives with the general form C~a~N~b~Si~c~P~d~H~(4-b-d)~ (where a+b+c+d=4). At both levels of theory, optimized electronic ground state neutral singlet gas phase (298.15 K, 1 atm) geometries were obtained for 24 of the 35 possible C/N/Si/P tetrahedrane derivatives. Corresponding enthalpies of formation were calculated using the atomization method. Triplet state neutral tetrahedron starting geometries for all compounds either resulted in cage opening or failed to converge. Only 9 cationic and 3 anionic forms converged to stable geometries that retained the tetrahedron cage and were absent imaginary frequencies, thereby allowing the calculation of adiabatic ionization energies and electron affinities

Performance of the major semiempirical, ab initio, and density functional theory methods in evaluating isomerization enthalpies for linear to branched heptanes

The gas phase standard state (298.15 K, 1 atm) isomerization enthalpy prediction performance of the major semiempirical, ab initio, and density functional levels of theory was investigated using the linear to branched heptanes. The M062X density functional, MP2 (and higher) levels of Moller-Plesset perturbation theory, and the CBS and Gaussian-n composite methods are best suited for thermodynamic studies of alkane derivative isomerizations expected during the processing of petroleum, biomass, coal, or other fuels. Where large molecular systems prohibit the use of higher levels of theory, the PM6 and PDDG semiempirical methods may offer an appropriate computational cost-accuracy compromise. Non-M062X density functionals are not recommended for theoretical studies of alkane derivative isomerizations