Second-Order Kinetic Rate Coefficients for the Aqueous-Phase Sulfate Radical (SO) Oxidation of Some Atmospherically Relevant Organic Compounds.

The sulfate anion radical (SO) is a reactive oxidant formed in the autoxidation chain of sulfur dioxide, among other sources. Recently, new formation pathways toward SO and other reactive sulfur species have been reported. This work investigated the second-order rate coefficients for the aqueous SO oxidation of the following important organic aerosol compounds (): 2-methyltetrol, 2-methyl-1,2,3-trihydroxy-4-sulfate, 2-methyl-1,2-dihydroxy-3-sulfate, 1,2-dihydroxyisoprene, 2-methyl-2,3-dihydroxy-1,4-dinitrate, 2-methyl-1,2,4-trihydroxy-3-nitrate, 2-methylglyceric acid, 2-methylglycerate, lactic acid, lactate, pyruvic acid, pyruvate.

Sulfur radical formation from the tropospheric irradiation of aqueous sulfate aerosols.

The sulfate anion radical (SO) is known to be formed in the autoxidation chain of sulfur dioxide and from minor reactions when sulfate or bisulfate ions are activated by OH radicals, NO radicals, or iron. Here, we report a source of SO, from the irradiation of the liquid water of sulfate-containing organic aerosol particles under natural sunlight and laboratory UV radiation. Irradiation of aqueous sulfate mixed with a variety of atmospherically relevant organic compounds degrades the organics well within the typical lifetime of aerosols in the atmosphere.

Gas-Phase Oxidation Rates and Products of 1,2-Dihydroxy Isoprene.

1,2-Dihydroxy isoprene (1,2-DHI), a product of isoprene oxidation from multiple chemical pathways, is produced in the atmosphere in large quantities; however, its chemical fate has not been comprehensively studied. Here, we perform chamber experiments to investigate its gas-phase reactions. We find that the reactions of 1,2-DHI with OH radicals and ozone are rapid ( = 8.

Second-Order Kinetic Rate Coefficients for the Aqueous-Phase Hydroxyl Radical (OH) Oxidation of Isoprene-Derived Secondary Organic Aerosol Compounds at 298 K.

The hydroxyl radical (OH) oxidation of the most abundant nonmethane volatile organic compound emitted to the atmosphere, isoprene (CH), produces a number of chemical species that partition to the condensed phase via gas-particle partitioning or form condensed-phase compounds via multiphase/heterogeneous chemistry to generate secondary organic aerosols (SOA). The SOA species in aerosol water or cloud/fog droplets may oxidize further via aqueous reaction with OH radicals, among other fates. Rate coefficients for compounds in isoprene's photochemical cascade are well constrained in the gas phase; however, a gap of information exists for the aqueous OH rate coefficients of the condensed-phased products, precluding the atmospheric modeling of the oxidative fate of isoprene-derived SOA.

Tuning the copper(II)/copper(I) redox potential for more robust copper-catalyzed C-N bond forming reactions.

Complexes of copper and 1,10-phenanthroline have been utilized for organic transformations over the last 50 years. In many cases these systems are impacted by reaction conditions and perform best under an inert atmosphere. Here we explore the role the 1,10-phenanthroline ligand plays on the electronic structure and redox properties of copper coordination complexes, and what benefit related ligands may provide to enhance copper-based coupling reactions.

Electrocatalytic reduction of CO with CCC-NHC pincer nickel complexes.

A CCC-NHC pincer Ni(ii)Cl complex was prepared according to the metallation/transmetallation methodology. It was fully characterized by electrochemical, NMR spectroscopic, theoretical, and X-ray crystallographic methods. The complex and its cation were evaluated for electrocatalytic reduction of CO under a variety of conditions and found to provide some of the fastest catalytic rates and highest substrate selectivities (COvs.