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UiO-66 and a muconic acid functionalized derivative of UiO-66 (UiO-66-MA) were synthesized via the solvothermal method to determine if the muconic acid could undergo a cheletropic reaction in the presence of sulfur dioxide inside the metal-organic framework (MOF). Both MOFs were exposed to a constant flow of sulfur dioxide, and UiO-66-MA was observed to take up three times more sulfur dioxide than unfunctionalized UiO-66. Despite the improved uptake of sulfur dioxide in UiO-66-MA, NMR and IR data indicate that no chemical change occurred to the muconic acid indicating that a cheletropic reaction did not occur. We thus propose that the increased adsorption is due to either an interaction between the sulfur dioxide and unbound carboxylic acid from the muconic acid or a favourable interaction between the butadiene of muconic acid and sulfur dioxide. Key words: sulfur dioxide, adsorption, UiO-66, breakthrough, metal-organic frameworks. Nous avons synthetise le compose UiO-66 et un derive fonctionnalise par l'acide muconique (UiO-66-MA) en utilisant une methode solvothermale afin de determiner si l'acide muconique pouvait subir une reaction chelotropique en presence de dioxyde de soufre a l'interieur du reseau metallo-organique (MOF, acronyme anglais pour metal-organic framework). Ces deux MOF ont ete exposes a un debit constant de dioxyde de soufre. Nous avons alors observe que le compose UiO-66-MA captait trois fois plus de dioxyde de soufre que le compose non fonctionnalise UiO-66. Bien que le compose UiO-66-MA capte plus de dioxyde de soufre, les donnees RMN et IR indiquent que la fonction acide muconique est demeuree intacte sur le plan chimique, ce qui exclut la possibilite qu'une reaction chelotropique ait eu lieu. Nous avancons donc l'hypothese que cette adsorption accrue soit attribuable a une interaction entre le dioxyde de soufre et un acide carboxylique non lie de l'acide muconique ou a une interaction favorable entre le butadiene de l'acide muconique et le dioxyde de soufre. [Traduit par la Redaction] Mots-cles : dioxyde de soufre, adsorption, UiO-66, percee, reseaux metallo-organiques., Introduction Sulfur dioxide is a by-product of fossil fuel burning. Under humid environments, sulfur dioxide rapidly reacts with water (e.g., in the atmosphere or lungs) to form sulfuric acid. As [...]

Molecular beam scattering experiments are used to investigate reactions of S[O.sub.2] at the surface of a molten alkali carbonate eutectic at 683 K. We find that two-thirds of the S[O.sub.2] molecules that thermalize at the surface of the melt are converted to gaseous C[O.sub.2] via the reaction S[O.sub.2](g) + C[O.sup.2-.sub.3] [right arrow] C[O.sub.2](g) + S[O.sup.2-.sub.3]. The C[O.sub.2] product is formed from S[O.sub.2] in less than [10.sup.-6]s, implying that the reaction takes place in a shallow liquid region less than 100 [Angstrom] deep. The reaction probability does not vary between 683 and 883 K, further' implying a compensation between decreasing S[O.sub.2] residence time in the near-interfacial region and increasing reactivity at higher temperatures. These results demonstrate the remarkable efficiency of S[O.sub.2] [right arrow], C[O.sub.2] conversion by molten carbonates, which appear to be much more reactive than dry calcium carbonate or wet slurries commonly used for flue gas desulfurization in coal-burning power plants. flue gas desulfurization | gas scrubbing | gas-liquid reactions | liquid surface | molecular beam scattering doi/ 10.1073/pnas.0910993107

Anthropogenic activities, dominated by emissions of sulfur dioxide (S[O.sub.2]), have perturbed the global sulfur (S) cycle. Uncertainties in timescales of S transport and chemistry in the atmosphere lead to uncertainties in the predicted impact of S emissions. Measurements of cosmogenic [sup.35]S may potentially be used to resolve existing uncertainties in the photochemical and chemical transformation of S in the environment. The lack of a simple, effective, and highly sensitive technique to measure [sup.35]S activity in samples with low activities may explain the scarcity of published measurements. We present a set of new sample handling and measurement procedures optimized for the measurement of [sup.35]S in natural samples with activities as low as 0.20 dpm above background (2[sigma], integration time = 2 hr). We also report simultaneous measurements of aerosol ([sup.35]S[O.sub.4]) and gas phase ([sup.35]S[O.sub.2]) collected at inland and coastal locations; the range of observed activities corresponds to S[O.sub.2] residence lifetimes of 0.2 [+ or -] 0.04 (coastal) - 22.3 d[+ or -] 0.04 (inland). These optimized techniques offer the potential for resolving atmospheric processes that occur on 6-12-hour timescales as well as resolving transport phenomena such as stratospheric mixing into the troposphere. aerosol sulfate | sulfur cycle | dry deposition | sulfur dioxide residence times www.pnas.org/cgi/doi/10.1073/pnas.0901168107

This research was aimed at recovering Fe and Al compounds to produce a useful complex coagulant from fly ash using [H.sub.2]S[O.sub.4] and S[O.sub.2] from flue gas oxidized to S[O.sub.3] by NaCl[O.sub.3]. The reaction kinetics of wet S[O.sub.2] scrubbing from simulated flue gas with fly ash slurry was studied. The S[O.sub.2] scrubbing experiments were carried out in a jacketed glass reactor system with a simulated flue gas containing S[O.sub.2] and [N.sub.2] in the gas phase and fly ash slurry in the liquid phase. Sodium chlorate was added to oxidize S[O.sub.2] to S[O.sub.3], adding [H.sub.2]S[O.sub.4] in the slurry. The reaction orders of both [Fe.sub.2][O.sub.3] and [Al.sub.2][O.sub.3] extraction from fly ash slurry were shown to be 1.5. The empirical Arrhenius expressions were also derived from the reaction rate constants obtained at each reaction temperature. The mass transfer process of S[O.sub.2] with Cl[O.sup.-.sub.3] was evaluated using a two-film theory model. DOI: 10.1061/(ASCE)EE.1943-7870.0000155 CE Database subject headings: Fly ash; Absorption; Kinetics; Coagulation; Wastewater management; Slurries. Author keywords: Fly ash; SO2 absorption; Reaction kinetics.

Collision depopulation cross sections of 13 single, highly vibrationally excited levels with 45000 [cm.sup.-1] energy in the electronic ground state of S[O.sub.2] are measured. The relaxation cross sections of these highly excited states, range from 27 to 187 [Angstrom.sub.2] with an average of 71 [Angstrom.sub.2].

The importance of Coulomb correlation effects was demonstrated by comparing the LIs and DIs at nono-correlated levels (HF and CIS) and those at correlated levels (CCSD and EOM-CCSD). The findings indicated that Coulomb correlation is important in determining the magnitude of the LIs and DIs and obtaining geometries that are close to experiment.

An attempt is made to explore the reactivity of the reactive bifunctional surface intermediate as a function of the abundance of adsorbed water. The mechanism of the interfacial chemistry of CaC[O.sub.3] in the presence of important atmospheric trace gases that corrode or chemically react with CaC[O.sub.3] such as C[O.sub.2], S[O.sub.2], and atmospheric acidity such as HN[O.sub.3] and HCl.

A proposed model for molecular dynamics simulation of liquid sulfur dioxide, SO2 is reviewed and thermodynamic, structural, dynamical properties were calculated for a large range of thermodynamic states. Predicted (P,V,T) of simulated system agrees with an elaborated equation of state proposed for liquid SO(sub 2) and calculated heat capacity, expansion coefficient, isothermal compressibility are in good agreement with experimental data.

A new methodology for [n +1] radical annulation using sulfur dioxide as a geminal radical acceptor/ donor is presented. This methodology provides a novel route to the formation of five-, six-, and seven-membered cyclic sulfones utilizing a radical chain mechanism under very mild conditions.

The stabilization of cyclic-O(sub 3) with transition metals is studied using density functional theory. It is found that it is possible to use one-photon coherent anti-Stroke Raman Spectroscopy (CARS) scheme to detect the formation of cyclic-O(sub 3) and cyclic-SO(sub 2) because of the vibrational and electronic state spacings.

An investigation of the excited-state dynamics of SO2(H2O)(sub n) clusters following excitation by ultrafast laser pulses to 4.7 eV and 9.3 eV is presented. A lack of cluster size dependence in the measured time constants indicates surface solvation of SO2 rather than a cluster structure with the SO2 molecule fully encompassed by water molecules.

A study of the excited-state dynamics of (SO2)(sub m) clusters following excitation by ultrafast laser pulses in the range of 4.5 eV (coupled (super 1)A2, (super 1)B1 states) and 9 eV (F band) is presented. Results for the coupled (super 1)A2 and (super 1)B1 states are in good agreement with published computational work on the properties of these coupled states.

Quantum chemical methods at the Gaussian-2 and -3 levels of theory are used to investigate the reactions between H2S, SO2 and S2O such as might occur in the front-end furnace of the Claus process. The results show that the apparent extent of interaction between H2S and SO2 in the front-end furnace of the modified Claus process might be qualitatively accounted for through the simultaneous thermolysis and oxidation of H2S.

A thermal decomposition method that measures aerosol sulfur at the nanogram level directly from the collection substrate is described. A thermal decomposition apparatus was designed. A stainless steel strip was used as the aerosol collection substrate. A 0.1 mol/L Mn[Cl.sub.2] solution was added as the thermal decomposition catalyst. Currents were passed through the strip where aerosol particles had been deposited. In this way, the strip was heated at 780 [+ or -] 10 [degrees]C, and particulate sulfur was evaporated. A sulfur dioxide analyzer (SDA) with flame photometric detector (FPD) was used to detect gaseous sulfur. High sulfur recoveries from [(N[H.sub.4]).sub.2]S[O.sub.4] and other inorganic sulfates, such as N[H.sub.4]HS[O.sub.4], [K.sub.2]S[O.sub.4], MgS[O.sub.4], and Ca[SO.sub.4], were obtained. From the sulfur blank and the calibration, a lower limited detection of 0.2 ng of sulfur and the determination range of 3.3-167 ng of sulfur were estimated. The method is effective for measuring the sulfate size distributions of urban aerosols in a small sample air volume of 50-60 L. The method is applicable to measuring the sulfur in aqueous extracts of size-segregated urban aerosols collected by impactor and comparing the results with the sulfate data measured by ion chromatography.

A trinuclear rhenium sulfide cluster complex [(Ph3P)2N][Re3(mu3-S)2(mu-SO2)Cl6(PMe2Ph)3] is synthesized from Re3S7Cl6(PMe2Ph)3] by reaction with O2. The oxygen atoms on the SO2 ligand react with phosphines or phosphites to form phosphine oxides or phosphates and the original cluster complex is recovered.

The desulfurization of sulfur dioxide and thiophene on molybdenum carbide surfaces, alpha-Mo2C(001) and alpha-MoC(001), and on a Mo8C12 nanoparticle was studied with density functional theory. The study revealed unexpected ligand and steric effects.

A new and clean method that yields free S2O by a hetero retro-Diels-Alder reaction is presented. The computational rationalization of the chemical properties of S2O and its disproportionation to SO2 and S3 is described.

Clusters of SO2 are interrogated using pump-probe spectroscopy employing a femtosecond laser system coupled to a reflection time-of-flight mass spectrometer. Upon excitation of the C state of SO2 with 397.5 nm light and 3990.0 nm light, it was found that the photodissociation of SO2 clusters involves multiple reaction pathways.

An investigation has been conducted on the effects of phenol (C6H5OH) catechin [C6H4(OH)2] and gallic acid [HOOCC6H2(OH)3] on the kinetics of aqueous SO2 oxidation by molecular oxygen for dilute systems. The consequences of the inhibition in the environment are discussed.

The novel C-C bond forming reaction that combines electron-rich dienes and alkenes with sulfur dioxide to develop combinatorial, one-pot, four-component syntheses of polyfunctional sulfones, sulfonamides, and sulfonic esters is described.

A study of the S-isotope fractionation ratios f = (k(sub OH+)(super 34)SO2)/(k(sub OH+)(super 32)SO2) for the gas-phase oxidation of SO2 by OH radicals, using RRKM transition-state theory is presented. The results show that there is evolution of stratospheric aerosol sulfur isotopic composition after volcanic SO2 injections above 15 km and the (super 34)S enrichment of tropospheric sulfate aerosol during the summer months

An investigation of uptake of SO2 and H2O2 by ice surfaces in a low temperature coated-wall flow tube coupled to an electron-impact, quadrupole mass spectrometer, which monitors the changes in the SO2 and H2O2 partial pressure, is presented. The experiments show that both S(IV) and H2O2 have low retention efficiencies after supercooled cloud droplets freeze, and the uptakes are sufficiently small that scavenging of SO2 And H2O2 by ice clouds would not be significant.

A study of the heterogeneous uptake of SO2 on alpha-Al2O3 and MgO particles at 296K, where transmission FT-IR experiments reveal that under dry conditions SO2 reacts with alpha-Al2O3 and sulfite on MgO to form strongly absorbed bisulfite, HSO3- (aq) and sulfite, SO3-2 (aq).

The resonance-enhanced multiphoton ionization with time-of-flight product imaging was used to study the SO(sub 2) + hv -> SO((super 3)sigma(super -)) + O(super 3)P(sub 2) channel in the ultra violet photodissociation of sulfur dioxide at photolysis wavelengths between 202 and 207 nm. The data suggested that the predissociation mechanism below 203.0 nm involved an avoided crossing with the repulsive singlet state (super 1)A(sub 1).

Research is done on heterogeneous interaction of SO2 on both the H202-ice surface and the water-ice surface has been examined in a flow reactor interfaced with a differentially pumped quadrupole mass spectrometer. The results observed were that the uptake of SO2 on ice and snow surfaces was enhanced by the presence of H2O2 in ice at the temperature of the upper troposphere and lower stratosphere.

A study is done on the uptake of gas-phase SO2, H2S, and CO2 by aqueous solutions, which was examined as a function of pH and temperature using droplet train flow reactor and bubble train reactor apparatuses. In conclusion, as far as possible, the rate coefficients for SO2 and H2S have been determined in the experiment for the first time.

Aminoalkynes and related heterocyclic systems react with CF3SO3H for generating dicationic electrophiles that can react with benzene and other arenes. These novel species are composed of vinyl cations with adjacent positive charge centers that can be used to prepare products with good yields from inter and intramolecular reactions.

The free radical displacement reactions at sulfoxide centers are used for modeling regioselectivity of the homolytic cleavage of S-adenosylmethionine (SAM) by the radical SAM enzymes. The selectivity in the radical SAM reactions is described by the geometry of the free radical displacement mechanism, which is needed by the chemical reaction and is arranged in the active site by the radical SAM proteins.

The palladium-catalyzed three-component coupling of aryl iodides, sulfur dioxide and hydrazines is described that has delivered aryl N-aminosulfonamides. The colorless crystalline solid DABCO.[(S[O.sub.2]).sub.2] is used as a convenient source of sulfur dioxide, where the reaction has tolerated variation of both the aryl iodide and hydrazine coupling partners.