Sulfuryl Fluoride Research Articles

Novel use of aliphatic n-methyl ketones as a fumigant and alternative to methyl bromide for insect control.

Fumigants like phosphine, methyl bromide and sulfuryl fluoride are highly effective for the control of structural, storage and agricultural arthropod pests. Unfortunately, many of these synthetic compounds are highly toxic to people, many pests have developed resistance to these compounds and methyl bromide, the 'gold standard' for fumigants, was de-registered because of its contribution to depletion of the stratospheric ozone layer. Alternative fumigant chemistry is needed. Several plant species produce n-aliphatic methyl ketones to prevent plant herbivory. To examine the use of methyl ketones as a fumigant, structure-mortality studies were conducted using the red imported fire ant, Solenopsis invicta Buren, as a model. A new easy-to-use, inexpensive and disposable bioassay system was developed for this study. The LC50 values for heptanone, octanone, nonanone and undecanone were 4.27, 5.11, 5.26 and 8.21 µg/cm3 of ambient air, respectively. Although heptanone, octanone and nonanone were more effective than undecanone, subsequent research was conducted with 2-undecanone because this compound already has US Environmental Protection Agency (EPA) registration as a biopesticide. In dose-response field studies, 12.4 mL of undecanone injected into mounds was the lowest application rate that produced no ant activity in the mound with no re-establishment of ants. Reagent grade undecanone was more cost-effective than methyl bromide for fire ants, adult German cockroaches and tobacco budworm eggs, but slightly more expensive for adult flour beetles. The naturally occurring methyl ketone undecanone has the potential to be an alternative to current fumigants for a variety of pest applications. © 2017 Society of Chemical Industry.

Does sorption of sulfuryl fluoride by wheat reduce its efficacy against adults and eggs of Rhyzopertha dominica?

Despite its growing importance as a fumigant for grain, there is no information on the impact of sorption on the efficacy of sulfuryl fluoride (SF) against target insect pests. Eggs and adults of a major grain pest, Rhyzopertha dominica, living in wheat (12% m.c.), were fumigated with SF at 0.5, 1, and 2 mg/L for 168 h at 25 °C. Sorption of the fumigant by the grain followed an exponential decay and reduced the mortality rates of both adults and eggs. The partition ratio (K), a measure of physical sorption, had a strong impact on mortality of both adults and eggs. The quadratic model showed the best fit to the data and turning points in the relationship indicated that although mortality increased as concentration increased, physical sorption removed fumigant resulting in a decrease in the mortality rate. There was a linear relationship between mortality and the rate of sorption (k) of SF by the wheat. At each concentration, mortality rate increased as k increased despite sorption continuing, indicating that the chemical sorption rate had little impact on mortality. Sorption of SF into the commodity has the potential to reduce the biological efficacy of the fumigant resulting in potential control failures. Concentration x time protocols may need to be revised to account for this phenomenon.

Ex Situ Generation of Sulfuryl Fluoride for the Synthesis of Aryl Fluorosulfates.

A convenient transformation of phenols into the corresponding aryl fluorosulfates is presented: the first protocol to completely circumvent direct handling of gaseous sulfuryl fluoride (SO2F2). The proposed method employs 1,1'-sulfonyldiimidazole as a precursor to generate near-stoichiometric amounts of SO2F2 gas using a two-chamber reactor. With NMR studies, it was shown that this ex situ gas evolution is extremely rapid, and a variety of phenols and hydroxylated heteroarenes were fluorosulfated in good to excellent yields.

Line position analysis of the ([formula omitted]) bending triad of SO2F2 using the [formula omitted]Top Data System

Sulfuryl fluoride (SO2F2) is of a fundamental interest due to its nearly tetrahedral symmetry, making it, thereby, an intermediate case between spherical and asymmetric-top molecules. It is also a widely-used insecticide and an atmospheric pollutant. A new high-resolution infrared spectrum of the (ν9,ν7,ν3) bending triad of SO2F2 in the 550cm−1 region has been recorded at 165K with a spectral resolution of 0.00102cm−1 at the AILES beamline of the SOLEIL Synchrotron.Analysis has been performed in the O(3)⊃Td⊃C2v group chain using a specific model and programs based on tensorial formalism, group theory and vibrational extrapolation method. This model is adapted to the case of XY2Z2 asymmetric-top molecules with C2v symmetry developed by Rotger et al. (2002). This approach enables studying any rovibrational band or polyad with a systematic development of all rovibrational interactions.A total of 6058 IR lines has been assigned and fitted in position with a global root mean square deviation (RMS) of 0.484×10−3cm−1. This result improves the previous analyses performed by Bürger et al. (2002) and Rotger et al. (2006).

Historical greenhouse gas concentrations for climate modelling (CMIP6)

Abstract. Atmospheric greenhouse gas (GHG) concentrations are at unprecedented, record-high levels compared to the last 800 000 years. Those elevated GHG concentrations warm the planet and – partially offset by net cooling effects by aerosols – are largely responsible for the observed warming over the past 150 years. An accurate representation of GHG concentrations is hence important to understand and model recent climate change. So far, community efforts to create composite datasets of GHG concentrations with seasonal and latitudinal information have focused on marine boundary layer conditions and recent trends since the 1980s. Here, we provide consolidated datasets of historical atmospheric concentrations (mole fractions) of 43 GHGs to be used in the Climate Model Intercomparison Project – Phase 6 (CMIP6) experiments. The presented datasets are based on AGAGE and NOAA networks, firn and ice core data, and archived air data, and a large set of published studies. In contrast to previous intercomparisons, the new datasets are latitudinally resolved and include seasonality. We focus on the period 1850–2014 for historical CMIP6 runs, but data are also provided for the last 2000 years. We provide consolidated datasets in various spatiotemporal resolutions for carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), as well as 40 other GHGs, namely 17 ozone-depleting substances, 11 hydrofluorocarbons (HFCs), 9 perfluorocarbons (PFCs), sulfur hexafluoride (SF6), nitrogen trifluoride (NF3) and sulfuryl fluoride (SO2F2). In addition, we provide three equivalence species that aggregate concentrations of GHGs other than CO2, CH4 and N2O, weighted by their radiative forcing efficiencies. For the year 1850, which is used for pre-industrial control runs, we estimate annual global-mean surface concentrations of CO2 at 284.3 ppm, CH4 at 808.2 ppb and N2O at 273.0 ppb. The data are available at https://esgf-node.llnl.gov/search/input4mips/ and http://www.climatecollege.unimelb.edu.au/cmip6. While the minimum CMIP6 recommendation is to use the global- and annual-mean time series, modelling groups can also choose our monthly and latitudinally resolved concentrations, which imply a stronger radiative forcing in the Northern Hemisphere winter (due to the latitudinal gradient and seasonality).

Multiple Approaches to the In Situ Generation of Anhydrous Tetraalkylammonium Fluoride Salts for SNAr Fluorination Reactions.

This article focuses on the development of practical approaches to the in situ generation of anhydrous fluoride salts for applications in nucleophilic aromatic substitution (SNAr) reactions. We report herein that a variety of combinations of inexpensive nucleophiles (e.g., tetraalkylammonium cyanide and phenoxide salts) and fluorine-containing electrophiles (e.g., acid fluoride, fluoroformate, benzenesulfonyl fluoride, and aryl fluorosulfonate derivatives) are effective for this transformation. Ultimately, we demonstrate that the combination of tetramethylammonium 2,6-dimethylphenoxide and sulfuryl fluoride (SO2F2) serves as a particularly practical route to anhydrous tetramethylammonium fluoride. This procedure is applied to the SNAr fluorination of a range of electron-deficient aryl and heteroaryl chlorides as well as nitroarenes.

Rapid Screening of Sulfuryl Fluoride as a Potential Phytosanitary Treatment for a Broad Selection of Fungi Relevant to Forestry

Abstract Increasing restrictions on the use of methyl bromide have created an urgent need to find suitable replacements that are effective in eliminating exotic pest establishments via trade in wood products. Efficacy data for established phytosanitary fumigants have primarily focused on arthropods and nematodes, whereas limited information exists for plant pathogens and fungi relevant to forestry. A rapid screening process was developed to evaluate efficacy and compare relative tolerance to fumigation treatments for a broad selection of relevant fungi under laboratory conditions. Sulfuryl fluoride (SF) fumigations were conducted in 10-liter glass chambers at six target concentrations (40 to 240 mg liter−1) at 15°C and 20°C for 24-, 48-, and 72-hour exposure times against 23 fungal species represented with 35 isolates. Fungi were grown on sterilized barley grain and then distributed in felt-covered borosilicate glass tubes to allow uninhibited gas penetration during fumigation while minimizing the risk of fungal contamination. This allowed simultaneous testing of numerous species and isolates, followed by 100 percent recovery of controls without contamination. Results demonstrate that SF is an effective fumigant for a broad range of fungi. Several fungi and isolates were found to consistently be among the most tolerant to the fumigant treatment. These species may serve as a benchmark for screening SF in fumigations of logs and other wood products. Methods developed here will be useful in efficacy screening of other methyl bromide fumigant alternatives.

Dermal absorption of fumigant gases during HAZMAT incident exposure scenarios-Methyl bromide, sulfuryl fluoride, and chloropicrin.

Accidental or intentional releases of toxic gases or vapors are the most common occurrence in hazardous material (HAZMAT) incidents that result in human injuries. The most serious hazard from exposure to gases or vapors is via the respiratory system. Dermal uptake, as a secondary route, is still a concern, most acutely for the unprotected public. There is a limited evidence base describing skin absorption of toxic gases and vapors in HAZMAT exposure scenarios, which are relatively brief compared with traditional test periods for skin absorption studies. We describe research designed to provide experimental data to support decision-making by first responders regarding skin decontamination in HAZMAT-focused exposure scenarios involving toxic gases. We present findings for three common fumigants, methyl bromide, sulfuryl fluoride, and chloropicrin assessed using an Organization for Economic Co-operation and Development in vitro toxicology protocol utilizing human skin and gas/vapor exposures. Results indicate that for atmospheric concentrations that would be lethal via inhalation (LCLo), intact skin provides an excellent barrier to exposures up to 30 min, with little influence of common clothing fabric and high temperature and humidity conditions. The findings may challenge the current HAZMAT dogma requiring mass personal decontamination by strip and shower for short-term exposures to sulfuryl fluoride and chloropicrin gas/vapor.

Negative Reagent Ions for Real Time Detection Using SIFT-MS

Direct analysis techniques have greatly simplified analytical methods used to monitor analytes at trace levels in air samples. One of these methods, Selected Ion Flow Tube-Mass Spectrometry (SIFT-MS), has proven to be particularly effective because of its speed and ease of use. The range of analytes accessible using the SIFT-MS technique has been extended by this work as it introduces five new negatively charged reagent ions (O−, OH−, O2−, NO2−, and NO3−) from the same microwave powered ion source of moist air used to generate the reagent ions traditionally used (H3O+, NO+, and O2+). Results are presented using a nitrogen carrier gas showing the linearity with concentration of a number of analytes not readily accessible to positive reagent ions (CO2 from ppbv to 40,000 ppmv, sulfuryl fluoride and HCl). The range of analytes open to the SIFT-MS technique has been extended and selectivity enhanced using negative reagent ions to include CCl3NO2, SO2F2, HCN, CH3Cl, PH3, C2H4Br2, HF, HCl, SO2, SO3, and NO2.

Click chemistry reaches a new dimension

In 2014, K. Barry Sharpless and coworkers at Scripps Research Institute California developed sulfur fluoride exchange (SuFEx), a simple and rapid click chemistry reaction that uses sulfuryl fluoride (SO2F2) to make carbon-sulfate links. They used the technique to synthesize disulfates, polysulfate polymers, and other linear products. Suhua Li, Sharpless, and coworkers have now devised a variation that kicks SuFEx click chemistry into another dimension. Using thionyl tetrafluoride (SOF4) instead of SO2F2 as a SuFEx reagent enables them to make up to three tetrahedrally oriented connections to each sulfur hub molecule instead of two linear linkages (Angew. Chem. Int. Ed. 2017, DOI: 10.1002/anie.201611048). Thionyl tetrafluoride reacts initially with a primary amino group, forming a tetrahedral iminosulfur product with two fluoride “handles.” One fluoride or both can then react with aryl alcohols or alkyl amines to create products that are doubly or triply substituted along the sulfur hub’s tetrahedral axes. Potential applications

Quantum cascade laser-based photoacoustic sulfuryl fluoride sensing

Although sulfuryl fluoride (SO2F2) is an efficient fumigant that does not react with the surface of indoor materials and does not reduce the stratospheric ozone shield, there are some concerns about its use. It is a toxic gas that attacks the central nervous system, and its global warming potential (GWP) value is 4780 for 100 years’ time. Therefore, it is a clear necessity of implementing detection methods for tracing such a molecule. In this work a sensitive photoacoustic setup was built to detect SO2F2 at concentrations of parts per billion by volume (ppbv). The symmetric S–O stretching mode was excited by a continuous-wave quantum cascade laser with radiation wavenumber ranging from 1275.7 to 1269.3 cm−1. The photoacoustic signal was generated by modulating the laser wavenumber at the first longitudinal mode of the photoacoustic cell with amplitude depth of 5 × 10−3 cm−1. The detection of a minimum SO2F2 concentration of 20 ppbv was achieved.

Nucleophilic Deoxyfluorination of Phenols via Aryl Fluorosulfonate Intermediates.

This report describes a method for the deoxyfluorination of phenols with sulfuryl fluoride (SO2F2) and tetramethylammonium fluoride (NMe4F) via aryl fluorosulfonate (ArOFs) intermediates. We first demonstrate that the reaction of ArOFs with NMe4F proceeds under mild conditions (often at room temperature) to afford a broad range of electronically diverse and functional group-rich aryl fluoride products. This transformation was then translated to a one-pot conversion of phenols to aryl fluorides using the combination of SO2F2 and NMe4F. Ab initio calculations suggest that carbon-fluorine bond formation proceeds via a concerted transition state rather than a discrete Meisenheimer intermediate.

Phosphine resistance does not confer cross-resistance to sulfuryl fluoride in four major stored grain insect pests.

Susceptibility to phosphine (PH3 ) and sulfuryl fluoride (SF) and cross-resistance to SF were evaluated in two life stages (eggs and adults) of key grain insect pests, Rhyzopertha dominca (F.), Sitophilus oryzae (L.), Cryptolestes ferrugineus (Stephens), and Tribolium castaneum (Herbst). This study was performed with an aim to integrate SF into phosphine resistance management programmes in Australia. Characterisation of susceptibility and resistance to phosphine in eggs and adults showed that C. ferrugineus was the most tolerant as well as resistant species. Mortality responses of eggs and adults to SF at 25 °C revealed T. castaneum to be the most tolerant species followed by S. oryzae, C. ferrugineus and R. dominica. A high dose range of SF, 50.8-62.2 mg L-1 over 48 h, representing c (concentration) × t (time) products of 2438-2985 gh m-3 , was required for complete control of eggs of T. castaneum, whereas eggs of the least tolerant R. dominca required only 630 gh m-3 for 48 h (13.13 mg L-1 ). Mortality response of eggs and adults of phosphine-resistant strains to SF in all four species confirmed the lack of cross-resistance to SF. Our research concludes that phosphine resistance does not confer cross-resistance to SF in grain insect pests irrespective of the variation in levels of tolerance to SF itself or resistance to phosphine in their egg and adult stages. While our study confirms that SF has potential as a 'phosphine resistance breaker', the observed higher tolerance in eggs stresses the importance of developing SF fumigation protocols with longer exposure periods. © 2016 Society of Chemical Industry.

Effect of sulfuryl fluoride fumigation on dried fig quality

Effect of sulfuryl fluoride fumigation on dried fig quality

Does Fumigation of Durum Wheat and Semolina with Sulfuryl Fluoride Affect Quality of the Grain, Semolina, and Derived Spaghetti and Bread?

There is no information on the effect of sulfuryl fluoride (SF) on durum wheat technological properties and products made from fumigated durum wheat. Durum wheat and semolina were exposed to a range of SF applications under conditions that might be typically encountered in bulk storage facilities used in many countries. SF greatly reduced the germination percentage of fumigated durum wheat, with increasing impact under higher SF concentration, grain moisture content, and fumigation temperature. SF greatly reduced seed germination percentage, impacting more the higher the SF concentration. SF had little to no effect on grain test weight, 1,000‐grain weight, hardness, protein content, semolina ash content, and mixograph properties. At the highest SF concentration (31.25 mg/L for 48 h) there was a tendency for pasta cooking loss to be increased but still acceptable, and other pasta properties were largely unaffected. Fumigation with SF did not have any impact on the baking properties of a wholemeal durum flour–commercial flour mix. Therefore, SF is not recommended if the grains are to be used as seeds for agricultural production, but for the production of semolina, pasta, and bread, SF used under typical fumigation conditions has little to no impact on technological properties of durum wheat.

Direct introduction of R-SO2F moieties into proteins and protein-polymer conjugation using SuFEx chemistry

The modification of proteins with reactive handles has facilitated the use of these biomolecules in diverse fields including drug delivery, diagnostics, environmental remediation, and cell culture matrices. Recently, a new “click” type reaction, sulfur(VI) fluoride exchange (SuFEx), was reported between sulfuryl fluoride and various organic moieties (e.g. hydroxyl, amine) to yield a sulfamoyl fluoride (NSO2F) or fluorosulfate (OSO2F) moiety under biphasic conditions. The model protein bovine serum albumin (BSA) was reacted with SO2F2 gas under biphasic conditions to yield SO2F functionalized protein. The resultant BSA-SO2F was characterized using gel electrophoresis, mass spectroscopy and Fourier transmission infrared spectroscopy to confirm the addition of SO2F functional group. SuFEx modification of BSA caused a marked change in the pH dependent size and zeta potential of the protein as well as increased the protein’s denaturation temperature. Crucially, BSA-SO2F was demonstrated to be biocompatible after 72 h incubation with A549 lung endothelial cells. Due to the unique and elective reactivity of the SO2F group with amines, BSA-SO2F could be self-condensed to form a biocompatible hydrogel that was used in co-culture with HEK 293 cells. In addition, polyethylene glycol (PEG) with reactive OSO2F groups at chain end was conjugated with BSA under various pH conditions through SuFEx chemistry. This communication, to our knowledge, is the first report of the application of the SuFEx in the field of bioconjugates.

Preparation and Application of TiO2 Nanotube Array Gas Sensor for SF6-Insulated Equipment Detection: a Review.

Since Zwilling and co-workers first introduced the electrochemical anodization method to prepare TiO2 nanotubes in 1999, it has attracted a lot of researches due to its outstanding gas response and selectivity, making it widely used in gas detection field. This review presents an introduction to the sensor applications of TiO2 nanotube arrays (TNTAs) in sulfur hexafluoride (SF6)-insulated equipment, which is used to evaluate and diagnose the insulation status of SF6-insulated equipment by detecting their typical decomposition products of SF6: sulfur dioxide (SO2), thionyl fluoride (SOF2), and sulfuryl fluoride (SO2F2). The synthesis and sensing properties of TiO2 nanotubes are discussed first. Then, it is followed by discussing the theoretical sensing to the typical SF6 decomposition products, SO2, SOF2, and SO2F2, which analyzes the sensing mechanism at the molecular level. Finally, the gas response of pure and modified TiO2 nanotubes sensor to SO2, SOF2, and SO2F2 is provided according to the change of resistance in experimental observation.

Aryl fluorosulfonates set new electrophile standard

Palladium-catalyzed amination in which an aryl halide or aryl triflate electrophile is coupled with an aryl or alkyl amine is one of the most popular reactions in organic chemistry. Streamlining this fundamental chemistry is hard to do, yet Patrick S. Hanley and coworkers at Dow Chemical have reported a breakthrough by developing an in situ method for generating aryl fluorosulfonates as alternative electrophiles in aminations (ACS Catal. 2016, DOI: 10.1021/acscatal.6b00865). The Dow team and other research groups previously reported using premade aryl fluorosulfonates for Suzuki couplings with aryl boronates. But the team’s one-pot amination method goes further. The researchers treated phenols with sulfuryl fluoride and a base at room temperature followed by addition of an amine coupling partner to create amination products. They found that aryl fluorosulfonates outperform other common electrophiles. In addition, the phenols can be sourced from biobased materials that are less expensive and more sustainab...

Palladium- and Nickel-Catalyzed Amination of Aryl Fluorosulfonates

Examples of the palladium- and nickel-catalyzed amination of aryl fluorosulfonates with aromatic and alkyl amines are described. Aniline is coupled to a diverse series of aryl fluorosulfonates catalyzed by the combination of CpPd(cinammyl) and Xantphos, and the relative reactivity of aryl fluorosulfonates to undergo Pd-catalyzed amination was compared with other common aryl electrophiles. In addition, we report the direct amination of a phenol by in situ formation of an aryl fluorosulfonate by reaction with sulfuryl fluoride and base followed by subsequent amination to form a new C–N bond. Finally, we report examples of the nickel-catalyzed amination of aryl fluorosulfonates catalyzed by the combination of Ni(COD)2 and DPPF in the presence of MeCN. The high reactivity of the aryl fluorosulfonate electrophile with generic palladium and nickel catalyst systems, combined with its simple preparation from sulfuryl fluoride will enable commercial amination reactions of abundant phenolic raw materials.

Effectiveness of Sulfuryl Fluoride Fumigation for the Control of Phosphine-Resistant Grain Insects Infesting Stored Wheat.

A field experiment was conducted in eight 13.6-MT steel bins containing 6.8 MT each of wheat to assess efficacy of sulfuryl fluoride or SF fumigant to control phosphine-resistant and susceptible Rhyzopertha dominica (F.) and Tribolium castaneum (Herbst). Approximately 400 adults of each type of beetle were added to each bin. Additionally, muslin bags containing immature stages and adults, with their respective diets, were also placed in bins. Four bins were fumigated with SF and others were untreated control bins. The SF dosages in treated bins ranged from 1,196–1,467 mg-h/liter. Mortality of adults in each bag was assessed 5 d postfumigation; diet minus adults was incubated in a jar, and number of adults counted after 8 wk. No significant change occurred in number of insect-damaged kernels in SF-treated bins. In trier samples from SF-treated bins, R. dominica numbers declined from 24 prefumigation to 0 at 3- and 6-wk postfumigation; T. castaneum numbers were unchanged. In WBII traps from SF-treated bins, numbers R. dominica and T. castaneum declined from 25 and 33, respectively, prefumigation to 0 or near 0 at 3- and 6-wk postfumigation. Mortalities of resistant and susceptible adult R. dominica, and adult and large larvae of T. castaneum in SF-treated bags was 100%. For all four types of beetles, adult numbers in jars associated with SF-treated bins were 0 or near 0. Results show SF is effective against all life stages of phosphine-resistant R. dominica and T. castaneum, and can be used for phosphine resistance management.