[A case of recurrent convulsions caused by acute sulfuryl fluoride gas poisoning].

Sulfuryl fluoride is a kind of pesticide with strong permeability, convenient use at low temperature, non-corrosive and other characteristics, which can kill food pests and has strong lethality to termites. In acute sulfuryl fluoride poisoning, patients can see recurrent convulsions, epileptic electroencephalogram abnormalities such as matrix spikes or high amplitude spikes. In this paper, a patient with sulfuryl fluoride poisoning with convulsion-based mental system symptoms was reported, and after clinical treatment with dexamethasone and phenobarbital sodium, the patient was cured and discharged.

Electrochemical Generation of Hydroxide and Hydrogen Peroxide for Hydrolysis of Sulfuryl Fluoride Fumigant.

The post-harvest fumigant, sulfuryl fluoride (SO2F2), is a >1000-fold more potent greenhouse gas than carbon dioxide and methane. Pilot studies have shown that SO2F2 fumes vented from fumigation chambers can be captured and hydrolyzed by hydroxide (OH-) and hydrogen peroxide (H2O2) at pH ∼ 12 in a scrubber, producing SO42- and F- as waste salts. To reduce the costs and challenges associated with purchasing and mixing these reagents onsite, this study evaluates the electrochemical generation of OH- and H2O2 within spent scrubbing solution, taking advantage of the waste SO42- and F- as free sources of electrolyte. The study used a gas diffusion electrode constructed from carbon paper coated with carbon black as a catalyst selective for the reduction of O2 to H2O2. Under galvanostatic conditions, the study evaluated the effect of electrochemical conditions, including applied cathodic current density and electrolyte strength. Within an electrolyte containing 200 mM SO42- and 400 mM F-, comparable to the waste salts generated by a SO2F2 scrubbing event, the system produced 250 mM H2O2 at pH 12.6 within 4 h with a Faradaic efficiency of 98.8% for O2 reduction to H2O2. In a scrubbing-water sample from lab-scale fumigation, the system generated ∼200 mM H2O2 at pH 13.5 within 4 h with a Faradaic efficiency of 75.6%. A comparison of the costs to purchase NaOH and H2O2 against the electricity costs for electrochemical treatment indicated that the electrochemical approach could be 38-71% lower, depending on the local cost of electricity.

Activation of SO2F2 at a Rhodium PNP Pincer Complex: Ligand Supported S-F Bond Cleavage to Generate NSO2F Derivatives.

The κ2-(P,N)-phosphine ligand precursor NH(CH2CH2PCy2)2 can be used for the synthesis of the rhodium(I) complex [Rh(CO){ĸ3-(P,N,P)-Cy2PC2H4NHC2H4PCy2}][Cl] (1). The deprotonated complex [Rh(CO){ĸ3-(P,N,P)-Cy2PC2H4NC2H4PCy2}] (2) shows a cooperative reactivity of the PNP ligand in the activation reaction of SO2F2 to yield the rhodium fluorido complex trans-[Rh(F)(CO){ĸ2-(P,P)-Cy2PC2H4N(SO2F)C2H4PCy2}]2 (3) by S-F bond cleavage. It is remarkable that no reaction was observed when 3 was treated with hydrogen sources e. g. dihydrogen, organosilicon compounds such as triethylsilane or TMS-CF3 and different fluorine sources such as SF4 or Selectfluor®. However, the treatment of complex 3 with XeF2 in the presence of CsF resulted in the formation of the unique fluorido rhodium(III) complex cis,trans-[Rh(F)3(CO){ĸ2-(P,P)-Cy2PC2H4N(SO2F)C2H4PCy2}]2 (4). In the presence of pyridine(HF)X or BF3 the fluorido complex 3 converted into the dicationic complexes [Rh(CO){ĸ2-(P,P)-Cy2PC2H4N(SO2F)C2H4PCy2}]2[XF]2, X=HF (5) or BF3 (6), respectively.

Synthesis of aliphatic nitriles from cyclobutanone oxime mediated by sulfuryl fluoride (SO2F2).

A SO2F2-mediated ring-opening cross-coupling of cyclobutanone oxime derivatives with alkenes was developed for the construction of a range of δ-olefin-containing aliphatic nitriles with (E)-configuration selectivity. This new method features wide substrate scope, mild conditions, and direct N-O activation.

New Chemical Transformations Involving SO2 F2 -Mediated Alcohol Activation.

Sulfuryl fluoride is a gas produced on a multi-ton scale for its use as a fumigant. In the last decades, it has gained interest in organic synthesis as a reagent with unique properties in terms of stability and reactivity when compared to other sulfur-based reagents. Sulfuryl fluoride has not only been used for sulfur-fluoride exchange (SuFEx) chemistry but also encountered applications in classic organic synthesis as an efficient activator of both alcohols and phenols, forming a triflate surrogate, namely a fluorosulfonate. A long-standing industrial collaboration in our research group drove our work on the sulfuryl fluoride-mediated transformations that will be highlighted below. We will first describe recent works on metal-catalyzed transformations from aryl fluorosulfonates while emphasizing the one-pot processes from phenol derivatives. In a second section, nucleophilic substitution reactions on polyfluoroalkyl alcohols will be discussed and the value of polyfluoroalkyl fluorosulfonates in comparison to alternative triflate and halide reagents will be brought to light.

Traceless N-Polyfluoroalkylation of Weakly Nucleophilic Nitrogen Containing Compounds.

Here we report an efficient access to high-value N-polyfluoroalkyl anilines, primary polyfluoroalkylamines and N,N-bis(polyfluoroalkyl)amines, via N-polyfluoroalkylation of sulfonamides and phthalimide derivatives using sulfuryl fluoride (SO2 F2 ). The in situ formation of polyfluoroalkyl fluorosulfonates from commercially available fluorinated alcohols and economical sulfuryl fluoride is highly advantageous given that some polyfluoroalkyl halides are ozone-depleting substances (ODS) regulated by the Montreal protocol. This general method is applied to the polyfluoroalkylation of a variety of sulfonamides, N-sulfonyl carbamates and phthalimide with a wide tolerance of functional groups. The process thus provides viable access for industry to N-(polyfluoroalkyl)anilines as well as primary and secondary N-(polyfluoroalkyl)amines, which are very valuable but not easily accessible building blocks for life science applications.

Targeted medical examinations for workers exposed to fumigants.

Fumigants are gaseous pesticides or biocides which eradicate pests by suffocation or poisoning. Worker exposure to fumigants is mainly via inhalation, followed by dermal contact and ingestion, leading to various acute and chronic health effects. Implementation of appropriate workplace controls such as adequate ventilation, training and personal protective equipment ensure that exposure to fumigants are kept to the lowest level as practically possible. In addition, routine medical examinations also allow for doctors to identify and manage possible exposure to fumigants and ascertain workers' fitness to work.While management guidelines after an acute exposure to such fumigants is clear and consistent, the guidelines on routine medical examination for fumigators is sparse. Components of the medical examinations vary according to the fumigant, workers are exposed to and its chronic health effects. Hence, this paper highlights the health hazards of commonly utilised fumigants; Methyl Bromide, Hydrogen Cyanide, Hydrogen Phosphide and Sulfuryl Fluoride; and outlines the guidance for routine medical examinations for exposed fumigators.

Towards a Miniaturized Photoacoustic Detector for the Infrared Spectroscopic Analysis of SO2F2 and Refrigerants.

Sulfuryl fluoride (SO2F2) is a toxic and potent greenhouse gas that is currently widely used as a fumigant insecticide in houses, food, and shipping containers. Though it poses a major hazard to humans, its detection is still carried out manually and only on a random basis. In this paper, we present a two-chamber photoacoustic approach for continuous SO2F2 sensing. Because of the high toxicity of SO2F2, the concept is to use a non-toxic substituent gas with similar absorption characteristics in the photoacoustic detector chamber, i.e., to measure SO2F2 indirectly. The refrigerants R227ea, R125, R134a, and propene were identified as possible substituents using a Fourier-transform infrared (FTIR) spectroscopic analysis. The resulting infrared spectra were used to simulate the sensitivity of the substituents of a photoacoustic sensor to SO2F2 in different concentration ranges and at different optical path lengths. The simulations showed that R227ea has the highest sensitivity to SO2F2 among the substituents and is therefore a promising substituent detector gas. Simulations concerning the possible cross-sensitivity of the photoacoustic detectors to H2O and CO2 were also performed. These results are the first step towards the development of a miniaturized, sensitive, and cost-effective photoacoustic sensor system for SO2F2.

A co-fumigation strategy utilizing reduced rates of phosphine (PH3 ) and sulfuryl fluoride (SF) to control strongly resistant rusty grain beetle, Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae).

BACKGROUND: Managing resistance to phosphine (PH3 ) in rusty grain beetle, Cryptolestes ferrugineus, is challenging, as strongly resistant insects of this species require very high concentrations over lengthy exposure periods (>10 days). Recently, approaches that enhance the efficacy of PH3 have gained momentum to control this pest, especially co-fumigations. In this study, efficacy of co-fumigating PH3 with another commercially available fumigant, sulfuryl fluoride (SF), has been evaluated against adults and eggs of two PH3 -resistant strains of C. ferrugineus. Concentrations of the mixture, representing lower than current application rates of both fumigants, were tested towards its field use. RESULTS: Co-fumigation of PH3 with SF was achieved in two patterns: over a continuous exposure period of 168 h simultaneously and sequentially over two periods of 78 h, in which insects were exposed to SF first followed by PH3 with 12 h aeration in-between. Results of simultaneous fumigations identified two effective co-fumigation rates, SF 185 + PH3 168 g hm-3 and SF 370 + PH3 84 g hm-3 that yielded complete control of adults and eggs. These two rates also were equally effective when they were applied sequentially and produced consistent results. Irrespective of application methods, concentrations of both PH3 and SF failed individually in achieving complete mortality of either adults or eggs or both. CONCLUSION: Our results confirmed that a co-fumigation strategy involving half the current standard rate of PH3 (84 g hm-3 ) with one-fourth of the current maximal registered rate of SF (370 g hm-3 ) can provide effective control of strongly PH3 -resistant C. ferrugineus.

Field Evaluations of Sulfuryl Fluoride Fumigation for Control of the Common Bed Bug (Hemiptera: Cimicidae), Using a 1.9× Dosage Factor in Motor Vehicles and Filled Cargo Trailers.

This study investigated the efficacy of using Vikane gas fumigant (sulfuryl fluoride) at the 1.9× dosage rate for eliminating bed bugs (Cimex lectularius L.) in two challenging infestation situations: personal vehicles, and confined spaces densely packed with personal belongings. The vehicles used in this study were large minivans with seating that folded into the floor. The confined spaces were cargo trailers filled to 85% capacity with books, furniture, and other household items. Each van and trailer was equipped with ~90 sentinel bed bugs consisting of three groups of 9-11 bed bug eggs, 10 nymphs, and 10 adults. The Vikane Fumiguide calculator was used to determine the target dosage (g-h/m3) to apply in each replicate (e.g., one van or trailer). Sulfuryl fluoride concentrations were measured throughout the fumigation process using a Spectros SF-ReportIR. Concentration readings were input into the Fumiguide to determine when the accumulated dosage (g-h/m3) was achieved, and when aeration should be initiated. After aeration was complete, the sentinel bed bugs were removed from the replicates and bed bug nymph and adult mortality was recorded. Bed bug eggs were monitored for 23 d to determine latent mortality. Fumigated bed bug mortality for each replication was 100% regardless of life stage. Latent mortality was observed in a single bed bug egg, but the first instar never fully eclosed. This study determined that fumigation with sulfuryl fluoride at the 1.9× dosage factor is an effective method for eliminating resistant bed bugs from vehicles and personal belongings in densely packed situations.

Review of the existing maximum residue levels for sulfuryl fluoride according to Article 12 of Regulation (EC) No 396/2005.

According to Article 12 of Regulation (EC) No 396/2005, EFSA has reviewed the maximum residue levels (MRLs) currently established at European level for the pesticide active substance sulfuryl fluoride. To assess the occurrence of sulfuryl fluoride and fluoride ion residues in plants, processed commodities and livestock, EFSA considered the conclusions derived in the framework of Directive 91/414/EEC, the MRLs established by the Codex Alimentarius Commission as well as the European authorisations reported by Member States (including the supporting residues data). Based on the assessment of the available data, MRLs were calculated, but a consumer risk assessment could be carried out for sulfuryl fluoride only. Although no apparent risk to consumers was identified for sulfuryl fluoride, a standard consumer risk assessment to fluoride ion could not be performed, lacking information on the toxicological reference values for fluoride. Hence, an 'overall' consumer risk assessment could not be performed, only tentative MRLs proposal could be derived and measures for reduction of the consumer exposure should also be considered. Nevertheless, considering that fluoride ion is naturally occurring in food of plant and animal origin, EFSA performed an indicative calculation of the consumer exposure to estimate whether the uses currently authorised will contribute significantly to the overall consumer exposure to fluoride.

One-Pot Substitution of Aliphatic Alcohols Mediated by Sulfuryl Fluoride.

The Mitsunobu reaction is a powerful transformation for the one-pot activation and substitution of aliphatic alcohols. Significant efforts have focused on modifying the classic conditions to overcome problems associated with purification from phosphine-based byproducts. Herein, we report a phosphine free method for alcohol activation and substitution that is mediated by sulfuryl fluoride. This new method is effective for a wide range of primary alcohols using phthalimide, di-tert-butyl-iminodicarboxylate, and aromatic thiol nucleophiles in 74 % average yield. Activated carbon nucleophiles and a deactivated phenol were also effective for this reaction in good yields. Secondary alcohols were also successful substrates using aryl thiols, affording the corresponding sulfides in 56 % average yield with enantiomeric ratios up to 99:1. This new protocol has a distinct synthetic advantage over many existing phosphine-based methods as the byproducts are readily separable. This feature was exploited in several examples that did not require chromatography for purification. Furthermore, the mild reaction conditions enabled further in situ derivatization for the one-pot conversion of alcohols to amines or sulfones. This method also provides a boarder nucleophile scope compared to existing phosphine-free methods.

Sulfuryl Fluoride Mediated Synthesis of Amides and Amidines from Ketoximes via Beckmann Rearrangement.

A metal-free and redox-neutral method for Beckmann rearrangement employing inexpensive and readily available SO2 F2 gas is described. The reported transformation proceeds at ambient temperature and is compatible with a wide range of sterically and electronically diverse aromatic, heteroaromatic, aliphatic and lignin-like oximes providing amides in good to excellent yields. The reaction proceeds through the formation of an imidoyl fluoride intermediate that can also be used for the synthesis of amidines.

Installation of -SO2F groups onto primary amides.

A protocol of SO2F2-mediated installation of sulfonyl fluoride onto primary amides has been developed providing a new portal to sulfur(VI) fluoride exchange (SuFEx) click chemistry. The generated molecules contain pharmaceutically important amide and -SO2F moieties for application in the discovery of new therapeutics.

Sulfuryl Fluoride Poisonings in Structural Fumigation, a Highly Regulated Industry-Potential Causes and Solutions.

Structural fumigations using sulfuryl fluoride for the extermination of dry-wood termites are conducted by the thousands in California and other warm-weather states. Sulfuryl fluoride is an odorless gas that targets the nervous system and can cause respiratory irritation, pulmonary edema, nausea, vomiting, seizures, and death. Structural voids or compartments such as wall sockets, crawl spaces, cabinets, or cells in air mattresses may create ongoing exposure after a structure has been certified as safe. The authors describe a case of potential sulfuryl fluoride exposure to a family following home fumigation. Despite regulation, sulfuryl fluoride poisonings from structural fumigations continue to occur. This article examines the physical characteristics of sulfuryl fluoride and the regulatory oversight of its application, in an effort to understand how and why these poisonings happen. Increasing aeration times of fumigated structures, overseeing monitoring efficacy, and using technology to capture clearance data could reduce sulfuryl fluoride exposure and illness.

SO2F2-mediated transformation of 2'-hydroxyacetophenones to benzo-oxetes.

A catalyst-free novel and efficient methodology for the challenging synthesis of benzo-oxetes from 2'-hydroxyacetophenones mediated by sulfuryl fluoride (SO2F2) gas has been realized. The combination of 2'-hydroxyacetophenones and SO2F2 furnishes synthetically challenging benzo-oxetanes in moderate to excellent yields. The highlight of this work is the design and synthesis of strained four-membered oxete rings.

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

BACKGROUND: 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. RESULTS: 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. CONCLUSION: 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.

Sulfur(VI) fluoride exchange (SuFEx): another good reaction for click chemistry.

Aryl sulfonyl chlorides (e.g. Ts-Cl) are beloved of organic chemists as the most commonly used S(VI) electrophiles, and the parent sulfuryl chloride, O2 S(VI) Cl2 , has also been relied on to create sulfates and sulfamides. However, the desired halide substitution event is often defeated by destruction of the sulfur electrophile because the S(VI) Cl bond is exceedingly sensitive to reductive collapse yielding S(IV) species and Cl(-) . Fortunately, the use of sulfur(VI) fluorides (e.g., R-SO2 -F and SO2 F2 ) leaves only the substitution pathway open. As with most of click chemistry, many essential features of sulfur(VI) fluoride reactivity were discovered long ago in Germany.6a Surprisingly, this extraordinary work faded from view rather abruptly in the mid-20th century. Here we seek to revive it, along with John Hyatt's unnoticed 1979 full paper exposition on CH2 CH-SO2 -F, the most perfect Michael acceptor ever found.98 To this history we add several new observations, including that the otherwise very stable gas SO2 F2 has excellent reactivity under the right circumstances. We also show that proton or silicon centers can activate the exchange of SF bonds for SO bonds to make functional products, and that the sulfate connector is surprisingly stable toward hydrolysis. Applications of this controllable ligation chemistry to small molecules, polymers, and biomolecules are discussed.

Evaluation of sulfuryl fluoride as a soil fumigant in China.

BACKGROUND: Root-knot nematodes and soil-borne diseases constrain the rapid development of protected agriculture in China, especially while phasing out methyl bromide (MB). The fumigant sulfuryl fluoride (SF) is currently used as an alternative to MB for the disinfestation of buildings and post-harvest commodities. Our experiments aimed to evaluate a novel application of SF as a soil fumigant in greenhouses in China. RESULTS: Dose-response experiments indicated that SF has good efficacy on root-knot nematodes (Meloidogyne spp.) and moderate activity against Fusarium spp. and weeds (Digitaria sanguinalis (L.) Scop. and Abutilon theophrasti Medicus). The field trials indicates that SF has good efficacy, between 80 and 94%, on Meloidogyne spp., and Fusarium spp. at the rates of 25-50 g m(-2) in tomato and cucumber in Beijing and Shandong Province. Marketable yield and plant vigour was not significantly different in SF and MB treatments. SF has lower emissions than MB during the fumigation operation. It is simple to apply, can be used at low temperature, and has a short plant-back time. SF was found to be an economically feasible alternative to MB for nematode control in China. CONCLUSION: SF can be used as a soil fumigant to control root-knot nematodes and to reduce the levels of key soil pathogens.