Reaction Of Dimethyl Sulfide Research Articles

Time-resolved FRS detection of OH radical for chemical reactions rate measurement

The time-resolved Faraday rotation spectroscopy method with a DFB diode laser at 1434 nm was used to detect the hydroxyl radical OH in the first overtone region. Experiments were made at the most intense Q(3/2) line of the 2Π3/2 electronic term. The sufficient concentration for radical measurement is 2 × 1012 cm−3, with the resolving time approximately 10−6 s. This resolution is sufficient for studying fast chemical reactions, which was demonstrated by measuring the rate constant of the OH and dimethylsulfide reaction.

Chamber studies of OH + dimethyl sulfoxide and dimethyl disulfide: insights into the dimethyl sulfide oxidation mechanism.

The oxidation of dimethyl sulfide (DMS) in the marine atmosphere represents an important natural source of non-sea-salt sulfate aerosol, but the chemical mechanisms underlying this process remain uncertain. While recent studies have focused on the role of the peroxy radical isomerization channel in DMS oxidation, this work revisits the impact of the other channels (OH addition and OH abstraction followed by bimolecular RO2 reaction) on aerosol formation from DMS. Due to the presence of common intermediate species, the oxidation of dimethyl sulfoxide (DMSO) and dimethyl disulfide (DMDS) can shed light on these two DMS reaction channels; they are also both atmospherically relevant species in their own right. This work examines the OH oxidation of DMSO and DMDS, using chamber experiments monitored by chemical ionization mass spectrometry and aerosol mass spectrometry to study the full range of sulfur-containing products across a range of NO concentrations. The oxidation of both compounds is found to lead to rapid aerosol formation (which does not involve the intermediate formation of SO2), with a substantial fraction (14%-47 % S yield for DMSO and 5 %-21 % for DMDS) of reacted sulfur ending up in the particle phase and the highest yields observed under elevated NO conditions. Aerosol is observed to consist mainly of sulfate, methanesulfonic acid, and methanesulfinic acid. In the gas phase, the NOx dependence of several products, including SO2 and S2-containing organosulfur species, suggest reaction pathways not included in current mechanisms. Based on the commonalities with the DMS oxidation mechanism, DMSO and DMDS results are used to reconstruct DMS aerosol yields; these reconstructions roughly match DMS aerosol yield measurements from the literature but differ in composition, underscoring remaining uncertainties in sulfur chemistry. This work indicates that both the abstraction and addition channels contribute to rapid aerosol formation from DMS and highlights the need for more study into the fate of small sulfur radical intermediates (e.g., CH3S, CH3SO2, and CH3SO3) that are thought to play central roles in the DMS oxidation mechanism.

Smartphone-based digital colorimetric measurement of dimethyl sulfide in wastewater

A simple and low-cost method for the measurement of dimethyl sulfide (DMS) in wastewater was developed using digital imaging colorimetry based on a smartphone. This method involved the generation of a pink color through the complexation reaction of DMS with sodium nitroprusside and subsequent acidification. A smartphone camera recorded the developed color through a digital image of the colored reaction mixture and color values in the red (R), green (G) and (B) blue color space were obtained through digital image analysis. The G value was found to provide a basis for the sensitive measurement of DMS. Light box parameters (position and distance of the light source relative to the camera) and reaction parameters (NaOH concentration, reaction time and HCl concentration) were optimized. This method exhibited linearity in the working range of 500–6000 μg kg−1 with a Pearson coefficient of 0.996. The sensitivity, which was based on the slope of the calibration line, was calculated to be −0.017 (μg kg−1)−1, and the limit of detection was 222 μgkg−1. Good precision (0.8 to 1.3% relative standard deviation) was obtained. The G value exhibited good correlation (Pearson correlation coefficient = 0.997) with the absorbance obtained from a spectrophotometer. Measurement of the DMS of a wastewater sample yielded a result which was in agreement (98 % recovery) with the results of a reference GC-FPD analysis, validating its capability for an accurate measurement.

Study of heterogeneous reaction of dimethyl sulfide on atmospheric-like particulate TiO2

Dimethyl sulfide (DMS) related to solar radiation and greenhouse effect is one of the most important volatile sulfides and its' oxidation products are also important contributors to acid rain. It is of great importance to study the consumption and reactions of DMS in the atmosphere. In this work, atmospheric-like particulate TiO2 was selected to study the reaction mechanism of DMS on TiO2 with the purpose to explore the possible heterogeneous oxidation of DMS. The results showed that the heterogeneous reaction of DMS with TiO2 occurred under the condition of illumination, which is a first-order-like reaction with the rate constant K = 2.83 × 10−4/s, the initial reaction uptake coefficient and the steady reaction uptake coefficient indicated the occupation of products and by-products on the surface of TiO2. The heterogeneous reaction mechanism of DMS studied by aerosol time-of-flight mass spectrometry (ATOFMS) suggested that DMS underwent a series of complex chemical reactions with sulfate and various sulfur-containing gas products, in which hydroxyl radicals might play an important role.

Reaction of DMS and HOBr as a Sink for Marine DMS and an Inhibitor of Bromoform Formation

Recently, we suggested that hypobromous acid (HOBr) is a sink for the marine volatile organic sulfur compound dimethyl sulfide (DMS). However, HOBr is also known to react with reactive moieties of dissolved organic matter (DOM) such as phenolic compounds to form bromoform (CHBr3) and other brominated compounds. The reaction between HOBr and DMS may thus compete with the reaction between HOBr and DOM. To study this potential competition, kinetic batch and diffusion-reactor experiments with DMS, HOBr, and DOM were performed. Based on the reaction kinetics, we modeled concentrations of DMS, HOBr, and CHBr3 during typical algal bloom fluxes of DMS and HOBr (10-13 to 10-9 M s-1). For an intermediate to high HOBr flux (≥10-11 M s-1) and a DMS flux ≤10-11 M s-1, the model shows that the DMS degradation by HOBr was higher than for photochemical oxidation, biological consumption, and sea-air gas exchange combined. For HOBr fluxes ≤10-11 M s-1 and a DMS flux of 10-11 M s-1, our model shows that CHBr3 decreases by 86% compared to a lower DMS flux of 10-12 M s-1. Therefore, the reaction between HOBr and DMS likely not only presents a sink for DMS but also may lead to suppressed CHBr3 formation.

Heterogeneous Reaction of Dimethyl Sulfide with Iodine Oxide in a Temperature Range of 291–365 K

A reaction of the iodine oxide (IO) radical with dimethyl sulfide (DMS) in a temperature range of 291–365 K was studied using atomic iodine resonance fluorescence. It was found that this reaction was mainly heterogeneous under the experimental conditions, and the rate constant of the heterogeneous reaction was almost an order of magnitude higher than the rate constant of a homogeneous reaction. The temperature dependence of the rate constant of this reaction can be represented by the following expression: k(T) = 1.5 × 10–14 [±3 × 10–15 cm3 molecule–1 s–1] exp(7150[±800 J/mol]/RT). The conditions under which the heterogeneous reaction of DMS with the IO radical can play a noticeable role in the oxidation of DMS in the atmosphere are discussed.

The reaction of dimethyl sulfide with the Criegee intermediates CH2OO and (CH3)2COO: Theoretical investigations

In this research, the reactions of two simple Criegee intermediates formaldehyde oxide and acetone oxide with dimethyl sulfide is explored theoretically. The well-tested meta-GGA density functional theory method M11-L is employed to locate the structures of stationary points on the potential energy surface of the title reactions. Statistical rate theories such as transition state theory (TST) and RRKM theory are employed to determine the dominant products of the reactions. It is found that both reactions occur via relatively strong van der Waals complexes leading to CS bonded adducts, IM1C and IM1D. These initial adducts decompose to yield other intermediates and products. According to the present theoretical thermodynamics and kinetics calculations, IM1C adduct could be formed in considerable amount in atmospheric condition. However, the reaction of (CH3)2COO with dimethyl sulfide is not of atmospheric significance.

Kinetics of dimethyl sulfide (DMS) reactions with isoprene-derived Criegee intermediates studied with direct UV absorption

Abstract. Criegee intermediates (CIs) are formed in the ozonolysis of unsaturated hydrocarbons and play a role in atmospheric chemistry as a non-photolytic OH source or a strong oxidant. Using a relative rate method in an ozonolysis experiment, Newland et al. (2015) reported high reactivity of isoprene-derived Criegee intermediates towards dimethyl sulfide (DMS) relative to that towards SO2 with the ratio of the rate coefficients kDMS+CI/kSO2+CI = 3.5 ± 1.8. Here we reinvestigated the kinetics of DMS reactions with two major Criegee intermediates formed in isoprene ozonolysis, CH2OO, and methyl vinyl ketone oxide (MVKO). The individual CI was prepared following the reported photolytic method with suitable (diiodo) precursors in the presence of O2. The concentration of CH2OO or MVKO was monitored directly in real time through their intense UV–visible absorption. Our results indicate the reactions of DMS with CH2OO and MVKO are both very slow; the upper limits of the rate coefficients are 4 orders of magnitude smaller than the rate coefficient reported by Newland et al. (2015) These results suggest that the ozonolysis experiment could be complicated such that interpretation should be careful and these CIs would not oxidize atmospheric DMS at any substantial level.

Light-Driven Metal-Free Direct Deoxygenation of Alcohols under Mild Conditions.

SummaryHydroxyl is widely found in organic molecules as functional group and its deprivation plays an inevitable role in organic synthesis. However, the direct cleavage of Csp3-O bond in alcohols with high selectivity and efficiency, especially without the assistance of metal catalyst, has been a formidable challenge because of its strong bond dissociation energy and unfavorable thermodynamics. Herein, an efficient metal-free strategy that enables direct deoxygenation of alcohols has been developed for the first time, with hydrazine as the reductant induced by light. This protocol features mild reaction conditions, excellent functional group tolerance, and abundant and easily available starting materials, rendering selective deoxygenation of a variety of 1° and 2° alcohols, vicinal diols, and β-1 and even β-O-4 models of natural wood lignin. This strategy is also highlighted by its “traceless” and non-toxic by-products N2 and H2, as readily escapable gases. Mechanistic studies demonstrated dimethyl sulfide being a key intermediate in this transformation.

Selective Desorption of Ethylene after Dimethyl Sulfide Reaction on Cold Gold Surface

Ethylene is mostly generated from nonrenewable petroleum feedstocks. To reduce the environmental footprint, sustainable sources and less energy demanding methodologies are highly encouraged. Here we show that ethylene is produced from the reaction of dimethyl sulfide on the polycrystalline gold surface, maintained at 90 K. The ion detection ratio is measured to (8.5 ± 1.1)%, leading to a conversion rate of 52% in (450 ± 60)s. The reaction is investigated theoretically for three specific surfaces, Au(111), Au(110)(1 × 1) and Au(110)(1 × 3). The flat surface is found to be ineffective for conversion, while cooperative pairwise molecular mechanism is operative at the Au(110) surfaces. Pure ethylene is finally selectively desorbed from the surface by a thermal heating at 105 K. The laboratory findings can be applicable to nanoscale chemistry but may guide the optimization of larger scale methodologies.

Six-Coordinate Nitrato Complexes of Iron Porphyrins with Trans S-Donor Ligands.

The reaction of dimethyl sulfide (DMS) and tetrahydrothiophene (THT) with thin, amorphous layers of the nitrato complexes Fe(Por)(η2-O2NO) (Por = meso-tetraphenylporphyrinato dianion or meso-tetra- p-tolylporphyrinato dianion) at low temperature leads to formation of the corresponding six-coordinate complexes Fe(Por)(L)(η1-ONO2) (L = DMS, THT) as characterized by Fourier transform infrared and optical spectroscopy measurements. Adduct formation was accompanied by bidentate-to-monodentate linkage isomerization of the nitrato ligand, with the FeIII center remaining in a high-spin electronic state. These adducts are thermally unstable; warming to room temperature restores the initial Fe(Por)(η2-O2NO) species.

Pd(II) and Pt(II) complexes of α-keto stabilized sulfur ylide: Synthesis, structural, theoretical and catalytic activity studies

Reaction of dimethyl sulfide with 2, 3′-dibromoacetophenone led to formation of sulfonium salt [Me2SCH2C(O)C6H4-m-Br]Br (1). The resulted sulfonium salt was treated with NaOH and gave the α-keto stabilized sulfur ylide Me2SC(H)C(O)C6H4-m-Br (2). This ligand was reacted with [MCl2(cod)] (M = Pd, Pt; cod = 1,5-cyclooctadiene) to form the new cis- and trans-[MCl2(ylide)2] (M = Pd (cis- and trans-3), Pt (cis- and trans-4)) complexes. Characterization of the obtained compounds was performed by elemental analysis, IR, 1H and 13C NMR. Recrystallization of dichlorobis(ylide) palladium(II) and platinum(II) complexes from DMSO solution yielded the crystalline products, which X-ray diffraction data revealed that the both compounds were crystallized as cis-[MCl2(ylide)(DMSO)] (M = Pd (5), Pt (6)) complexes. Also, a theoretical study on structure and nature of the MC bonding between the Y ligand (ylide) and [MCl2·DMSO] fragments in [YMCl2·DMSO] (M = Pd, Pt) complexes has been reported via NBO and energy-decomposition analysis (EDA). Furthermore, the palladium catalyzed Suzuki-Miyaura reaction of various aryl chlorides with arylboronic acids was performed. The results showed that the Pd(II) complexes cis- and trans-3 catalyzed efficiently coupling reactions at low catalyst loading and short reaction time.

Dimethyl sulfide protects against oxidative stress and extends lifespan via a methionine sulfoxide reductase A-dependent catalytic mechanism.

SummaryMethionine (Met) sulfoxide reductase A (MsrA) is a key endogenous antioxidative enzyme with longevity benefits in animals. Only very few approaches have been reported to enhance MsrA function. Recent reports have indicated that the antioxidant capability of MsrA may involve a Met oxidase activity that facilities the reaction of Met with reactive oxygen species (ROS). Herein, we used a homology modeling approach to search the substrates for the oxidase activity of MsrA. We found that dimethyl sulfide (DMS), a main metabolite that produced by marine algae, emerged as a good substrate for MsrA‐catalytic antioxidation. MsrA bounds to DMS and promoted its antioxidant capacity via facilitating the reaction of DMS with ROS through a sulfonium intermediate at residues Cys72, Tyr103, and Glu115, followed by the release of dimethyl sulfoxide (DMSO). DMS reduced the antimycin A‐induced ROS generation in cultured PC12 cells and alleviated oxidative stress. Supplement of DMS exhibited cytoprotection and extended longevity in both Caenorhabditis elegans and Drosophila. MsrA knockdown abolished the cytoprotective effect and the longevity benefits of DMS. Furthermore, we found that the level of physiologic DMS was at the low micromolar range in different tissues of mammals and its level decreased after aging. This study opened a new window to elucidate the biological role of DMS and other low‐molecular sulfides in the cytoprotection and aging.

A new Pd(II) complex of a sulfur ylide; Synthesis, X-ray characterization, theoretical study and catalytic activity toward the Suzuki–Miyaura reaction

The new sulfonium salt [SMe2CH2C(O)C6H4-m-OCH3]Br (1) was synthesized from the reaction of dimethyl sulfide and 2-bromo-3′-methoxyacetophenone. Further treatment with NaOH 10% gave the α-keto stabilized sulfur ylide SMe2C(H)C(O)C6H4-m-OCH3 (2). This ligand was reacted with the dichloro(1,5-cyclooctadiene)palladium(II) complex, [PdCl2(cod)], in a 2:1 ratio to give the new Cα-coordinated complexes cis- and trans-[PdCl2(SMe2C(H)C(O)C6H4-m-OCH3)2] (3a and 3b). Characterization of the obtained compounds was performed by elemental analysis, IR, 1H, 13C NMR and mass spectroscopies. Since complexes 3a and 3b were insoluble in most organic solvents, we chose DMSO as a suitable solvent for the NMR spectroscopies. Crystallization of above solution led to the formation of single crystals. The X-ray analysis results revealed that complex 3a has undergone a ligand replacement reaction and the complex [PdCl2(SMe2C(H)C(O)C6H4-m-OCH3)·DMSO] (4) was formed. This complex has two Cl atoms in cis positions, one sulfur ylide and one S-coordinated DMSO as ligands. The air/moisture stable complexes 3a and 3b were employed as efficient catalysts for the Suzuki–Miyaura cross-coupling reaction of several aryl halides. The coupled products of these reactions were obtained in good to excellent yields and purity, with short reaction times and low catalyst loading. Also a theoretical study on the structure and nature of the Pd–C bond in complex 4 is reported here at the BP86/def2-SVP level of theory.

Theoretical Study on the OH with Dimethyl Sulfide Reaction in the Presence of Water

The gas phase reaction between dimethylsulfide (DMSO) and hydroxyl rad- ical (OH) without and with a single water molecule are investigated employing the quantum chemical calculations at the b3lyp/aug-cc-pvtz and mp2/aug-cc-pvtz levels of theory, respectively. We have been given five paths of OH radical with DMSO (A , B, C, D and E). The geometries and computed energies not only indicate that water molecule produces a catalytic effect for path A and path B, but produces a negative ef- fect for path C, path D and path E. We also give the rate constants to support the above result. We can draw the conclusion that water molecule can influence the reaction process, through forming new molecular compounds.

Optimisation of a fast DMS sensor (FDS) for real time quantification of dimethyl sulfide production by algae

Production of dimethyl sulfide (DMS) from marine samples is often quantified using gas chromatography techniques. Typically, these are labour intensive and have a slow sample turnover rate. Here we demonstrate the use of a portable fast DMS sensor (FDS) that utilises the chemiluminescent reaction of DMS and ozone to measure DMS production in aqueous samples, with a maximum frequency of 10 Hz. We have developed a protocol for quantifying DMS production that removes potential signal interference from other biogenic trace gases such as isoprene (2-methyl-1,3-butadiene) and hydrogen sulfide. The detection limit was 0.89 pM (0.02 ppbv) when using a DMS standard gas mixture. The lowest DMS production rates quantified with the FDS and verified using conventional gas chromatography with flame photometric detection (GC-FPD) were around 0.01 nmol min−1. There was a strong correlation in DMS production when comparing the FDS and GC-FPD techniques with a range of marine samples (e.g., r2 = 0.94 for Emiliania huxleyi). However, the combined dataset showed the FDS measured 22% higher DMS production than the GC-FPD, with the differences in rates likely due to interfering gases, for example hydrogen sulfide and isoprene. This possible overestimation of DMS production is smaller than the two-fold difference in DMS production between day and night samples from a culture of E. huxleyi. The response time of the instrument to changes in DMS production is method dependent (e.g., geometry of incubation vessel, bubble size) and was approximately 4 min under our conditions when using a culture of E.huxleyi (800 ml) with aeration at 100 ml min−1. We suggest the FDS can reduce sample handling, is suitable for short- and long-term measurements of DMS production in algal cultures, and will widen the range of DMS research in marine environments.

NEXAFS and XPS Studies of (CH3)2S Adsorption on Rh(PVP) Nanoparticle

We have studied the adsorption reaction of dimethyl sulfide (DMS) on the Rh-polyvinylpyrrolidone (Rh(PVP)) nanoparticles by using AFM, XPS and NEXAFS techniques. The AFM images show the morphology of the Rh(PVP) nanoparticles depends on the amount of them. The XPS results indicate that the dissociation reaction of DMS into atomic S does not depend upon the existence of the Rh(PVP) nanoparticles. The NEXAFS results show that there is a strong chemical bonding between Rh(PVP) nanoparticle and atomic S. [DOI: 10.1380/ejssnt.2010.233]

Rate constant of the gas phase reaction of dimethyl sulfide (CH 3SCH 3) with ozone

The gas phase reaction of ozone with dimethyl sulfide (DMS) has been studied in our self-made chamber. Experiments were conducted under supposedly pseudo-first-order decay conditions, keeping [DMS] 0 > 10[O 3] 0, but having different combinations of [DMS] 0 and [O 3] 0. Cyclohexane was added into the reactor to eliminate the effect of OH radicals. A value of (1.04 ± 0.21) × 10 −19 cm 3 molecule −1 s −1 for rate constant was obtained under room temperature of about 301 K. The wall effects and the role of cyclohexane are discussed. Our results enrich the kinetics data of atmospheric chemistry, and further confirm that the gas phase reaction of DMS with ozone is not important for the loss of DMS in the atmosphere.

Synthesis of some new 2,4,6-trisubstituted phenyl pyrimidines using 4-nitro and 4-fluorophenacyldimethylsulfonium bromides with aromatic aldehydes

4-Nitrophenacyldimethylsulfonium bromide and 4-fluorophenacyldimethylsulfonium bromide have been prepared by the reaction of dimethyl sulfide with 4-substitutedphenacyl bromide in benzene at reflux temperature under nitrogen atmosphere. These sulfonium salts on treatment with NaOH gave 4-nitrophenacylidenedimethylsulfurane and 4-fluorophenacylidenedimethylsulfurane. The reaction of these sulfonium salts and sulfuranes with various aromatic aldehydes is carried out in presence of ammonium acetate and acetic acid at reflux in an atmosphere of nitrogen to give 2,4,6-triarylpyrimidines in 35-80% yields. Ammonium acetate in acetic acid was used as aza cyclization agent. The structures of new pyrimidines were confirmed on the basis of IR and NMR spectral data.

Peroxynitrite Reactions with Dimethylsulfide and Dimethylselenide: An Experimental Study

The kinetics of the peroxynitrite (ONOO- and HOONO, PN for both) reaction with (Me)2X (X = S and Se, dimethyl sulfide (DMS) and dimethylselenide (DMSe)) was studied. The reaction is first order with respect to both PN and (Me)2X concentrations. (Me)2XO and NO2- were formed with 100% yield based on PN in all cases except in the DMS reaction with HOONO, where the yield was ∼80%. DMSe is much more reactive than DMS toward both ONOO- and HOONO, while HOONO reacts much faster than ONOO- with both (Me)2X. The activation entropies (in cal deg-1 mol-1) and enthalpies (given in parentheses, in kcal/mol) for the reactions of DMS and DMSe with HOONO were determined to be −23 ± 3 (5.9 ± 0.5) and −20.5 ± 3 (4.6 ± 0.5), respectively. The corresponding values for the reaction with ONOO- were −29 ± 3 (9.7 ± 0.6) and −28 ± 3 (7.2 ± 0.5). A partial replacement of water with an organic cosolvent resulted in a decrease in the rate of reaction of ONOO- with both DMS and DMSe, while it had no effect on the rates of reaction wi...