Organic Sulfides Research Articles

Encapsulated peroxophosphotungstates catalyst into magnetic MOF: Magnetically recoverable heterogeneous high efficiency desulfurization catalyst

High activity peroxophosphotungstates with different organic cations were encapsulated into the metal-organic framework modified by magnetic nanoparticle (Fe2O3/MIL-101) to prepare the magnetic supported catalysts, which were used to improve the diesel desulfurization efficiency. The desulfurization result shows that one selected catalyst, (BTA)3PW4 @Fe2O3/MIL-101, possesses high catalytic activity in the oxidation of various organic sulfides with H2O2 as green oxidant. The catalyst can be magnetically recycled and reused for ten consecutive cycles without significant decrease in activity. Based on the GC-MS and EPR results, it is confirmed that sulfides are oxidized to corresponding sulfones in the presence of •OH radical. In a word, the high activity, good stability and reusability of catalyst prepared in this work make it have a good prospect of industrial application.

Recent innovations in various methods of harmful gases conversion and its mechanism in poultry farms

Poultry breeding takes place in intensive, high-production systems characterized by high animal density, which is a source of harmful emission of odorous volatile organic compounds (VOCs), ammonia (NH3), hydrogen sulfide (H2S) and greenhouse gases, which in turn sustain animal welfare. This study identified and examined the characteristics of chemical compounds emitted in intensive poultry farming (laying hens, broilers) and their toxicity, which led to recommending methods of deodorization. Emphasis was placed on the law relative to air purification in poultry farms. Various methods of air treatment in poultry farms have been described: the modification of animal diet to improve nutrient retention and decrease the amount of their excrement; chemical oxidation technologies (ozonation, photocatalysis, Fenton reaction); various types/brands of biofilters, bioscrubbers and membrane reactors. Numerous studies show that biofilters can reduce ammonia emissions by 51%, hydrogen sulfide by 80%, odors by 67%, while scrubbers brings down ammonia emissions by 77% and odors by 42%, and the application of UV light lowers ammonia emissions by 28%, hydrogen sulfide by 55%, odors by 69% and VOCs by 52%. The paper presents both the solutions currently used in poultry farming and those which are currently in the research and development phase and, as innovative solutions, could be implemented in the near future.

N-Butanol or isobutanol as a value-added fuel additive to inhibit microbial degradation of stored gasoline

Biofouling of gasoline can occur during fuel storage caused by bacteria and fungi that form a biofilm at a fuel/water interface and that produce organic acids and sulfides. Fuel additives are applied to gasoline to prevent biofouling but are relatively expensive, are not always effective against biofilms, and do not contribute to the combustibility of gasoline. Bio-isobutanol is an approved, certified advanced biofuel and is added up to 16% (v/v) in gasoline blends “iBut16”; n-butanol blends are currently under review. Microorganisms are inhibited by n-butanol or isobutanol when the aqueous concentration reaches >2-3% (w/v). We determined that n-butanol partitions into the aqueous phase of a model gasoline/water system reaching concentrations of 42 g/L and up to 48 g/L from gasoline blends at 10% and 24% (v/v), respectively. Likewise, isobutanol blended in gasoline at 10% and 24% (v/v) partitioned into an aqueous phase at 45 g/L and 53 g/L, respectively. Several bacterial and fungal strains that originate from fuel storage tanks, or are known to be solvent tolerant, were evaluated for their potential growth in a range of n- and isobutanol concentrations. Growth rates for all strains tested were reduced by 40–100% relative to untreated controls in n- and isobutanol concentrations of 1.5 and 2.0% (v/v). No observable growth occurred for any of the microorganisms in solvent concentrations at 3.0% (v/v). T amphiphilic and chaotropic properties of n- or isobutanol help them inhibit microbial growth and could serve as effective biocides during fuel storage as well as being valuable fuel additives.

Design, Synthesis, and Applications of ortho -Sulfur Substituted Arylphosphanes

Design, Synthesis, and Applications of <i>ortho</i> -Sulfur Substituted Arylphosphanes

Diaryl-pyrazinoporphyrins – Prospective photocatalysts for efficient sulfoxidation

New promising photoactive functionalized pyrazinoporphyrins were prepared and preliminarily tested as homogeneous catalysts in the photooxidation of organic sulfides. An extremely low loading of the catalysts (10−3 mol%) allowed oxidation of thioanizole to the corresponding sulfoxide with the conversion of 98–100%, TON ca. 95060–98000 and TOF ca. 5941–6125, providing the selectivity of the corresponding sulfoxide formation of 97–98%. A survey of the meso-substituents of the porphyrin was performed allowing determination of optimal derivatives providing high catalytic activity together with sufficient stability and solubility under reaction conditions and along the synthetic pathway. The results obtained upon variation of the electronic nature of the substituents at the sulfur atom allowed to reveal promising prospective for further systematic application of pyrazinoporphyrin photosensitizers. The presence of the diethoxyphosphoryl- and methoxycarbonyl-substituents in the prepared compounds allows to consider them as prospective starting materials for further grafting to solid supports and thus as a platform for the development of heterogeneous photocatalysts.

Characteristics and Health Risk Assessment of Heavy Metal Pollution in Haikou Bay and Adjacent Seas.

Heavy metal contamination in coastal waters may pose a serious threat to aquatic products and human health. This study aimed to gain a better understanding of the pollution-induced by heavy metals in Haikou Bay and adjacent seas and assessed the potential ecological risk. The spatial distributions of heavy metals including Cu, Pb, Zn, Cd, Cr, Hg, and As were analyzed in the surface and bottom water, surface sediment, and five species of fish collected from Haikou Bay and adjacent seas. For seawater, the results showed that the horizontal distribution of the seven heavy metal elements in the study area had no uniform pattern due to the influence of complex factors, such as land-based runoff, port shipping, and ocean current movement. In contrast, the vertical distribution of these heavy metal elements, except for Zn and Cd, showed high concentrations in the surface water and low concentrations in the bottom water. Due to the symbiotic relationship between Zn and Cd, the distributions of these two elements were similar in the study areas. Different from the complex distribution of heavy metals in water, the highest concentrations of these elements in surface sediment all occurred at station 11 except for Pb. Our study revealed that organic carbon and sulfide are important factors affecting the heavy metal concentrations in the surface sediments. Heavy metals in waters and surface sediment were lower than the quality standard of class I according to the China National Standard for Seawater Quality and the sediment quality, except for Zn in water, suggesting that the seawater and surface sediment in Haikou Bay and adjacent seas has not been polluted by heavy metals. Additionally, the heavy metal As was the main element affecting the quality of fish in this study area, and attention should be paid in the future. The target hazard quotient (THQ) values of seven heavy metal elements in fish were all lower than 1.0, indicating that eating fish in this area will not pose a risk to human health. These results provide valuable information for further understanding the status of heavy metal pollution in Haikou Bay and adjacent seas and the development of targeted conversation measures for the environment and fish consumers.

Improvement of the adsorption-absorption vapor recovery unit for cleaning the gas-air mixture from volatile organic compounds and hydrogen sulfide when loading naphtha on marine tankers

The article proposes the improvement of adsorption and absorption plants for the recovery of naphtha vapors through the use of a sulfur compounds purification unit. This unit allows you to remove environmentally hazardous sulfur components from naphtha vapors, which adversely affect adsorption filters, without increasing the temperature and significant pressure drop of the gas-air mixture. The relevance of the study is due to the fact that marine terminals are objects of significant emissions of hydrocarbons and sulfur compounds. Intensive evaporation of naphtha during the filling process leads to air pollution and loss of valuable product. Vapor recovery units with a desulfurization unit are designed to solve the problem, however, their implementation at loading facilities requires the installation of additional flow stimulators and, as a rule, additional electricity consumption. The main purpose of the study was to find ways to improve environmental safety and improve adsorption and absorption vapor recovery units at existing sea tanker loading facilities, taking into account the current level of their technical equipment. It established that the use of the proposed desulphurization unit makes it possible to expect a reduction in energy consumption due to the absence of flow stimulators (gas blowers), as well as an increase in the operation of adsorption filters by 35-45%. The effectiveness of modeling the purification of low-pressure gas from hydrogen sulfide has been confirmed by studies on a laboratory installation including a desulfurization reactor. Purification of gas from hydrogen sulfide using a chelated iron complex ensures the conversion of hydrogen sulfide into sulfur, while the residual content of hydrogen sulfide can be reduced to less than 1 ppm. The implementation of catalytic purification by a chelated iron complex in a disk film apparatus makes it possible to purify the gas-air mixture from hydrogen sulfide impurities.

Electrical sensing of volatile organic compounds in exhaled breath for disease diagnosis

In recent years, electrical sensors toward breath volatolomics have attracted increasing interest owing to their wide feasibility in noninvasive disease diagnostics. In this article, the working principles of active nanomaterials (e.g. metal oxides, polymers, and nanocarbon) toward volatile organic compounds are presented, with a special focus on the influence of surface chemistry and structural feature of these nanomaterials on the sensing performance. The latest and representative achievements on the direct analysis of three typical exhaled volatile organic compounds, including acetone, ammonia, and hydrogen sulfide, that are recognized as important disease biomarkers, are highlighted, indicating the capability of the electrical sensors in enabling noninvasive diagnosis and real-time monitoring. The opportunities and challenges in this field are provided in the end, with an emphasis on the background interference and data recognition which are key factors in developing prospective electrical sensors toward volatolomics analysis.

Geochemical characterization of natural gases in the pre-salt section of the Santos Basin (Brazil) focused on hydrocarbons and volatile organic sulfur compounds

The objective of this work is to characterize the geochemistry of a suite of natural gas samples from five fields in order to improve the understanding of the lacustrine petroleum system of the pre-salt section from the Santos Basin (Brazil). Additionally, the distribution of volatile organic sulfur compounds (VOSC) in petroleum reservoirs was examined to investigate possible applications to petroleum systems assessments. The hydrocarbon gases were generated by thermogenic processes associated with the oil window. The 13C-enriched values for C1 (>−40‰) were interpreted as an organic source signature rather than an indication of thermal maturity, except for the oil occurrence (Field B), where a different fluid charge mainly composed of methane and CO2 from a minor external kitchen area in the Santos Basin was identified. The molecular composition and the carbon and hydrogen isotopic data of the hydrocarbon gases, when combined with the VOSC molecular compositional data, allow the identification of four gas families associated with different kitchens and/or migrations pathways. The total VOSC concentrations range from 0.7 to 23.9 ppm by volume (ppmV). The organic sulfides are mainly composed of carbonyl sulfide (COS) and diethyl sulfide. The main thiol compound is ethanethiol. The cyclic VOSC are primarily composed of thiophene, with a negligible amount of branched thiophenes (<0.1 ppmV). H2S showed a strong positive Pearson's correlation with COS and methanethiol (MeSH) concentrations (r = 0.943 and 0.807, respectively). This suggests that COS and MeSH formation was linked to H2S generation and/or post-catagenetic interactions between hydrocarbons and H2S, mainly related to thermochemical sulfate reduction (TSR). In contrast, the distribution of higher molecular weight VOSC seems to be controlled by source rock facies, rather than H2S concentration. Principal component analysis of the VOSC compositional data identified some subgroups within the gas families mainly associated with TSR. The results presented in this work reveal that VOSC can be an important auxiliary tool in petroleum system studies.

2,5-Dimercapto-1,3,4-thiadiazole/acetylene black@polypropylene separator for inhibiting the shuttle effect and electrocatalyzing electrode reactions in Li-S batteries

The dissolution and shuttle effect of lithium polysulfide (LiPS) hinder the commercial development of Li-S batteries. Anchoring LiPS and accelerating the electrochemical reaction of the S electrodes can improve the electrochemical performance of the battery. Here, a redox-activity organic sulfide poly(2,5-dimercapto-1,3,4-thiadiazole) (PDMcT)/acetylene black (AB)-modified polypropylene (PP) separator (PDMcT3/AB-PP) is reported to be a shuttle-inhibiting layer and electrocatalyst for Li-S batteries. PDMcT has a redox potential window similar to that of S. During the discharge/charge process of the Li-S battery, the S-S bond of PDMcT is broken and forms DMcT·LiSx (x = 4–8). This is helpful for anchoring LiPSs and electrocatalyzing the electrochemical conversion reaction of sulfur, which can effectively restrain the shuttle effect of LiPSs and accelerate the speed of the electrochemical reaction. The high electrolyte affinity of AB with good electronic conductivity improves the electrolyte wettability of the separator, which is conducive to the rapid transport of lithium ions and improves the rate performance of the Li-S battery. Compared with the PP (284 mAh gS−1) and AB-PP separators (617 mAh gS−1), the sulfur electrode with the PDMcT3/AB-PP separator delivers a high discharge specific capacity of 821 mAh gS−1 at 0.2 mA cm−2. With such a functional composite separator, a greatly increased specific capacity and improved cyclability are achieved for the S electrode. In lithium (or sodium) sulfur batteries, this type of compound containing a similar S-S bond structure can inhibit the shuttle effect of LiPS and adjust the kinetic behavior of the LiPS conversion reaction.

Metal speciation in sludges: a tool to evaluate risks of land application and to track heavy metal contamination in sewage network.

The agricultural spreading of dehydrated sewage sludge from urban sewage treatment plants is economically profitable provided that the soil agronomic quality and the absence of contamination, in particular of heavy metals, are maintained. We evaluated the variability of sludge between five treatment plants in northern Algeria. We determined parameters that account for their agronomic quality and total content of Ag, Cd, Co, Cr, Cu, Ni, Pb, Ti and Zn. The speciation of metals, which determines their bioavailability, was characterized by sequential extraction into five fractions: easily exchangeable, acid-soluble, bound to carbonates and Fe-sulphides, bound to Fe-Mn oxides, bound to organic matter or sulphides, residual. All the sludges analysed showed satisfactory properties for plant growth. High total Ni contents for three of the sludges indicated that they were not landfillable under French or Chinese regulations. Ni, however, was contained in poorly bioavailable fractions and therefore presented a low risk to soils. In contrast, the total Cu was lower than the regulatory limit values, but mainly contained in very bioavailable fractions whose accumulation over time could reach toxic levels for plants over a period of 3 to 11years depending on the sludges. These results showed that regulations are not adapted and must take into account the bioavailability with regard to the characteristics of the soils on which to spread. The speciation of metals in the sludge has also, on the one hand, made it possible to identify the zone of the sewerage network in which the sources of contamination must be sought and, on the other hand, has given indications on the possible nature of these sources.

Characterization of Asphalt Aging by Analytical Techniques: A Review on Progress and Perspectives

This review describes the chemical composition of asphalt, which is relevant for the development of materials with higher quality and durability. Asphalt aging can occur in the short term (during machining and storage periods) and the long-term (during the time the pavement is exposed to the environment). To understand the effect of aging on the chemical and physical properties of asphalt, we reviewed the short-term (rolling-thin film oven test (RTFOT) and its variations) and long-term (pressure aging vessel (PAV) and its variations) aging methods and the effects of the sun’s ultraviolet radiation (Suntest and its variations). We also explored the main chemical reactions that occur in the aging processes, such as oxidation, polymerization, and aromatization. For a more accurate assessment of the classes of compounds that undergo aging reactions, fractionation techniques have been developed over the years, such as separation of asphalt into saturates, naphthenic-aromatics, resins, asphaltenes, organic sulfides, nitrogenates, and oxygenates, among others. Despite several studies on the theme of asphalt aging, it is still necessary to understand the phenomena that occur in those processes.

Chemical Speciation and Leaching Behavior of Hazardous Trace Elements in Coal Combustion Products from Coal-Fired Power Stations in China.

This paper reports on the chemical speciation and leaching behavior of a selected group of hazardous trace pollutants in lignite and lignite-petcoke blend co-combustion products from three power stations in China. The evaluation of speciation results showed that, during combustion, oxidizable elements, mainly As and Mo, bound to organic matter and sulfides in coals were mostly transferred to easily water-soluble forms or to slightly acidic states in the ashes. This manner was the most readily bioavailable condition for such an environment. The evaluation of the leaching results shows that the use of petroleum coke as co-fuel has an impact on the ash composition and on the leaching behavior of some inorganic trace pollutants such as Mo and V. The leaching results compared to the European waste acceptance criteria for landfills reveal that the Mo and As’ leaching yield brand the coal combustion products as materials that necessitate preventative measures to reduce their potential leaching. Future work will be focused on the application of our novel chemical stabilization method to these coal ashes to reduce the mobility of elements such as Mo and As, and other potentially leachable elements, and on the use of the resulting ash with aggregate products as a substitute for concrete production.

Nrf2 Activation Protects Against Organic Dust and Hydrogen Sulfide Exposure Induced Epithelial Barrier Loss and K. pneumoniae Invasion.

Agriculture workers report various respiratory symptoms owing to occupational exposure to organic dust (OD) and various gases. Previously, we demonstrated that pre-exposure to hydrogen sulfide (H2S) alters the host response to OD and induces oxidative stress. Nrf2 is a master-regulator of host antioxidant response and exposures to toxicants is known to reduce Nrf2 activity. The OD exposure-induced lung inflammation is known to increase susceptibility to a secondary microbial infection. We tested the hypothesis that repeated exposure to OD or H2S leads to loss of Nrf2, loss of epithelial cell integrity and that activation of Nrf2 rescues this epithelial barrier dysfunction. Primary normal human bronchial epithelial (NHBE) cells or mouse precision cut-lung slices (PCLS) were treated with media, swine confinement facility organic dust extract (ODE) or H2S or ODE+H2S for one or five days. Cells were also pretreated with vehicle control (DMSO) or RTA-408, a Nrf2 activator. Acute exposure to H2S and ODE+H2S altered the cell morphology, decreased the viability as per the MTT assay, and reduced the Nrf2 expression as well as increased the keap1 levels in NHBE cells. Repeated exposure to ODE or H2S or ODE+H2S induced oxidative stress and cytokine production, decreased tight junction protein occludin and cytoskeletal protein ezrin expression, disrupted epithelial integrity and resulted in increased Klebsiella pneumoniae invasion. RTA-408 (pharmacological activator of Nrf2) activated Nrf2 by decreasing keap1 levels and reduced ODE+H2S-induced changes including reversing loss of barrier integrity, inflammatory cytokine production and microbial invasion in PCLS but not in NHBE cell model. We conclude that Nrf2 activation has a partial protective function against ODE and H2S.

Rapid Assessment of Meat Freshness by the Differential Sensing of Organic Sulfides Emitted during Spoilage.

In this work, we report the fabrication of a two-member fluorescence sensor array that enables the assessment of three stages (fresh, slightly spoiled, and moderately or severely spoiled) of meat spoilage. The first member of the array, which has strong chalcogen bonding and sulfur-π interactions with organic sulfides, exhibits very high sensitivity, while the second member of the array, which has weak chalcogen bonding and sulfur-π interactions with organic sulfides, exhibits lower sensitivity. On the basis of the combined fluorescence responses of the two members, three stages of meat spoilage, including fresh, slightly spoiled, and moderately or severely spoiled, can be monitored. Notably, using the volatiles collected from 5 g of meat products over a short period of time (1 min), this two-member sensor array achieves sensitive responses to the organic sulfides emitted from the meats. The capacity of this method to rapidly assess meat freshness facilitates its practical application, as illustrated by the monitoring of the freshness of chicken and pork products in the real world.

Practically Accessible All‐Solid‐State Batteries Enabled by Organosulfide Cathodes and Sulfide Electrolytes

AbstractThe combination of organic electrode materials and sulfide electrolytes is expected to enable the development of all‐solid‐state organic batteries featuring high energy density, safety, and sustainability. Here, thiuram hexasulfide is first reported as a low‐cost and high‐capacity cathode material for solid‐state organic batteries based on sulfide electrolytes. Notably, a capacity of ≈600 mA h g−1 is delivered and the capacity retention is 80.8% after 500 cycles. An electrochemically reversible change of the cathode interface is revealed upon cycling. The full cell displays an oscillating stress change of up to 0.6 MPa during cycling, predominated by the anode side. The energy density is 1140 Wh kg−1 at the material level and 376 Wh kg−1 at the electrode level, which are among the best‐reported organic cathodes to date. A high areal capacity of 10.4 mA h cm−2 is reached with a high mass loading cathode. A dry‐film approach is further explored to manufacture sheet‐type cells. The free‐standing Li6PS5Cl film with a thickness of only 48 µm demonstrates an ultralow areal resistance of 3.9 Ω cm2, which significantly boosts the cell‐level energy density and reduces the cell internal resistance.

Responses of microbial community composition and function to biochar and irrigation management and the linkage to Cr transformation in paddy soil

Combining biochar with irrigation management to alter the microbial community is a sustainable method for remediating soils contaminated by heavy metals. However, studies on how these treatments promote Cr(VI) reduction are limited, and the corresponding microbial mechanisms are unclear. Therefore, we conducted a pot experiment to explore the responses of soil microbial communities to combined biochar amendment and irrigation management strategies and their involvement in Cr transformation in paddy soils. Six treatments were established using varying concentrations of biochar (0, 1, and 2% [w/w]) combined with two irrigation management strategies (continuous flooding [CF] and dry–wet alternation [DWA]). The results showed that the combined biochar addition and irrigation management strategy significantly altered soil pH, redox potential, organic matter content, and Fe(II) and sulfide concentrations. In addition, the Cr(VI) concentration under CF irrigation management was conspicuously lower (48.2–54.4%) than that under DWA irrigation management. Biochar amendment also resulted in a substantial reduction (8.8–27.4%) in Cr(VI) concentration. Moreover, the changes in soil physicochemical properties remarkably affected the soil microbial community. The microbial diversity and abundance significantly increased with biochar amendment. Furthermore, the combined biochar amendment and CF strategy stimulated the growth of Geobacter- and Anaeromyxobacter-related Fe(III)-reducing bacteria, Gallionella-related Fe(II)-oxidizing bacteria, and Desulfovibro- and Clostridium-related sulfate-reducing bacteria, which simultaneously facilitated the generation of Fe(II) and sulfide, thereby enhancing Cr(VI) reduction. Consequently, our results suggest that the effectively increased abundance of Fe-reducing/oxidizing bacteria and sulfate-reducing bacteria via combined CF irrigation management and biochar addition may be a key factor in reducing Cr(VI) in paddy soil. The keystone genera responsible for Cr(VI) reduction were Geobacter, Anaeromyxobacter, Gallionella, Desulfovibro, and Clostridium. This study provides novel insights into the coupling mechanism of the Fe/S/Cr transformation mediated by Fe-reducing/oxidizing bacteria and sulfate-reducing bacteria.

Sustainable approaches in the catalytic synthesis of optically active and inactive diaryl sulfoxides

Sulfoxidation of organic sulfides is a straightforward method for the selective preparation of sulfoxides. Traditionally, toxic or hazardous oxidizing agents, such as toxic metal oxides and peroxides, in stoichiometric amounts were usually used for these chemical transformations. Modern trends in the greener synthesis and fabrication of inorganic, organic, and coordination compounds, materials, nanomaterials, hybrids, and nanocomposites are discussed. Greener techniques have been applied to synthesize both well-known chemical compounds by more sustainable routes and completely new materials. Hence, a wide variety of sulfenylation reactions methods have been reported recently. This review has been completed with more recent advances in the synthesis of optically active and inactive diaryl sulfoxides using fundamentally significant sulfenylation reactions because they provide an efficient and clean methodology for the synthesis of diaryl sulfoxides and heteroaryl aryl sulfoxides. The synthesis of these sulfoxides can be achieved employing three different routes: (A) via the arylation of sulfenate anions generated from aryl 2-(trimethylsilyl) ethyl sulfoxides, βsulfinyl esters, allylic sulfenate esters, the thermal fragmentation of tert-butyl sulfoxides, aryl methyl sulfoxides, benzyl aryl sulfoxides, and aryl 2-(Trimethylsilyl) ethyl sulfoxides; (B), in an interesting approach, symmetric/asymmetric diaryl sulfoxides have been prepared via the arylation of sulfinyl cation generated from sulfinic acids (salts), 1-bromovinyl p-tolyl sulfoxide, DABSO/Trimethylsilyl Chloride, and poly sulfinylpiperazine; (C), in this procedure, diaryl sulfoxides have been prepared via reaction of thiols and diazonium salts, catalyzed by both silver to generate a thiyl radical from the thiol and photoredox catalysts to form aryl radicals from the aryl diazonium salts. We begin with an overview of the sulfoxides synthesis, followed by a summary of categorized recent progress according to the reaction type. We hope this review will help to stimulate the further development of greener syntheses of diaryl sulfoxides.

Recent Advances in Catalytic Oxidation of Organic Sulfides: Applications of Metal-Ionic Liquid Catalytic Systems.

Catalytic oxidation of organic sulfides is of considerable significance in industrial chemistry and fuel industry. Therefore, numerous methods have been developed for the oxidation. Metal-containing ionic liquid-based catalysts can catalyze the selective oxidation reactions and are highly used in chemical processes, which have also been used as effective solvents, reaction media, extractants, and catalysts for the oxidation of organic sulfides including oxidative desulfurization of fuel oil. Recently, much attention is being drawn to the preparation of heterogenous catalysts based on the immobilization of metal- or nonmetal-containing ILs on diverse solid supports, which can be easily separated after the completion reaction and recycled. Therefore, there is still an increasing interest in developing new and efficient catalytic procedures for the oxidation of organic sulfides. In this review, we have outlined the recent advances in catalytic oxidation of organic sulfides including oxidative desulfurization of fuel oil. The versatilities and adaptabilities of metal–ionic liquid catalytic systems in the selective oxidation of sulfides are considered a powerful research field in these transformations.

Association and mechanism of garlic consumption with gastrointestinal cancer risk: A systematic review and meta-analysis.

Gastrointestinal cancer is one of the most commonly diagnosed cancer type worldwide, with millions of cases per year. The aim of this review was to investigate the relationship between garlic intake and the risk reduction of gastrointestinal cancer. We performed saturated data mining on various public domain databases, including PubMed (https://pubmed.ncbi.nlm.nih.gov/), Embase (https://www.embase.com/landing?status=grey), and Cochrane Library (https://www.cochranelibrary.com/), with key terms including: ‘garlic’, ‘allium’, ‘stomach’, ‘gastric’, ‘colon’, ‘neoplasms’, ‘cancer’ and ‘tumor’. Furthermore, we identified additional references through expert manual curation. Finally, a meta-analysis was conducted to determine whether garlic intake reduces the risk of gastric and/or colorectal cancer. The association between garlic intake and reduction in the risk of gastric cancer [odds ratio (OR)=0.65, 95% confidence interval (CI)=0.49-0.87, P<0.001] were clear. Nine studies on garlic intake and colorectal cancer showed that garlic reduced cancer risk with a statistical significance (OR=0.75, 95% CI=0.65-0.87, P<0.001). We summarized that four main organic sulfides in garlic, diallyl disulfide (DADS), diallyl trisulfide (DATS), S-allylmercaptocysteine (SAMC) and allicin, may contribute to the regulation of tumor cell apoptosis, migration and the cell cycle. We identified the association between garlic intake and reduced risk of gastric and colorectal cancers and hypothesized that the active ingredients in garlic may act on multiple pathways to reduce the risk of gastrointestinal tumors according to published papers. Importantly, the potential tumor-preventing effect of these garlic ingredients warrants further investigation in regards to the specific mechanism of the underlying antitumor activities.