Ethanethiol Research Articles

Highly efficient adsorption of ethyl mercaptan on hierarchical porous carbon derived from rice husk

In this work, rice husk-derived hierarchical porous carbon (HPC) was developed as a high-performance adsorbent for ethyl mercaptan removal. Various characterization methods were used to comprehensively characterize the HPC adsorbent. HPC-2 exhibited an adsorption capacity of 118.1 mg/g for ethyl mercaptan at 500 ppm and a space velocity of 12000 h−1, outperforming similar materials reported previously. The high adsorption capacity was attributed to the material’s well-developed microporosity and the abundance of hydroxyl groups (–OH) on its surface, facilitating the chemisorption of ethyl mercaptan. Given the chemically adsorbed nature of sulfur compounds, N2 thermal regeneration was insufficient to fully recover the adsorbent’s performance. However, oxidative regeneration using O2/N2 (3/97 v/v) at 250 °C successfully removed these compounds and restored desulfurization efficiency, likely due to oxygen-assisted reactions on the adsorbent surface. This study provides valuable insights for effectively treating sulfur-containing odorous gases in the air.

Applied Investigation of Methyl, Ethyl, Propyl, and Butyl Mercaptan as Potential Poisons in the Gas Phase Polymerization Reaction of Propylene.

The polypropylene (PP) synthesis process is crucial in the plastics industry, requiring precise control as it directly impacts the catalytic activity and the final product's performance. This study investigates the effects of trace amounts of four different mercaptans on the polymerization of propylene using a fourth-generation Ziegler-Natta (ZN) catalyst. Various concentrations of these mercaptans were tested, and results showed that their presence significantly reduced the melt flow index (MFI) of the final PP. The most notable MFI decrease occurred at 37.17 ppm of propyl mercaptan and 52.60 ppm of butyl mercaptan. Methyl and ethyl mercaptan also reduced the MFI at lower concentrations, indicating that mercaptans act as inhibitors by slowing down the polymerization process and reducing the fluidity of molten PP. The highest MFI increase was observed at lower concentrations of each mercaptan, suggesting that smaller molecular inhibitors require less concentration. This trend was also seen in the catalyst's productivity, where lower concentrations of methyl mercaptan reduced PP production more effectively than higher concentrations of butyl mercaptan. Fourier transform infrared spectroscopy (FTIR) identified interactions between the mercaptans and the ZN catalyst. Computational analysis further supported these findings, providing insights into the molecular interactions and suggesting possible inhibition mechanisms that could impact the final properties of polypropylene.

Abiotic Production of Dimethyl Sulfide, Carbonyl Sulfide, and Other Organosulfur Gases via Photochemistry: Implications for Biosignatures and Metabolic Potential

Among the atmospheric gases that have been proposed as possible biosignatures in exoplanetary atmospheres, organosulfur gases are currently considered one of the more robust indicators of extant life. These gases include dimethyl sulfide (DMS; CH3SCH3), carbonyl sulfide (OCS), and carbon disulfide (CS2), which are predominantly secondary metabolic products of living organisms on Earth. Here we present results that challenge this interpretation and provide constraints on the robustness of organosulfur gases as biosignatures. Through laboratory photochemical experiments, we show the abiotic production of organosulfur gases, including DMS, OCS, methane thiol (CH3SH), ethane thiol (C2H5SH), CS2, and ethyl methyl sulfide (CH3CH2SCH3) via photochemistry in analog atmospheres. Gas-phase products of H2S/CH4/N2 haze photochemistry, with or without CO2, were collected and analyzed using gas chromatography equipped with sulfur chemiluminescence detection. Depending on the starting conditions, we estimate that DMS, OCS, CH3SH, CH3CH2SH, CS2, and CH3CH2SCH3 are produced in mixing ratios >10−1 ppmv. We further demonstrate that as the mixing ratio of CO2 increases, so does the relative importance of OCS compared to DMS. Although our results constrain the robustness of common organosulfur gases as biosignatures, the presence of these compounds may serve as an indicator of metabolic potential on exoplanets.

Mercaptans in malodorants break disulfide bridges in human serum albumin and form adducts suitable as biomarkers of exposure in vitro.

Malodorants comprise notoriously smelling mercaptans and might be applied for crowd control. Because exposure to malodorants may lead to irritation of the respiratory system, choking, and coma, bioanalytical verification of poisoning might be required in a medical and forensic context. We herein present the detection and identification of novel biomarkers of exposure to ethyl mercaptan, n-butyl mercaptan, tert-butyl mercaptan, and iso-amyl mercaptan. These alkyl thiol compounds were found to form disulfide adducts in human serum albumin (HSA) in plasma in vitro with the only non-disulfide-bridged Cys34 residue and with other residues being part of the disulfide-bridged pattern in HSA. After proteinase K-catalyzed proteolysis, adducts of all mercaptans were detected simultaneously as the tripeptide Cys34*ProPhe and the dipeptides Cys369*Tyr, ValCys316*, and Cysx*Ala (x denominates either Positions 91, 200, 253, 361, and/or 448) by a sensitive micro-liquid chromatography-electrospray ionization tandem mass spectrometry (μLC-ESI MS/MS) method working in the scheduled multiple reaction monitoring (sMRM) mode. Time- and concentration-dependent adduct formations while exposure and proteolysis were investigated and the suitability of adducts as biomarkers of exposure was elaborated. Adducts at Cys34 showed the lowest limits of identification (LOIs, 6nM to 1.2μM mercaptan in plasma) and superior stability in plasma at 37°C. Therefore, Cys34*ProPhe appears as the most promising target to prove exposure to mercaptans at least in vitro.

Oxidation Performance During Adsorption of Ethyl Mercaptan by Ag-MnO2 Nanosheets

Oxidation Performance During Adsorption of Ethyl Mercaptan by Ag-MnO2 Nanosheets

Synchronous catalytic elimination of malodorous mercaptans based VOCs: Controlling byproducts and revealing sites-pathway relationship

Controlling byproducts and unveiling “sites-pathway” relationship during synchronous catalytic degradation of sulfur-containing VOCs mixtures remains a huge challenge due to their variability, multi-components and multiple-sites characteristics. This work proposes the competitive adsorption combined with bifunctional catalysts as a strategy to avoid malodorous sulfur-containing byproducts. Experimental and theoretical researches demonstrated that ceria incorporated ZSM-5 was a bifunctional material with the coupled, but geometrically separated oxygen site and acid site, while praseodymium-incorporated one was a dual acid site catalyst. A “sites-pathway” relationship for decomposing a mixture of methyl mercaptan (CH3SH) and ethyl mercaptan (C2H5SH) was revealed, i.e., C2H5SH occupies preferentially on acid site, whereas CH3SH is converted into intermediate of CH3SCH3 over acid site, and then CH3SCH3 is forced to occupy on oxygen site, which accelerates the oxidation of CH3SCH3 to CO2. This work provides mechanistic understanding of “sites-pathway” relationship to control toxic byproducts for simultaneous catalytic degradation of sulfur-containing VOCs mixtures.

Disulfide-adducts with cysteine residues in human serum albumin prove exposure to malodorous mercaptans in vitro

Malodorants are mixtures containing mercaptans, which trigger the flight instinct upon exposure and might thus be deployed in military and civilian defense scenarios. Exposure to mercaptans might lead to unconsciousness, thus representing a possible threat for health. Therefore, we developed and validated a bioanalytical procedure for the simultaneous detection and identification of corresponding biomarkers for the verification of exposure to mercaptans. Disulfide-adducts of ethyl mercaptan (SEt), n-butyl mercaptan (SnBu), tert-butyl mercaptan (StBu) and iso-amyl mercaptan (SiAm) with cysteine (Cys) residues in human serum albumin (HSA) were formed by in vitro incubation of human plasma. After pronase-catalyzed proteolysis, reaction products were identified as adducts of the single amino acid Cys and the dipeptide cysteine-proline (Cys34Pro) detected by a sensitive μLC-ESI MS/MS method working in the scheduled multiple reaction monitoring (sMRM) mode. Dose-response studies showed linearity for the yield of Cys34Pro-adducts in the range from 6 nM to 300 μM of mercaptans in plasma and limits of identification (LOI) were in the range from 60 nM to 6 μM. Cys34-adducts showed stability for at least 6 days in plasma (37 °C). The presented disulfide-biomarkers expand the spectrum for bioanalytical verification procedures and might be helpful to prove exposure to malodorants.

Adsorption behavior and mechanism of ethyl mercaptan in natural gas on Cu-modified hexaniobate nanotubes

The presence of sulfur compounds in natural gas seriously affects the yield of hydrogen production from natural gas reforming and the lifespan of catalysts. This study aims to clarify the characteristics and mechanism of the removal of ethyl mercaptan (EM) in equilibrium CH4 by Cu-modified hexaniobate nanotubes (Cu-HNT-450), which was synthesized through a method of copper ions exchange-flocculation-calculation. The EM breakthrough adsorption experiments and the valence state of copper and the types of sulfur on Cu-HNT-450 during dynamic tests were investigated. The removal of EM is mainly achieved through the chemical adsorption of CuO, Cu2O and oxygen on Cu-HNT-450. In the process of EM removal, catalytic oxidation, sulfonate formation and reactive adsorption lead to the formation of sulfide, copper sulfonate and copper thiolate, respectively. Cu-HNT-450 has the highest breakthrough adsorption capacity for EM, reaching 103.6 mg/g at 50 °C. The exhausted Cu-HNT-450 can also be regenerated by thermal treatment at different temperatures under nitrogen atmosphere. However, due to the strong chemical adsorption of sulfur containing compounds, the recovery of nitrogen thermal regeneration removal efficiency is limited. This research work provides guidance for the design of mercaptans removal catalysts and deepens the understanding of the reaction mechanism of mercaptans removal.

Experimental Study on the Adsorption of Sulfide on Stainless Steel Surface

This work characterized the microstructure of stainless steel before and after adsorption. At the same time, the adsorption experiments at different temperatures and the adsorption characteristic experiment were carried out. The results show that chemical adsorption has taken place on the surface of stainless steel. The change of temperature has little effect on the functional groups of the stainless-steel surface after adsorption. Hydrogen sulfide showed the largest adsorption capacity and fastest rate, while methyl and ethyl mercaptan performed second. Carbonyl sulfide exhibited the smallest adsorption capacity and slowest rate.

Selective deep desulfurization of liquefied petroleum gas on Ni/ZnO-based catalyst

Process of selective deep desulfurization of liquefied petroleum gas (LPG) was developed using a Ni/ZnO-based catalyst. Ethyl mercaptan, dimethyl disulfide and methyl disulfide were used as model compounds in LPG to investigate sulfides conversion over different catalysts. All three model sulfides were totally removed over the composite catalyst at above 300 °C in hydrogen atmosphere. Desulfurization of LPG from FCC unit were studied in a micro-fixed bed reactor, and scaled up in a fixed-fluidized bed reactor. Results showed that highly selective desulfurization of LPG could be achieved using the composite catalyst when the sulfur loading of catalyst was in a particular range. The sulfur content of LPG could be decreased to lower than 2.0 μg·g−1 with an olefin loss ratio of less than 1.5 %. X-ray photoelectron spectroscopy (XPS) characterization indicated that the interaction of Ni with S strengthened with the increasing of sulfur loading. Density functional theory calculations showed that the pre-coated S on Ni (111) surface increased the adsorption energy difference between propylene and sulfides which was helpful for the retention of propylene during desulfurization on Ni/ZnO-based catalyst.

Влияние различных типов поверхностно-активных веществ на эмиссию газов и микробиоту жидкой фракции навозных стоков

Various surfactants are widely used in modern industrial animal husbandry. As part of detergents and pharmacological veterinary preparations, surfactants inevitably fall into manure effluents (ME), resulting in a change in the properties of ME. The study of the effect of various types of surfactants on the gas release and microbiota of the liquid fraction (LF) of ME was carried out on the example of surfactants with different biocidal activity: sodium laureth sulfate – anionactive surfactant (AS), lauryldimethylamine oxide – nonionic surfactant (NS) and benzalkonium chloride – cationic surfactant (CS). The studies were conducted under laboratory conditions. The total observation time since the introduction of additives in the LF (0,01 g per 1 liter) was 14 days. The obtained data shows changes in the dynamics of greenhouse gases (CH4 and CO2) and odor-forming substances (H2S, NH3, RSH) emission, as well as in the composition of the microbiota of biofilms and bacterioplankton, under the influence of surfactants. The dynamics of the CH4 emission differ from those of other gases. The use of CS leads to a gradual increase in CH4 emission a week after application. This may be due to increased permeability of the cytoplasmic membranes of methanogenic archaea with increased chemical resistance. The application of various types of surfactants into the LF has different effects on the dynamics of the odor-forming substances emission, and the active emission period of mercaptans becomes longer. The highest level of ethyl mercaptan was observed in the option with NS. There was no significant difference in the effect of low concentrations of various surfactants on the microbiota of LF, however the AS has a more pronounced bacteriostatic effect on set of indicators. The most tolerant to the effects of all types of surfactants were Clostridia, which dominates the microbiota biofilms and bacterioplankton. Fungi were the second most abundant in biofilms of the LF.

An ultra-long stability of lanthanum (La) modified molecular sieve for catalytic degradation of typical sulfur-containing VOCs in a near-real environment

The catalytic degradation of typical sulfur-containing VOCs, ethyl mercaptan (C2H5SH), in a near-real environment remains a challenge task. In this study, an ultra-long stability of 600 h for degradation of C2H5SH was obtained over La doped ZSM-5, and the corresponding catalytic performance, reaction and deactivation mechanism were investigated by a series of ex situ and in situ characterizations. Furthermore, the influence law of other low-carbon mercaptans, such as methyl mercaptan (CH3SH), propyl mercaptan (C3H7SH), and butyl mercaptan (C4H9SH) as well as the moisture on their stability were investigated. The slight deactivation by designed experiment revealed a distinguished reversible moisture-induced deactivation mechanism, where moisture promoted the formation of carbonate related species that covers the active sites, while this deactivation could be recovered by a simple temperature-lifting strategy. This work provides a theoretical guidance for catalytic degradation of mixed sulfur-containing VOCs under the presence of moisture.

Portable chemical detection platform for on-site monitoring of odorant levels in natural gas

The adequate odorization of natural gas is critical to identify gas leaks and to reduce accidents. To ensure odorization, natural gas utility companies collect samples to be processed at core facilities or a trained human technician smells a diluted natural gas sample. In this work, we report a detection platform that addresses the lack of mobile solutions capable of providing quantitative analysis of mercaptans, a class of compounds used to odorize natural gas. Detailed description of the platform hardware and software components is provided. Designed to be portable, the platform hardware facilitates extraction of mercaptans from natural gas, separation of individual mercaptan species, and quantification of odorant concentration, with results reported at point-of-sampling. The software was developed to accommodate skilled users as well as minimally trained operators. Detection and quantification of six commonly used mercaptan compounds (ethyl mercaptan, dimethyl sulfide, n-propylmercaptan, isopropyl mercaptan, tert‑butyl mercaptan, and tetrahydrothiophene) at typical odorizing concentrations of 0.1–5 ppm was performed using the device. We demonstrate the potential of this technology to ensure natural gas odorizing concentrations throughout distribution systems.

Insight into the poisoning effects and mechanisms of CH3SH, CH3CH2SH, CH3SCH3, and CH3CH2SCH2CH3 on Pt/C catalysts in fuel cell HOR

Trace amounts of sulphion can threaten the performance and lifespan of proton exchange membrane fuel cells (PEMFCs). The fuel mainly originates from refinery hydrogen, in which methyl mercaptan (MeSH), ethyl mercaptan (EtSH), dimethyl sulfide (DMS) and ethyl sulfide (EMS) inevitably exist. Herein, their negative effects are investigated on PEMFC and rotating disk electrode (RDE) levels, and the poisoning mechanisms are revealed by structural characterizations and density functional theory (DFT) calculations. The result indicates that MeSH and EtSH are 1.6 times more threatening than H2S, therefore, it is essential to limit the content of MeSH and EtSH. Nevertheless, the poisoning effect of DMS and EMS is weak enough to be tolerated. Moreover, the findings that the occupation of top site on Pt (111) weakly affects the hydrogen oxidation reaction (HOR) would contribute to the design of new catalysts with stronger toxicity resistance. This work is significant for the durability improvement of PEMFCs.

Identifying the environmental hotspots of sulfur-free odorant for LPG storage and filling by life cycle approach

The main objective of this study is to determine the potential environmental impact of storage and filling the liquefied petroleum gas (LPG) with sulfur-containing (ethyl mercaptan) and sulfur-free (Greenodor) odorants by comparative life cycle assessment (LCA). The LCA was carried out within the scope of ISO 14040 and 14044 Standards in a facility that stores and fills LPG and potential environmental impact was calculated for eleven different impact categories. According to the characterization results, it was determined that the overseas transportation process had the highest impact among all impact categories. Because environmental impact was suppressed by other processes in characterization results due to the very low inclusion of the odorants in LPG, the percentage contribution of consumption of both odorants was compared and it was revealed that Greenodor had a lower environmental impact in all mid-point impact categories. For both tanker and cylinder filling, the impact category with the highest difference was photochemical oxidation with a rate of 79 %. The lowest difference was found in the global warming impact category with 18 % for tanker filling and 19 % for cylinder filling. Considering uncertainty analysis results for LPG tanker filling, Greenodor preceded ethyl mercaptan for all mid-point categories. However, in terms of LPG cylinder filling, there was no significant difference between two odorants.

Adsorption performance of calcined coal gangue for ethyl mercaptan

ABSTRACT The modified coal gangue with different structures were used as the adsorbents which were prepared via the calcination process with the different temperature, time and atmosphere. The calcined coal gangues were characterized by XRD, FT-IR, TGA, SEM-Mapping, EDS, nitrogen adsorption-desorption isotherms and XPS. The adsorption performance of calcined coal gangue was evaluated via the adsorption of ethyl mercaptan in methane gas. The results show that the internal structures of coal gangue are affected by the calcination temperature and calcination time. The main components in the coal gangue are changed from kaolin to amorphous metakaolin, and the adsorption activity of coal gangue is greatly improved. The carbon content, especially the content of functional groups C-O and C=O in the coal gangue is changed in the difference of calcination atmosphere. When the calcination temperature, time and air content are set at 600°C, 3 h and 0.1 respectively, the breakthrough adsorption capacity of calcined coal gangue for ethyl mercaptan is 39.32 mg·g−1. The coal gangue modified by a simple calcination method has strong adsorption desulfurization performance and this is a typical example of treating waste by waste.

Formation of a P162- Ink from Elemental Red Phosphorus in a Thiol-Amine Mixture.

A P162- polyphosphide dianion ink was produced by the reaction of red phosphorus with a binary thiol-amine mixture of ethanethiol (ET) and ethylenediamine (en). The polyphosphide was identified by solution 31P NMR spectroscopy and electrospray ionization mass spectrometry. This solute was compared to the reaction products of white phosphorus (P4) and other elemental pnictides in the same solvent system. The reaction of P4 with ET and en gives the same P162- polyphosphide; however, the easier handling and lower reactivity of red phosphorus highlights the novelty of that reaction. Elemental arsenic and antimony both give mononuclear pnictogen-sulfide-thiolate complexes upon reaction with ET and en under otherwise identical conditions, with this difference likely resulting from the greater covalency and tendency of phosphorus to form P-P bonds.

Construction, formation mechanism and adsorption properties for ethyl mercaptan of H2Nb4O11 nanotubes

Designing an efficient adsorbent for removal mercaptans is of great importance to the purification of natural gas. Low-dimensional protonated nanomaterials with abundant surface hydroxyl and Brønsted acid (BA) sites have been the promising candidates for the adsorption desulfurization. Herein, a novel niobate nanotubes, H2Nb4O11 nanotubes (HNO-NTs), were constructed through a two-step intercalation strategy following freeze drying under vacuum as highly active solid acid adsorbents. The formation mechanism and textural features of the as-prepared HNO-NTs were investigated. The resulted HNO-NTs are more regular than H4Nb6O17 nanotubes, and the specific surface area of the former (ca. 222.6 m2 g−1) is higher than that of the latter (174.0 m2 g−1). The dynamic adsorption experiments shown that HNO-NTs have a high ethyl mercaptan (EM) adsorptive capacity of 52.27 mg∙g−1 with a gas hourly space velocity (GHSV) of 6000 h−1, which is greatly improved compare with that of H4Nb6O17 nanotubes (26.84 mg∙g−1). Moreover, the regenerated HNO-NTs still maintained an excellent performance after ten adsorption-desorption cycles. Finally, the possible mechanism of the adsorption of EM over HNO-NTs was proposed. This work is expected to provide a new strategy to synthesize polyniobate nanotubes and use as adsorption separation.

ZnTi‐LDH Nanosheets Prepared Solvothermically in Ethylene Glycol Studied for their Adsorption Performance towards Ethyl Mercaptan**

AbstractEthyl mercaptan (Et‐SH) is a common sulfide in natural gas. It is toxic and can cause equipment corrosion and catalyst poisoning, which needs to be properly handled. In present paper, Zn−Ti layered double hydroxide and its nanosheets were prepared by hydrothermal method and solvothermal method using ethylene glycol (EG) as a reaction medium, respectively. The desulfurization capabilities of the as‐prepared samples were evaluated through the adsorption of Et‐SH from methane gas. The results show that the desulfurization performance of the samples prepared by solvothermal method is significantly elevated comparing that of sample prepared by hydrothermal method. The washing solvent in the post‐treatment of the samples obtained by solvothermal method has great influence on its desulfurization performance. Density Functional Theory (DFT) calculations indicate that the H atom of hydroxyl group on the surface of nanosheet is the main active site for adsorption of Et‐SH. The strong hybridization between S 3p orbitals and H 1s orbitals promote the formation of S⋅⋅⋅H bond.

Experimental study on removal of mercaptans from gas streams by 1-butyl-3-methyl-imidazolyl alanine

Mercaptans as volatile organic sulfur compounds would cause environmental pollution. Researches are focused on the removal of mercaptans by solvent absorption method. In this work, a new efficient absorbent of 1-butyl-3-methylimidazolyl alanine ([Bmim]Ala) was prepared and evaluated by the removal of mercaptans from the model gas containing methyl mercaptan (MeSH, 307.6 mg/m3), ethyl mercaptan (EtSH, 201.1 mg/m3) and propyl mercaptan (PrSH, 149.9 mg/m3) in nitrogen. The results showed that the removal rate of MeSH, EtSH and PrSH was 97.77, 98.12 and 100.00%, respectively, at a temperature of 35 °C and a pressure of 1.00 bar for 2 min. After 6 recycling times, [Bmim]Ala remained a good performance for the removal of mercaptans. The desulfurization mechanism was proposed that the absorption sites were mainly on the alanine anion (Ala−) and Ala− could be replaced by the thiol anion (RS−) to form a new ionic liquid 1-butyl-3-methylimidazolyl thiolate ([Bmim]+RS−). Meanwhile, since the electrostatic interaction between -COO− in Ala− and H-g on the imidazolium cation could be destroyed by the -SH group, the -COO− group would interact with mercaptans to form a strong H-bond. The amino in Ala− and the -SH group could form Lewis acid-base compounds.