Methyl Formate Research Articles

The effect of flue gas contaminants on electrochemical reduction of CO2 to methyl formate in a dual methanol/water electrolysis system

CO 2 electroreduction to value-added products has promise as a scalable technique for mitigating climate change, but CO 2 purification requirements raise the overall process cost. Direct reduction of flue gas is thus an attractive approach, but the sensitivity of the catalyst activity to flue gas contaminants and increased hydrogen evolution with diluted CO 2 have been major challenges. Herein, flue gas electroreduction in a methyl formate synthesis route has been investigated on a Pb-catalyzed electrode in acidic methanol catholyte with an aqueous anolyte for promotion of a sustainable water oxidation half-reaction. Contaminant concentrations of 50 ppm SO 2 and NO each had a minimal effect on the product faradaic efficiencies, whereas 4% O 2 led to a notable improvement in partial current density for methyl formate attributed to the improved durability of the catalyst surface oxide. Decreased CO 2 concentration showed a corresponding decline in current density attributed to CO 2 mass transfer limitations. • Study of the effects of flue gas contaminants and CO 2 concentration • Pb-catalyzed methyl formate production from CO 2 and methanol • High-performance tolerance to SO 2 and NO impurities • Improved performance with dilute O 2 Increasing atmospheric CO 2 is contributing to anthropogenic climate change. Industrial utilization of CO 2 can add economic value to this waste product and provide a route to decreased greenhouse gas emissions. Direct electroreduction of post-combustion flue gas would bypass expensive and energy-intensive carbon capture technologies and improve the overall economics of the process. However, the contaminants in flue gas and the lower partial pressure of CO 2 can deleteriously affect the electrolyzer performance. Herein, the influence of flue gas components and combined simulated flue gas feedstock on the electrochemical reduction of CO 2 in a methyl formate synthesis route has been investigated on a Pb-catalyzed cathode in acidic methanol in conjunction with water at the anode for a sustainable reaction. The results show promise for a viable route to produce a chemical not reported in aqueous CO 2 electroreduction directly from the output of a fossil fuel utility or similar industrial process. The feasibility of electrochemical reduction of waste carbon dioxide from industrial flue gas was investigated in an uncommon methanol/water dual electrolyte approach targeting a methyl formate product. The work demonstrates a pathway to produce a chemical not formed in aqueous CO 2 reduction that is largely compatible with direct operation from flue gas.

Effect of exogenous and endogenous sulfide on the production and the export of methylmercury by sulfate-reducing bacteria.

Mercury (Hg) is a global pollutant of environmental and health concern; its methylated form, methylmercury (MeHg), is a potent neurotoxin. Sulfur-containing molecules play a role in MeHg production by microorganisms. While sulfides are considered to limit Hg methylation, sulfate and cysteine were shown to favor this process. However, these two forms can be endogenously converted by microorganisms into sulfide. Here, we explore the effect of sulfide (produced by the cell or supplied exogenously) on Hg methylation. For this purpose, Pseudodesulfovibrio hydrargyri BerOc1 was cultivated in non-sulfidogenic conditions with addition of cysteine and sulfide as well as in sulfidogenic conditions. We report that Hg methylation depends on sulfide concentration in the culture and the sulfides produced by cysteine degradation or sulfate reduction could affect the Hg methylation pattern. Hg methylation was independent of hgcA expression. Interestingly, MeHg production was maximal at 0.1-0.5mM of sulfides. Besides, a strong positive correlation between MeHg in the extracellular medium and the increase of sulfide concentrations was observed, suggesting a facilitated MeHg export with sulfide and/or higher desorption from the cell. We suggest that sulfides (exogenous or endogenous) play a key role in controlling mercury methylation and should be considered when investigating the impact of Hg in natural environments.

Infrared intensities of methyl acetate, an interstellar compound - comparisons of three organic esters

The mid-infrared (IR) spectra of the simplest aliphatic esters have been studied in the past in the solid, liquid, and gas phases with an emphasis on vibrational frequencies and peak assignments. However, relatively little has been published on the IR intensities of the amorphous forms of these compounds. These IR intensities are of particular interest to the astrochemical community as they are needed to help quantify laboratory measurements of the formation and destruction of extraterrestrial molecules, including esters. Here we report and compare IR intensities of three organic esters: methyl formate, methyl acetate, and methyl propionate, all studied with the same equipment and procedures. Of these three esters, our main interest is with methyl acetate, for which little quantitative IR work is available. For each ester, we report apparent absorption coefficients and band strengths, and compare them to earlier work. We also have calculated the first IR optical constants for both amorphous and crystalline methyl acetate. We use our new results to measure vapor pressures and a sublimation enthalpy for methyl acetate and to comment on a radiation-chemical experiment with methyl acetate and how it can be better quantified.

Size and Methylation Index of Cell-Free and Cell-Surface-Bound DNA in Blood of Breast Cancer Patients in the Contest of Liquid Biopsy.

Aberrantly methylated circulating DNA (cirDNA) has proven to be a good cancer marker, but its detection is limited by low concentrations, fragmentation, and insufficiency. Since the methylated cirDNA was shown to be more stable in circulation than the unmethylated one and was shown to bind with the blood cell surface, we studied the concentration, representation, and fragmentation of tumor-derived methylated DNA in cell-free and cell-surface-associated DNA. We found that long DNA fragments (more than 10 kb) are mainly associated with the surface of blood cells. However, in plasma short DNA fragments (100–1000 bp) were also found along with long DNA fragments. Isolation of short fragments after separation of cirDNA in 6% PAGE followed by quantitative PCR (L1 element) has shown that short DNA fragments in healthy females represent 22% versus 0.5–4.4% in breast cancer patients. The methylated form of the RARβ2 gene was detected only in long DNA fragments by Real-time TaqMan PCR of bisulfite-converted DNA. The methylation index of cirDNA from healthy women was estimated at 0%, 9%, and 7% in plasma, PBS-EDTA, and trypsin eluates from the surface of blood cells, respectively. The methylation index of breast cancer patients’ DNA was found to be 33%, 15%, and 61% in the same fractions confirming the overrepresentation of methylated DNA in csbDNA.

Effects of ethanol and methyl formate additions on characteristics of pre-vaporised palm methyl ester laminar diffusion flame

Motivated by the growing interest in the application of renewable fuels and combustion efficiency, gaining a detailed understanding of the effect of oxygenated additives on the structure and shape of the biodiesel laminar coflow diffusion flame is of fundamental and practical importance. In the experiment, the amount of ethanol and methyl formate in the nitrogen-diluted biodiesel mixtures was 10% vol. while maintaining a constant fuel mole fraction. The results showed that adding ethanol and methyl formate decreased the flame height regardless of the variation of the fuel jet velocities, with methyl formate demonstrating a greater reduction effect on the flame height. Besides that, the addition of these oxygenated additives has a significant influence on the flame stability, which was characterised by the parameters such as liftoff height, liftoff velocity, and blowout velocity. The oxygenated additives addition reduced the flame stability limit, with methyl formate showing a greater decrease in flame stability limit based on the observation of the blowout velocity. The dilution effect of the oxygenated additives was identified as the dominant effect on the flame structure and stabilisation through the decoupling analysis when compared to the thermal and chemical effects. Further analysis revealed that the difference in the influence of the oxygenated additives on the combustion characteristics was attributed to the physicochemical properties of the fuel mixtures, such as the molecular diffusivity, energy density, and fuel decomposition. These parameters can be fundamentally related to the difference in the molecular structures between ethanol and methyl formate. On the other hand, the addition of these oxygenated additives decreased both carbon monoxide and nitrogen oxide concentrations; however, the differences in the pollutant concentrations between ethanol and methyl formate were insignificant.

Electrolyte-Layer-Tunable ATR-SEIRAS for Simultaneous Detection of Adsorbed and Dissolved Species in Electrochemistry.

A balanced detection of both adsorbates and dissolved species is very important for the clarification of the electrochemical reaction mechanism yet remains a major challenge for different modes of electrochemical infrared (IR) spectroscopy. Among others, conventional attenuated total reflection-surface-enhanced IR absorption spectroscopy (ATR-SEIRAS) is far less sensitive to low-concentration solution species than to surface species. We report herein an electrochemical wide-frequency ATR-SEIRAS with a novel thin-layer flow cell design, fulfilling the simultaneous detection of the variations of surface and solution species. This setup consists of a silicon wafer (with one side micromachined and the other side metallized), a thin-layer electrolyte structure with tunable thickness and flow rate, and a tilt-correction system based on laser collimation, enabling a well-controlled mass transport within the electrolyte layer and the spectral differentiation of solution species from adsorbates. Using acidic methanol oxidation on a Pt film electrode as a model system, besides SEIRA bands for adsorbed CO and formate intermediates, IR spectral signals for dissolved products CO2, formic acid, and methyl formate can be readily identified for a quiescent electrolyte layer of ∼20 μm, which are otherwise undetected with conventional ATR-SEIRAS, as indicated by the trend of spectral features with increasing thickness or flow rate.

FAUST

Aims. Methanol is a ubiquitous species commonly found in the molecular interstellar medium. It is also a crucial seed species for the build-up of chemical complexity in star forming regions. Thus, understanding how its abundance evolves during the star formation process and whether it enriches the emerging planetary system is of paramount importance. Methods. We used new data from the ALMA Large Program FAUST (Fifty AU STudy of the chemistry in the disc/envelope system of solar protostars) to study the methanol line emission towards the [BHB2007] 11 protobinary system (sources A and B), where a complex structure of filaments connecting the two sources with a larger circumbinary disc has previously been detected. Results. Twelve methanol lines have been detected with upper energies in the [45–537] K range along with one 13CH3OH transition and one methyl formate (CH3OCHO) line blended with one of the methanol transitions. The methanol emission is compact (FWHM ~ 0.5″) and encompasses both protostars, which are separated by only 0.2″ (28 au). In addition, the overall methanol line emission presents three velocity components, which are not spatially resolved by our observations. Nonetheless, a detailed analysis of the spatial origin of these three components suggests that they are associated with three different spatial regions, with two of them close to 11B and the third one associated with 11A. A radiative transfer analysis of the methanol lines gives a kinetic temperature of [100–140] K, an H2 volume density of 106–107 cm−3 and column density of a few 1018 cm−2 in all three components with a source size of ~0.15″. Thus, this hot and dense gas is highly enriched in methanol with an abundance as high as 10−5. Using previous continuum data, we show that dust opacity can potentially completely absorb the methanol line emission from the two binary objects. Conclusions. Although we cannot firmly exclude other possibilities, we suggest that the detected hot methanol is resulting from the shocked gas from the incoming filaments streaming towards [BHB2007] 11A and B, respectively. Higher spatial resolution observations are necessary to confirm this hypothesis.

Ice Age: Chemodynamical Modeling of Cha-MMS1 to Predict New Solid-phase Species for Detection with JWST

Chemical models and experiments indicate that interstellar dust grains and their ice mantles play an important role in the production of complex organic molecules (COMs). To date, the most complex solid-phase molecule detected with certainty in the interstellar medium is methanol, but the James Webb Space Telescope (JWST) may be able to identify still larger organic species. In this study, we use a coupled chemodynamical model to predict new candidate species for JWST detection toward the young star-forming core Cha-MMS1, combining the gas–grain chemical kinetic code MAGICKAL with a 1D radiative hydrodynamics simulation using Athena++. With this model, the relative abundances of the main ice constituents with respect to water toward the core center match well with typical observational values, providing a firm basis to explore the ice chemistry. Six oxygen-bearing COMs (ethanol, dimethyl ether, acetaldehyde, methyl formate, methoxy methanol, and acetic acid), as well as formic acid, show abundances as high as, or exceeding, 0.01% with respect to water ice. Based on the modeled ice composition, the infrared spectrum is synthesized to diagnose the detectability of the new ice species. The contribution of COMs to IR absorption bands is minor compared to the main ice constituents, and the identification of COM ice toward the core center of Cha-MMS1 with the JWST NIRCAM/Wide Field Slitless Spectroscopy (2.4–5.0 μm) may be unlikely. However, MIRI observations (5–28 μm) toward COM-rich environments where solid-phase COM abundances exceed 1% with respect to the column density of water ice might reveal the distinctive ice features of COMs.

Cover Feature: A “Power‐to‐X” Route to Acetic Acid via Palladium‐Catalyzed Isomerization of Methyl Formate (ChemSusChem 16/2022)

Cover Feature: A “Power‐to‐X” Route to Acetic Acid via Palladium‐Catalyzed Isomerization of Methyl Formate (ChemSusChem 16/2022)

Impacts of Forest Fire Ash on Aquatic Mercury Cycling.

Mercury (Hg) is a ubiquitous contaminant in the environment and its methylated form, methylmercury (MeHg), poses a worldwide health concern for humans and wildlife, primarily through fish consumption. Global production of forest fire ash, derived from wildfires and prescribed burns, is rapidly increasing due to a warming climate, but their interactions with aqueous and sedimentary Hg are poorly understood. Herein, we compared the differences of wildfire ash with activated carbon and biochar on the sorption of aqueous inorganic Hg and sedimentary Hg methylation. Sorption of aqueous inorganic Hg was greatest for wildfire ash materials (up to 0.21 μg g-1 or 2.2 μg g-1 C) among all of the solid sorbents evaluated. A similar Hg adsorption mechanism for activated carbon, biochar made of walnut, and wildfire ash was found that involves the formation of complexes between Hg and oxygen-containing functional groups, especially the -COO group. Notably, increasing dissolved organic matter from 2.4 to 70 mg C L-1 remarkably reduced Hg sorption (up to 40% reduction) and increased the time required to reach Hg-sorbent pseudo-equilibrium. Surprisingly, biochar and wildfire ash, but not activated carbon, stimulated MeHg production during anoxic sediment incubation, possibly due to the release of labile organic matter. Overall, our study indicates that while wildfire ash can sequester aqueous Hg, the leaching of its labile organic matter may promote production of toxic MeHg in anoxic sediments, which has an important implication for potential MeHg contamination in downstream aquatic ecosystems after wildfires.

Laminar flame propagation of acetone and 2-butanone at normal to high pressures: Insight into fuel molecular structure effects of ketones

This work reports an experimental and kinetic modeling investigation on the laminar flame propagation of acetone and 2-butanone at normal to high pressures. The experiments were performed in a high-pressure constant-volume cylindrical combustion vessel at 1–10 atm, 423 K and equivalence ratios of 0.7–1.5. A kinetic model of acetone and 2-butanone combustion was developed from our recent pentanone model [Li et al., Proc. Combust. Inst. 38 (2021) 2135–2142] and validated against experimental data in this work and in literature. Together with our recently reported data of 3-pentanone, remarkable fuel molecular structure effects were observed in the laminar flame propagation of the three C3C5 ketones. The laminar burning velocity increases in the order of acetone, 2-butanone and 3-pentanone, while the pressure effects in laminar burning velocity reduces in the same order. Modeling analysis was performed to provide insight into the key pathways in flames of acetone and 2-butanone. The differences in radical pools are concluded to be responsible for the observed fuel molecular structure effects on laminar burning velocity. The favored formation of methyl in acetone flames inhibits its reactivity and leads to the slowest laminar flame propagation, while the easiest formation of ethyl in 3-pentanone flames results in the highest reactivity and fastest laminar flame propagation. Furthermore, the LBVs of acetone and 3-pentanone exhibit the strongest and weakest pressure effects respectively, which can be attributed to the influence of fuel molecular structures through two crucial pressure-dependent reactions CH3 + H (+M) = CH4 (+M) and C2H4 + H (+M) = C2H5 (+M).

A "Power-to-X" Route to Acetic Acid via Palladium-Catalyzed Isomerization of Methyl Formate.

The synthesis of acetic acid by formal isomerization of methyl formate (MF) was investigated using molecular catalysts. The base‐catalyzed decarbonylation of MF, yielding CO and methanol in situ, was integrated with their palladium‐catalyzed recombination for the synthesis of acetic acid and methyl acetate in a one pot reaction. The complex [Pd(Cl)2(dppe)] [dppe=1,2‐bis(diphenylphosphino)‐ethane] in combination with NaI as iodide source and NaOMe as base were identified as promising molecular components to enable the overall conversion. Sequential application of the statistical methods design of experiments and simplex optimization was used in combination with thermodynamic analysis of the competing reaction pathways for experimental planning and data analysis. Starting from a proof‐of‐principle with a turnover number (TON) of 11, the catalytic system could thus be optimized to allow quantitative conversion of MF with a TON of 43000, whereby a yield of 83 % of acetate groups and a yield of 74 % for free acetic acid was obtained.

Effects of the m6Am methyltransferase PCIF1 on cell proliferation and survival in gliomas

BackgroundPrevious studies have suggested an important role for N6-methyladenosine (m6A) modification in the proliferation of glioma cells. N6, 2′-O-dimethyladenosine (m6Am) is another methylated form affecting the fate and function of most RNA. PCIF1 has recently been identified as the sole m6Am methyltransferase in mammalian mRNA. However, it remains unknown about the role of PCIF1 in the growth and survival of glioma cells. MethodsWe constructed glioma cell lines that stably downregulated/upregulated PCIF1, established intracranial xenograft models using these cell lines, and employed the following methods for investigations: CCK-8, EdU, colony formation, flow cytometry, qRT-PCR, Western blot, and immunohistochemistry. FindingsDownregulating PCIF1 promoted glioma cell proliferation, while overexpressing PCIF1 showed the opposite effects. Overexpression of PCIF1 blocked cell cycle progression and induced apoptosis in glioma cells, which was further confirmed by alterations in the expression of cell checkpoint proteins and apoptotic markers. Interestingly, disruption of PCIF1 methyltransferase activity slightly reversed the effect of PCIF1 overexpression on cell proliferation, but had no significant reversal effects on cell cycle progression or apoptosis. Knockdown of PCIF1 promoted the growth of gliomas, while overexpressing PCIF1 inhibited tumor growth and prolonged the survival time of tumor-bearing mice. In addition, the mRNA and protein levels of PCIF1 were gradually decreased with the increase of WHO grade in glioma tissues, but there was no significant correlation with patient survival. InterpretationThese results indicated that PCIF1 played a suppressing role in glioma growth and survival, which may not entirely depend on its methyltransferase activity.

Electrochemical contributions: Adolph Wilhelm Hermann Kolbe (1818–1884)

Hermann Kolbe (Figure 1) was a German scientist who greatly contributed to the development of organic chemistry, transforming it to the state as we know it now. Kolbe pioneered organic synthesis from inorganic sources and introduced the term “synthesis” in the meaning how we use it in chemistry now. His name is associated with several synthetic reactions in organic chemistry, e.g., the Kolbe-Schmitt reaction in the preparation of aspirin, the Kolbe nitrile synthesis, etc. His work is particularly remembered in connection to electrolysis of carboxylic acids resulting in the synthesis of various organic compounds, known as the Kolbe reaction. The Kolbe reaction (Figure 2), proceeding as the electrolysis, results in the oxidative decarboxylation of carboxylic acids yielding free radicals, which dimerize producing symmetrical products. For example, the Kolbe electrolysis process can proceed in an aqueous solution of sodium acetate (Figure 2). The acetate ions get decomposed and form methyl radicals. These combine with other free methyl radicals, which leads to the generation of ethane. In general, Kolbe's electrolysis method uses sodium salts of fatty acids to form the corresponding alkanes as products (D. Klüh, W. Waldmüller, M. Gaderer, Clean. Technol. 2021, 3, 1–18). A similar electrochemical synthesis can be used to produce more sophisticated products (Figure 2B). If the initial mixture includes two different acids, the reaction results in three different products from the cross-reaction of two different free radicals. The Kolbe electrolytic decarboxylation of 1,2-dicarboxylic acids results in the formation of double or triple chemical bonds (Figure 3). When carboxylic groups are located at a longer distance in a molecule, the electrolytic decarboxylation may result in the intramolecular radical cyclization of the reaction product. It should be noted that the Kolbe electrolysis reaction may result in the formation of numerous byproducts (Figure 4). The formation of side products depends on the ease of the follow-up oxidation, which leads to carbenium ions, and their subsequent rearrangements. The exact mechanism and kinetics study of the electrochemical Kolbe process have been investigated confirming the complexity of the electrochemical reaction (A.K. Vijh, B.E. Conway, Chem. Rev. 1967, 67, 6, 623-664). The author declares no conflict of interest.

Electrochemical Reduction of Flue Gas CO2 in a Dual Methanol/Water Electrolysis System for the Synthesis of Methyl Formate

The conversion of waste CO2 to value-added chemicals through electrochemical reduction is a promising technology for mitigating climate change while simultaneously providing economic opportunities. The use of the nonaqueous solvent methanol allows for higher CO2 solubility and novel products through the incorporation of methanol as an intermediate. In this work, the electrochemistry of CO2 reduction in acidic methanol catholyte at a Pb working electrode was investigated while using a separate aqueous anolyte to promote a sustainable water oxidation half-reaction. The selectivity among methyl formate (a product unique to reduction of CO2 in methanol), formic acid, and formate was critically dependent on the catholyte pH, with a faradaic efficiency for methyl formate as high as 75% measured in pH < 2. Tests with simulated flue gas as the feedstock have shown a high level of tolerance for the Pb-catalyzed electrolysis to SO2, NO, and dilute O2 contaminants.

Comparative evaluation of the effect of L-Arginine and L-Homoarginine supplementation on reproductive physiology in ewes

L-Arginine (LA) is a well-known amino acid involved in vital physiological processes. However, the physiological function of its methylated form known as L-Homoarginine (LHA), is not well understood. The aim of this study was to study the comparative effects of LA and LHA treatment on selected metabolites and parameters of reproductive physiology in non-pregnant ewes. Twelve Deccani ewes were selected and randomly distributed into 3 groups: Control, LA treated group and LHA group. Blood samples were collected for the evaluation of blood indices and hormone levels. Overall, nitrite, ovary weight, surface follicle number, estrogen, insulin like growth factor-1 (IGF-1), vascular endothelial growth factor (VEGF) showed an increase in the LA and LHA treated animals. On the other side, the levels of progesterone, inteleukin-1 beta (IL-1β), IL-6, tumor necrosis factor-alpha (TNF-α) were found to be decreased in LA and LHA group. Ovary size was not affected by LA and LHA treatment groups. In comparison with LA, the ovary weight, surface follicle number, estrogen levels and IL-6 expression were higher in LHA treated animals. The expression of VEGF indicated improved angiogenesis in the treated animals. Further, the expression of heat shock protein-27 (HSP-27) and HSP-70 were differentially modulated by LA and LHA. This data reinforces the beneficial role of LA and its metabolites LHA on the ovarian physiology and functionality and also reveals the potent role of LHA as an alternative to LA treatment in enhancing the reproductive ability in non-pregnant ewes.

FAUST VI. VLA1623−2417 B: a new laboratory for astrochemistry around protostars on 50 au scale

ABSTRACT The ALMA (Atacama Large Millimeter Array) interferometer, with its unprecedented combination of high sensitivity and high angular resolution, allows for (sub-)mm wavelength mapping of protostellar systems at Solar system scales. Astrochemistry has benefitted from imaging interstellar complex organic molecules in these jet–disc systems. Here, we report the first detection of methanol (CH3OH) and methyl formate (HCOOCH3) emission towards the triple protostellar system VLA1623−2417 A1+A2+B, obtained in the context of the ALMA Large Programme FAUST (Fifty AU STudy of the chemistry in the disc/envelope system of solar-like protostars). Compact methanol emission is detected in lines from Eu = 45 K up to 61 K and 537 K towards components A1 and B, respectively. Large velocity gradient analysis of the CH3OH lines towards VLA1623−2417 B indicates a size of 0.11–0.34 arcsec (14–45 au), a column density $N_{\rm CH_3OH}$ = 1016–1017 cm−2, kinetic temperature ≥ 170 K, and volume density ≥ 108 cm−3. A local thermodynamic equilibrium approach is used for VLA1623−2417 A1, given the limited Eu range, and yields Trot ≤ 135 K. The methanol emission around both VLA1623−2417 A1 and B shows velocity gradients along the main axis of each disc. Although the axial geometry of the two discs is similar, the observed velocity gradients are reversed. The CH3OH spectra from B show two broad (4–5 km s−1) peaks, which are red- and blueshifted by ∼ 6–7 km s−1 from the systemic velocity. Assuming a chemically enriched ring within the accretion disc, close to the centrifugal barrier, its radius is calculated to be 33 au. The methanol spectra towards A1 are somewhat narrower (∼ 4 km s−1), implying a radius of 12–24 au.

Probing the pyrolysis of methyl formate in the dilute gas phase by synchrotron radiation and theory

AbstractThe thermal dissociation of the atmospheric constituent methyl formate was probed by coupling pyrolysis with imaging photoelectron photoion coincidence spectroscopy (iPEPICO) using synchrotron VUV radiation at the Swiss Light Source (SLS). iPEPICO allows threshold photoelectron spectra to be obtained for pyrolysis products, distinguishing isomers and separating ionic and neutral dissociation pathways. In this work, the pyrolysis products of dilute methyl formate, CH3OC(O)H, were elucidated to be CH3OH + CO, 2 CH2O and CH4 + CO2 as in part distinct from the dissociation of the radical cation (CH3OH+• + CO and CH2OH+ + HCO). Density functional theory, CCSD(T), and CBS‐QB3 calculations were used to describe the experimentally observed reaction mechanisms, and the thermal decomposition kinetics and the competition between the reaction channels are addressed in a statistical model. One result of the theoretical model is that CH2O formation was predicted to come directly from methyl formate at temperatures below 1200 K, while above 1800 K, it is formed primarily from the thermal decomposition of methanol.

Destruction of dimethyl ether and methyl formate by collisions with He+ (Corrigendum)

Destruction of dimethyl ether and methyl formate by collisions with He⁺ <i>(Corrigendum)</i>

Methylene-tetrahydrofolate reductase gene C677T and A1298C polymorphisms as a risk factor for Crimean-Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever (CCHF) is a deadly viral disease. Methylene-tetrahydrofolate reductase (MTHFR) has an important role in folate metabolism, and also in the formation of new cells, DNA synthesis, repair and methylation. We aimed to examine the relationship between MTHFR gene C677T (Ala222Val, rs1801133) and A1298C (Glu429Ala, rs1801131) polymorphisms with CCHF in a Turkish population. Totally 273 participants were included in the current study. One hundred forty-one participants were CCHF patients and one hundred thirty-two participants were healthy controls. The polymerase chain reaction (PCR) and further restriction fragment length polymorphism (RFLP) assays were applied to determine the genotypes of MTHFR polymorphisms. We did not find any differences between the CCHF patients and healthy controls in terms of allele and genotype distributions of both the C677T and A1298C polymorphisms. In composite genotype analysis between different groups, the frequency of CT-AA composite genotype, which is formed by C677T-A1298C polymorphisms, was found to be significantly higher in Mild CCHF patients compared to both Severe CCHF patients and controls (p = 0.036 and p = 0.008, respectively). In conclusion, in this study, we found a relationship between CCHF and MTHFR gene polymorphisms. CT-AA composite genotype of MTHFR gene C677T and A1298C polymorphisms showed a predisposition to Mild CCHF.