Search

A low cost, highly sensitive sensor with easy fabrication has been successfully developed to detect variations in the concentration of sucrose solutions using a microfiber probe sensor. The microfiber probe was fabricated using a flame brushing mixture of butane and oxygen with single-mode optical fiber material and pulled on both sides to achieve a size of 16.48 µm. These microfiber probes were characterized into two sensor probe shapes: straight and u-shaped, to measure variations in the sucrose solution concentration. The results for both probe shapes showed a decrease in peak output intensity and a shift in peak wavelength as the sucrose concentration increased from 0.5% to 3%. The straight shape exhibited a sensitivity of 0.241 dBm/% with a slope linearity of 99.5% and a resolution of 0.0415%, while the U-shape had a sensitivity of 2.692 dBm/% with a slope linearity of 90.6% and a resolution of 0.0030%. The measurement spectra results indicated significant differences in u-shape at each concentration. In conclusion, both microfiber sensor probe shapes exhibited excellent performance and are suitable for use as chemical sensors to measure variations in solutions. [ABSTRACT FROM AUTHOR]

Hierarchical defect-rich UiO-66 membrane showing unprecedented CO 2 /N 2 and n -/ i -C 4 H 10 separation performances was prepared through combining hollow-structured UiO-66 seeds with epitaxial growth under single-mode microwave heating. Ultrathin-oriented selective top layer, hollow-structured bottom layer, and high missing-linker number in the framework were concurrently achieved in the membrane. [Display omitted] [ABSTRACT FROM AUTHOR]

Saturated three-dimensional carbocycles have gained increasing prominence in synthetic and medicinal chemistry. In particular, bicyclo[2.1.1]hexanes (BCHs) have been identified as the molecular replacement for benzenes. Here, we present facile access to a variety of BCHs via a stepwise two-electron formal (3 + 2) cycloaddition between silyl enol ethers and bicyclo[1.1.0]butanes (BCBs) under Lewis acid catalysis. The reaction features wide functional group tolerance for silyl enol ethers, allowing the efficient construction of two vicinal quaternary carbon centers and a silyl-protected tertiary alcohol unit in a streamlined fashion. Interestingly, the reaction with conjugated silyl dienol ethers can provide access to bicyclo[4.1.1]octanes (BCOs) equipped with silyl enol ethers that facilitate further transformation. The utilities of this methodology are demonstrated by the late-stage modification of natural products, transformations of tertiary alcohol units on bicyclo[2.1.1]hexane frameworks, and derivatization of silyl enol ethers on bicyclo[4.1.1]octanes, delivering functionalized bicycles that are traditionally inaccessible. Saturated three-dimensional carbocycles have gained increasing prominence in synthetic and medicinal chemistry. Here, the authors present facile access to a variety of bicyclo[2.1.1]hexanes via a stepwise two-electron formal (3 + 2) cycloaddition between silyl enol ethers and bicyclo[1.1.0]butanes under Lewis acid catalysis. [ABSTRACT FROM AUTHOR]

The highly strained bicyclo[1.1.0]butanes (BCBs) have exhibited excellent synthetic value and have attracted increasing attention in the field of organic synthesis. However, the mechanism of the activation of such materials under organocatalysis has been studied little. In the present study, the mechanism and origin of stereoselectivity for a chiral Brønsted acid (CBA)-catalyzed isomerization reaction of BCB were systematically investigated using the DFT method. Based on computational results, the β-H elimination step is the stereoselectivity-determining step, through which the S-configured product is generated preferentially. Furthermore, non-covalent interaction (NCI) and atom-in-molecule (AIM) analyses were performed to disclose the origin of the stereoselectivity and show the relatively many and strong noncovalent interactions to be the key for stabilizing the S-configured transition state and thus inducing the stereoselectivity. [ABSTRACT FROM AUTHOR]

We report the first mass photometric characterization of nanoaggregates of atomically precise nanoclusters (NCs) in solution. The differently-sized nanoaggregates of silver–gold alloy NCs, [Ag11−xAux(DPPB)5Cl5O2]2+ [x = 1–5 and DPPB = 1,4-bis(diphenylphosphino)butane], formed in solution, were examined by mass photometry (MP) with a protein calibration. In addition, we conducted MP studies of varying solvent composition to understand the structural evolution of nanoaggregates. The masses of nanoaggregates were correlated to structures of 15 to 50 nm diameter observed in cryo-electron microscopy. [ABSTRACT FROM AUTHOR]

n‐C4H10 and iso‐C4H10 are both important petrochemical raw materials. Considering the coexistence of the isomers in the production process, it is necessary to achieve their efficient separation through an economical way. However, to obtain high‐purity n‐C4H10 and iso‐C4H10 in one‐step separation process, developing iso‐C4H10‐exclusion adsorbents with high n‐C4H10 adsorption capacity is crucial. Herein, we report a cage‐like MOF (SIFSIX‐Cu‐TPA) with small windows and large cavities which can selectively allow smaller n‐C4H10 enter the pore and accommodate a large amount of n‐C4H10 simultaneously. Adsorption isotherms reveal that SIFSIX‐Cu‐TPA not only completely excludes iso‐C4H10 in a wide temperature range, but also exhibits a very high n‐C4H10 adsorption capacity of 94.2 cm3 g−1 at 100 kPa and 298 K, which is the highest value among iso‐C4H10‐exclusion‐type adsorbents. Breakthrough experiments show that SIFSIX‐Cu‐TPA has excellent n/iso‐C4H10 separation performance and can achieve a record‐high productivity of iso‐C4H10 (3.2 mol kg−1) with high purity (>99.95 %) as well as 3.0 mol kg−1 of n‐C4H10 (>99 %) in one separation circle. More importantly, SIFSIX‐Cu‐TPA can realize the efficient separation of butanes at different flow rates, temperatures, as well as under high humid condition, which indicates that SIFSIX‐Cu‐TPA can be deemed as an ideal platform for industrial butane isomers separation. [ABSTRACT FROM AUTHOR]

Aromatic hydrocarbons (benzene, toluene, xylene) are valuable intermediates in the chemical and petrochemical industries, so the conversion of butane into aromatics is an important catalytic process from both scientific and industrial viewpoints. In addition to the production of aromatic compounds, the production of hydrogen during aromatization of lower alkanes is also of interest. This review describes industrial processes and presents the main achievements in the field of scientific research into butane aromatization on heterogeneous catalysts over the past 15 years. Current problems and possible directions of studies on the development of catalysts for aromatization of C4 hydrocarbons are also discussed. [ABSTRACT FROM AUTHOR]

In this paper, the foam-like multi-stage porous 3wt%Al-KIT-6-4T(WI) catalyst was prepared and employed for efficient catalyzing biomass-derived GVL to butene. It is found that the prepared 3wt%Al-KIT-6-4T(WI) catalyst possess abundant mesoporous and presented the foam-like microstructure. Due to this, the 3wt%Al-KIT-6-4T(WI) catalyst has large specific surface area (517.09 m2·g−1) and adequate amount of surface acid sites (both Brønsted and Lewis acid site). The special microstructure further improves the mass transfer efficiency of reactants and products. Under the optimized reaction conditions, the butene yield over the 3wt%Al-KIT-6-4T(WI) catalyst can up to 93.78% at 300 °C, after reacting 240 min. Moreover, the 3wt%Al-KIT-6-4T(WI) catalyst still showed excellent regeneration stability, and above 72% butene yield can be maintained after 7th cycle tests. [ABSTRACT FROM AUTHOR]

Different from the Qaidam basin with about 320 billion m3 microbial gas, only limited microbial gases were found from the Junggar basin with similarly abundant type III kerogen. To determine whether microbial gases have not yet identified, natural gas samples from the Carboniferous to Cretaceous in the Junggar basin have been analyzed for chemical and stable isotope compositions. The results reveal some of the gases from the Mahu sag, Zhongguai, Luliang and Wu-Xia areas in the basin may have mixed with microbial gas leading to straight ethane to butane trends with a "dogleg" light methane in the Chung's plot. Primary microbial gas from degradation of immature sedimentary organic matter is found to occur in the Mahu sag and secondary microbial gas from biodegradation of oils and propane occurred in the Zhongguai, Luliang and Beisantai areas where the associated oils were biodegraded to produce calcites with δ13C values from + 22.10‰ to + 22.16‰ or propane was biodegraded leading to its 13C enrichment. Microbial CH4 in the Mahu sag is most likely to have migrated up from the Lower Wuerhe Formation coal-bearing strata by the end of the Triassic, and secondary microbial gas in Zhongguai and Beisantan uplifts may have generated after the reservoirs were uplifted during the period of the Middle and Late Jurassic. This study suggests widespread distribution of microbial gas and shows the potential to find large microbial gas accumulation in the basin. [ABSTRACT FROM AUTHOR]

The peak explosion pressure and maximum rate of pressure rise of explosions in confined spaces are key safety parameters to evaluate the hazard of processes running in closed vessels and to design enclosures able to withstand explosions or of their vents used as relief devices. These properties are examined in the present paper, for hydrogen-hydrocarbon-air mixtures at sub-atmospheric pressures, using propane and n -butane as test fuels and variable hydrogen ratios between 0 and 0.3. The experimental study was carried out in a sphere and a cylindrical chamber at room temperature and sub-atmospheric pressures (between 0.3 and 1.0 bar). On the basis of pressure recordings, the characteristic explosion indices, i.e., the maximum explosion pressure (p max), maximum rate of pressure rise ((dp/dt) max), deflagration index (K G), and time to peak pressure (θ max) were derived. Numerical simulations were used to determine the adiabatic explosion pressures and adiabatic flame temperatures of isochoric combustion. The effects of initial pressure (p 0), hydrogen concentration, and shape and size of the explosion vessel on explosion indices are discussed. For each hydrogen concentration of the blended fuels, linear correlations p max = f(p 0) and (dp/dt) max = f(p 0) were found. In addition, the heat loss to the walls during explosion propagation was estimated on the basis of the difference between the adiabatic and experimental explosion pressures. The amount of heat lost increases with the increase of hydrogen blending ratio and vessel asymmetry. • Hydrogen-blended propane-air and butane-air explosions were studied in two closed vessels. • The experiments were performed at various initial pressures between 0.3 and 1.0 bar. • As Hydrogen blending ratio increases, the explosion pressure, the maximum rate of pressure rise, and the severity factor increase. • The increase of hydrogen blending ratio results in the decrease of the explosion times. • The observed variations depend largely on the volume and shape of the explosion vessel. [ABSTRACT FROM AUTHOR]

Developing high-performance and low-cost protein purification materials is of great importance to meet the demands for highly purified proteins in biotechnological industries. Herein, a facile strategy was developed to design and construct high-efficiency protein absorption and separation media by combining aerogels' molding techniques and impregnation processes. Poly (ethylene-co-vinyl alcohol) (EVOH) nanofibrous aerogels (NFAs) were modified by grafting butane tetracarboxylic acid (BTCA) over them in situ. This modification was carried out using polyphosphoric acid as a catalyst. The resulting EVOH/BTCA NFAs exhibited favorable comprehensive properties. Benefiting from the highly interconnected porous structure, good underwater compressive properties, and abundant absorption ligands, the obtained EVOH/BTCA NFAs possessed a high static absorption capacity of 1082.13 mg/g to lysozyme and a short absorption equilibrium time of about 6 h. A high saturated dynamic absorption capacity for lysozyme (716.85 mg/g) was also realized solely by gravity. Furthermore, EVOH/BTCA NFAs displayed excellent reusability, good acid and alkaline resistance, and unique absorption selectivity performance. The successful synthesis of such aerogels can provide a potential candidate for next-generation protein absorbents for bio-separation and purification engineering. [ABSTRACT FROM AUTHOR]

Within a medicinal chemist's toolbox, one of the most effective strategies to improve the overall properties of a biologically active compound is bioisosteric replacement. Ever since the first example of replacing benzene with a bicyclo[1.1.1]pentane (BCP) group was published in the late 1990s,[1] the medicinal chemistry community has continually been expanding the scope of such phenyl bioisosteric replacements. Recent interest from academia has focused on novel synthetic strategies to access C(sp3)‐rich bicyclic hydrocarbons with expanded ring sizes. Herein, we summarize some of these transformations and reveal that most rely on strain releasing cycloadditions with bicyclo[1.1.0]butane (BCB) and bicyclo[2.1.0]pentane (housane). We have organized this review based on the mechanism of such strain release strategies, namely, carbene cycloadditions, energy transfer photocatalyzed cycloadditions, electron transfer catalyzed cycloadditions, and polar cycloadditions. [ABSTRACT FROM AUTHOR]

The Marplex Convention was established to prevent the manufacture of unmarked plastic explosives and stipulates that a volatile detection agent must be added at the time of manufacture. However, to-date, laboratory testing remains the internationally accepted practice for identifying and quantifying the taggants stipulated in the Convention. In this project, portable FTIR and Raman instruments were tested for their ability to detect 2,3-dimethyl-2,3-dinitrobutane (DMDNB), the chemical marker incorporated in plastic explosives that are manufactured within Australia. While both FTIR and Raman instruments detected solid DMDNB (98% purity), field analysis of plastic explosives at an Australian Defence establishment showed that both FTIR and Raman spectra were matched the relevant explosive (RDX or PETN), rather than the DMDNB taggant. For all three plastic explosives tested, the concentration of DMDNB was measured by SPME-GC-MS to be between 1.8 and 2%, greater than the minimum 1% concentration stipulated by the Marplex Convention. Additional testing with a plastic explosive analogue confirmed that the minor absorption peaks that would characterize low concentrations of DMDNB were masked by absorption bands from other compounds within the solid. Thus, while both FTIR and Raman spectroscopy are suitable for detection of plastic explosives, neither rely on the presence of DMDNB for detection. It is likely that similar results would be found for other taggants stipulated by the Marplex Convention, given they are also present in concentrations less than 1%. [ABSTRACT FROM AUTHOR]

Herein, we have synthesized multifunctionalized 2‐oxa‐3‐azabicyclo[3.1.1]heptanes, which are considered potential bioisosteres for meta‐substituted arenes, through Eu(OTf)3‐catalyzed formal dipolar [4π+2σ] cycloaddition of bicyclo[1.1.0]butanes with nitrones. This methodology represents the initial instance of fabricating bicyclo[3.1.1]heptanes adorned with multiple heteroatoms. The protocol exhibits both mild reaction conditions and a good tolerance for various functional groups. Computational density functional theory calculations support that the reaction mechanism likely involves a nucleophilic addition of nitrones to bicyclo[1.1.0]butanes, succeeded by an intramolecular cyclization. The synthetic utility of this novel protocol has been demonstrated in the concise synthesis of the analogue of Rupatadine. [ABSTRACT FROM AUTHOR]

A new iodine-rich imidazole derivative 1,4-bis(4,5-diiodo-1H-imidazol-1-yl)butane (bimbI4, 1) features multiple I⋯I interactions in the solid state. Using 1 as a precursor, we prepared 1D and 2D coordination polymers of Co(II) and Cu(I) – {[Co(bimbI4)Cl2]·1.5DMF}n (2) and {[Cu2I2(bimbI4)]}n (3), respectively, also featuring extended systems of halogen bonds within their structures. [ABSTRACT FROM AUTHOR]

Electrochemical CO2 reduction can convert CO2 to value‐added chemicals, but its selectivity toward C3+ products are very limited. One possible solution is to run the reactions in hybrid processes by coupling electrocatalysis with other catalytic routes. In this contribution, we report the cascade electrocatalytic and thermocatalytic reduction of CO2 to propionaldehyde. Using Cu(OH)2 nanowires as the precatalyst, CO2/H2O is reduced to concentrated C2H4, CO, and H2 gases in a zero‐gap membrane electrode assembly (MEA) reactor. The thermochemical hydroformylation reaction is separately investigated with a series of rhodium‐phosphine complexes. The best candidate is identified to be the one with the 1,4‐bis(diphenylphosphino)butane diphosphine ligand, which exhibits a propionaldehyde turnover number of 1148 under a mild temperature and close‐to‐atmospheric pressure. By coupling and optimizing the upstream CO2 electroreduction and downstream hydroformylation reaction, we achieve a propionaldehyde selectivity of ~38 % and a total C3 oxygenate selectivity of 44 % based on reduced CO2. These values represent a more than seven times improvement over the best prior electrochemical system alone or over two times improvement over other hybrid systems. [ABSTRACT FROM AUTHOR]

The preparation of vanadium-phosphate catalysts by Atomic Layer Deposition (ALD) was studied for application to selective oxidation of n-butane to maleic anhydride (MA). Modification of bulk V2O5 by ALD with trimethylphosphate significantly increased the selectivity to MA but the catalyst performance was still much worse than that observed for bulk vanadium phosphate (VPO). Silica-supported VPO was then prepared by ALD of P and V and compared to a VPO/SiO2 catalyst prepared by impregnation. Raman spectra showed that the ALD-prepared materials were more homogeneous, and temperature-programmed desorption of 2-propanol demonstrated that the VPO phase covered the silica more uniformly when deposited by ALD. However, the bulk VPO catalyst remained the most selective for MA. Possible reasons for why the supported catalysts showed lower performance are discussed and suggestions made for improving these catalysts. [ABSTRACT FROM AUTHOR]

Liquefied petroleum gas (LPG) is considered one of the gases widely used in many industrial and residential sectors. Still, due to its different compositions, mainly propane (C3H8) and butane (C4H10), it can have other combustion characteristics. This paper aims to conduct an experimental analysis to study the impact of LPG composition on the stability map (limits of blowoff and flashback) of the premixed flame in a tangential swirl burner. Four LPG mixtures were used with different proportions of ethane (C2H6), propane (C3H8), butane (C4H10), and pentane (C5H12). Three burner nozzles at diameters of 20, 25, and 30 mm have been used, which gave three swirl numbers of 0.918, 1.148, and 1.377, respectively. The results indicate that increasing the swirl number (S) from 0.918 to 1.377 for all LPG mixtures accelerated the flashback propensity (getting worse) while the blowoff resistance improved; thus, a rising S gave a better stability map. As for the effect of the LPG composition, it was found that the maximum flame temperature was for the LPG mixture containing high percentages of butane (C4H10), while the lowest was for the mixture containing fewer percentages of butane. Changing the LPG composition had an apparent effect on the flashback limits and a slight effect on the blowoff limits; it was found that mixtures containing high percentages of butane increased flame speeds and increased the flashback propensity. Compared to LPG mixtures, the flame stability map was widest for LPG mixtures containing lower percentages of butane. Therefore, LPG with propane (C3H8) proportions higher than butane (C4H10) reduces flame temperature, flame speeds, and flashback propensity, thus improving the stability map. [ABSTRACT FROM AUTHOR]

MFI zeolite is one of the most attractive molecular sieve materials for selective adsorption and separation of C4 hydrocarbon isomers. Grand Canonical Monte Carlo and molecular dynamics simulations were used to explore the correlation between the channel structure, adsorption thermodynamics, and kinetic behavior of butane isomers. The results of single component and binary competitive adsorption isotherms of n-butane/i-butane at 273 K, 303 K, 343 K, and 373 K showed excellent low pressure loading and adsorption selectivity for n-butane on MFI zeolite. Density distribution maps and Radial Distribution Function data revealed different preferential adsorption sites for n-butane and i-butane molecules in MFI zeolite. Because of van der Waals repulsion, the adsorption energy of i-butane is less than that of n-butane, making i-butane less apt to be adsorbed in the sinusoidal and straight channels but preferentially in the cross channel of MFI zeolite. Additionally, the mean square displacement and the calculated diffusion coefficient showed that the diffusion rate of n-butane is faster than that of i-butane by more than two orders of magnitude. These findings clarify the molecular mechanism of selective adsorption and separation of n-butane/i-butane on rationally designed MFI zeolite-based materials. [ABSTRACT FROM AUTHOR]

Real-time sensing of hydrogen sulfide (H2S) at room temperature is important to ensure the safety of humans and the environment. Four kinds of different nanocomposites, such as MXene Ti3C2Tx, Ti3AlC2, WS2, and MoSe2/NiCo2O4, were synthesized using the hydrothermal method in this paper. Initially, the intrinsic properties of the synthesized nanocomposites were studied using different techniques. P-type butane and H2S-sensing behaviors of nanocomposites were performed and analyzed deeply. Four sensor sheets were fabricated using a spin-coating method. The gas sensor was distinctly part of the chemiresistor class. The MXene Ti3C2Tx/NiCo2O4-based gas sensor detected the highest response (16) toward 10 ppm H2S at room temperature. In comparison, the sensor detected the highest response (9.8) toward 4000 ppm butane at 90 °C compared with the other three fabricated sensors (Ti3AlC2, WS2, and MoSe2/NiCo2O4). The MXene Ti3C2Tx/NiCo2O4 sensor showed excellent responses, minimum limits of detection (0.1 ppm H2S and 5 ppm butane), long-term stability, and good reproducibility compared with the other fabricated sensors. The highest sensing properties toward H2S and butane were accredited to p–p heterojunctions, higher BET surface areas, increased oxygen species, etc. These simply synthesized nanocomposites and fabricated sensors present a novel method for tracing H2S and butane at the lowest concentration to prevent different gas-exposure-related diseases. [ABSTRACT FROM AUTHOR]

In this review, the current state of affairs in the novel field of the group 14 element clusters based on the bicyclo[1.1.0]butane framework, namely, bicyclo[1.1.0]butane, [1.1.1]propellane, and tricyclo[2.1.0.02,5]pentane derivatives, are overviewed. Structural similarities and differences between these three classes of highly strained polycyclic compounds are considered from the viewpoint of the critically important nature of their bridgehead bonds. Synthetic strategies towards bicyclo[1.1.0]butanes, [1.1.1]propellanes, and tricyclo[2.1.0.02,5]pentanes, as well as their peculiar structural and bonding features, and specific reactivity, are also presented and discussed in this review. [ABSTRACT FROM AUTHOR]

The purpose of this research was to determine the technical feasibility of extracting amaranth seed oil with butane in a subcritical state and to take advantage of the cake generated. To this end, a type of non-germinated grain was characterized, oil was extracted from a germinated grain and the characterized one, the oil obtained was characterized, and the protein was extracted from the defatted cake of the non-germinated one. It was found that the non-germinated grain was made up of 13.33% protein, 7.24% fat, and 9.02% moisture, the optimum yield of this grain was 91%, for the germinated grain, a maximum value of 6.63% for oil mass. By comparing the characteristics of both oils, higher quality was found in the non-germinated oil, and the maximum protein extraction productivity was 5.15%. Thus, it has been concluded that this extraction method is technically feasible. [ABSTRACT FROM AUTHOR]

Background: Butane is present as propellant gas in deodorants, shaving foam tubes and air fresheners. In our study, potential allergic effects of chronic inhalation of butane on nasal mucosa of rats were evaluated. Objective: To discover the effects of butane gas on nasal mucosa in rats and determine its potential allergic effects. Methods: An experimental study was conducted on Wistar Albino rats. Animals were divided into two groups as experimental and control. The experimental group was exposed to butane for 100 days. Coronal slices of 5 pm thickness were taken from the nasal cavities of the animals. Eosinophils, goblet cells, lymphocytes and eosinophil exocytosis were evaluated in slices. Results: An increase was found in eosinophil counts in the experimental group (p < 0.001); between the groups, lymphocyte infiltration, amount of goblet cells and eosinophil exocytosis were similar (p > 0.05). A positive correlation was observed between lymphocyte infiltration and eosinophil exocytosis in the experimental group (p = 0.0001). Conclusion: According to our study, butane may create inflammation in nasal mucosa. [ABSTRACT FROM AUTHOR]

Polypyrrole has gained more attention in conducting polymer science due to its ease of preparation and many advantages. In this article, by chemical oxidation method, three different polypyrroles were prepared using ferric chloride as an oxidant, including surfactant and natural directing agent, and named the samples PPY-1, PPY-2, and PPY-3. XRD, XPS, EDX, FT-IR, SEM, and electrical conductivity was used to characterize the synthesized polypyrrole. XRD confirms that the prepared samples were polypyrrole by showing peaks in the range of 20°–23°. SEM analysis shows that the sizes are between 120 and 180 nm. The present research work is a modest attempt to demonstrate for the first-time detection of hazardous gas using natural directing agent during polypyrrole synthesis. The prepared samples were used for the sensing of butane. PPY-2 shows a high electrical conductivity of 14 × 10–3 S cm−1 and gas sensing with a sensitivity value of 42.03 with lesser response and recovery time. This study reveals the fabrication of low-cost materials for butane sensors. Schematic diagram for the preparation of polypyrrole and its applications. [ABSTRACT FROM AUTHOR]

Solvent inhalation is still an important public health problem that is responsible morbidity and mortality of young people worldwide and has adverse effects on society. In Turkey, solvent inhalation is the most common substance abuse following smoking and alcohol addiction, and butane and propane have been reported to be the most frequently inhaled substances. In this study, the crime scene information is presented, with the pathology and toxicology analysis results of two cases of death due to inhalation of n-butane, one as suicide and the other accidentally. Although clinical findings were described in detail in cases hospitalized due to butane gas inhalation and in death cases, the number of articles describing crime scene and autopsy findings is limited. In this case report, it is aimed to describe of the findings that they may encounter during the crime scene and death examination, especially for general practitioners and autopsy findings of cases. Consequently, it is important for the general practitioners participating in the corpse examination to be careful about the crime scene and the findings on the corpse, for accurate toxicological analyzes and accurate determination of the cause of death. These physicians should give clues to forensic experts about signs such as thinner, glue, or gas source near the corpse, a plastic bag placed on the head of the corpse, vomit stains near the corpse or on their clothing.

Deep eutectic solvents (DESs) are now considered a new class of ionic liquid analogs that have been generously used in various fields. Herein, vanadium phosphorus oxide (VPO) catalysts are synthesized in combination with a deep eutectic solvent containing rare earth metal (rEDES), and their catalytic performance in n-butane selective oxidation to produce maleic anhydride (MA) is evaluated. The rE-DES is produced from the interaction of choline chloride (ChCl) and rare earth metal salts (Cerium, Europium, Lanthanum, and Samarium metal salt) (ChCl:rE = 1:0.5-1:3) under mild conditions. It was found that DESs served as structural modifiers and electronic promoters during VPO synthesis. It regulated the chemical state of the catalyst surface, such as the vanadium valence state, acid-base properties, and ratios of V4+/V5+, Lat--O/Sur--O and P/V. Various characterization techniques, such as FT-IR, DSC, XRD, SEM, EDS, TEM, Raman, TGA, NH3-TPD, and XPS, were used to examine its physical and chemical characteristics. These characteristics were correlated with the catalytic performance. The VPO catalyst modified by rE-DES showed a significant enhancement of n-butane conversion and MA selectivity while suppressing the selectivity of CO and CO2 as well as the CO/CO2 ratio compared to the unpromoted VPO catalyst. Especially for Ce-DES-VPO, it increased the n-butane conversion and MA mass yield up to approximately 11% and 10%, respectively. In addition, we evaluated the catalytic performance under different activation atmospheres. [ABSTRACT FROM AUTHOR]

Herein, we develop a new approach to directly access architecturally complex polycyclic indolines from readily available indoles and bicyclo[1.1.0]butanes (BCBs) through formal cycloaddition promoted by commercially available Lewis acids. The reaction proceeded through a stepwise pathway involving a nucleophilic addition of indoles to BCBs followed by an intramolecular Mannich reaction to form rigid indoline‐fused polycyclic structures, which resemble polycyclic indole alkaloids. This new reaction tolerated a wide range of indoles and BCBs, thereby allowing the one‐step construction of various rigid indoline polycycles containing up to four contiguous quaternary carbon centers. [ABSTRACT FROM AUTHOR]

Gas sensing is a critical research area in aerospace, military, medical, and industrial environments, as it helps prevent risks to human health and the environment caused by toxic gases. Propane and butane, commonly used as fuels in household and industrial settings, are toxic and flammable gases that need to be effectively detected to avoid leakage or explosion accidents. To address this, nanomaterial-based gas sensors are being developed with low power consumption and operating temperatures. In this study, two-dimensional nitrogenated holey graphene (C2N) based sensors are used for the first time for the identification of butane and propane gases. The sensor consists of two C2N electrodes connected via a C2N channel. The C2N sensor design was enhanced by replacing the C2N electrodes with gold electrodes and adding a gate terminal under the channel. The resistive method is employed to detect butane and propane gases by measuring the variation in the electrical conductivity of the sensor due to exposure to these target molecules. To investigate the electronic transport properties, such as transmission spectra, density of states and current, first principles simulations of the C2N-based sensors is conducted using Quantumwise Atomistix Toolkit (ATK). The detection method relies on the alteration of the FET's electrical current at specific gate voltages due to the presence of these gases. This proposed sensor offers the potential for small size and low-cost gas sensing applications. The designed sensor aims to effectively detect propane and butane gases. By leveraging the unique properties of C2N and utilizing advanced simulation tools, this sensor could provide high sensitivity and accuracy in detecting propane and butane gases. Such an advancement in gas sensing technology holds significant promise for ensuring safety in various environments. [ABSTRACT FROM AUTHOR]

Position-specific (PS) carbon isotope compositions of light hydrocarbons such as propane and butane isomers (n-butane and i-butane) can provide a wealth of information on the history of natural gases in the subsurface reservoirs and other environments. For PS carbon isotope analysis of butane isomers, we have established a GC-pyrolysis-GC-isotope ratio mass spectrometry method with demonstrated accuracy. With this method, we analyzed PS δ13C values of butane isomers generated from the systematic laboratory pyrolysis experiments of three different kerogen types (I, II, and III) at temperatures of 310–430 °C with corresponding thermal maturity (Easy %R o) ranging from 0.7 to 3.3. The observed evolution in the abundances of butane isomers can be interpreted and semi-quantitatively modeled based on the abundances of different C C bonds within the kerogens at low maturity and thermal degradation of butane isomers at high maturity. The δ13C values at the central sites of both nC 4 and iC 4 were heavier than those at the terminal positions, similar to our previous observations of propane. Their isotopic evolution with the maturity were controlled largely by kinetic isotope effects associated with breaking of different C C bonds during the generation and degradation of butane isomers. Kinetic Monte Carlo (kMC) simulations of n-butane generated from thermal cracking of model kerogens (I, II, and III) and an oil with a series of reactions (homolytic cleavage, β-scission, radical isomerization, H-abstraction, and termination by radical recombination) provided generally consistent results with the experimental observations, although the difference in PS δ13C values between the central and terminal positions are somewhat overestimated. On the other hand, the kMC simulation with homolytic cleavage and capping reactions alone produced significant deviations from the experimental results. Re-assessment of very limited data of PS δ13C values of natural butanes with our experimental and simulation results show that biodegradation significantly increased δ13C values at the central positions, not only of propane, but also of both butane isomers. This study lays a foundation and demonstrates the potential of PS isotope geochemistry of butane isomers to further improve our understanding of the sources, and geochemical and microbial processes of light hydrocarbons in the subsurface and other natural environments. [ABSTRACT FROM AUTHOR]

Multi element compound-specific stable isotope analysis (ME-CSIA) is a tool to assess (bio)chemical reactions of molecules in the environment based on their isotopic fingerprints. To that effect, ME-CSIA concepts are initially developed with laboratory model experiments to determine the isotope fractionation factors specific for distinct (bio)chemical reactions. Here, we determined for the first time the carbon and hydrogen isotope fractionation factors for the monooxygenation of the short-chain alkanes ethane, propane, and butane. As model organism we used Thauera butanivorans strain Bu-B1211 which employs a non-haem iron monooxygenase (butane monooxygenase) to activate alkanes. Monooxygenation of alkanes was associated with strong carbon and hydrogen isotope effects: εbulkC = -2.95 ± 0.5 ‰ for ethane, -2.68 ± 0.1 ‰ for propane, -1.19 ± 0.18 ‰ for butane; εbulkH = -56.3 ± 15 ‰ for ethane, -40.5 ± 2.3 ‰ for propane, -14.6 ± 3.6 ‰ for butane. This resulted in lambda (Λ ≈ εHbulk/εCbulk) values of 16.2 ± 3.7 for ethane, 13.2 ± 0.7 for propane, and 11.4 ± 2.8 for butane. The results show that ME-CSIA can be used to track the occurrence and impact of monooxygenase-dependent aerobic processes converting short-chain alkanes in natural settings like marine and terrestrial seeps, gas reservoirs, and other geological formations impacted by natural gas. [ABSTRACT FROM AUTHOR]

The article describes the methods of modification of glass fibers, threads and composite materials made of glass fibers. In the work, the twisted glass thread and electrically insulating glass tape were investigated. Plasma treatment was used to modify the threads. Plasma type is nonequilibrium, low temperature; type of discharge—radio-frequency capacitive. The aim of the work is to study the strength properties of yarns and tapes, before and after treatment in low-temperature plasma.The plasma modification of the threads in the argon/propane-butane and propane-butane gases medium at 4 kV has been found to increase the breaking load strength of glass threads up to 23%.The subsequent treatment of the tapes in the propane butane medium increases the strength to 5%. [ABSTRACT FROM AUTHOR]

Copyright of Van Tip Dergisi is the property of Yuzuncu Yil University, Faculty of Medicine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

During high-temperature pulse pyrolysis of acyclic butanes and pentanes under adiabatic compression conditions, cyclopropane, a stressed cyclic hydrocarbon, was found among the reaction products in small quantities for the first time. The analysis of the reaction products was performed by gas chromatography using three capillary columns of different polarity, selectivity and sufficient efficiency. The identification of reaction products, including cyclopropane, was performed using retention times of individual substances and model mixtures, as well as comparing chromatograms with reference chromatograms from the literature and the ScanView Application Database. It was shown that the chromatographic peak attributed to cyclopropane could not be a ghost peak. Additional confirmation of this conclusion was obtained in a series of experiments on the pyrolysis of n-butane at a reduced initial temperature of the adiabatic compression reactor (from 120 °C to 50 °C) and a modified mode of GC analysis. Cyclopropane yields as a function of maximum temperature have a bell-shaped asymmetric dependence. The maximum value of the yield of cyclopropane increases with the transition from normal alkanes to isoalkanes, and from pentanes to butanes; for n-pentane, 0.009 wt. %, and for isobutene, ≈0.017 wt. %. During the pulse pyrolysis of isobutane, n-butane, isopentane and n-pentane, cyclopropane is not a primary product. Further theoretical and experimental studies are needed to establish the mechanism of cyclopropane formation during pyrolysis of C4–C5 acyclic alkanes.