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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]

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]

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]

High energy consumption and low thermal efficiency are the main problems associated with convection hot air dryers. The effect of various energy sources on tomato drying in a convective dryer was performed. In particular, drying experiments were performed on a convection dryer at two types of heat energy sources, electric and butane-gas, air velocity 1.0, 1.5, and 2 m/s, and air temperature 40, 50, and 60 °C. The rising temperature from 40 to 60 °C caused a reduction of the drying period by 24.8, 22.1, and 21.5% at 1.0, 1.5, and 2.0 m/s, respectively. Minimum energy consumption of 3.83 kW.h was recorded using the electrically heated system while minimizing energy consumption of 0.82 kW.h was detected for the convection gas dryer at 60 °C and 1.0 m/s. The lowest SEC was recorded at 17.44 kWh/kg using gas dryers, while a maximum SEC (112.05 kWh/kg) was observed at the electric dryer under 60 °C and 2.0 m/s. The gas dryer had a thermal efficiency ranging from 50.32 to 78.77%, while the electrically heated dryer had a thermal efficiency ranging from 34.86 to 50.34%. Moreover, applying the butane gas as a heat source for drying had various advantages over the conventional electric system, such as less overall energy consumption with more effectiveness under all conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Butane separation performance of industrial-scale monolithic silicalite-1 membranes was reported for the first time. • Separation performance was affected by test parameters and concentration polarization. • The extent of concentration polarization was quantified by CPI. • Correlation of CPI and separation performance of membrane was done for prediction. • Membrane area of monolithic membrane is 10 times higher than that of tubular one. Developing an energy-saving membrane technology is important for the separation of hydrocarbon isomers. For the first time, separation performance of large-size 19-channel monolithic silicalite-1 membranes and the correlation of the performance with concentration polarization index were reported for separating industrial n-/i- butane (n-/i- C4) mixtures. The effective membrane area of each element was up to 0.1 square meters. Four membranes showed average n- C4 permeance and n-/i -C4 separation factor of (3.8 ± 0.1) × 10-8 mol/(m2 s Pa) and 27.5 ± 0.58 at 333 K, respectively. The impact of operating parameters and concentration polarization on separation performance of the typical monolithic membrane were investigated. Two solutions were proposed to reduce the influence of concentration polarization. The correlation of separation performance and concentration polarization can be used for performance prediction. The large-size silicalite-1 membranes exhibited long-term stability in the separation of butane isomers. [ABSTRACT FROM AUTHOR]

The sequential extraction of spent coffee grounds (SCG) oil by compressed propane and butane (CPE and CBE) followed by the extraction of phenolic compounds by supercritical CO 2 (scCO 2) plus solvent was studied. Extraction with CPE and CBE at different conditions of pressure (2 – 10 MPa), temperature (40 – 80 ˚C), particle size (0.356 and 0.867 mm), static extraction time (0, 10, 30 and 60 min), dynamic extraction time (25 and 60 min) and solvent flow rate (1, 2 and 3 g/min) reached the maximum extraction yield around 11.5 wt%, and with similar overall extraction curves. The second step of extraction with scCO 2 +EtOH (2:1) increased the recovery of phenolics (expressed as GAE, gallic acid equivalent) from 0.9 mg GAE/g SCG (single-step extraction scCO 2 +EtOH (2:1) to 3.88 mg GAE/g SCG (second step of sequential extraction). The results showed the technical feasibility of the extraction of oil and phenolic extracts by the studied approach. [Display omitted] • The sequential extractions produced high extraction yields from SGC. • Compressed propane and butane efficiently extracted neutral lipids SGC. • Extracts obtained with polar solvents presented high TPC. • The findings indicated SGC as a biorefinery platform. [ABSTRACT FROM AUTHOR]

[Display omitted] • Microscopic mechanism of phase transition difference of butane isomers is revealed. • Effect mechanism of kerogen and quartz on butane phase behavior is clarified. • Critical pore size of confinement effect on n-butane critical property is quantified. • Adsorption dynamic and thermodynamic characteristics of butane are elucidated. • Coupling interaction of butane structure and nanoporous structure is elaborated. Phase behavior of light hydrocarbon isomers in nanoscale pores of shale reservoirs differs from that in the bulk state, and its microscopic characteristics and molecular mechanisms remain to be clarified. This study employs the grand canonical Monte Carlo method to simulate the phase behavior of butane isomers in shale nanopores, and discusses the impacts of nanopore size and shale components. By coupling the molecular structure of butane with the structural characteristics of shale nanopores, the shift in the critical properties of butane isomers is elucidated, and the microscopic mechanisms by which nanoconfinement effects influence the phase behavior of butane is revealed. The results show that the confinement effect can reduce the critical temperature of butane by 17 % and the critical pressure by 82 %. When the slit size reaches 16 nm and 22 nm, respectively, the critical temperature and pressure of n-butane are essentially the same as in bulk. Compared to kerogen, the potential energy and physical density of the n-butane adsorption layer on the quartz wall are stronger, leading to a greater shift in the critical properties of the confined n-butane. Compared to n-butane, isobutane is more accessible to the internal and surface micropores of the kerogen matrix due to its smaller molecular size, which results in a greater confinement effect of isobutane by the kerogen. The results of this work improve the understanding of the phase transition behavior of confined fluids in nanoporous media. [ABSTRACT FROM AUTHOR]

Farmed large yellow croaker fish have stronger fishy smell and less tender texture than wild-caught ones, mostly caused by the high fat accumulation from aquaculture feeding patterns. To improve the commercial value of fillets, this study investigated a mild subcritical fluid treatment with subcritical butane (SBE) and dimethyl ether (SDME). Changes in the chemical compositions, volatile flavor compounds (VFCs) and protein denaturation were determined for 1–5 h treatments. The results showed 24 % and 44 % defatting levels under SBE and SDME treatment, respectively. GC-MS showed that SDME could induce a significant reduction of total VFC content, especially for the dominant aldehydes. There was less n-nonanal (14.65–40.13 mg/kg) and octanal content (1.67–7.21 mg/kg), no detection of trans, trans-2,4-decadienal in the SDME treated samples in comparison to those treated with SBE. The results showed that SDME treatment for 3 h had the best defatting effect, good deodorization effect and less degradation of fish protein. [Display omitted] • Subcritical fluids (dimethyl ether and butane) could reduce the fat content of fish by up to 44 %. • Subcritical dimethyl ether (SDME) exhibited both lipid and water removal from materials. • Dominant fishy volatile flavor compounds (VFCs) were suppressed over processing times. • SDME induced lower muscle protein denaturation than the use of subcritical butane. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dew points of hydrogen-rich binary mixtures were measured with low uncertainty. • Hydrogen can affect pressure measurement devices, thus increasing uncertainty. • Detailed comparisons with the GERG-2008 equation of state are presented. • New experimental results significantly improve the current data situation. • Data will help improve thermodynamic calculations for decarbonizing gas grids. Dew-point measurements were performed for hydrogen-rich binary mixtures with hydrocarbon mole fractions of 0.09995 C 3 H 8 , 0.1499 C 3 H 8 , 0.0513 n -C 4 H 10, and 0.09888 n -C 4 H 10 using a modified microwave re-entrant cavity apparatus. Isochoric measurements were conducted in the temperature range of (256 to 286) K with pressures up to 6.8 MPa and 2.0 MPa for mixtures containing propane and n -butane, respectively. The combined expanded uncertainties (k = 2) in dew-point temperature and pressure were estimated to be between (0.35 and 2.0) K and (0.0011 and 0.030) MPa. The agreement with predictions of the GERG-2008 equation of state is within 5.5%. However, better agreement with predicted values was achieved using a cubic equation recently developed in-house. Moreover, experiments with short- and long-term exposure of pressure sensors to hydrogen have shown that pressure measurement, and thus the uncertainty, can be affected; further investigation on this matter is therefore inevitable to improve hydrogen thermophysical property data. [ABSTRACT FROM AUTHOR]

An isolated cyanide-bridged {FeIII 2 FeII} n one-dimensional double-zigzag chain {[Fe(Tp)(CN) 3 ] 2 Fe(btb)} n (Tp = hydrotris(pyrazolyl)borate, btb = 1,4-(1H-1,2,4-triazole)butane) has been synthesized via hydrothermal reaction. Single-crystal X-ray data, magnetic measurement, and infrared (IR) absorption spectra indicate that this complex exhibits thermal and light induced spin transition behavior in the Fe(II) sites. [Display omitted] • A cyanide-bridged {FeIII 2 FeII} n 1D double-zigzag chain has been synthesised. • This complex exhibits thermal induced spin transition in the Fe(II) sites. • Light-induced excited spin-state trapping of this complex was also observed at low temperature. A cyanide-bridged {FeIII 2 FeII} n one-dimensional chain {[Fe(Tp)(CN) 3 ] 2 Fe(btb)} n (1) (Tp = hydrotris(pyrazolyl)borate, btb = 1,4-(1H-1,2,4-triazole)butane) has been synthesized via the hydrothermal reaction of Li[Fe(Tp)(CN) 3 ], btb, and FeII(ClO 4) 2 ·6H 2 O at 120 °C. Single-crystal X-ray analysis reveals that compound 1 is an isolated neutral mixed-valence {FeIII 2 FeII} n double-zigzag chain with each [FeIII(Tp)(CN) 3 ]− unit connecting with two Fe(II) centres via two of its three CN− groups in the cis -positions, and two triazole groups from btb coordinated with Fe(II) ion in its axial positions. Single-crystal data obtained at different temperature together with magnetic data indicate that complex 1 exhibits thermal induced spin transition in the Fe(II) sites with T 1/2 ≈ 165 K. Additionally, light-induced excited spin-state trapping (LIESST) of 1 was also observed at low temperature. [ABSTRACT FROM AUTHOR]

• Various volatile substances for recreational purposes exert a euphoria-inducing response in humans. • The inhalation of these substances it is involving younger age groups. • Death is usually caused by cardiac arrhythmias with ventricular tachycardia, ventricular fibrillation, vagal stimulation and catecholamine release, respiratory center depression, ab ingestis, and laryngeal edema. • Toxicological investigations were performed in 56 cases. Blood concentrations were found to be higher than 100 μg/L in all butane-linked deceases. Different matrices are investigated, with an homogeneous butane concentration. • Most cases were accidental deaths of chronic users or abusers of butane, only 11/58 were suicides. • When suspected, death due to butane inhalation must be demonstrated by a quick and correct sampling of blood and tissues. Volatile substance abuse is widespread among adolescents due to its easy availability and methods of consumption. Inhalant abuse represents a current problematic issue, causing significant morbidity and mortality due to direct toxicity on several target organs and displacement of gas which results in a lack of oxygen. This review aims to evaluate post-mortem and toxicological investigations in cases of suspected butane intoxication. We performed comprehensive research using the Preferred Reporting Items for Systematic Review (PRISMA) standards. Forty scientific papers fulfilled the inclusion criteria. A total of 58 cases of butane-related deaths were found. Among these, we found 11 cases of suicide (18%), 1 case of homicide (2%), 44 cases of accidental poisoning (76%), and 2 cases of work-related deaths (4%). Autopsy and post-mortem examinations were performed in 54 cases, whereas toxicological analyses were presented in 56 cases. In autopsy, pulmonary edema (51%) and poli-visceral congestion (59%) were the most common findings. When death by butane inhalation is hypothesized, autopsy and histological findings may be nonspecific, therefore toxicological investigations assume a crucial role along with attention to the methods used to collect biological samples. [ABSTRACT FROM AUTHOR]

The ambient temperature is a non-negligible factor when evaluating the adsorption performance of automobile activated carbon. In this study, dynamic tests of butane adsorption on activated carbon were carried out at ambient temperatures of 293 K, 313 K, and 333 K. In addition, molecular simulation method was used to analyze the influence mechanism of temperature on the adsorption performance of activated carbon. The results show that the working capacity of automotive activated carbon decreases by 15.9% to 20.2% and the butane breakthrough time is shortened by 21.4% to 37.5%, as the ambient temperature is increased from 293 K to 333 K. In the high temperature environment, the thermal movement of the gas molecules is more intense so that the kinetic energy and diffusion coefficient of the butane molecules are increased. When activated carbon adsorbs multilayer butane molecules, the temperature increase mainly reduces the adsorption sites after the first adsorption layer (around 5.5 Å). [Display omitted] • High temperatures reduce the adsorption capacity of automotive activated carbon. • The kinetic energy and diffusion coefficient of the butane molecules are increased in the high temperature environment. • The temperature increase mainly reduces the adsorption sites after the first adsorption layer (around 5.5 Å). [ABSTRACT FROM AUTHOR]

• The optimal enzymes were selected for each reaction of the (S)-1,2,4-butanetriol artificial synthetic pathway. • A recombinant strain E. coli BL21(DE3) was constructed to co-expressing these four genes. • The cultivation of the recombinant E. coli strain and reaction conditions were optimized. • (S)-1,2,4-Butanetriol was synthesized in one-pot from 200 g/L d -xylose in 74% isolated yield and >99% ee using the E. coli whole cells. (S)-1,2,4-butanotriol is an important four carbon platform compound with extensive applications in many fields. Traditional chemical methods involving harsh reaction conditions and poor selectivity are environmentally unfriendly. Biosynthetic methods have made significant progress, but still cannot meet the needs of industrial production. In this study, a whole-cell biocatalytic system have been developed for the efficient production of (S)-1,2,4-butanotriol from d- xylose. d -xylose dehydrogenase (CcXylB), d -xylonate dehydratase (TaXylD), 2-keto acid decarboxylase (SaPDC) and aldehyde reductase (EqAdhP) with high activity were obtained by screening the libraries of these enzymes. The plasmid pRSFDuet-TaXylD-T7-CcXylB-SaPDC-T7-EqAdhP (P5) was constructed and introduced into E. coli BL21(DE3) to give the recombinant strain E. coli BL21(DE3)-P5, which could completely convert 200 g/L d -xylose to (S)-1,2,4-butanotriol in 74% isolated yield and >99% ee under the optimized cultivation and reaction conditions. This study provides a high-performance biocatalyst with potential industrial application for the synthesis of (S)-1,2,4-butanotriol from renewable resources. [Display omitted] [ABSTRACT FROM AUTHOR]

Adsorption of Ni(II) from aqueous solution by using the butane tetracarboxylic acid (BTCA) modified peanut shell cellulose as sorbent was examined in the batch system. The optimal modification conditions of cellulose were butane tetracarboxylic 0.05 g/g, sodium dihydrogen phosphate 0.15 g/g, reaction temperature 140°C, and reaction time 90 min. The nickel ions removal rate by the BTCA-modified cellulose increased with the increasing temperature in the range of 20°C–45°C. Ni(II) adsorption onto the BTCA-modified cellulose was successfully described by the pseudo-second- order kinetic and Langmuir isotherm models. According to the thermodynamic parameters, the results indicated that Ni(II) adsorption onto the BTCA-modified cellulose was spontaneous and endothermic in nature. [ABSTRACT FROM AUTHOR]

In this study, oxygen vacancies were introduced into the hematite (α-Fe 2 O 3) photoanode via a simple and rapid butane flame annealing method. The presence of oxygen vacancies were demonstrated by high-resolution transmission electron microscopy (HRTEM), electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS). The photocurrent density of optimum α-Fe 2 O 3 electrodes was 0.67 mA cm-2 at 1.23 V RHE , about 2.7 times higher than that of N 2 annealed electrode. Our study showed that butane flame annealing process can introduce oxygen vacancies defects in Fe 2 O 3 electrodes, which would improve carrier transfer efficiency, increase electron density, enhance water oxidation activity, and narrow the light optical bandgap. The use of butane flame annealing is a simple and effective strategy to enhance the PEC performance of hematite thin films. • Fe 2 O 3 photoanodes with oxygen vacancies were successfully synthesized through butane flame annealing. • Oxygen vacancies can improve charge transfer efficiency and increase the utilization rate of photogenerated holes at the interface. • The method of annealing with butane flame is simple and time-saving. • The FA-Fe 2 O 3 electrode achievs a light current density of 0.67 mA cm-2 at 1.23 V RHE. [ABSTRACT FROM AUTHOR]

[Display omitted] A bis-adamantane-spiro-fused 1,3-bis(triisopropylsilyl)-1,3-disilabicyclo[1.1.0]butane equilibrates with the corresponding 2,3-bis(triisopropylsilyl)-1,3-disilabuta-1,3-diene with a ratio of 1:19. The 1,3-disilabuta-1,3-diene was fully characterized by a combination of multinuclear NMR and UV-VIS spectroscopies, elemental analysis, and single-crystal X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

• Membrane from polyethylene with radiation-grafted sulfonated polystyrene was used. • The membrane allows the selective separation of paraffins and C4 olefins mixtures. • Separation selectivity/permeability increase with rising the gas flow humidity. The possibility of paraffins and C4 olefins mixture separation on membranes made of polyethylene with radiation-grafted sulfonated polystyrene is shown. The selective separation is achieved due to the butenes and isobutene facilitated transfer in the form of a π-complex with a proton. Moreover, despite the significantly larger cross-sectional size, obstructing the transfer, isobutene molecules are also transferred much faster than butane, and the separation coefficient reaches 3.8. An unusual fact was discovered of separation selectivity and permeability increase with the separated gases flow humidity rise. [ABSTRACT FROM AUTHOR]

• Single-effect absorption refrigeration system is simulated using aspen HYSYS. • Commercial butane as refrigerant and commercial hydrocarbons as absorbents are used. • Optimal working fluid is found to be butane/heavy naphtha. • Performance changes marginally with butane recovery unlike reboiler temperature. • Butane/heavy naphtha system competes effectively with current commercial chillers. A heat-powered single-effect absorption refrigeration system operating with commercial n-butane as a refrigerant and six commercial hydrocarbons (stabilized condensate, light naphtha, heavy naphtha, reformate, light reformate and heavy reformate) as absorbents was studied. The main target of the study was actuating these systems to the available waste heat. Simulation models were created using Aspen HYSYS process simulator. The main parameters of an absorption refrigeration system, using the proposed working fluids, were compared at different evaporator, condenser and absorber temperatures to select the best working fluid. Moreover, a focused interpretation was given to the behavior of the best system at different operating conditions. Furthermore, the effect of both butane recovery and purity, in the generator, on the performance of the best system was investigated. Results revealed that, among the proposed working fluids, the best performance was achieved by butane/heavy naphtha. It could achieve a Coefficient of Performance (COP) of 0.78 at evaporator temperature of 20 °C and both condenser and absorber temperatures of 30 °C. The COP passed through a different maximum value at certain recovery for each evaporator temperature and condenser and absorber temperatures and similar behavior was observed for purity. Low reboiler temperatures were feasible at low butane recoveries with almost the same COP of the high butane recoveries. Generally, Butane/heavy naphtha system could compete effectively with the commercial absorption refrigeration systems, within their range of operating conditions, without experiencing their limitations. [ABSTRACT FROM AUTHOR]

• The coordination ability of 1,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)butane ligand toward dichloride palladium (II) and platinum(II) has been investigated. • The molecular structure of palladium (II) and platinum(II) complexes displays two M•••H γ –C(sp3) anagostic interactions. • The palladium (II) and platinum(II) atoms in the complexes adopt a trigonal prism geometry. Two nine-membered metallocycles of PdII (1) and PtII (2) containing 1,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)butane ligand (L1) have been prepared and their structures were determined by IR, NMR spectroscopy, and by single-crystal X-ray diffraction analysis. The molecular structures of L1 display that the pyrazolyl groups adopt an anti -conformation, while in 1 and 2 a discrete nine-membered monometallic macrocycle is generated by the assembly of one ligand and one metal atom, and the ring adopts a twist-chair-boat conformation. The ligand L1 in complexes 1 and 2 acts as cis- chelating ligand via a κ2 N,N coordination mode by the nitrogen atoms of the pyrazolyl rings. In compounds 1 and 2 the metal center adopts a planar geometry. The molecular structure of 1 and 2 also revealed two intramolecular anagostic interactions M•••Hγ–C(sp3) (M = Pd and Pt) with M•••H distances between 2.689 and 2.780 Å, which are important to stabilize the nine membered ring formed. Considering those two M•••Hγ interactions, the ligand L1 generates a κ4 N,N,H,H coordination mode and the metal centers adopt a trigonal prism geometry. The crystal packing of L1, 1 and 2 displayed supramolecular networks promoted mainly by C–H•••π interactions, which were analyzed by Hirshfeld Surface Analysis [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Semi-industrial-scale silicalite-1 membranes are applied to n -butane/methane separation. • The membranes have excellent separation performance for n -butane/methane mixtures. • The highest n -butane/methane separation factor of 935 so far is obtained. • Semi-industrial-scale silicalite-1 membranes display good long-term stability. The semi-industrial-scale tubular silicalite-1 membranes with a thickness of 8.4–8.9 µm were prepared and used for the separation of n -butane/methane mixture for the first time. The membranes remained highly [h0h] oriented. The effects of temperature, pressure and feed flow rate (Reynold numbers) on the separation performance for the 6-cm-long and 50-cm-long membranes were investigated. Separation stability of the semi-industrial-scale tubular silicalite-1 membrane was studied. The short silicalite-1 membranes displayed the highest n -butane/methane separation factor of 935 among the literature data so far and a permeance of n -butane of 0.5 × 10−8 mol/(m2 s Pa) at 243 K. Two long silicalite-1 membranes showed n- butane permeances of 3.1 × 10−8 and 1.9 × 10−8 mol/(m2 s Pa) and n- butane/methane separation factors of 72 and 110 at 298 K in the 10/90 mol% n -butane/methane mixture, respectively. The results displayed that silicalite-1 membranes have great potential application for removal of n -butane from natural gas mixtures. [ABSTRACT FROM AUTHOR]

• Butane and propane are the most threatening causes of death among inhalants. • It is difficult to detect butane in biological samples that will lapse over time. • The detection window of metabolites was confirmed through animal study. • 2-Methyl-2-propanol and acetone were the main metabolites. • Butane inhalation can be confirmed by detection of metabolites. Worldwide, various inhalants are widely abused for recreational purposes, with butane and propane emerging as among the most commonly misused volatile substances, posing a significant risk of sudden death. The rapid elimination and oxidation of these highly volatile compounds upon inhalation necessitate the identification of butane and propane along with their metabolites in biological samples. Hence, the primary objective of this study is twofold: firstly, to establish a method for analyzing butane, propane, and metabolites, and secondly, to demonstrate the detection window and exposure indicators associated with the inhalation of butane and propane. In pursuit of this objective, we developed analytical methods for the determination of isobutane, n -butane, propane, and their nine metabolites in both blood and urine. Headspace-gas chromatography–mass spectrometry (GC–MS) and solid-phase microextraction-GC–MS were employed for the analyses, demonstrating acceptable precision and accuracy. An animal study revealed that isobutane and n -butane were only detectable below the limit of quantification (LOQ) in rat blood 5 min after exposure. Meanwhile, the three major metabolites—2-methyl-2-propanol, 2-butanol, and 2-butanone—were observed 5 min after exposure but persisted in rat urine even 5 h post-exposure. Additionally, human urine samples identified other metabolites, including acetone, acetoin, and 2,3-butanediol isomers. The presence of specific metabolites corresponding to each inhalant confirmed the abuse of butane and propane. This comprehensive approach provides valuable insights into the detection and assessment of inhalation to these volatile substances. [ABSTRACT FROM AUTHOR]

• Steam thermal plasma is applied for pyrolysis of simulated natural gas. • Simulated natural gas is converted into the hydrogen and carbon black. • Comparison of experimental and theoretically predicted outputs is performed. • Higher hydrocarbons in natural gas decrease the effectivity of methane conversion. • Higher hydrocarbons in natural gas decrease specific energy requirement. Pyrolysis of simulated natural gas (NG) was studied experimentally in the reactor equipped with a steam thermal plasma torch. Simulated NG consisted of 75 % of methane, 15 % of ethane, 5 % of propane and 5 % of butane. Experimental composition of the output gas was compared with the equilibrium calculations corresponding to the gaseous mixture entering the reactor. NG input flow rate 100 slm was considered the best in terms of agreement between the experimental and calculated compositions. Consequently, for this flow rate, the majority of natural gas was reformed into the mixture of hydrogen and solid carbon. For the NG input flow rates of respectively, 200 slm and 500 slm, a non-negligible amount of unconverted methane (from 37 slm to 155 slm) was found to remain in the output gas. On the other hand, the specific energy requirement with respect to the produced hydrogen was better for 500 slm of NG (1.1–1.6 kWh/m3.H 2) than for 200 slm (1.8–2.7 kWh/m3.H 2) or 100 slm (3.2–3.6 kWh/m3.H 2). In all the studied experimental conditions, practically no CO 2 was formed, only a small amount of CO corresponding to oxygen from the steam plasma was detected. A comparison with the previously published works, where methane and natural gas were not distinguished, showed that NG composition can play an important role in the pyrolysis process. In particular, the presence of higher hydrocarbons decreased the effectivity of methane conversion and also reduced the specific energy requirement, with respect to the pure methane pyrolysis. [ABSTRACT FROM AUTHOR]

In this study, the kinetics, thermodynamics, and optimization of the subcritical butane extraction of Acer truncatum seed oil were investigated. The effects of experimental parameters on the extraction yield and efficiency was studied and optimized by response surface methodology, with the optimum time, temperature, and liquid/solid ratio (mL/g) of 44 min, 52 °C, and 3.4, respectively. The extraction efficiency could reach up to 94.50 % after twice extraction under optimized conditions. The extraction kinetics was determined by a modified Fick's law model and the activation energy of the effective diffusion coefficient was obtained as 23.26 kJ/mol. The enthalpy change and the entropy change were both positive with values of 20.06 kJ/mol and 70.02 J/(mol·K), respectively, while The Gibbs free energy change was negative in the temperature range. Finally, the comparisons of extraction efficiency, fatty acid composition, and properties were made for subcritical extraction and other three methods. [Display omitted] • Subcritical butane extraction shows high extraction efficiency of ATSO with 94.50 %. • Kinetics and thermodynamics were determined and verified by proposed models. • Single extraction efficiency of 78.01 % was optimized using response surface methodology. • Components of fatty acids in ATSO were confirmed with nervonic acid of 5.32–5.75 %. [ABSTRACT FROM AUTHOR]

When do molecular dynamics (MD) simulations yield better agreement with experimental macroscopic measurements of diffusivities of guest molecules in zeolites? We report studies to show that simulations of n-hexane and 2,2-dimethyl butane in 'powder' samples of zeolite BEA (as compared to single-crystal sample) lead to a better agreement with ZLC diffusivity measurements previously reported by Bárcia et al. The results suggest that main reason why MD simulations until now could not reproduce the measurement from macroscopic techniques such as uptake and gas chromatography is because all simulations employed 'single-crystal' sample. Implications of these results on 'sample preparation' which is considered very important in experiments but never planned in simulations are discussed. The results further demonstrate that the changes in diffusivities, as well as activation energies that are observed between single crystal and 'powder' sample are not only dependent on the nature of the zeolite sample, but also on the type of guest molecule, i.e., the changes on going from 'single crystal' to 'powder' sample for n-hexane and 2,2-dimethyl butane are not the same. Image 1 • Powder sample show better agreement with properties from experimental techniques. • Inter-crystalline region plays a major role in the diffusivities (D s) of guests. • Inhomogeneity in the sample leads to large activation energy, E a. • Values of D s and E a depend on zeolite sample as well as type of guest molecule. [ABSTRACT FROM AUTHOR]

Three novel heteropolyanion-based Brønsted acidic ionic liquids (BAILs), butane mono sulfoacid-functionalized 1,10-phenanthrolinum, butane mono and bis sulfoacid-functionalized 1,4-dimethylpiperazinium salts of phosphortungstate catalyst (PhBs 1 -PW, [PipBs 1 ] 3 -PW and [PipBs 2 ] 3 -(PW) 2) were synthesized and well characterized with FTIR, 1H and 13C NMR, Electro-Spray Ionization Mass Spectrometry (ESI-MS), Elemental analysis (CHNS), EDX and TG analysis techniques. The esterification reactions of monocarboxylic acids with monohydric alcohols were carried out using these catalysts. The introduced catalysts present a self-separation performance after reaction, which can be easily recovered and quite steadily reused as confirmed by six-run recycling test. Moreover, bis sulfoacid-functionalized 1,4-dimethylpiperazinium salt of phosphortungstate showed the best catalytic performance among the prepared catalysts for the esterification reaction. • Three classes of novel SO3H-functionalized polyoxometalate-based ionic liquids were synthesized. • The esterification reactions were efficiently catalyzed in the presence of introduced ionic liquids. • The catalysts were easily separable and reusable up to six runs. • The procedure is simple and green. • Very low leaching of the polyoxometalate anion was observed. [ABSTRACT FROM AUTHOR]

α II -V 1- x M x OPO 4 (M = W,Mo). • Solution combustion synthesis (SCS) leads to a variety of phase pure catalysts. • Doping with Mo and W tunes the oxidation state of V in VOPO 4 between 4+ and 5+. • α II -(V 1- x W x)OPO 4 reaches selectivities of maleic anhydride of more than 30%. • α II type solid solutions are a flexible platform for further research. The vanadyl pyrophosphate (VPP) based catalyst is unique in converting n -butane selectively (60–70%) into maleic anhydride (MAN), whereas a MAN selectivity of 20% may be regarded as high for structurally different catalyst systems. We present novel vanadium phosphorus oxides and mixed metal phosphate solid solutions tested for n -butane oxidation to MAN with a selectivity of >30%. The majority of the catalysts were prepared by solution combustion synthesis. (V 1- x W x)OPO 4 with α II structure was found to be more active and selective in the oxidation of n -butane compared to β -VOPO 4. By adjusting the tungsten content the oxidation state of vanadium in (V 1- x W x)OPO 4 can be tuned between 4.74 and 4.99, which is regarded as a key factor for MAN production. All catalysts were structurally stable, but the specific surface area increased during the reaction, as detected by X-ray diffraction and N 2 physisorption, respectively. (V 1- x Mo x)OPO 4 was also stable, but the MAN selectivity was lower compared to β -VOPO 4. Low conversions result from the low surface area of the screening samples, however, could be overcome by advanced synthesis protocols. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Oriented silicalite-1 membranes were prepared by microwave heating. • Synthesis time by microwave heating was saved by over 90%. • Membrane orientation was changed compared to the conventional one. • Membrane by microwave heating was more n -butane-selective. Abstract Highly (h0h) -oriented silicalite-1 membranes were fast prepared on the inner surface of α-alumina tubes by microwave heating within only 2 h. Membrane microstructure including orientation, thickness and defect densities are closely related to the synthesis conditions such as synthesis time, synthesis temperature and heating method. Membrane synthesis by microwave heating at optimized conditions displayed good reproducibility. The best silicalite-1 membrane displayed n- butane permeance of 1.3 × 10−7 mol (m2 s Pa)−1 and n- butane/ i- butane separation factor of 45 for an equimolar n- butane/ i- butane binary mixture at 333 K. The mixture n- butane/ i- butane separation selectivity was higher than the ideal separation factor. Single gas permeations for six gases through the typical membrane were measured as functions of temperature and pressure. The effects of temperature, pressure and feed concentration on mixed-gas separation performance of the typical silicalite-1 membrane prepared by microwave heating were also studied in comparison with the membrane by conventional heating. Both membranes showed the similar trends with respect to temperature and pressure. Silicalite-1 membranes prepared by microwave heating were more n -butane-selective than these by conventional heating in the test ranges of temperature and pressure. [ABSTRACT FROM AUTHOR]

The effect of hydrogen (H 2) addition in the laminar burning velocity (LBV) of n-butane-air at elevated temperatures is described in this paper. For various equivalence ratios (ϕ), ranging from 0.7 to 1.3, LBV was measured for 20%, 40% and 60% H 2 addition to n-butane using a preheated mesoscale diverging channel technique. Using this experimental technique, LBV measurements were conducted for unburnt mixture temperature up to 450 K. The maximum burning velocity has been obtained at equivalence ratio 1.1 for all the mixture conditions. The LBV results at atmospheric condition for n-butane-hydrogen-air mixture were obtained by extrapolating the experimental data at elevated temperatures. "Heat flux method" experimental setup was used for measuring the LBV of n-butane-hydrogen-air mixture at atmospheric condition. The results obtained for LBV at atmospheric conditions with the two different methods at 0%, 20%, 40% and 60% H 2 composition in n-butane were found to be in good agreement. The experimental results of LBV for n-butane were compared with the numerical predictions using USC mech II, Aramco mech 2.0 and LLNL reaction mechanisms. The numerical predictions of LBV using Aramco mech 2.0 shows good agreement with experimental data at rich, lean and stoichiometric mixture conditions. • The effect of H 2 addition in the LBV of n-butane is studied. • LBV at elevated temperatures is measured using diverging channel setup. • Temperature exponent decreases with addition of hydrogen. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Synthesis parameters of silicalite-1 membrane were optimized. • Highly (h 0 h)-oriented silicalite-1 membranes were better than (h 0 h)& c -oriented one. • The best membrane displayed excellent performance for butane isomer separation. Abstract Tubular oriented silicalite-1 membranes were prepared on the inner surface of α -alumina tubes by secondary (seeded) growth. Membrane microstructures including orientation, thickness and defect densities which affected membrane performance could be regulated by synthesis optimization for butane isomer separation. Synthesis parameters such as synthesis temperature, synthesis time and solution composition were modified. Membrane orientation was greatly affected by synthesis temperature. Two typical membranes of highly (h 0 h)-oriented and mixed (h 0 h)&c-oriented membranes were obtained after synthesis optimization. Four highly (h 0 h)-oriented silicalite-1 membranes prepared under optimized synthesis conditions showed ideal H 2 /SF 6 selectivities of 1325 ± 35, which was much higher than that of mixed (h 0 h)& c -oriented membrane M3 (3 0 0), indicating that the former membranes had fewer boundary defects. These highly (h 0 h)-oriented membranes displayed n -butane permeances and separation factors were (2.26 ± 0.23) × 10−7 mol (m2 s Pa)−1 and 32.7 ± 2.5 for an equimolar n -butane/ i -butane mixture at 333 K, respectively. The low deviations in permeance and selectivity indicate that membrane synthesis had a good reproducibility. This average n -butane permeance for these highly (h 0 h)-oriented membranes was 4 times higher than that of mixed (h 0 h)& c -oriented membrane M3. Both kinds of highly (h 0 h)- and (h 0 h)& c - silicalite-1 membranes displayed the similar trend with test temperature and pressure. [ABSTRACT FROM AUTHOR]

Abstract Rate-Controlled Constrained-Equilibrium (RCCE) is a model order reduction method which assumes that the non-equilibrium states of a system can be described by a sequence of constrained-equilibrium states subject to a small number of constraints. It can be used to predict ignition delay time with good accuracy and low computational cost. In this paper RCCE approach has been further developed for applying to the oxidation of n-butane for ignition study and prediction of a constant volume, constant internal energy system over a wide range of initial temperatures, pressures and equivalence ratios. The USC-Mech II (109 species and 781 reactions, without nitrogen chemistry) is chosen as chemical kinetic mechanism for n-butane oxidation for Detailed Kinetic Model (DKM). The constraint selection for n-butane/oxygen mixture starts from the eight universal constraints for carbon-fuel oxidation. Additional species constraints are selected based on researchers' experience to have the best performance with the minimum number of constraints. The selected 17 constraints have been used to predict ignition delay times for butane combustion. The results of RCCE method are compared with those of detailed kinetic model and experimental data to verify the effectiveness of constraints and the efficiency of RCCE. Rate-Controlled Constrained-Equilibrium results show good agreements with DKM results under different initial temperatures, pressures and equivalence ratios. Even better performance than DKM has been achieved by the selected 17 constraints when the results are compared with shock tube experimental data from literature with initial temperatures 1200–1500 K and initial pressures 2–20 atm. It has been applied to predict the ignition delay time of butane/air mixture over a wide range of initial temperatures, initial pressures and equivalence ratios. [ABSTRACT FROM AUTHOR]

Abstract A two-stage combustor with 1st-stage premixed fuel-rich combustion, integrated micro-tubular flame-assisted fuel cell (FFC) and 2nd-stage, fuel-lean combustion is described. The current state of research in direct flame fuel cells (DFFCs) is assessed and the dilemma of obtaining high power density, high electrical efficiency and no soot is discussed. A method for deriving the maximum theoretical electrical efficiency from a FFC based system is developed. A method for comparing methane, propane and butane in the two-stage combustor with integrated FFC is developed. Methane, propane and butane are tested at different equivalence ratios and flow rates to assess the power density and electrical efficiency. High power density (>300 mW cm−2) and high electrical efficiency (>1.2%) are achieved for equivalence ratios below 1.6. Methane is found to achieve higher power density and electrical efficiency at lower equivalence ratios compared to propane and butane. Soot formation is avoided by operating below the critical sooting limit. Highlights • A method for deriving the theoretical maximum electrical efficiency is discussed. • Methane, propane and butane fuels are compared based on equivalent energy input. • Combustion of methane generates higher syngas at lower equivalence ratios (1.2–1.3). • A high power density of ∼328 mW cm−2 is achieved in methane combustion exhaust. • A high electrical efficiency (>1.2%) is achieved compared to previous work. [ABSTRACT FROM AUTHOR]

Abstract This research experimentally investigates a prototype compressor in a high temperature heat pump for industrial waste heat recovery from 50 °C to heat delivery at 115 °C. Compressors are the limiting component in the development of high temperature heat pumps due to the high discharge pressure and temperature. The prototype compressor is tested with butane due to its favourable thermodynamic properties within the operating conditions. The compressor allows the heat pump to provide heating for industrial processes such as pasteurization, drying, sterilization and other processes which require high temperature heat. The heat pump will replace the heating capacities of low-pressure steam boilers. It will also provide cooling for industrial waste heat or other cooling demands, replacing cooling capacities from cooling towers. The experimental setup consists of a 20 kW heat pump designed with the flexibility for multiple operating conditions applicable to different industrial applications. The compressor is designed to enable suction and discharge temperatures up to 80 °C and 140 °C respectively. It is found to have a total compressor efficiency of 74% and a volumetric efficiency of 83%. The results showed good operating parameters (temperature, pressure) and the potential for even higher temperature heat delivery. [ABSTRACT FROM AUTHOR]

Abstract In order to investigate the pressure-dependent effects of carbon chain growth from methyl radical, pyrolysis experiments of butane-2,3‑dione (also known as diacetyl) were conducted both in a flow reactor over 780–1520 K at low and atmospheric pressures and in a jet-stirred reactor (JSR) over 650–1130 K at 10 bar. Identification and quantification of the intermediates were achieved by synchrotron vacuum ultraviolet photoionization mass spectrometry in a flow reactor and Fourier transform infrared spectrometry and gas chromatography in a JSR. A pyrolysis model of butane-2,3‑dione, incorporating the sub-mechanisms of butane-2,3‑dione, ketene, C1–C4 hydrocarbons and the formation of benzene, was developed from our recently reported C1 model in this work. It was validated against the present pyrolysis data of butane-2,3‑dione and the pyrolysis data of C2–C4 hydrocarbon fuels and ketene in the literature. Generally, the present model could reasonably predict all the experimental targets. Based on the rate of production analysis, the unimolecular decomposition reaction (CH 3 COCOCH 3 (+ M) = 2CH 3 CO (+ M)) is the dominant pathway to consume the fuel at low pressure. However, at atmospheric and high pressures, both the unimolecular decomposition reaction and the H abstraction reaction of butane-2,3‑dione by methyl radical are important. Ketene, acetone and acetaldehyde were measured in this work and their formation is also pressure dependent. For the methyl-related growth chemistry, addition-elimination reactions play an important role at low pressure. Their contribution becomes less at atmospheric pressure and can be neglected at high pressure. In contrast, the combination reactions are responsible for methyl-related growth at high pressure. For the formation of benzene, the recombination of propargyl radical is the most important pathway at low pressure, while the H-assisted isomerization reaction of fulvene becomes dominant at atmospheric and high pressures. [ABSTRACT FROM AUTHOR]

Abstract The fluid phase behavior characterization at nanoscale is a challenging and significant problem for many processes such as polymer analysis, drug delivery, carbon dioxide storage, and petroleum production, among others. It is commonly accepted that the fluid phase behavior in sub-10 nm pores is considerably different than the phase behavior in bulk environment. In this study, experiments using the lab-on-a-chip approach has been conducted to measure and visualize n-Butane condensation pressure in nano-scale slit pores of 50 nm, 10 nm, and 4 nm. The result shows that n-Butane dewpoint pressure can deviate as high as 14% from its original value due to the confinement effect. Molecular simulation has also been performed with a purpose to model the experimental results. The simulation results show a good agreement with the experimental data and prove the significant impact of the confinement effect. [ABSTRACT FROM AUTHOR]

Graphical abstract Three new binuclear platinum(II) complexes were synthesized and characterized. Those complexes exhibited high binding affinities for calf thymus DNA and potent topoisomerase I inhibitory activities, and significant cytotoxicity activities. Abstract Three binuclear platinum(II) complexes, 1 ([Pt 2 (L)Cl 2 ]Cl 2), 2 ([Pt 2 (L)Br 2 ]Br 2) and 3 ([Pt 2 (L)I 2 ]I 2) (where L = 1,4-bi-[4′-(4-Hydroxyphenyl)-2,2′,6′,2″-terpyridine] butane) were synthesized and characterized by nuclear magnetic resonance, elemental analysis and mass spectrometry. The crystal structure of the new ligand L was determined by single crystal X-ray crystallography, and π–π stacking interactions were revealed in the geometry. Interactions of complexes with calf thymus DNA have been investigated by UV–Vis spectroscopy and fluorescence spectroscopy. Due to the structural differences, binuclear complex 3 exhibited higher binding affinity for calf thymus DNA with a DNA-binding constant K b of 8.72 × 106 M−1. The competitive study indicated that the ethidium bromide (EB) can displaced by complexes 1 – 3 from the DNA-EB conjugation. The concentration-dependence unwinding of supercoiled circular plasmid pBR322 DNA by complexes 1 – 3 was observed via agarose gel electrophoresis. Meanwhile, complexes displayed obvious activities for inhibition of topoisomerase I. Herein the halogen leaving groups Cl−/Br−/I− presented in 1 – 3 showed significant effect on DNA binding and topoisomerase I inhibition activities. An evaluation of in vitro cytotoxicity for three complexes was performed by MTT assay in two cancer cell lines and normal cells as the control, respectively. [ABSTRACT FROM AUTHOR]

Highlights • Burning velocity of premixed butane flame was studied by MZI/Schlieren. • Effect of Re and equivalence ratio was determined experimentally. • With Al nanoparticles Re has a prominent effect on the temperature enhancement. • The laminar burning velocity of the flame was positively affected by nanoparticle. Abstract This paper investigates the effects of aluminum nanoparticles on a premixed butane-air flame using optical methods. The experiments are performed for a range of equivalence ratios in rich/lean environments (0.8 ≤ φ ≤ 1.2) and laminar steady flame conditions (50 ≤ Re ≤ 200). The aluminum nanoparticles are added up to 5 wt%. The Mach-Zehnder interferometry technique and Schlieren photography method are applied to obtain the flame temperature and its laminar burning velocity. Addition of nanoparticles caused a higher temperature flame in most cases. Also, the laminar flame speed was affected positively by the aluminum nanoparticles. A maximum augmentation of 237 K was observed in the flame maximum temperature. Also, the laminar flame speed was enhanced by 18.9% and 29.1% in the cases of adding aluminum nanoparticles by 2 wt% and 5 wt%, respectively. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Effect of microwave heating on the performance of a catalytic gas-solid fluidized bed reactor. • Novel experimental data from a lab-scale microwave heating-assisted fluidized bed reactor. • Energy balance modeling to obtain gas temperature employing particle and bulk temperature measurements. • Enhanced catalytic selective oxidation of hydrocarbons by microwave heating mechanism. Abstract Catalytic oxidation is widely acknowledged as the most promising technology for the conversion of hydrocarbon feedstocks to a variety of bulk industrial chemicals. The formation of undesired by-products through secondary gas-phase reactions has been underscored as the limiting step for this technology. In this study, microwave heating is proposed to challenge the evolution of undesired by-products based on the exclusive selective heating mechanism. This task is accomplished through a significantly higher solid (as microwave receptors) temperature compared to the gas phase temperature according to the principles of microwave irradiation approach. In order to highlight the influence of microwave heating on the overall performance of a gas-solid fluidized bed reactor, a simulation study was attempted for a model reactive system. Thus, catalytic oxidation of n-butane over the fluidized vanadium phosphorous oxide catalyst to produce maleic anhydride was selected as the model reaction. The bed hydrodynamics was described by a dynamic two-phase flow model while a kinetic model, adopted from the available literature, represented the reaction feature of the reactor. The original experimental data from a lab-scale microwave-heated fluidized bed reactor and the respective energy balance modeling were employed to describe the temperature distribution between bulk, solids, and gas segments of the simulated bed for the microwave heating scenario. The simulation study indicated that when competitive gas and solid phase reactions are occurring in a gas-solid fluidized bed reactor, the application of microwave selective heating approach can significantly enhance the overall performance of the reactor in comparison with the conventional heating, where solids, bulk, and bed temperatures are identical. Consequently, the application of microwave heating has been proposed as a promising approach to promote catalytic selective oxidation of hydrocarbons. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Optimization under uncertainty is increasingly important for reactor design. • An improved algorithm for reactor design under uncertainty is proposed. • Specialized cubature rules for uncertainty propagation are applied. • Significant performance enhancement compared to existing approach. • New approach demonstrated on the reactor design for maleic anhydride synthesis. Abstract In the present work we propose an efficient and general algorithm for optimization under uncertainty based on the work of Srinivasan et al. (2003). We use specialized cubature rules to speed up the uncertainty propagation step which results in a significant reduction of the overall computational effort. The approach is illustrated by studying the optimal design of a fixed bed reactor for the synthesis of maleic anhydride from raffinate II feedstock, where the amount of n -butane and n -butenes in the feed is assumed to be uncertain. Applying the algorithm results in a robustified reactor design which shows significantly less temperature constraint violations and runaway conditions while still satisfying reactor performance criteria such as minimally required conversion and maximum allowable pressure drop. [ABSTRACT FROM AUTHOR]

Abstract The effect of different substituents on the excited state intramolecular proton transfer (ESIPT) of 1-aryl-2-(furan-2-yl)butane-1,3-diones (AYFBD), namely OFBD, TFBD, MFBD and FFBD are studied by employing the density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. By comparing the geometric configurations and infrared vibrational spectra of the first excited state (S 1) with those of the ground state (S 0), it can be concluded that the intramolecular hydrogen bonds are strengthened in S 1 state. The calculated peaks of absorption and fluorescence spectra of AYFBD derivatives in keto form are consistent with experimental results reported previously (Journal of Organic Chemistry , 2017, 82 , 12097). We can also confirm that the intensities of the intramolecular hydrogen bonds in the S 1 state are enhanced by analyzing the frontier molecular orbitals and the infrared spectra. To further investigate the ESIPT mechanism of AYFBD derivatives, the potential energy curves (PECs) of S 0 and S 1 states are scanned by varying O 1 H 2 distance, which demonstrates that ESIPT occurs in the S 1 state of all the AYFBD derivatives and follows the order: FFBD > MFBD > TFBD > OFBD. Highlights • The intramolecular hydrogen bond of AYFBDs derivatives are enhanced in S 1 state. • The electronic spectra of AYFBDs derivatives in EtOH solvent were simulated, which demonstrate that the experimental fluorescence peaks are attributed to both the enol and keto forms. • According to the potential energy curves of S 0 state and S 1 state, the AYFBDs molecules of ESIPT follows this order: OFBD > TFBD > MFBD > FFBD. [ABSTRACT FROM AUTHOR]

The synthesis of carbon-encapsulated copper nanoparticles (Cu&C NPs) by the high-productive method of the electrical explosion of wire (EEW) is presented. Copper wire was evaporated by high-energy electrical current pulses. Evaporation of Cu and the consequent condensation of spherical nanoparticles took place in argon with the controlled addition of butane, which provided encapsulation of copper nanoparticles in carbon shells. Carbon was deposited in the form of several graphite layers, which completely covered the surface. The encapsulation diminished the agglomeration of carbon-encapsulated copper nanoparticles (Cu@C NPs) during their condensation and substantially diminished their average diameter. Upon the deposition of about 4 % of carbon, the average diameter of nanoparticles decreased more than three-fold – from 130 to about 40 nm. Simultaneously, the specific surface area of Cu@C NPs increased from 7 to 35 m2/g. The deposited dense and gas tight carbon shells protected the surface of particles from oxidation. It prevented the self-ignition of as-synthesized nanoparticles at the exposure to ambient air and provided stability to oxidation during long-term storage as well. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • 37 stable products of oxidation measured by GC and FTIR. • Hydroperoxides and ketohydroperoxides were detected by Orbitrap. • Products of third O 2 addition on fuel's radicals were detected. • Hydroxyl or hydroperoxyl groups in the products were characterized by H/D exchange. The autoxidation of n-butane was studied experimentally in a jet-stirred reactor at 1 atm (560–720 K) and 10 atm (530–1030 K) for an equivalence ratio of 1. Samples of reacting mixtures were analysed in the gas phase by gas chromatography (GC) using several detectors (Flame ionization detector, thermal conductivity detector, quadrupole mass spectrometer), hydrogen peroxide analyser, and Fourier transform infrared spectroscopy. In addition to the fuel and oxygen, 37 products were quantified. Liquid phase samples were obtained by trapping the reacting mixtures in cooled acetonitrile (273 K). The liquid samples were analysed by high resolution mass spectrometry (HRMS Orbitrap Q-Exactive), either after flow injection or separation by high pressure liquid chromatography (HPLC). Besides stable species, several other low-temperature oxidation products, such as hydroperoxides and ketohydroperoxides, were detected. Products of third O 2 addition on fuel's radicals were also detected by high resolution mass spectrometry. To assess the presence of hydroxyl or hydroperoxyl groups in the products of oxidation we performed H/D exchange with D 2 O. Qualitative and quantitative results showed the same trends in terms of variation of mole fractions and signal intensities versus reacting temperature. Kinetic modelling was performed using a literature detailed kinetic reaction mechanism already used to simulate previous n -butane oxidation experiments in the cool-flame regime, showing that improvements are needed to better describe the oxidation of n -butane under the present conditions. [ABSTRACT FROM AUTHOR]

A mesophase precursor of carbon foam was synthesized by the pyrolysis of a propane-butane technical mixture; the precursor was shown to comprise polycyclic aromatic structures with the boiling point range from 200° to 400°C and above. The study revealed that the composition of the mesophase precursor can change with time, prolongation of which leads to the formation of higher molecular compounds. The formation of cellular carbon foam and its structure were studied; the possibility of obtaining closed and open cellular species was demonstrated. According to XRD, TEM and Raman spectroscopy data, the carbon material constituting the foam is nonporous and its nanostructure is typical of the carbon materials with a low ordering of graphene layers. A 70–80 nm thick carbon film in closed cellular carbon foam has a higher ordering of graphene layers and is readily removed in an air atmosphere (10 min, 850 °C) with the formation of open cellular carbon foam. The obtained carbon foam possesses high chemical and thermal stability and could be applied in the adsorption catalytic technologies. It was shown in experiments that this carbon material with a density 0.02 g•cm−3and oil capacity above 20 g•g−1 is promising for use as a regenerable petroleum sorbent. [Display omitted] • Thermopolycondensation of liquid pyrolysis products of propane-butane mix. • Effect of mesophase precursor on formation cellular carbon foam. • Carbon foam framework is nonporous with a low ordering of graphene layers. • Carbon foam as regenerable absorbent for collecting petroleum from water surface. [ABSTRACT FROM AUTHOR]

Sulforaphane has received attention in recent years due to its biological properties; it is found in broccoli seeds but must be released by enzymatic action from its precursor molecule. In this study, a novel process to purification of sulforaphane from broccoli seeds is described. The procedure is divided in three consecutive steps: 1) hydrolysis and extraction, 2) adsorption/desorption of crude extract, and 3) bleaching step. The adsorption capacity (65–74 mg/g) and sulforaphane recovery (67–79%) were consistent in the adsorption/desorption step, which is important because it is possible to obtain up to 40% of sulforaphane content. Maximum bleaching was reached at 15–20 min, increasing the purity of sulforaphane considerably. It is possible to obtain 90% of bleaching and good recoveries. Purified sulforaphane from broccoli seed extracts was identified by mass spectrometry. Infrared and ultraviolet spectroscopy confirms the presence of sulforaphane in each step as well its separation and purification. [ABSTRACT FROM AUTHOR]

Highlights • Postmortem butane analysis were performed in two fatal butane poisoning cases. • Butane concentration in the left heart blood was lower than in the right heart blood. • This difference may indicate interrupted gas inhalation immediately before death. • High butane level ratios of fat to blood are compatible with long exposure time. • Comparing between different samples is useful for interpreting the results. Abstract Fatal accidents during butane abuse frequently occur in Japan and in many countries around the world. Although analytical data about butane concentration in postmortem samples is being accumulated, when using the data to determine the cause of death, careful interpretation is required because the gas is easily diffused. Two fatal butane poisoning cases were encountered, and butane quantification of autopsy samples obtained from left and right heart blood, femoral blood, kidney, liver, lung, brain and fatty tissues was performed. In both cases, butane concentration in the left heart blood was lower than in the right heart blood or the femoral blood, despite gas inhalation. These findings may indicate that the deceased individuals interrupted gas inhalation and inhaled room air immediately before their death, therefore ruling out asphyxia due to anoxia as the mechanism of death. Case 1, which was suspected to be a not acute death, showed a very high butane concentration ratio of fatty tissues to femoral blood of over 70. Case 2 was considered an acute death, and the butane concentration ratio of fatty tissues to femoral blood was 8.2. These results are consistent with previously reported findings showing that much higher ratios of fatty tissues to blood are compatible with long survival time. In conclusion, the comparison of butane concentration among different samples, including left heart blood versus right heart blood and fatty tissues versus blood, is useful when interpreting the result of postmortem butane analysis to examine the mechanism of death and survival time. [ABSTRACT FROM AUTHOR]

Industrial catalytic reactors are made of steel, operate at high temperatures and pressures and contain hazardous chemicals. What happens inside remains hidden. Reactor optimization requires costly trial and error or is based on simplified mathematical models employing more or less accurate transport correlations and reaction kinetics. In the present work a pilot-scale fixed-bed reactor was developed for measuring concentration and temperature profiles for n -butane oxidation to maleic anhydride on vanadyl pyrophosphate catalyst pellets under industrially-relevant conditions. The reactor was equipped with five heating zones. The reactor was modeled by particle-resolved computational fluid dynamics. The catalyst bed was created by discrete element simulation and the result was validated by comparison with experimental radial porosity profiles. Catalytic chemistry was included by a kinetic model of intrinsic reaction rates. Transport resistances and packing deviations were lumped in reaction rate multipliers determined by fitting the model to profiles measured at a uniform reactor wall temperature. Simulation results reveal strong inhomogeneities inside the bed. A hot-spot develops at uniform wall temperature. At this hot-spot temperature differences of 40 K exist on one and the same pellet with negative impact on maleic anhydride selectivity and catalyst lifetime. An optimized wall temperature profile was derived by combining knowledge from the experimental profiles at uniform wall temperature and the CFD results. A gradual increasing temperature was predicted by the model to eliminate the hot-spot and increase integral maleic anhydride selectivity at constant n -butane conversion. This prediction was confirmed by experiment. At 80% n -butane conversion the maleic anhydride selectivity could be improved by 2%. Facing the scale of the process, this improvement translates into significant n -butane savings, reduced CO x emissions and increased revenue. [ABSTRACT FROM AUTHOR]

Three new coordination polymers of {[Cd(bib) 3 ](ClO 4 ) 2 } n ( 1 ), [Cd(μ 2 -bip) 2 (N 3 ) 2 ] n ( 2 ) and [Cd(μ-bib Me )Cl 2 ] n ( 3 ) were prepared by using the neutral N-donor ligands 1,4-bis(imidazolyl)butane ( bib ), 1,3-bis(imidazolyl)propane ( bip ) and 1,4-bis(2-methylimidazolyl)butane ( bib Me ) and CdX 2 (X = ClO 4 − , N 3 − and Cl − ). The results of the X-ray measurements demonstrate that in the crystal structure of 1 and 2 the cadmium(II) ion adopts CdN 6 octahedral geometry while, in the structure of 3 , the metal ion forms CdN 2 Cl 2 tetrahedral geometry. In compound 1 , six bib ligands are coordinated to one central cadmium(II) to form an open 3D 2-fold interpenetrating framework of the α-polonium ( pcu ) type topology, while in compound 2 and 3 the N 3 − or Cl − groups are terminally bonded to the metal center and each linker compound ( bip or bib Me ) acts as bridging ligand connecting two metal ions to form a one-dimensional zig-zag chain. The adjacent 1D chains of complex 2 and 3 are further extended into a non-covalent 2D network structure by C H⋯N and C H⋯Cl intermolecular hydrogen bonds, respectively. The complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • C C bonds rupture is inevitable for n -butane dehydrogenation over Ni-Sn/SiO 2 catalyst. • Secondary reactions of butenes also result in low butenes selectivity to some extent. • Rapid deactivation of Ni-Sn/SiO 2 is mostly caused by coke generated by 1,3-butadiene. Abstract Compared with i -butane dehydrogenation over Ni-Sn/SiO 2 catalyst, the conversion is higher for n -butane dehydrogenation, the selectivity to butenes is obviously lower, and the catalyst deactivates more rapidly. In order to clarify the difference, adsorption modes of n -butane and 1-butene along with desorption activation energy of 1-butene were determined by in-situ FTIR and TPD. n -Butane is adsorbed on Ni-Sn surface with a H atom in methyl, and the formed intermediates are prone to the rupture of C C bonds, leading to the lower selectivity to butenes. In addition, secondary reactions of butenes also play an important role in decreased selectivity, but to a less extent due to the medium desorption activation of butenes (58 kJ mol−1 for 1-butene, for example). The generation of coke is the third reason for lower selectivity. The rapid deactivation of Ni-Sn/SiO 2 catalyst mainly results from the formation of 1,3-butadiene, coke precursor, by further dehydrogenation of butenes. [ABSTRACT FROM AUTHOR]

The oxidative dehydrogenation of n -butane to 1,3-butadiene using CO 2 as a soft oxidant is investigated over oxide-supported NiFe bimetallic catalysts. Dry reforming of n -butane with CO 2 to syngas is also studied under identical conditions for comparison. The Ni 1 Fe 3 /CeO 2 catalyst is identified as a promising catalyst for the oxidative dehydrogenation to 1,3-butadiene via the C H bond cleavage, while the Ni 3 Fe 1 /CeO 2 catalyst mainly promotes the dry reforming pathway via the C C bond scission. The oxidation states of Ni and Fe are determined by X-ray absorption fine structure (XAFS) measurements under reaction conditions. Density functional theory (DFT) calculations are performed to further understand the different reaction pathways. Furthermore, the effect of oxide supports is studied for the Ni 1 Fe 3 bimetallic catalysts, showing that highly reducible supports, CeO 2 and CeO 2 -ZrO 2 , promote the production of 1,3-butadiene, whereas the ZrO 2 support significantly suppresses the oxidative dehydrogenation. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Density and saturation pressure of butane/bitumen systems are measured. • Effect of a second solvent on PVT data of butane/bitumen system is studied. • Composition of the heavy and light cuts is measured by SimDist. • Engineering of the solvent composition based on experiments is recommended. Abstract Solvent-aided bitumen recovery processes are relatively new approaches to reduce the negative environmental impacts and production costs of steam assisted gravity drainage (SAGD). Thermo-physical properties of these systems such as density, viscosity, phase partitioning and saturation pressure are of great importance in design of solvent-aided processes. Butane is a promising solvent for solvent-aided bitumen recovery processes. Addition of light or heavier solvents to butane can provide an engineering solution to improve the efficiency of solvent-aided processes. In this study, equilibrium measurements of butane and bitumen mixture were conducted at temperatures of 40 and 60 °C and pressures well above vapour pressure of the solvent. Then, the effect of introducing a second solvent as an additive to the butane–bitumen mixture was investigated. Propane, toluene and dimethyl ether were added to the original mixtures of butane and bitumen in separate sets of experiments and changes in thermo-physical properties were determined. It was determined that adding butane can lower the viscosity of the bitumen by several orders of magnitude. It was also concluded that although propane can significantly increase the saturation pressure of the mixture, it results in higher amount of asphaltene precipitation. The effect of dimethyl ether however is favourable because not only increases the vapour pressure but also reduces the asphaltene precipitation similar to toluene. [ABSTRACT FROM AUTHOR]