Presence Of Mixture Research Articles

Determination of hydrate phase equilibrium (H-L-V) data for the binary CO2–CH4 gas mixture in the presence of 1,3 dioxolane

Present work details the determination of three phase hydrate equilibrium data (H-L-V) using temperature search method for the binary CO2/CH4 gas mixture (50:50 molar ratio) in presence of 1,3 dioxolane (DIOX). DIOX concentration used for phase equilibrium determination were 1,3 and 5.56 mol% respectively. In the presence of DIOX, it was observed that phase equilibrium curve was shifted right with respect to the curve using same gas mixture with no additive (pure water). This indicates that the presence of DIOX moderates the hydrate formation equilibrium conditions. Also, as DIOX concentration increases from 1 mol% to 5.56 mol%, a decrement in phase equilibrium pressure at same temperatures was observed, confirming the potential of DIOX as an effective thermodynamic promoter. Enthalpy of hydrate dissociation was calculated for CO2/CH4 gas mixture in presence of DIOX using Clausius- Clapeyron plot and it was found to be 90.81±6.55 KJ/mol which confirms the sII structure of CO2-CH4-DIOX mixed hydrate. Besides providing the phase equilibrium data of formed hydrates with CO2/CH4 gas mixture using different concentration of DIOX, the present study will aid in determining suitable experimental conditions for examining kinetics and performing separation studies of CO2/CH4 gas mixture through hydrate formation.

Optical-pumping enantio-conversion of chiral mixtures in presence of tunneling between chiral states

Enantio-conversion of chiral mixtures, converting the mixtures composed of left- and right-handed chiral molecules into the homochiral ensembles, has become an important research topic in chemical and biological fields. In previous studies on enantio-conversion, the tunneling interaction between the left- and right-handed chiral states was often neglected. However, for certain chiral molecules, this tunneling interaction is significant and cannot be ignored. Here we propose a scheme for enantio-conversion of chiral mixtures through optical pumping based on a four-level model of chiral molecules, comprising two chiral ground states and two achiral excited states, with a tunneling interaction between the chiral states. Under one-photon large detuning and two-photon resonance conditions, one of the achiral excited states is eliminated adiabatically. By well designing the detuning and coupling strengths of the electromagnetic fields, the tunneling interaction between two chiral states and the interaction between one of the chiral states and the remaining achiral excited state can be eliminated. Consequently, one chiral state remains unchanged, while the other can be excited to an achiral excited state, establishing chiral-state-selective excitations. By numerically calculating the populations of two chiral ground states and the enantiomeric excess, we observe that high-efficiency enantio-conversion is achieved under the combined effects of system dissipation and chiral-state-selective excitations.

Incubation of ombrotrophic bog litter and mixtures of Sphagnum, Betula and Calluna results in the formation of single litter-specific decomposition patterns

Peat accumulation is the result of an imbalance between the biomass production and the reduced decomposition of organic matter, which has allowed peatlands to accumulate high levels of carbon over time. Sphagnum-dominated peatlands are among the most threatened ecosystems due to increasing anthropogenic pressures and harsher environmental conditions caused by climate change. The resulting changes in vegetation alter litter interactions and change decomposition patterns by altering nutrient cycling, hydrological conditions and carbon sequestration capacity of bogs. The aim of this study was to identify decomposition patterns for different bog litter types and mixtures over time. We sampled litter from an ombrotrophic bog (Sphagnum, Betula, Calluna), prepared mixtures of litter types and incubated our samples under laboratory conditions. We evaluated decomposition proxies and used k-means clustering to detect the formation of litter- and mixture-specific decomposition patterns over time. Sphagnum litter had a consistently low decomposition and its presence in mixtures reduced enzymatic activities. Initially, Betula litter added high amounts of N and labile C compounds to leachates. k-means clustering revealed a typical initial decomposition pattern (i.e. lowest decomposition directly after starting the incubation, followed by highest decomposition rates, and a steady decrease until the end) for most litter types, except for Sphagnum. Litter-specific decomposition patterns emerged after 14 days. Betula litter did not enhance decomposition of other litter types in our short-term incubation, but additional nutrient inputs could alter peat-litter interactions in the long term, increasing the risk of losing the carbon sink function of nutrient-poor bogs.

Impacts of hydrotropes on clouding phenomena and physico-chemical parameters coupled with the triton X 100 & promethazine hydrochloride mixture

ABSTRACT Phase separation behaviour of non-ionic surfactants (NISs)-drug in aq. hydrotropes (HDTs) has appealed interest to researcher over the decades. Herein, we have investigated clouding phenomenon and physico-chemical variables of TX 100 and promethazine hydrochloride (PMH) drug mixture in presence of different HDTs. Study reveals that cloud point (CP) is dependent on the concentration of HDTs in aqueous media. CP values increase with the augmentation of HDTs concentrations while CP values at nearly 100 mmol kg−1 HDTs follow the trend: . The positive standard Gibbs free energy () values signify the non-spontaneity of phase separation in all experimental cases. The positive values of decrease with the augmentation of HDTs concentration. The observed and values are positive at low concentration of HDTs which demonstrates that hydrophobic interactions are the key forces of interaction among the studied ingredients. At high concentration of HDTs, the observed and values are found to be negative which demonstrates the enthalpy control process and the presence of exothermic interactions amongst TX 100, HDTs, and promethazine hydrochloride (PMH) drug in aqueous media. The thermodynamic properties of transfer, as well as enthalpy entropy compensation entities, were calculated and presented with proper clarification.

Adsorption of Individual and Mixtures of β-Blockers and Copper in Soils and Sediments.

The (bio)availability of pharmaceuticals at solid/water interfaces is governed by their sorption, which determines their concentrations in groundwaters and surface waters in contact with biota, and can be affected by the presence of other contaminants such as metallic trace elements likely to compete for adsorption sites and form complexes with pharmaceuticals. We studied the adsorption of the pharmaceuticals propranolol and sotalol-two β-blockers-on one soil and one sediment using batch experiments to assess their (bio)availability. The influence of contact time, pH, and concentration was studied. As in the real environment these contaminants are not alone but in mixtures, and they were studied alone, simultaneously added, and in the presence of Cu2+ , which is known to form coordination complexes with propranolol and sotalol, but their presence in mixtures did not alter their adsorption properties. Sotalol was more mobile in water and thus more bioavailable for organisms than propranolol. The mobility in surface waters of both β-blockers and thus their bioavailabity for organisms is more important than their risk of transfer to groundwater during rainwater infiltration and to surface water due to runoff. Environ Toxicol Chem 2022;41:2700-2707. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Phase separation of a binary mixture with an external force field

Phase separation in liquid mixtures in presence of external forces is studied here using the phase field model. A thermodynamic analysis identifies the equilibrium distribution of species, showing that the external force leverages on the thermodynamic repulsion between partially miscible species by spreading stratification beyond what would happen in ideal conditions. The dynamic behavior of the mixture is described in terms of three characteristic numbers (i.e., fluidity, Schmidt and Bond numbers), where the Bond number dictates the timescale of mixture evolution. Three cases are considered, where the mixture is assumed to be initially in a stable, unstable or metastable state. In all cases, the external force breaks the symmetry of the process. When the mixture is initially unstable, phase separation is a fast spinodal decomposition, leading to a complete segregation of phases. For initially metastable mixtures, the external force primarily induces species stratification, followed by a much slower nucleation process.

Stability Indicating RP-HPLC-DAD Method For Simultaneous Estimation of Atorvastatin Calcium and Teneligliptin Hydrobromide Hydrate in Synthetic Mixture

RP-HPLC stability indicating specific, precise, accurate, cost-effective and isocratic method was developed and validated for quantitative analysis of Atorvastatin calcium and Teneligliptin hydrobromide hydrate in synthetic mixture with presence of its degradants. Separation was achieved by using Gemini, C18, using mobile phase composition [Methanol: 20 mM Ammonium acetate (70:30 v/v)] using a flow rate of 1.0 ml/min, injection volume 10µl with UV detection at 245 nm. Atorvastatin calcium and Teneligliptin hydrobromide hydrate were eluted with retention time 7.47min and 4.74min respectively. This method was validated as per ICH guideline Q2(R1). The calibration plots were over the concentration range of 10-100 μg/ml and 5-50 μg/ml for Atorvastatin calcium and Teneligliptin hydrobromide hydrate with correlation coefficient 1 and 0.9999 respectively. Percentage recovery was obtained between 98.00-100.51 % and 98.90-100.7 % for Atorvastatin calcium and Teneligliptin hydrobromide hydrate respectively. In case of Precision, Repeatability and Robustness RSD should be found less than 2. LOD were found to be 1.22 μg/ml and 0.54 μg/ml and LOQ were found to be 3.70 μg/ml and 1.64 μg/ml for Atorvastatin calcium and Teneligliptin hydrobromide hydrate respectively. The results showed that the developed method is appropriate for the routine analysis of Atorvastatin calcium and Teneligliptin hydrobromide hydrate in a synthetic mixture in presence of its degradants.

Study on Corrosion Resistance of Carbon Steel in HF/HCl Acid Mixture in Presence of Lycoris radiata and Lycoris chinensis Leaf Extract as Environmentally Friendly Corrosion Inhibitor

Study on Corrosion Resistance of Carbon Steel in HF/HCl Acid Mixture in Presence of Lycoris radiata and Lycoris chinensis Leaf Extract as Environmentally Friendly Corrosion Inhibitor

Chemometric Quality Assessment of Doxylamine Succinate With Its Degradation Product: Implementation of Two Predictive Models on UV-Spectrophotometric Data of Anti-Emetic Binary Mixture.

The combination of pyridoxine hydrochloride (PYR) and doxylamine succinate (DOX) as an antiemetic binary mixture is used to treat nausea and vomiting during pregnancy. Two validated, accurate, and selective chemometric models were developed to assay binary mixture in the presence of DOX oxidative degradation product (DOX DEG) that could be characterized using LC-MS. Partial least squares (PLS) regression and principal component regression (PCR) were selected for the determination of our binary mixture in presence of degradation. To exhibit a training set of 25 mixtures that had various percentages of tested substances in five level 3 variables, an experimental design was chosen. A set of 18 synthetic mixtures in the concentration range 10.0-50.0 μg/mL, 12.00-20.0 μg/mL, and 6.0-30.0 μg/mL for PYR, DOX, and DOX DEG, respectively, were used in the construction of the calibration models.Then set of seven synthetic mixtures with different concentrations were used in the construction of the validation models. In validation samples with low root mean square error of prediction (RMSEP), the suggested models successfully predicted the concentrations of our drugs. The models developed were evaluated by RMSEP calculation, and the values obtained were 0.341, 0.196, and 0.388 for PYR, DOX, and DOX DEG, respectively, using PLS. While using PCR, RMSEP calculation and the values obtained were 0.400, 0.256, and 0.375 for PYR, DOX, and DOX DEG, respectively. The developed models were validated according to ICH strategies. The corresponding methods are suitable to determine PYR and DOX in pure form, pharmaceutical dosage form, and in the presence of DOX DEG product. The study of drug breakdown pathways is very important nowadays, so even in the presence of degradation and extreme spectral overlapping, the suggested PLS and PCR spectrophotometric approaches were able to identify PYR and DOX.

On the mass-conserving Allen-Cahn approximation for incompressible binary fluids

This paper is devoted to the global well-posedness of two Diffuse Interface systems modeling the motion of an incompressible two-phase fluid mixture in presence of capillarity effects in a bounded smooth domain Ω⊂Rd, d=2,3. We focus on dissipative mixing effects originating from the mass-conserving Allen-Cahn dynamics with the physically relevant Flory-Huggins potential. More precisely, we study the mass-conserving Navier-Stokes-Allen-Cahn system for nonhomogeneous fluids and the mass-conserving Euler-Allen-Cahn system for homogeneous fluids. We prove existence and uniqueness of global weak and strong solutions as well as their property of separation from the pure states. In our analysis, we combine the energy and entropy estimates, a novel end-point estimate of the product of two functions, a new estimate for the Stokes problem with non-constant viscosity, and logarithmic type Gronwall arguments.

Aqueous solutions of organic acids as effective solvents for levodopa extraction from Mucuna pruriens seeds

• Aqueous solutions of organic acids are promising substitutes for organic solvents. • Performance in the extraction of L-dopa from the seeds of M. Pruriens was assessed. • High purity and yields of L-dopa have been achieved with the investigated compounds. Levodopa is an amino acid commonly used in the treatment of Parkinson’s disease found in several plants, such as Mucuna pruriens . The extraction of levodopa from biomass has been achieved using methanol, ethanol:water mixtures in presence of ascorbic acid, chloroform in alkaline media, and acetonitrile. Aiming at finding more sustainable solvents and develop efficient extraction processes, in this work, aqueous solutions of carboxylic acids (acetic, propionic, citric, glycolic, and lactic acid) and (poly)alcohols (ethanol, ethylene glycol and glycerol) were studied for the extraction of levodopa from Mucuna pruriens seeds. An initial screening with aqueous solutions of these compounds (at 50 wt%) was conducted at 50 °C, with an extraction time of 90 min at a solid/liquid (biomass/solvent) ratio of 1:10. Based on these results, citric acid aqueous solutions were identified as the best solvent, and an experimental design was carried out to optimize the temperature (T), solid/liquid ratio (S:L) and concentration of acid (wt.%), with the following optimal extraction conditions found: T = 60 °C, S:L = 1:7 and concentration of acid at 58 wt%. Under these optimal conditions, an extraction efficiency of 9.2 ± 0.1 wt% of levodopa was achieved. The recovery of levodopa from the acidic aqueous solution was achieved using an ion exchange column, allowing the recovery of approximately 84% of levodopa. The solvent was shown to be reusable in three successive extraction cycles, with no significant losses in the extraction efficiency of levodopa. The results here obtained show that citric acid aqueous solutions can lead to the effective extraction of levodopa from seeds of Mucuna pruriens, serving as basis for the development of more effective and environmentally friendly processes to recover natural products with therapeutic properties.

Absolute Absorption Cross-Section of the Ã←X˜ Electronic Transition of the Ethyl Peroxy Radical and Rate Constant of Its Cross Reaction with HO2

The absolute absorption cross-section of the ethyl peroxy radical C2H5O2 in the Ã←X˜ electronic transition with the peak wavelength at 7596 cm−1 has been determined by the method of dual wavelengths time resolved continuous wave cavity ring down spectroscopy. C2H5O2 radicals were generated from pulsed 351 nm photolysis of C2H6/Cl2 mixture in presence of 100 Torr O2 at T = 295 K. C2H5O2 radicals were detected on one of the CRDS paths. Two methods have been applied for the determination of the C2H5O2 absorption cross-section: (i) based on Cl-atoms being converted alternatively to either C2H5O2 by adding C2H6 or to hydro peroxy radicals, HO2, by adding CH3OH to the mixture, whereby HO2 was reliably quantified on the second CRDS path in the 2ν1 vibrational overtone at 6638.2 cm−1 (ii) based on the reaction of C2H5O2 with HO2, measured under either excess HO2 or under excess C2H5O2 concentration. Both methods lead to the same peak absorption cross-section for C2H5O2 at 7596 cm−1 of σ = (1.0 ± 0.2) × 10−20 cm2. The rate constant for the cross reaction between of C2H5O2 and HO2 has been measured to be (6.2 ± 1.5) × 10−12 cm3 molecule−1 s−1.

Validated RP-LC Methods for Investigating the Degradation Behavior of Acefylline: Application for Analysis in Two Binary Mixtures

Background: Acefylline (Acef) is a derivative of theophylline that has bronchodilator effects. Two binary mixtures were marketed for Acef: Acefylline piperazine/ Phenobarbitone (Acef-P/Phen) and Acefylline heptaminol/ Cinnarizine (Acef-H/ Cinn). To our knowledge none of the reported methods had the capacity to determine Acef in its binary mixture in presence of its degradation products and potential impurity theophylline (Theo). Methods: Two validated RP-LC methods were established for the determination of Acef-P/Phen and Acef-H/ Cinn in presence of Acef degradation products and its potential impurity Theo. A complete study of the forced acidic, alkaline and oxidative degradation of Acef was presented. The methods were based on LC separation on RP C18 columns using isocratic and gradient elution for Acef-P /Phen and Acef-H /Cinn mixtures, respectively. Different chromatographic conditions were examined and optimized. Results: Linear responses were attained over concentration ranges of 75-500/15-1000 μg/mL and 100-1000 /50- 500 μg/mL with mean percentage recoveries of (100.72±1.23)%/ (99.29±1.12)% and (100.44±1.27)%/ (99.01±0.97)% for Acef-P/Phen and Acef-H /Cinn, respectively. ICH guidelines were used for methods validation and all parameters were found to be acceptable. Conclusion: The methods showed to be accurate, precise and specific for the analysis of Acef-P/Phen and AcefH /Cinn in drug substance, drug product and in laboratory prepared mixtures in presence of Theo and up to 50% of degradation products. The structures of the main degradation products and the expected degradation pathway were suggested using the MS data.

Investigation of aggregation behavior of ionic surfactant mixture in crystal violet dye solution at different temperatures and solvent compositions: Conductivity and theoretical approach

The conductometric measurement technique was utilized to have an in-depth knowledge on the aggregation behavior of a mixture of two ionic surfactants – sodium dodecyl sulfate (SDS; a common anionic surfactant) and cetyltrimethylammonium bromide (CTAB; a cationic surfactant), in crystal violet (CV) and CV + ethanol (5 and 10% (w/w)) solution media. The related micellar and thermodynamic parameters of the mixed system have been assessed and presented in this paper. The cmc values of pure SDS/CTAB, & their mixture in presence of CV dye, were observed to decrease and thus the insertion of CV favors the micellization of pure and mixed micelle. Also, the cmc values of the mixture of SDS & CTAB undergo a drop with increasing the concentration of CTAB at a specific temperature and these cmc fall in the middle of the detected cmc of SDS & CTAB micelles in all the media studied. The observed values of cmc are lower in magnitude in comparison to the ideal cmc and the numerical values of the interaction parameter (β) are negative, which manifests the existence of attractive interaction between SDS and CTAB surfactants in presence of CV dye. The cmc values are also dependent on the fluctuation of experimental temperature. The micellar mole fraction of component 1 (CTAB) in SDS + CTAB mixture (X1Rub) and the ideal micellar mole fraction (X1id) was obtained to be relatively greater than the related stoichiometric mole fraction (α1) of component 1 (CTAB). The activity coefficients (f1Rub and f2Rub) remained below unity in all test cases, suggesting an attractive interaction in the mixed micellar system. The obtained thermodynamic parameters demonstrate that the single and mixed micellization phenomena are spontaneous and the main driving forces are hydrophobic and exothermic in nature.

Characterization of simultaneous uptake of xylose and glucose in Caldicellulosiruptor kronotskyensis for optimal hydrogen production

BackgroundCaldicellulosiruptor kronotskyensis has gained interest for its ability to grow on various lignocellulosic biomass. The aim of this study was to investigate the growth profiles of C. kronotskyensis in the presence of mixtures of glucose–xylose. Recently, we characterized a diauxic-like pattern for C. saccharolyticus on lignocellulosic sugar mixtures. In this study, we aimed to investigate further whether C. kronotskyensis has adapted to uptake glucose in the disaccharide form (cellobiose) rather than the monosaccharide (glucose).ResultsInterestingly, growth of C. kronotskyensis on glucose and xylose mixtures did not display diauxic-like growth patterns. Closer investigation revealed that, in contrast to C. saccharolyticus, C. kronotskyensis does not possess a second uptake system for glucose. Both C. saccharolyticus and C. kronotskyensis share the characteristics of preferring xylose over glucose. Growth on xylose was twice as fast (μmax = 0.57 h−1) as on glucose (μmax = 0.28 h−1). A study of the sugar uptake was made with different glucose–xylose ratios to find a kinetic relationship between the two sugars for transport into the cell. High concentrations of glucose inhibited xylose uptake and vice versa. The inhibition constants were estimated to be KI,glu = 0.01 cmol L−1 and KI,xyl = 0.001 cmol L−1, hence glucose uptake was more severely inhibited by xylose uptake. Bioinformatics analysis could not exclude that C. kronotskyensis possesses more than one transporter for glucose. As a next step it was investigated whether glucose uptake by C. kronotskyensis improved in the form of cellobiose. Indeed, cellobiose is taken up faster than glucose; nevertheless, the growth rate on each sugar remained similar.ConclusionsC. kronotskyensis possesses a xylose transporter that might take up glucose at an inferior rate even in the absence of xylose. Alternatively, glucose can be taken up in the form of cellobiose, but growth performance is still inferior to growth on xylose. Therefore, we propose that the catabolism of C. kronotskyensis has adapted more strongly to pentose rather than hexose, thereby having obtained a specific survival edge in thermophilic lignocellulosic degradation communities.

Free Swelling Behaviour of Bentonite-sand Mixtures in Presence of Pore Fluids of Different Dielectric Constants

The free swelling behaviour of bentonite sand mixtures have been studied using different percentage of ethanol-water and methanol-water solutions. Free swell index tests were conducted at different proportion of ethanol and methanol with distilled water(0%, 20%, 40%, 60%, 80% and 100%). Free swell index (FSI), modified free swell index (MFSI) and free swell ratio (FSR) were determined from the results obtained from the tests. FSI, MFSI and FSR decrease with the increase of ethanol as well as methanol percentage. Good linear correlation have been observed between the dielectric constants of the pore fluids and FSI and MFSI of the bentonite sand mixtures. The study focuses on the significant influence of dielectric constants of different percentage of ethanol and methanol water solution on the free swell of bentonite-sand mixtures. Keywords: Free swell index; modified free swell index; dielectric constant; bentonite; ethanol, methanol

Selective adsorption of CO2 from gas mixture by P-decorated C24N24 fullerene assisted by an electric field: A DFT approach

Selective, reversible and tailored adsorption of CO2 from gas mixture is always demanded to control global warming. We for the first time used P-decorated C24N24 fullerene for selective separation of CO2 from N2/CO2 mixture in the presence of an electric field by using density functional theory methods. The computed geometrical parameters evince that the binding distances and bond angles (OCO) are remarkably reduced in electric field and that transformed the physisorption to chemisorption by increasing the field from 0.012 to 0.013 au. The adsorption/desorption of CO2 over the substrate can be easily controlled by switching on and off the electric field. This study reveals that P@C24N24 is a selective adsorbent of CO2 from N2/CO2 mixture and will help the future synthesis of selective, controllable and regenerable adsorbent for the CO2 separation from gas mixture in presence of electric field.

Green analysis of newly approved binary omeprazole/aspirin mixture in presence of aspirin impurity using ultra-high-performance liquid chromatography and thin-layer chromatography methods.

Two green, simple, and accurate chromatographic methods were developed and validated for the simultaneous determination of omeprazole and aspirin mixture in the presence of salicylic acid, a major impurity of aspirin. Method A is a reversed-phase ultra-high-performance liquid chromatography; the separation was performed on a C18 column, with a mobile phase composed of ethanol:0.1% aqueous solution of triethylamine acidified with orthophosphoric acid (pH 3) (30:70, v/v) at 0.15 mL/min flow rate and 230 nm. Omeprazole, aspirin, and aspirin impurity retention times were 7.47, 4.40, and 5.13 min, respectively. Good linearity was achieved in the concentration ranges of 5-80, 5-85, and 3-50 μg/mL for the three mentioned components, respectively. Method B is thin-layer chromatography (TLC) where silica gel TLC F254 plates were utilized to achieve separation using ethanol:ethyl acetate (2:8, v/v) as a developing system at 240 nm. The resulted Rf values were 0.83, 0.65, and 0.23 for omeprazole, aspirin, and impurity, respectively. The concentration ranges of 0.1-3 μg/band for the three drugs showed good linearity. The proposed methods are eco-friendly and greener when compared to the already reported method (Microchemical Journal, 152, 104350). This is the first use of TLC method for the determination of the three drugs. International Council for Harmonization (ICH) guidelines were followed to ensure the validity of developed methods.

Influence of Large Molecular Guest Species on the Formation of CH <sub>4</sub> and CO <sub>2</sub> Hydrates

Methane hydrates in nature are considered as a future energy resource for natural gas due to their abundance in nature. The presence of all three structures of clathrate hydrates in the nature have been reported. Structural transition in clathrate hydrates in particular with regards to sH hydrates and the influence of large guest molecules is still not well understood. In the current work, we synthesize mixed hydrate of CO2 & CH4 mixture in presence of sH formers, neo-hexane (NH) and tert-butylmethylether (TBME). High-pressure in-situ differential scanning calorimetry was employed to investigate the phase transformation between soild-liquid-gas. We confirmed that CO2 lean mixture (24% CO2 & 76% CH4) forms structure H (sH) hydrate, while CO2 rich mixture (76% CO2 & 24% CH4) forms structure I (sI) hydrate. This study presents new insights to understand the dynamic preference of methane and carbon dioxide in three different types of cages in sH hydrate.

Mutual inhibition effect of hydrogen and ammonia in oxidation processes and the role of ammonia as “strong” collider in third-molecular reactions

Ammonia/hydrogen interaction in oxidation chemistry has been extensively valued for traditional flames, while no-experimental evidences have been provided at lower temperatures, relevant for MILD combustion. Herein, ter-molecular reactions play a fundamental role, boosted by “strong” colliders (CO2, H2O). H2O “strong” collider nature derives from its polar nature. Ammonia exhibits a polar behavior similar to water. Given this background, the aim of this work is to value the “strong” collisional nature of ammonia through experimental tests in a Jet Stirred Flow Reactor for H2–O2/Ar or N2 mixtures in presence of H2O or NH3. Results show NH3 inhibits H2 reactivity more than H2O. Numerical analyses suggest a hydrogen/ammonia mutual inhibiting effect under MILD conditions. Simulations are very sensitive to the declaration of NH3 third-body collisional efficiencies in third-molecular reactions in detailed kinetic mechanisms. These effects may infer the possibility to develop economic hydrogen transport/store systems while minimizing ammonia production costs.